amduat-api/src/amduatd.c

#define _POSIX_C_SOURCE 200809L

#include "amduat/asl/artifact_io.h"
#include "amduat/asl/asl_store_fs.h"
#include "amduat/asl/asl_store_fs_meta.h"
#include "amduat/asl/ref_text.h"
#include "amduat/asl/store.h"
#include "amduat/asl/ref_derive.h"
#include "amduat/enc/asl1_core_codec.h"
#include "amduat/enc/pel1_result.h"
#include "amduat/enc/pel_program_dag.h"
#include "amduat/enc/tgk1_edge.h"
#include "amduat/format/pel.h"
#include "amduat/tgk/core.h"
#include "amduat/pel/program_dag.h"
#include "amduat/pel/program_dag_desc.h"
#include "amduat/pel/opreg_kernel.h"
#include "amduat/pel/run.h"
#include "amduat/util/hex.h"

#include <errno.h>
#include <signal.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <string.h>
#include <fcntl.h>

#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/un.h>
#include <unistd.h>

typedef struct amduatd_strbuf {
  char *data;
  size_t len;
  size_t cap;
} amduatd_strbuf_t;

static bool amduatd_http_send_json(int fd,
                                  int code,
                                  const char *reason,
                                  const char *json,
                                  bool head_only);

static bool amduatd_send_json_error(int fd,
                                   int code,
                                   const char *reason,
                                   const char *msg);

static void amduatd_strbuf_free(amduatd_strbuf_t *b);
static bool amduatd_strbuf_append_cstr(amduatd_strbuf_t *b, const char *s);
static bool amduatd_strbuf_append_char(amduatd_strbuf_t *b, char c);

static const char *const AMDUATD_DEFAULT_ROOT = ".amduat-asl";
static const char *const AMDUATD_DEFAULT_SOCK = "amduatd.sock";
static const char *const AMDUATD_EDGES_FILE = ".amduatd.edges";

static const uint32_t AMDUATD_TGK_EDGE_TYPE = 0u;

typedef struct {
  amduat_reference_t *refs;
  size_t len;
  size_t cap;
} amduatd_ref_list_t;

static void amduatd_ref_list_free(amduatd_ref_list_t *list) {
  size_t i;
  if (list == NULL) {
    return;
  }
  for (i = 0; i < list->len; ++i) {
    amduat_reference_free(&list->refs[i]);
  }
  free(list->refs);
  list->refs = NULL;
  list->len = 0;
  list->cap = 0;
}

static bool amduatd_ref_list_push(amduatd_ref_list_t *list,
                                 amduat_reference_t ref) {
  amduat_reference_t cloned;
  amduat_reference_t *next;

  if (list == NULL) {
    return false;
  }
  memset(&cloned, 0, sizeof(cloned));
  if (!amduat_reference_clone(ref, &cloned)) {
    return false;
  }
  if (list->len == list->cap) {
    size_t next_cap = list->cap != 0 ? list->cap * 2u : 64u;
    next = (amduat_reference_t *)realloc(list->refs,
                                         next_cap * sizeof(*list->refs));
    if (next == NULL) {
      amduat_reference_free(&cloned);
      return false;
    }
    list->refs = next;
    list->cap = next_cap;
  }
  list->refs[list->len++] = cloned;
  return true;
}

typedef struct {
  const char *root_path;
  char edges_path[1024];
  amduat_reference_t rel_aliases_ref;
  amduat_reference_t rel_materializes_ref;
  amduatd_ref_list_t edge_refs;
} amduatd_concepts_t;

static void amduatd_concepts_free(amduatd_concepts_t *c) {
  if (c == NULL) {
    return;
  }
  amduat_reference_free(&c->rel_aliases_ref);
  amduat_reference_free(&c->rel_materializes_ref);
  amduatd_ref_list_free(&c->edge_refs);
}

static const char k_amduatd_contract_v1_json[] =
    "{"
    "\"contract\":\"AMDUATD/API/1\","
    "\"base_path\":\"/v1\","
    "\"endpoints\":["
    "{\"method\":\"GET\",\"path\":\"/v1/ui\"},"
    "{\"method\":\"GET\",\"path\":\"/v1/meta\"},"
    "{\"method\":\"HEAD\",\"path\":\"/v1/meta\"},"
    "{\"method\":\"GET\",\"path\":\"/v1/contract\"},"
    "{\"method\":\"POST\",\"path\":\"/v1/concepts\"},"
    "{\"method\":\"GET\",\"path\":\"/v1/concepts\"},"
    "{\"method\":\"GET\",\"path\":\"/v1/concepts/{name}\"},"
    "{\"method\":\"POST\",\"path\":\"/v1/concepts/{name}/publish\"},"
    "{\"method\":\"GET\",\"path\":\"/v1/resolve/{name}\"},"
    "{\"method\":\"POST\",\"path\":\"/v1/artifacts\"},"
    "{\"method\":\"GET\",\"path\":\"/v1/artifacts/{ref}\"},"
    "{\"method\":\"HEAD\",\"path\":\"/v1/artifacts/{ref}\"},"
    "{\"method\":\"GET\",\"path\":\"/v1/artifacts/{ref}?format=info\"},"
    "{\"method\":\"POST\",\"path\":\"/v1/pel/run\"},"
    "{\"method\":\"POST\",\"path\":\"/v1/pel/programs\"}"
    "],"
    "\"schemas\":{"
    "\"pel_run_request\":{"
    "\"type\":\"object\","
    "\"required\":[\"program_ref\",\"input_refs\"],"
    "\"properties\":{"
    "\"program_ref\":{\"type\":\"string\",\"description\":\"hex ref or concept name\"},"
    "\"input_refs\":{\"type\":\"array\",\"items\":{\"type\":\"string\",\"description\":\"hex ref or concept name\"}},"
    "\"params_ref\":{\"type\":\"string\",\"description\":\"hex ref or concept name\"},"
    "\"scheme_ref\":{\"type\":\"string\",\"description\":\"hex ref or 'dag'\"}"
    "}"
    "},"
    "\"pel_run_response\":{"
    "\"type\":\"object\","
    "\"required\":[\"result_ref\",\"output_refs\",\"status\"],"
    "\"properties\":{"
    "\"result_ref\":{\"type\":\"string\",\"description\":\"hex ref\"},"
    "\"trace_ref\":{\"type\":\"string\",\"description\":\"hex ref\"},"
    "\"output_refs\":{\"type\":\"array\",\"items\":{\"type\":\"string\",\"description\":\"hex ref\"}},"
    "\"status\":{\"type\":\"string\"}"
    "}"
    "},"
    "\"pel_program_author_request\":{"
    "\"type\":\"object\","
    "\"required\":[\"nodes\",\"roots\"],"
    "\"properties\":{"
    "\"nodes\":{\"type\":\"array\"},"
    "\"roots\":{\"type\":\"array\"}"
    "}"
    "}"
    "}"
    "}\n";

static const char k_amduatd_ui_html[] =
    "<!doctype html>\n"
    "<html lang=\"en\">\n"
    "<head>\n"
    "  <meta charset=\"utf-8\" />\n"
    "  <meta name=\"viewport\" content=\"width=device-width, initial-scale=1\" />\n"
    "  <title>amduatd — Concept editor</title>\n"
    "  <style>\n"
    "    :root{color-scheme:light dark;}\n"
    "    body{font-family:ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,Ubuntu,Cantarell,Noto Sans,Arial,sans-serif;margin:0;line-height:1.35;}\n"
    "    header,main{max-width:1100px;margin:0 auto;padding:18px;}\n"
    "    h1{margin:0 0 6px;font-size:18px;}\n"
    "    .muted{opacity:.75;font-size:13px;}\n"
    "    .grid{display:grid;grid-template-columns:1fr;gap:14px;}\n"
    "    @media (min-width: 980px){.grid{grid-template-columns:1.2fr .8fr;}}\n"
    "    .card{border:1px solid rgba(127,127,127,.35);border-radius:14px;padding:14px;background:rgba(127,127,127,.06);}\n"
    "    textarea,input,select{width:100%;box-sizing:border-box;border-radius:10px;padding:10px;border:1px solid rgba(127,127,127,.35);background:transparent;"
    "      font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,Liberation Mono,monospace;font-size:12.5px;}\n"
    "    textarea{min-height:420px;resize:vertical;}\n"
    "    button{border-radius:10px;padding:10px 12px;border:1px solid rgba(127,127,127,.35);background:rgba(127,127,127,.12);cursor:pointer;}\n"
    "    button:hover{background:rgba(127,127,127,.18);}\n"
    "    .row{display:flex;gap:10px;flex-wrap:wrap;align-items:center;}\n"
    "    .row > *{flex:1 1 auto;}\n"
    "    .row .btn{flex:0 0 auto;}\n"
    "    pre{white-space:pre-wrap;word-break:break-word;margin:0;padding:10px;border-radius:10px;border:1px solid rgba(127,127,127,.35);background:rgba(0,0,0,.08);"
    "      font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,Liberation Mono,monospace;font-size:12.5px;min-height:120px;}\n"
    "    a{color:inherit;}\n"
    "  </style>\n"
    "</head>\n"
    "<body>\n"
    "  <header>\n"
    "    <h1>amduatd — Concept editor</h1>\n"
    "    <div class=\"muted\">Load shows the latest materialized bytes; Save uploads a new artifact and publishes it as a new version.</div>\n"
    "  </header>\n"
    "  <main>\n"
    "    <div class=\"grid\">\n"
    "      <div class=\"card\">\n"
    "        <div class=\"row\">\n"
    "          <input id=\"conceptName\" placeholder=\"concept name (e.g. hello)\" />\n"
    "          <button class=\"btn\" id=\"btnConceptCreate\" type=\"button\">Create</button>\n"
    "          <button class=\"btn\" id=\"btnLoad\" type=\"button\">Load</button>\n"
    "          <button class=\"btn\" id=\"btnSave\" type=\"button\">Save</button>\n"
    "        </div>\n"
    "        <div class=\"row\" style=\"margin-top:10px;\">\n"
    "          <select id=\"mode\">\n"
    "            <option value=\"text\">bytes: text (utf-8)</option>\n"
    "            <option value=\"base64\">bytes: base64</option>\n"
    "            <option value=\"hex\">bytes: hex</option>\n"
    "            <option value=\"pel_program\">PEL program: JSON</option>\n"
    "          </select>\n"
    "          <input id=\"typeTag\" placeholder=\"X-Amduat-Type-Tag (optional)\" />\n"
    "          <input id=\"latestRef\" placeholder=\"latest_ref\" readonly />\n"
    "        </div>\n"
    "        <textarea id=\"editor\" spellcheck=\"false\" placeholder=\"(bytes or PEL program authoring JSON)\"></textarea>\n"
    "        <div class=\"row\" style=\"margin-top:10px;\">\n"
    "          <button class=\"btn\" id=\"btnProgramTemplate\" type=\"button\">Insert identity program</button>\n"
    "        </div>\n"
    "        <div class=\"row\" style=\"margin-top:10px;\">\n"
    "          <input id=\"publishRef\" placeholder=\"publish existing ref\" />\n"
    "          <button class=\"btn\" id=\"btnPublishRef\" type=\"button\">Publish ref</button>\n"
    "        </div>\n"
    "      </div>\n"
    "\n"
    "      <div class=\"card\">\n"
    "        <div class=\"muted\" style=\"margin-bottom:8px;\">Upload bytes (sets program_ref)</div>\n"
    "        <div class=\"row\">\n"
    "          <input id=\"uploadFile\" type=\"file\" />\n"
    "          <button class=\"btn\" id=\"btnUpload\" type=\"button\">Upload</button>\n"
    "        </div>\n"
    "        <hr style=\"border:none;border-top:1px solid rgba(127,127,127,.35);margin:14px 0;\" />\n"
    "        <div class=\"muted\" style=\"margin-bottom:8px;\">Run</div>\n"
    "        <input id=\"programRef\" placeholder=\"program_ref (hex ref or concept name)\" />\n"
    "        <div class=\"muted\" style=\"margin:10px 0 8px;\">input_refs (comma-separated hex refs or names)</div>\n"
    "        <input id=\"inputRefs\" placeholder=\"in0,in1,...\" />\n"
    "        <div class=\"muted\" style=\"margin:10px 0 8px;\">params_ref (optional)</div>\n"
    "        <input id=\"paramsRef\" placeholder=\"params\" />\n"
    "        <div class=\"muted\" style=\"margin:10px 0 8px;\">scheme_ref (optional, default dag)</div>\n"
    "        <input id=\"schemeRef\" placeholder=\"dag\" />\n"
    "        <div class=\"row\" style=\"margin-top:12px;\">\n"
    "          <button class=\"btn\" id=\"btnRun\" type=\"button\">Run</button>\n"
    "          <a class=\"muted\" href=\"/v1/contract\">/v1/contract</a>\n"
    "          <a class=\"muted\" href=\"/v1/meta\">/v1/meta</a>\n"
    "        </div>\n"
    "        <div class=\"muted\" style=\"margin:14px 0 8px;\">Response</div>\n"
    "        <pre id=\"out\"></pre>\n"
    "      </div>\n"
    "    </div>\n"
    "  </main>\n"
    "\n"
    "  <script>\n"
    "    const el = (id) => document.getElementById(id);\n"
    "    const out = (v) => { el('out').textContent = typeof v === 'string' ? v : JSON.stringify(v, null, 2); };\n"
    "    const td = new TextDecoder('utf-8');\n"
    "    const te = new TextEncoder();\n"
    "    const toHex = (u8) => Array.from(u8).map(b => b.toString(16).padStart(2,'0')).join('');\n"
    "    const fromHex = (s) => { const t=(s||'').trim(); if(t.length%2) throw new Error('hex length must be even'); const o=new Uint8Array(t.length/2); for(let i=0;i<o.length;i++){o[i]=parseInt(t.slice(i*2,i*2+2),16);} return o; };\n"
    "    const toB64 = (u8) => { let bin=''; for(let i=0;i<u8.length;i++) bin += String.fromCharCode(u8[i]); return btoa(bin); };\n"
    "    const fromB64 = (s) => { const bin=atob((s||'').trim()); const o=new Uint8Array(bin.length); for(let i=0;i<bin.length;i++) o[i]=bin.charCodeAt(i); return o; };\n"
    "\n"
    "    async function ensureConcept(name){\n"
    "      const resp = await fetch('/v1/concepts',{method:'POST',headers:{'Content-Type':'application/json'},body:JSON.stringify({name})});\n"
    "      if(!resp.ok) throw new Error(await resp.text());\n"
    "    }\n"
    "\n"
    "    async function loadConcept(){\n"
    "      const name = el('conceptName').value.trim();\n"
    "      if(!name){ out('missing concept name'); return; }\n"
    "      const resp = await fetch(`/v1/concepts/${encodeURIComponent(name)}`);\n"
    "      const text = await resp.text();\n"
    "      if(!resp.ok){ out(text); return; }\n"
    "      const j = JSON.parse(text);\n"
    "      el('latestRef').value = j.latest_ref || '';\n"
    "      el('programRef').value = name;\n"
    "      if(!j.latest_ref){ el('editor').value=''; out(text); return; }\n"
    "      const mode = el('mode').value;\n"
    "      const infoResp = await fetch(`/v1/artifacts/${j.latest_ref}?format=info`);\n"
    "      if(infoResp.ok){ const info = JSON.parse(await infoResp.text()); el('typeTag').value = info.has_type_tag ? info.type_tag : ''; }\n"
    "      if(mode === 'pel_program'){\n"
    "        if(!el('editor').value.trim()){\n"
    "          el('editor').value = JSON.stringify({\n"
    "            nodes:[{id:1,op:{name:'pel.bytes.concat',version:1},inputs:[{external:{input_index:0}}],params_hex:''}],\n"
    "            roots:[{node_id:1,output_index:0}]\n"
    "          }, null, 2);\n"
    "        }\n"
    "        out(text);\n"
    "        return;\n"
    "      }\n"
    "      const aResp = await fetch(`/v1/artifacts/${j.latest_ref}`);\n"
    "      if(!aResp.ok){ out(await aResp.text()); return; }\n"
    "      const u8 = new Uint8Array(await aResp.arrayBuffer());\n"
    "      if(mode==='hex') el('editor').value = toHex(u8);\n"
    "      else if(mode==='base64') el('editor').value = toB64(u8);\n"
    "      else el('editor').value = td.decode(u8);\n"
    "      out(text);\n"
    "    }\n"
    "\n"
    "    async function saveConcept(){\n"
    "      const name = el('conceptName').value.trim();\n"
    "      if(!name){ out('missing concept name'); return; }\n"
    "      await ensureConcept(name);\n"
    "      const mode = el('mode').value;\n"
    "      if(mode === 'pel_program'){\n"
    "        const body = JSON.parse(el('editor').value || '{}');\n"
    "        const mkResp = await fetch('/v1/pel/programs',{method:'POST',headers:{'Content-Type':'application/json'},body:JSON.stringify(body)});\n"
    "        const mkText = await mkResp.text();\n"
    "        if(!mkResp.ok){ out(mkText); return; }\n"
    "        const mk = JSON.parse(mkText);\n"
    "        const pref = mk.program_ref;\n"
    "        const pubResp = await fetch(`/v1/concepts/${encodeURIComponent(name)}/publish`,{method:'POST',headers:{'Content-Type':'application/json'},body:JSON.stringify({ref:pref})});\n"
    "        const pubText = await pubResp.text();\n"
    "        out(pubText);\n"
    "        if(pubResp.ok){ el('typeTag').value = '0x00000101'; await loadConcept(); }\n"
    "        return;\n"
    "      }\n"
    "      let u8;\n"
    "      if(mode==='hex') u8 = fromHex(el('editor').value);\n"
    "      else if(mode==='base64') u8 = fromB64(el('editor').value);\n"
    "      else u8 = te.encode(el('editor').value);\n"
    "      const headers = {'Content-Type':'application/octet-stream'};\n"
    "      const typeTag = el('typeTag').value.trim();\n"
    "      if(typeTag) headers['X-Amduat-Type-Tag'] = typeTag;\n"
    "      const putResp = await fetch('/v1/artifacts',{method:'POST',headers,body:u8});\n"
    "      const putText = await putResp.text();\n"
    "      if(!putResp.ok){ out(putText); return; }\n"
    "      const put = JSON.parse(putText);\n"
    "      const pubResp = await fetch(`/v1/concepts/${encodeURIComponent(name)}/publish`,{method:'POST',headers:{'Content-Type':'application/json'},body:JSON.stringify({ref:put.ref})});\n"
    "      const pubText = await pubResp.text();\n"
    "      out(pubText);\n"
    "      if(pubResp.ok) await loadConcept();\n"
    "    }\n"
    "\n"
    "    el('btnConceptCreate').addEventListener('click', async () => { try{ await ensureConcept(el('conceptName').value.trim()); out('{\"ok\":true}\\n'); }catch(e){ out(String(e)); } });\n"
    "    el('btnLoad').addEventListener('click', () => loadConcept().catch(e => out(String(e))));\n"
    "    el('btnSave').addEventListener('click', () => saveConcept().catch(e => out(String(e))));\n"
    "    el('mode').addEventListener('change', () => {\n"
    "      if(el('mode').value === 'pel_program'){\n"
    "        el('typeTag').value = '0x00000101';\n"
    "      }\n"
    "      loadConcept().catch(() => {});\n"
    "    });\n"
    "\n"
    "    el('btnProgramTemplate').addEventListener('click', () => {\n"
    "      el('mode').value = 'pel_program';\n"
    "      el('typeTag').value = '0x00000101';\n"
    "      el('editor').value = JSON.stringify({\n"
    "        nodes:[{id:1,op:{name:'pel.bytes.concat',version:1},inputs:[{external:{input_index:0}}],params_hex:''}],\n"
    "        roots:[{node_id:1,output_index:0}]\n"
    "      }, null, 2);\n"
    "    });\n"
    "\n"
    "    el('btnPublishRef').addEventListener('click', async () => {\n"
    "      try{\n"
    "        const name = el('conceptName').value.trim();\n"
    "        const ref = el('publishRef').value.trim();\n"
    "        if(!name||!ref){ out('missing name/ref'); return; }\n"
    "        await ensureConcept(name);\n"
    "        const resp = await fetch(`/v1/concepts/${encodeURIComponent(name)}/publish`,{method:'POST',headers:{'Content-Type':'application/json'},body:JSON.stringify({ref})});\n"
    "        out(await resp.text());\n"
    "      }catch(e){ out(String(e)); }\n"
    "    });\n"
    "\n"
    "    el('btnUpload').addEventListener('click', async () => {\n"
    "      try {\n"
    "        const file = el('uploadFile').files && el('uploadFile').files[0];\n"
    "        if (!file) { out('no file selected'); return; }\n"
    "        const resp = await fetch('/v1/artifacts', { method:'POST', headers:{'Content-Type':'application/octet-stream'}, body:file });\n"
    "        const text = await resp.text();\n"
    "        out(text);\n"
    "        if (resp.ok) { const j = JSON.parse(text); if (j && j.ref) el('programRef').value = j.ref; }\n"
    "      } catch (e) { out(String(e)); }\n"
    "    });\n"
    "\n"
    "    el('btnRun').addEventListener('click', async () => {\n"
    "      try {\n"
    "        const program_ref = el('programRef').value.trim();\n"
    "        const input_refs = (el('inputRefs').value || '').split(',').map(s => s.trim()).filter(Boolean);\n"
    "        const params_ref = el('paramsRef').value.trim();\n"
    "        const scheme_ref = el('schemeRef').value.trim();\n"
    "        const body = { program_ref, input_refs };\n"
    "        if (params_ref) body.params_ref = params_ref;\n"
    "        if (scheme_ref) body.scheme_ref = scheme_ref;\n"
    "        const resp = await fetch('/v1/pel/run', { method:'POST', headers:{'Content-Type':'application/json'}, body:JSON.stringify(body) });\n"
    "        out(await resp.text());\n"
    "      } catch (e) { out(String(e)); }\n"
    "    });\n"
    "  </script>\n"
    "</body>\n"
    "</html>\n";

static volatile sig_atomic_t amduatd_should_exit = 0;

static void amduatd_on_signal(int signo) {
  (void)signo;
  amduatd_should_exit = 1;
}

static bool amduatd_write_all(int fd, const uint8_t *buf, size_t len) {
  size_t off = 0;
  while (off < len) {
    ssize_t n = write(fd, buf + off, len - off);
    if (n < 0) {
      if (errno == EINTR) {
        continue;
      }
      return false;
    }
    if (n == 0) {
      return false;
    }
    off += (size_t)n;
  }
  return true;
}

static bool amduatd_read_exact(int fd, uint8_t *buf, size_t len);

static bool amduatd_read_file(const char *path, uint8_t **out, size_t *out_len) {
  uint8_t *buf = NULL;
  size_t cap = 0;
  size_t len = 0;
  FILE *f;

  if (out != NULL) {
    *out = NULL;
  }
  if (out_len != NULL) {
    *out_len = 0;
  }
  if (path == NULL || out == NULL || out_len == NULL) {
    return false;
  }
  f = fopen(path, "rb");
  if (f == NULL) {
    return false;
  }
  for (;;) {
    size_t n;
    if (len == cap) {
      size_t next_cap = cap != 0 ? cap * 2u : 4096u;
      uint8_t *next = (uint8_t *)realloc(buf, next_cap);
      if (next == NULL) {
        free(buf);
        fclose(f);
        return false;
      }
      buf = next;
      cap = next_cap;
    }
    n = fread(buf + len, 1, cap - len, f);
    len += n;
    if (n == 0) {
      if (ferror(f)) {
        free(buf);
        fclose(f);
        return false;
      }
      break;
    }
  }
  fclose(f);
  *out = buf;
  *out_len = len;
  return true;
}

static bool amduatd_read_urandom(uint8_t *out, size_t len) {
  int fd;
  if (out == NULL || len == 0) {
    return false;
  }
  fd = open("/dev/urandom", O_RDONLY);
  if (fd < 0) {
    return false;
  }
  if (!amduatd_read_exact(fd, out, len)) {
    close(fd);
    return false;
  }
  close(fd);
  return true;
}

static bool amduatd_name_valid(const char *name) {
  size_t i;
  size_t len;
  if (name == NULL) {
    return false;
  }
  len = strlen(name);
  if (len == 0 || len > 64) {
    return false;
  }
  for (i = 0; i < len; ++i) {
    unsigned char c = (unsigned char)name[i];
    if ((c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') || c == '_' ||
        c == '-' || c == '.' || c == '/') {
      continue;
    }
    return false;
  }
  return true;
}

static bool amduatd_build_prefixed_bytes(const char *prefix,
                                        const char *text,
                                        uint8_t **out,
                                        size_t *out_len) {
  size_t p_len;
  size_t t_len;
  size_t len;
  uint8_t *buf;

  if (out != NULL) {
    *out = NULL;
  }
  if (out_len != NULL) {
    *out_len = 0;
  }
  if (prefix == NULL || text == NULL || out == NULL || out_len == NULL) {
    return false;
  }
  p_len = strlen(prefix);
  t_len = strlen(text);
  if (p_len > SIZE_MAX - 1u || t_len > SIZE_MAX - (p_len + 1u)) {
    return false;
  }
  len = p_len + 1u + t_len;
  buf = (uint8_t *)malloc(len);
  if (buf == NULL) {
    return false;
  }
  memcpy(buf, prefix, p_len);
  buf[p_len] = 0;
  memcpy(buf + p_len + 1u, text, t_len);
  *out = buf;
  *out_len = len;
  return true;
}

static bool amduatd_concepts_seed_relation(amduat_asl_store_t *store,
                                          const amduat_asl_store_fs_config_t *cfg,
                                          const char *relation_name,
                                          amduat_reference_t *out_ref) {
  uint8_t *bytes = NULL;
  size_t bytes_len = 0;
  amduat_artifact_t artifact;

  if (out_ref == NULL) {
    return false;
  }
  *out_ref = amduat_reference(0u, amduat_octets(NULL, 0u));
  if (store == NULL || cfg == NULL || relation_name == NULL) {
    return false;
  }
  if (!amduatd_build_prefixed_bytes("AMDUATD/RELATION/1", relation_name, &bytes,
                                    &bytes_len)) {
    return false;
  }
  artifact = amduat_artifact(amduat_octets(bytes, bytes_len));
  if (!amduat_asl_ref_derive(artifact,
                             cfg->config.encoding_profile_id,
                             cfg->config.hash_id,
                             out_ref,
                             NULL)) {
    free(bytes);
    return false;
  }
  (void)amduat_asl_store_put(store, artifact, out_ref);
  free(bytes);
  return true;
}

static bool amduatd_concepts_init(amduatd_concepts_t *c,
                                 amduat_asl_store_t *store,
                                 const amduat_asl_store_fs_config_t *cfg,
                                 const char *root_path) {
  uint8_t *file_bytes = NULL;
  size_t file_len = 0;
  size_t i;

  if (c == NULL || store == NULL || cfg == NULL || root_path == NULL) {
    return false;
  }
  memset(c, 0, sizeof(*c));
  c->root_path = root_path;
  (void)snprintf(c->edges_path, sizeof(c->edges_path), "%s/%s", root_path,
                 AMDUATD_EDGES_FILE);

  if (!amduatd_concepts_seed_relation(store, cfg, "aliases",
                                     &c->rel_aliases_ref)) {
    return false;
  }
  if (!amduatd_concepts_seed_relation(store, cfg, "materializesAs",
                                     &c->rel_materializes_ref)) {
    return false;
  }

  if (!amduatd_read_file(c->edges_path, &file_bytes, &file_len)) {
    return true;
  }

  {
    char *text = (char *)file_bytes;
    char *line = text;
    char *end = text + file_len;
    while (line < end) {
      char *nl = memchr(line, '\n', (size_t)(end - line));
      size_t n = nl != NULL ? (size_t)(nl - line) : (size_t)(end - line);
      char *tmp;
      amduat_reference_t ref;
      bool ok;

      while (n != 0 && (line[n - 1] == '\r' || line[n - 1] == ' ' ||
                        line[n - 1] == '\t')) {
        n--;
      }
      while (n != 0 && (*line == ' ' || *line == '\t')) {
        line++;
        n--;
      }
      if (n != 0) {
        tmp = (char *)malloc(n + 1u);
        if (tmp == NULL) {
          free(file_bytes);
          return false;
        }
        memcpy(tmp, line, n);
        tmp[n] = '\0';
        memset(&ref, 0, sizeof(ref));
        ok = amduat_asl_ref_decode_hex(tmp, &ref);
        free(tmp);
        if (ok) {
          (void)amduatd_ref_list_push(&c->edge_refs, ref);
          amduat_reference_free(&ref);
        }
      }
      if (nl == NULL) {
        break;
      }
      line = nl + 1;
    }
  }

  free(file_bytes);

  for (i = 0; i < c->edge_refs.len; ++i) {
    if (c->edge_refs.refs[i].hash_id == 0 ||
        c->edge_refs.refs[i].digest.data == NULL ||
        c->edge_refs.refs[i].digest.len == 0) {
      continue;
    }
  }

  return true;
}

static bool amduatd_concepts_append_edge_ref(amduatd_concepts_t *c,
                                            amduat_reference_t edge_ref) {
  char *hex = NULL;
  FILE *f;
  bool ok;

  if (c == NULL) {
    return false;
  }
  if (!amduat_asl_ref_encode_hex(edge_ref, &hex)) {
    return false;
  }
  f = fopen(c->edges_path, "ab");
  if (f == NULL) {
    free(hex);
    return false;
  }
  ok = fprintf(f, "%s\n", hex) > 0;
  fclose(f);
  if (!ok) {
    free(hex);
    return false;
  }
  free(hex);
  return amduatd_ref_list_push(&c->edge_refs, edge_ref);
}

static bool amduatd_concepts_derive_name_ref(
    const amduat_asl_store_fs_config_t *cfg,
    const char *name,
    amduat_reference_t *out_ref) {
  uint8_t *bytes = NULL;
  size_t bytes_len = 0;
  amduat_artifact_t artifact;

  if (out_ref == NULL) {
    return false;
  }
  *out_ref = amduat_reference(0u, amduat_octets(NULL, 0u));
  if (cfg == NULL || name == NULL) {
    return false;
  }
  if (!amduatd_build_prefixed_bytes("AMDUATD/NAME/1", name, &bytes,
                                    &bytes_len)) {
    return false;
  }
  artifact = amduat_artifact(amduat_octets(bytes, bytes_len));
  if (!amduat_asl_ref_derive(artifact,
                             cfg->config.encoding_profile_id,
                             cfg->config.hash_id,
                             out_ref,
                             NULL)) {
    free(bytes);
    return false;
  }
  free(bytes);
  return true;
}

static bool amduatd_concepts_put_name_artifact(amduat_asl_store_t *store,
                                              const char *name,
                                              amduat_reference_t *out_ref) {
  uint8_t *bytes = NULL;
  size_t bytes_len = 0;
  amduat_artifact_t artifact;

  if (out_ref != NULL) {
    *out_ref = amduat_reference(0u, amduat_octets(NULL, 0u));
  }
  if (store == NULL || name == NULL || out_ref == NULL) {
    return false;
  }
  if (!amduatd_build_prefixed_bytes("AMDUATD/NAME/1", name, &bytes,
                                    &bytes_len)) {
    return false;
  }
  artifact = amduat_artifact(amduat_octets(bytes, bytes_len));
  if (amduat_asl_store_put(store, artifact, out_ref) != AMDUAT_ASL_STORE_OK) {
    free(bytes);
    return false;
  }
  free(bytes);
  return true;
}

static bool amduatd_concepts_put_concept_id(amduat_asl_store_t *store,
                                           const amduat_asl_store_fs_config_t *cfg,
                                           amduat_reference_t *out_ref) {
  uint8_t rnd[16];
  uint8_t *bytes = NULL;
  size_t bytes_len = 0;
  amduat_artifact_t artifact;

  if (out_ref != NULL) {
    *out_ref = amduat_reference(0u, amduat_octets(NULL, 0u));
  }
  if (store == NULL || cfg == NULL || out_ref == NULL) {
    return false;
  }
  if (!amduatd_read_urandom(rnd, sizeof(rnd))) {
    return false;
  }
  bytes_len = strlen("AMDUATD/CONCEPT-ID/1") + 1u + sizeof(rnd);
  bytes = (uint8_t *)malloc(bytes_len);
  if (bytes == NULL) {
    return false;
  }
  memcpy(bytes, "AMDUATD/CONCEPT-ID/1", strlen("AMDUATD/CONCEPT-ID/1"));
  bytes[strlen("AMDUATD/CONCEPT-ID/1")] = 0;
  memcpy(bytes + strlen("AMDUATD/CONCEPT-ID/1") + 1u, rnd, sizeof(rnd));
  artifact = amduat_artifact(amduat_octets(bytes, bytes_len));
  if (!amduat_asl_ref_derive(artifact,
                             cfg->config.encoding_profile_id,
                             cfg->config.hash_id,
                             out_ref,
                             NULL)) {
    free(bytes);
    return false;
  }
  if (amduat_asl_store_put(store, artifact, out_ref) != AMDUAT_ASL_STORE_OK) {
    free(bytes);
    return false;
  }
  free(bytes);
  return true;
}

static bool amduatd_concepts_put_edge(amduat_asl_store_t *store,
                                     amduatd_concepts_t *c,
                                     amduat_reference_t from,
                                     amduat_reference_t to,
                                     amduat_reference_t relation_concept_ref,
                                     amduat_reference_t *out_edge_ref) {
  amduat_tgk_edge_body_t edge;
  amduat_reference_t from_arr[1];
  amduat_reference_t to_arr[1];
  amduat_octets_t bytes;
  amduat_artifact_t artifact;

  if (out_edge_ref != NULL) {
    *out_edge_ref = amduat_reference(0u, amduat_octets(NULL, 0u));
  }
  if (store == NULL || c == NULL || out_edge_ref == NULL) {
    return false;
  }

  memset(&edge, 0, sizeof(edge));
  edge.type = AMDUATD_TGK_EDGE_TYPE;
  from_arr[0] = from;
  to_arr[0] = to;
  edge.from = from_arr;
  edge.from_len = 1;
  edge.to = to_arr;
  edge.to_len = 1;
  edge.payload = relation_concept_ref;

  bytes = amduat_octets(NULL, 0);
  if (!amduat_enc_tgk1_edge_encode_v1(&edge, &bytes)) {
    return false;
  }
  artifact = amduat_artifact_with_type(bytes,
                                       amduat_type_tag(AMDUAT_TYPE_TAG_TGK1_EDGE_V1));
  if (amduat_asl_store_put(store, artifact, out_edge_ref) != AMDUAT_ASL_STORE_OK) {
    free((void *)bytes.data);
    return false;
  }
  free((void *)bytes.data);
  return amduatd_concepts_append_edge_ref(c, *out_edge_ref);
}

static bool amduatd_concepts_lookup_alias(amduat_asl_store_t *store,
                                         const amduat_asl_store_fs_config_t *cfg,
                                         const amduatd_concepts_t *c,
                                         const char *name,
                                         amduat_reference_t *out_concept_ref) {
  amduat_reference_t name_ref;
  size_t i;

  if (out_concept_ref != NULL) {
    *out_concept_ref = amduat_reference(0u, amduat_octets(NULL, 0u));
  }
  if (store == NULL || cfg == NULL || c == NULL || name == NULL ||
      out_concept_ref == NULL) {
    return false;
  }
  if (!amduatd_concepts_derive_name_ref(cfg, name, &name_ref)) {
    return false;
  }

  for (i = c->edge_refs.len; i > 0; --i) {
    amduat_artifact_t artifact;
    amduat_tgk_edge_body_t edge;
    amduat_asl_store_error_t err;

    memset(&artifact, 0, sizeof(artifact));
    err = amduat_asl_store_get(store, c->edge_refs.refs[i - 1u], &artifact);
    if (err != AMDUAT_ASL_STORE_OK) {
      continue;
    }
    if (!artifact.has_type_tag ||
        artifact.type_tag.tag_id != AMDUAT_TYPE_TAG_TGK1_EDGE_V1) {
      amduat_asl_artifact_free(&artifact);
      continue;
    }
    memset(&edge, 0, sizeof(edge));
    if (!amduat_enc_tgk1_edge_decode_v1(artifact.bytes, &edge)) {
      amduat_asl_artifact_free(&artifact);
      continue;
    }
    if (edge.from_len == 1 && edge.to_len == 1 &&
        amduat_reference_eq(edge.payload, c->rel_aliases_ref) &&
        amduat_reference_eq(edge.from[0], name_ref)) {
      amduat_reference_clone(edge.to[0], out_concept_ref);
      amduat_enc_tgk1_edge_free(&edge);
      amduat_asl_artifact_free(&artifact);
      amduat_reference_free(&name_ref);
      return true;
    }
    amduat_enc_tgk1_edge_free(&edge);
    amduat_asl_artifact_free(&artifact);
  }

  amduat_reference_free(&name_ref);
  return false;
}

static bool amduatd_concepts_resolve_latest(amduat_asl_store_t *store,
                                           const amduatd_concepts_t *c,
                                           amduat_reference_t concept_ref,
                                           amduat_reference_t *out_ref) {
  size_t i;

  if (out_ref != NULL) {
    *out_ref = amduat_reference(0u, amduat_octets(NULL, 0u));
  }
  if (store == NULL || c == NULL || out_ref == NULL) {
    return false;
  }

  for (i = c->edge_refs.len; i > 0; --i) {
    amduat_artifact_t artifact;
    amduat_tgk_edge_body_t edge;
    amduat_asl_store_error_t err;

    memset(&artifact, 0, sizeof(artifact));
    err = amduat_asl_store_get(store, c->edge_refs.refs[i - 1u], &artifact);
    if (err != AMDUAT_ASL_STORE_OK) {
      continue;
    }
    if (!artifact.has_type_tag ||
        artifact.type_tag.tag_id != AMDUAT_TYPE_TAG_TGK1_EDGE_V1) {
      amduat_asl_artifact_free(&artifact);
      continue;
    }
    memset(&edge, 0, sizeof(edge));
    if (!amduat_enc_tgk1_edge_decode_v1(artifact.bytes, &edge)) {
      amduat_asl_artifact_free(&artifact);
      continue;
    }
    if (edge.from_len == 1 && edge.to_len == 1 &&
        amduat_reference_eq(edge.payload, c->rel_materializes_ref) &&
        amduat_reference_eq(edge.from[0], concept_ref)) {
      amduat_reference_clone(edge.to[0], out_ref);
      amduat_enc_tgk1_edge_free(&edge);
      amduat_asl_artifact_free(&artifact);
      return true;
    }
    amduat_enc_tgk1_edge_free(&edge);
    amduat_asl_artifact_free(&artifact);
  }

  return false;
}

static bool amduatd_parse_name_artifact(amduat_artifact_t artifact,
                                       char *out,
                                       size_t cap) {
  const uint8_t *bytes;
  size_t len;
  const char *prefix = "AMDUATD/NAME/1";
  size_t prefix_len;
  size_t i;
  size_t name_len;

  if (out != NULL && cap != 0) {
    out[0] = '\0';
  }
  if (out == NULL || cap == 0) {
    return false;
  }
  if (artifact.bytes.len != 0 && artifact.bytes.data == NULL) {
    return false;
  }
  bytes = artifact.bytes.data;
  len = artifact.bytes.len;
  prefix_len = strlen(prefix);
  if (len < prefix_len + 1u) {
    return false;
  }
  if (memcmp(bytes, prefix, prefix_len) != 0 || bytes[prefix_len] != 0) {
    return false;
  }
  for (i = prefix_len + 1u; i < len; ++i) {
    if (bytes[i] == 0) {
      return false;
    }
  }
  name_len = len - (prefix_len + 1u);
  if (name_len == 0 || name_len >= cap) {
    return false;
  }
  memcpy(out, bytes + prefix_len + 1u, name_len);
  out[name_len] = '\0';
  return amduatd_name_valid(out);
}

static bool amduatd_handle_get_concepts(int fd,
                                       amduat_asl_store_t *store,
                                       const amduatd_concepts_t *concepts) {
  amduatd_strbuf_t b;
  bool first = true;
  size_t i;

  if (store == NULL || concepts == NULL) {
    return amduatd_send_json_error(fd, 500, "Internal Server Error",
                                  "internal error");
  }
  memset(&b, 0, sizeof(b));
  if (!amduatd_strbuf_append_cstr(&b, "{\"concepts\":[")) {
    amduatd_strbuf_free(&b);
    return amduatd_send_json_error(fd, 500, "Internal Server Error", "oom");
  }

  for (i = 0; i < concepts->edge_refs.len; ++i) {
    amduat_reference_t edge_ref = concepts->edge_refs.refs[i];
    amduat_artifact_t artifact;
    amduat_tgk_edge_body_t edge;
    amduat_asl_store_error_t err;
    char name[128];
    char *concept_hex = NULL;

    memset(&artifact, 0, sizeof(artifact));
    err = amduat_asl_store_get(store, edge_ref, &artifact);
    if (err != AMDUAT_ASL_STORE_OK) {
      continue;
    }
    if (!artifact.has_type_tag ||
        artifact.type_tag.tag_id != AMDUAT_TYPE_TAG_TGK1_EDGE_V1) {
      amduat_asl_artifact_free(&artifact);
      continue;
    }
    memset(&edge, 0, sizeof(edge));
    if (!amduat_enc_tgk1_edge_decode_v1(artifact.bytes, &edge)) {
      amduat_asl_artifact_free(&artifact);
      continue;
    }
    if (!(edge.from_len == 1 && edge.to_len == 1 &&
          amduat_reference_eq(edge.payload, concepts->rel_aliases_ref))) {
      amduat_enc_tgk1_edge_free(&edge);
      amduat_asl_artifact_free(&artifact);
      continue;
    }
    amduat_asl_artifact_free(&artifact);

    memset(&artifact, 0, sizeof(artifact));
    err = amduat_asl_store_get(store, edge.from[0], &artifact);
    if (err != AMDUAT_ASL_STORE_OK ||
        !amduatd_parse_name_artifact(artifact, name, sizeof(name))) {
      amduat_enc_tgk1_edge_free(&edge);
      amduat_asl_artifact_free(&artifact);
      continue;
    }
    amduat_asl_artifact_free(&artifact);

    if (!amduat_asl_ref_encode_hex(edge.to[0], &concept_hex)) {
      amduat_enc_tgk1_edge_free(&edge);
      continue;
    }

    if (!first) {
      (void)amduatd_strbuf_append_char(&b, ',');
    }
    first = false;

    (void)amduatd_strbuf_append_cstr(&b, "{\"name\":\"");
    (void)amduatd_strbuf_append_cstr(&b, name);
    (void)amduatd_strbuf_append_cstr(&b, "\",\"concept_ref\":\"");
    (void)amduatd_strbuf_append_cstr(&b, concept_hex);
    (void)amduatd_strbuf_append_cstr(&b, "\"}");

    free(concept_hex);
    amduat_enc_tgk1_edge_free(&edge);
  }

  if (!amduatd_strbuf_append_cstr(&b, "]}\n")) {
    amduatd_strbuf_free(&b);
    return amduatd_send_json_error(fd, 500, "Internal Server Error", "oom");
  }
  {
    bool ok = amduatd_http_send_json(fd, 200, "OK", b.data, false);
    amduatd_strbuf_free(&b);
    return ok;
  }
}

static bool amduatd_handle_get_concept(int fd,
                                      amduat_asl_store_t *store,
                                      const amduat_asl_store_fs_config_t *cfg,
                                      const amduatd_concepts_t *concepts,
                                      const char *name) {
  amduat_reference_t concept_ref;
  amduat_reference_t latest_ref;
  amduatd_strbuf_t b;
  char *concept_hex = NULL;
  char *latest_hex = NULL;
  bool have_latest = false;
  size_t i;
  size_t version_count = 0;

  memset(&concept_ref, 0, sizeof(concept_ref));
  memset(&latest_ref, 0, sizeof(latest_ref));
  memset(&b, 0, sizeof(b));

  if (store == NULL || cfg == NULL || concepts == NULL || name == NULL) {
    return amduatd_send_json_error(fd, 500, "Internal Server Error",
                                  "internal error");
  }
  if (!amduatd_name_valid(name)) {
    return amduatd_send_json_error(fd, 400, "Bad Request", "invalid name");
  }
  if (!amduatd_concepts_lookup_alias(store, cfg, concepts, name, &concept_ref)) {
    return amduatd_send_json_error(fd, 404, "Not Found", "unknown concept");
  }
  if (amduatd_concepts_resolve_latest(store, concepts, concept_ref,
                                      &latest_ref)) {
    have_latest = true;
  }

  if (!amduat_asl_ref_encode_hex(concept_ref, &concept_hex)) {
    amduat_reference_free(&concept_ref);
    amduat_reference_free(&latest_ref);
    return amduatd_send_json_error(fd, 500, "Internal Server Error",
                                  "encode error");
  }
  if (have_latest) {
    if (!amduat_asl_ref_encode_hex(latest_ref, &latest_hex)) {
      free(concept_hex);
      amduat_reference_free(&concept_ref);
      amduat_reference_free(&latest_ref);
      return amduatd_send_json_error(fd, 500, "Internal Server Error",
                                    "encode error");
    }
  }

  if (!amduatd_strbuf_append_cstr(&b, "{")) {
    free(concept_hex);
    free(latest_hex);
    amduat_reference_free(&concept_ref);
    amduat_reference_free(&latest_ref);
    return amduatd_send_json_error(fd, 500, "Internal Server Error", "oom");
  }
  (void)amduatd_strbuf_append_cstr(&b, "\"name\":\"");
  (void)amduatd_strbuf_append_cstr(&b, name);
  (void)amduatd_strbuf_append_cstr(&b, "\",\"concept_ref\":\"");
  (void)amduatd_strbuf_append_cstr(&b, concept_hex);
  (void)amduatd_strbuf_append_cstr(&b, "\",\"latest_ref\":");
  if (latest_hex != NULL) {
    (void)amduatd_strbuf_append_cstr(&b, "\"");
    (void)amduatd_strbuf_append_cstr(&b, latest_hex);
    (void)amduatd_strbuf_append_cstr(&b, "\"");
  } else {
    (void)amduatd_strbuf_append_cstr(&b, "null");
  }
  (void)amduatd_strbuf_append_cstr(&b, ",\"versions\":[");

  for (i = 0; i < concepts->edge_refs.len; ++i) {
    amduat_reference_t edge_ref = concepts->edge_refs.refs[i];
    amduat_artifact_t artifact;
    amduat_tgk_edge_body_t edge;
    amduat_asl_store_error_t err;
    char *edge_hex = NULL;
    char *ref_hex = NULL;

    memset(&artifact, 0, sizeof(artifact));
    err = amduat_asl_store_get(store, edge_ref, &artifact);
    if (err != AMDUAT_ASL_STORE_OK) {
      continue;
    }
    if (!artifact.has_type_tag ||
        artifact.type_tag.tag_id != AMDUAT_TYPE_TAG_TGK1_EDGE_V1) {
      amduat_asl_artifact_free(&artifact);
      continue;
    }
    memset(&edge, 0, sizeof(edge));
    if (!amduat_enc_tgk1_edge_decode_v1(artifact.bytes, &edge)) {
      amduat_asl_artifact_free(&artifact);
      continue;
    }
    amduat_asl_artifact_free(&artifact);

    if (!(edge.from_len == 1 && edge.to_len == 1 &&
          amduat_reference_eq(edge.payload, concepts->rel_materializes_ref) &&
          amduat_reference_eq(edge.from[0], concept_ref))) {
      amduat_enc_tgk1_edge_free(&edge);
      continue;
    }

    if (!amduat_asl_ref_encode_hex(edge_ref, &edge_hex) ||
        !amduat_asl_ref_encode_hex(edge.to[0], &ref_hex)) {
      free(edge_hex);
      free(ref_hex);
      amduat_enc_tgk1_edge_free(&edge);
      continue;
    }

    if (version_count != 0) {
      (void)amduatd_strbuf_append_char(&b, ',');
    }
    version_count++;

    (void)amduatd_strbuf_append_cstr(&b, "{\"edge_ref\":\"");
    (void)amduatd_strbuf_append_cstr(&b, edge_hex);
    (void)amduatd_strbuf_append_cstr(&b, "\",\"ref\":\"");
    (void)amduatd_strbuf_append_cstr(&b, ref_hex);
    (void)amduatd_strbuf_append_cstr(&b, "\"}");

    free(edge_hex);
    free(ref_hex);
    amduat_enc_tgk1_edge_free(&edge);

    if (version_count >= 64u) {
      break;
    }
  }

  (void)amduatd_strbuf_append_cstr(&b, "]}\n");

  free(concept_hex);
  free(latest_hex);
  amduat_reference_free(&concept_ref);
  amduat_reference_free(&latest_ref);

  {
    bool ok = amduatd_http_send_json(fd, 200, "OK", b.data, false);
    amduatd_strbuf_free(&b);
    return ok;
  }
}

static bool amduatd_read_exact(int fd, uint8_t *buf, size_t len) {
  size_t off = 0;
  while (off < len) {
    ssize_t n = read(fd, buf + off, len - off);
    if (n < 0) {
      if (errno == EINTR) {
        continue;
      }
      return false;
    }
    if (n == 0) {
      return false;
    }
    off += (size_t)n;
  }
  return true;
}

static bool amduatd_read_line(int fd, char *buf, size_t cap, size_t *out_len) {
  size_t len = 0;
  while (len + 1 < cap) {
    char c = 0;
    ssize_t n = read(fd, &c, 1);
    if (n < 0) {
      if (errno == EINTR) {
        continue;
      }
      return false;
    }
    if (n == 0) {
      return false;
    }
    if (c == '\n') {
      break;
    }
    buf[len++] = c;
  }
  if (len == 0) {
    return false;
  }
  if (len > 0 && buf[len - 1] == '\r') {
    len--;
  }
  buf[len] = '\0';
  if (out_len != NULL) {
    *out_len = len;
  }
  return true;
}

typedef struct {
  char method[8];
  char path[1024];
  char content_type[128];
  char accept[128];
  char x_type_tag[64];
  size_t content_length;
} amduatd_http_req_t;

static void amduatd_http_req_init(amduatd_http_req_t *req) {
  memset(req, 0, sizeof(*req));
}

static bool amduatd_http_parse_request(int fd, amduatd_http_req_t *out_req) {
  char line[2048];
  size_t line_len = 0;
  char *sp1 = NULL;
  char *sp2 = NULL;

  if (out_req == NULL) {
    return false;
  }
  amduatd_http_req_init(out_req);

  if (!amduatd_read_line(fd, line, sizeof(line), &line_len)) {
    return false;
  }

  sp1 = strchr(line, ' ');
  if (sp1 == NULL) {
    return false;
  }
  *sp1++ = '\0';
  sp2 = strchr(sp1, ' ');
  if (sp2 == NULL) {
    return false;
  }
  *sp2++ = '\0';

  if (strlen(line) >= sizeof(out_req->method)) {
    return false;
  }
  strncpy(out_req->method, line, sizeof(out_req->method) - 1);

  if (strlen(sp1) >= sizeof(out_req->path)) {
    return false;
  }
  strncpy(out_req->path, sp1, sizeof(out_req->path) - 1);

  for (;;) {
    if (!amduatd_read_line(fd, line, sizeof(line), &line_len)) {
      return false;
    }
    if (line_len == 0) {
      break;
    }

    if (strncasecmp(line, "Content-Length:", 15) == 0) {
      const char *v = line + 15;
      while (*v == ' ' || *v == '\t') {
        v++;
      }
      out_req->content_length = (size_t)strtoull(v, NULL, 10);
    } else if (strncasecmp(line, "Content-Type:", 13) == 0) {
      const char *v = line + 13;
      while (*v == ' ' || *v == '\t') {
        v++;
      }
      strncpy(out_req->content_type, v, sizeof(out_req->content_type) - 1);
    } else if (strncasecmp(line, "Accept:", 7) == 0) {
      const char *v = line + 7;
      while (*v == ' ' || *v == '\t') {
        v++;
      }
      strncpy(out_req->accept, v, sizeof(out_req->accept) - 1);
    } else if (strncasecmp(line, "X-Amduat-Type-Tag:", 18) == 0) {
      const char *v = line + 18;
      while (*v == ' ' || *v == '\t') {
        v++;
      }
      strncpy(out_req->x_type_tag, v, sizeof(out_req->x_type_tag) - 1);
    }
  }

  return true;
}

static bool amduatd_http_send_status(int fd,
                                     int code,
                                     const char *reason,
                                     const char *content_type,
                                     const uint8_t *body,
                                     size_t body_len,
                                     bool head_only) {
  char hdr[512];
  int n = snprintf(hdr,
                   sizeof(hdr),
                   "HTTP/1.1 %d %s\r\n"
                   "Content-Length: %zu\r\n"
                   "Content-Type: %s\r\n"
                   "Connection: close\r\n"
                   "\r\n",
                   code,
                   reason != NULL ? reason : "",
                   body_len,
                   content_type != NULL ? content_type : "text/plain");
  if (n <= 0 || (size_t)n >= sizeof(hdr)) {
    return false;
  }
  if (!amduatd_write_all(fd, (const uint8_t *)hdr, (size_t)n)) {
    return false;
  }
  if (!head_only && body != NULL && body_len != 0) {
    return amduatd_write_all(fd, body, body_len);
  }
  return true;
}

static bool amduatd_http_send_text(int fd,
                                   int code,
                                   const char *reason,
                                   const char *text,
                                   bool head_only) {
  const uint8_t *body = (const uint8_t *)(text != NULL ? text : "");
  size_t len = text != NULL ? strlen(text) : 0;
  return amduatd_http_send_status(
      fd, code, reason, "text/plain; charset=utf-8", body, len, head_only);
}

static bool amduatd_http_send_json(int fd,
                                   int code,
                                   const char *reason,
                                   const char *json,
                                   bool head_only) {
  const uint8_t *body = (const uint8_t *)(json != NULL ? json : "{}");
  size_t len = json != NULL ? strlen(json) : 2;
  return amduatd_http_send_status(
      fd, code, reason, "application/json", body, len, head_only);
}

static bool amduatd_http_req_wants_html(const amduatd_http_req_t *req) {
  if (req == NULL) {
    return false;
  }
  if (req->accept[0] == '\0') {
    return false;
  }
  return strstr(req->accept, "text/html") != NULL;
}

static bool amduatd_http_send_not_found(int fd, const amduatd_http_req_t *req) {
  if (amduatd_http_req_wants_html(req)) {
    const char *path = (req != NULL && req->path[0] != '\0') ? req->path : "/";
    const char *method =
        (req != NULL && req->method[0] != '\0') ? req->method : "GET";
    char html[4096];
    int n = snprintf(
        html,
        sizeof(html),
        "<!doctype html>\n"
        "<html lang=\"en\">\n"
        "<head>\n"
        "  <meta charset=\"utf-8\" />\n"
        "  <meta name=\"viewport\" content=\"width=device-width, initial-scale=1\" />\n"
        "  <title>amduatd — Not Found</title>\n"
        "  <style>\n"
        "    :root{color-scheme:light dark;}\n"
        "    body{font-family:ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,Ubuntu,Cantarell,Noto Sans,Arial,sans-serif;"
        "         margin:0;line-height:1.4;}\n"
        "    .wrap{max-width:860px;margin:0 auto;padding:40px 20px;}\n"
        "    .card{border:1px solid rgba(127,127,127,.35);border-radius:14px;padding:22px;"
        "          background:rgba(127,127,127,.06);}\n"
        "    h1{margin:0 0 6px;font-size:22px;}\n"
        "    p{margin:8px 0;opacity:.9;}\n"
        "    code{font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,Liberation Mono,monospace;"
        "         font-size:13px;}\n"
        "    ul{margin:10px 0 0;padding-left:18px;}\n"
        "    a{color:inherit;}\n"
        "    .muted{opacity:.75;}\n"
        "  </style>\n"
        "</head>\n"
        "<body>\n"
        "  <div class=\"wrap\">\n"
        "    <div class=\"card\">\n"
        "      <h1>404 — Not Found</h1>\n"
        "      <p>amduatd didn’t recognize <code>%s %s</code>.</p>\n"
        "      <p class=\"muted\">Try one of these:</p>\n"
        "      <ul>\n"
        "        <li><a href=\"/v1/meta\">/v1/meta</a></li>\n"
        "        <li><a href=\"/v1/contract\">/v1/contract</a></li>\n"
        "      </ul>\n"
        "      <p class=\"muted\">Artifact bytes: <code>/v1/artifacts/&lt;ref&gt;</code></p>\n"
        "    </div>\n"
        "  </div>\n"
        "</body>\n"
        "</html>\n",
        method,
        path);
    if (n <= 0 || (size_t)n >= sizeof(html)) {
      return amduatd_http_send_text(fd, 404, "Not Found", "not found\n", false);
    }
    return amduatd_http_send_status(fd,
                                   404,
                                   "Not Found",
                                   "text/html; charset=utf-8",
                                   (const uint8_t *)html,
                                   (size_t)n,
                                   false);
  }
  return amduatd_http_send_text(fd, 404, "Not Found", "not found\n", false);
}

static const char *amduatd_query_param(const char *path,
                                       const char *key,
                                       char *out_value,
                                       size_t out_cap) {
  const char *q = strchr(path, '?');
  size_t key_len = 0;
  if (out_value != NULL && out_cap != 0) {
    out_value[0] = '\0';
  }
  if (q == NULL || key == NULL || out_value == NULL || out_cap == 0) {
    return NULL;
  }
  q++;
  key_len = strlen(key);

  while (*q != '\0') {
    const char *k = q;
    const char *eq = strchr(k, '=');
    const char *amp = strchr(k, '&');
    size_t klen = 0;
    const char *v = NULL;
    size_t vlen = 0;

    if (amp == NULL) {
      amp = q + strlen(q);
    }
    if (eq == NULL || eq > amp) {
      q = (*amp == '&') ? (amp + 1) : amp;
      continue;
    }
    klen = (size_t)(eq - k);
    if (klen == key_len && strncmp(k, key, key_len) == 0) {
      v = eq + 1;
      vlen = (size_t)(amp - v);
      if (vlen >= out_cap) {
        vlen = out_cap - 1;
      }
      memcpy(out_value, v, vlen);
      out_value[vlen] = '\0';
      return out_value;
    }
    q = (*amp == '&') ? (amp + 1) : amp;
  }

  return NULL;
}


static void amduatd_strbuf_free(amduatd_strbuf_t *b) {
  if (b == NULL) {
    return;
  }
  free(b->data);
  b->data = NULL;
  b->len = 0;
  b->cap = 0;
}

static bool amduatd_strbuf_reserve(amduatd_strbuf_t *b, size_t extra) {
  size_t need;
  size_t next_cap;
  char *next;

  if (b == NULL) {
    return false;
  }
  if (extra > (SIZE_MAX - b->len)) {
    return false;
  }
  need = b->len + extra;
  if (need <= b->cap) {
    return true;
  }
  next_cap = b->cap != 0 ? b->cap : 256u;
  while (next_cap < need) {
    if (next_cap > (SIZE_MAX / 2u)) {
      next_cap = need;
      break;
    }
    next_cap *= 2u;
  }
  next = (char *)realloc(b->data, next_cap);
  if (next == NULL) {
    return false;
  }
  b->data = next;
  b->cap = next_cap;
  return true;
}

static bool amduatd_strbuf_append(amduatd_strbuf_t *b,
                                 const char *s,
                                 size_t n) {
  if (b == NULL) {
    return false;
  }
  if (n == 0) {
    return true;
  }
  if (s == NULL) {
    return false;
  }
  if (!amduatd_strbuf_reserve(b, n + 1u)) {
    return false;
  }
  memcpy(b->data + b->len, s, n);
  b->len += n;
  b->data[b->len] = '\0';
  return true;
}

static bool amduatd_strbuf_append_cstr(amduatd_strbuf_t *b, const char *s) {
  return amduatd_strbuf_append(b, s != NULL ? s : "", s != NULL ? strlen(s) : 0u);
}

static bool amduatd_strbuf_append_char(amduatd_strbuf_t *b, char c) {
  return amduatd_strbuf_append(b, &c, 1u);
}

static const char *amduatd_json_skip_ws(const char *p, const char *end) {
  while (p < end) {
    char c = *p;
    if (c != ' ' && c != '\t' && c != '\n' && c != '\r') {
      break;
    }
    p++;
  }
  return p;
}

static bool amduatd_json_expect(const char **p,
                               const char *end,
                               char expected) {
  const char *cur;
  if (p == NULL || *p == NULL) {
    return false;
  }
  cur = amduatd_json_skip_ws(*p, end);
  if (cur >= end || *cur != expected) {
    return false;
  }
  *p = cur + 1;
  return true;
}

static bool amduatd_json_parse_string_noesc(const char **p,
                                           const char *end,
                                           const char **out_start,
                                           size_t *out_len) {
  const char *cur;
  const char *s;
  if (out_start != NULL) {
    *out_start = NULL;
  }
  if (out_len != NULL) {
    *out_len = 0;
  }
  if (p == NULL || *p == NULL) {
    return false;
  }
  cur = amduatd_json_skip_ws(*p, end);
  if (cur >= end || *cur != '"') {
    return false;
  }
  cur++;
  s = cur;
  while (cur < end) {
    unsigned char c = (unsigned char)*cur;
    if (c == '"') {
      if (out_start != NULL) {
        *out_start = s;
      }
      if (out_len != NULL) {
        *out_len = (size_t)(cur - s);
      }
      *p = cur + 1;
      return true;
    }
    if (c == '\\' || c < 0x20u) {
      return false;
    }
    cur++;
  }
  return false;
}

static bool amduatd_json_parse_u32(const char **p,
                                  const char *end,
                                  uint32_t *out) {
  const char *cur;
  const char *start;
  unsigned long long v;
  char *tmp = NULL;
  char *endp = NULL;
  size_t n;

  if (out != NULL) {
    *out = 0;
  }
  if (p == NULL || *p == NULL || out == NULL) {
    return false;
  }

  cur = amduatd_json_skip_ws(*p, end);
  start = cur;
  if (cur >= end) {
    return false;
  }
  if (*cur < '0' || *cur > '9') {
    return false;
  }
  cur++;
  while (cur < end && *cur >= '0' && *cur <= '9') {
    cur++;
  }
  n = (size_t)(cur - start);
  tmp = (char *)malloc(n + 1u);
  if (tmp == NULL) {
    return false;
  }
  memcpy(tmp, start, n);
  tmp[n] = '\0';
  errno = 0;
  v = strtoull(tmp, &endp, 10);
  free(tmp);
  if (errno != 0 || endp == NULL || *endp != '\0' || v > 0xffffffffULL) {
    return false;
  }
  *out = (uint32_t)v;
  *p = cur;
  return true;
}

static bool amduatd_json_skip_string(const char **p, const char *end) {
  const char *cur;
  if (p == NULL || *p == NULL) {
    return false;
  }
  cur = amduatd_json_skip_ws(*p, end);
  if (cur >= end || *cur != '"') {
    return false;
  }
  cur++;
  while (cur < end) {
    unsigned char c = (unsigned char)*cur++;
    if (c == '"') {
      *p = cur;
      return true;
    }
    if (c == '\\') {
      if (cur >= end) {
        return false;
      }
      cur++;
    } else if (c < 0x20u) {
      return false;
    }
  }
  return false;
}

static bool amduatd_json_skip_value(const char **p,
                                   const char *end,
                                   int depth);

static bool amduatd_json_skip_array(const char **p,
                                   const char *end,
                                   int depth) {
  const char *cur;
  if (!amduatd_json_expect(p, end, '[')) {
    return false;
  }
  cur = amduatd_json_skip_ws(*p, end);
  if (cur < end && *cur == ']') {
    *p = cur + 1;
    return true;
  }
  for (;;) {
    if (!amduatd_json_skip_value(p, end, depth + 1)) {
      return false;
    }
    cur = amduatd_json_skip_ws(*p, end);
    if (cur >= end) {
      return false;
    }
    if (*cur == ',') {
      *p = cur + 1;
      continue;
    }
    if (*cur == ']') {
      *p = cur + 1;
      return true;
    }
    return false;
  }
}

static bool amduatd_json_skip_object(const char **p,
                                    const char *end,
                                    int depth) {
  const char *cur;
  if (!amduatd_json_expect(p, end, '{')) {
    return false;
  }
  cur = amduatd_json_skip_ws(*p, end);
  if (cur < end && *cur == '}') {
    *p = cur + 1;
    return true;
  }
  for (;;) {
    if (!amduatd_json_skip_string(p, end)) {
      return false;
    }
    if (!amduatd_json_expect(p, end, ':')) {
      return false;
    }
    if (!amduatd_json_skip_value(p, end, depth + 1)) {
      return false;
    }
    cur = amduatd_json_skip_ws(*p, end);
    if (cur >= end) {
      return false;
    }
    if (*cur == ',') {
      *p = cur + 1;
      continue;
    }
    if (*cur == '}') {
      *p = cur + 1;
      return true;
    }
    return false;
  }
}

static bool amduatd_json_skip_value(const char **p,
                                   const char *end,
                                   int depth) {
  const char *cur;
  if (p == NULL || *p == NULL) {
    return false;
  }
  if (depth > 32) {
    return false;
  }
  cur = amduatd_json_skip_ws(*p, end);
  if (cur >= end) {
    return false;
  }
  if (*cur == '"') {
    return amduatd_json_skip_string(p, end);
  }
  if (*cur == '{') {
    return amduatd_json_skip_object(p, end, depth);
  }
  if (*cur == '[') {
    return amduatd_json_skip_array(p, end, depth);
  }
  if (*cur == 't' && (end - cur) >= 4 && memcmp(cur, "true", 4) == 0) {
    *p = cur + 4;
    return true;
  }
  if (*cur == 'f' && (end - cur) >= 5 && memcmp(cur, "false", 5) == 0) {
    *p = cur + 5;
    return true;
  }
  if (*cur == 'n' && (end - cur) >= 4 && memcmp(cur, "null", 4) == 0) {
    *p = cur + 4;
    return true;
  }
  if (*cur == '-' || (*cur >= '0' && *cur <= '9')) {
    cur++;
    while (cur < end) {
      char c = *cur;
      if ((c >= '0' && c <= '9') || c == '.' || c == 'e' || c == 'E' ||
          c == '+' || c == '-') {
        cur++;
        continue;
      }
      break;
    }
    *p = cur;
    return true;
  }
  return false;
}

static bool amduatd_copy_json_str(const char *s,
                                 size_t len,
                                 char **out) {
  char *buf;
  if (out == NULL) {
    return false;
  }
  *out = NULL;
  if (len > (SIZE_MAX - 1u)) {
    return false;
  }
  buf = (char *)malloc(len + 1u);
  if (buf == NULL) {
    return false;
  }
  if (len != 0) {
    memcpy(buf, s, len);
  }
  buf[len] = '\0';
  *out = buf;
  return true;
}

static bool amduatd_decode_ref_hex_str(const char *s,
                                      size_t len,
                                      amduat_reference_t *out_ref) {
  char *tmp = NULL;
  bool ok;
  if (out_ref == NULL) {
    return false;
  }
  memset(out_ref, 0, sizeof(*out_ref));
  if (!amduatd_copy_json_str(s, len, &tmp)) {
    return false;
  }
  ok = amduat_asl_ref_decode_hex(tmp, out_ref);
  free(tmp);
  return ok;
}

typedef enum {
  AMDUATD_REF_OK = 0,
  AMDUATD_REF_ERR_INVALID = 1,
  AMDUATD_REF_ERR_NOT_FOUND = 2,
  AMDUATD_REF_ERR_INTERNAL = 3
} amduatd_ref_status_t;

static amduatd_ref_status_t amduatd_decode_ref_or_name_latest(
    amduat_asl_store_t *store,
    const amduat_asl_store_fs_config_t *cfg,
    const amduatd_concepts_t *concepts,
    const char *s,
    size_t len,
    amduat_reference_t *out_ref) {
  amduat_reference_t concept_ref;
  char *tmp = NULL;

  if (out_ref != NULL) {
    memset(out_ref, 0, sizeof(*out_ref));
  }
  if (store == NULL || cfg == NULL || concepts == NULL || s == NULL ||
      out_ref == NULL) {
    return AMDUATD_REF_ERR_INTERNAL;
  }

  if (amduatd_decode_ref_hex_str(s, len, out_ref)) {
    return AMDUATD_REF_OK;
  }

  if (!amduatd_copy_json_str(s, len, &tmp)) {
    return AMDUATD_REF_ERR_INTERNAL;
  }
  if (!amduatd_name_valid(tmp)) {
    free(tmp);
    return AMDUATD_REF_ERR_INVALID;
  }
  memset(&concept_ref, 0, sizeof(concept_ref));
  if (!amduatd_concepts_lookup_alias(store, cfg, concepts, tmp, &concept_ref)) {
    free(tmp);
    return AMDUATD_REF_ERR_NOT_FOUND;
  }
  free(tmp);

  if (!amduatd_concepts_resolve_latest(store, concepts, concept_ref, out_ref)) {
    amduat_reference_free(&concept_ref);
    return AMDUATD_REF_ERR_NOT_FOUND;
  }
  amduat_reference_free(&concept_ref);
  return AMDUATD_REF_OK;
}

static bool amduatd_send_json_error(int fd,
                                   int code,
                                   const char *reason,
                                   const char *msg) {
  amduatd_strbuf_t b;
  memset(&b, 0, sizeof(b));
  if (!amduatd_strbuf_append_cstr(&b, "{\"error\":\"") ||
      !amduatd_strbuf_append_cstr(&b, msg != NULL ? msg : "error") ||
      !amduatd_strbuf_append_cstr(&b, "\"}\n")) {
    amduatd_strbuf_free(&b);
    return amduatd_http_send_text(fd, 500, "Internal Server Error", "error\n",
                                 false);
  }
  {
    bool ok = amduatd_http_send_json(fd, code, reason, b.data, false);
    amduatd_strbuf_free(&b);
    return ok;
  }
}

static void amduatd_path_without_query(const char *path,
                                       char *out,
                                       size_t cap) {
  const char *q = NULL;
  size_t n = 0;
  if (out == NULL || cap == 0) {
    return;
  }
  out[0] = '\0';
  if (path == NULL) {
    return;
  }
  q = strchr(path, '?');
  n = q != NULL ? (size_t)(q - path) : strlen(path);
  if (n >= cap) {
    n = cap - 1;
  }
  memcpy(out, path, n);
  out[n] = '\0';
}

static bool amduatd_parse_type_tag_hex(const char *text,
                                       bool *out_has_type_tag,
                                       amduat_type_tag_t *out_type_tag) {
  char *end = NULL;
  unsigned long v = 0;
  if (out_has_type_tag != NULL) {
    *out_has_type_tag = false;
  }
  if (text == NULL || text[0] == '\0' || out_type_tag == NULL ||
      out_has_type_tag == NULL) {
    return true;
  }
  errno = 0;
  v = strtoul(text, &end, 0);
  if (errno != 0 || end == text || *end != '\0' || v > 0xffffffffUL) {
    return false;
  }
  *out_has_type_tag = true;
  out_type_tag->tag_id = (uint32_t)v;
  return true;
}

static bool amduatd_handle_meta(int fd,
                                const amduat_asl_store_fs_config_t *cfg,
                                amduat_reference_t api_contract_ref,
                                bool head_only) {
  char json[1024];
  char *contract_hex = NULL;
  int n;

  if (api_contract_ref.hash_id != 0 && api_contract_ref.digest.data != NULL &&
      api_contract_ref.digest.len != 0) {
    (void)amduat_asl_ref_encode_hex(api_contract_ref, &contract_hex);
  }

  if (contract_hex != NULL) {
    n = snprintf(json,
                 sizeof(json),
                 "{"
                 "\"store_id\":\"%s\","
                 "\"encoding_profile_id\":\"0x%04x\","
                 "\"hash_id\":\"0x%04x\","
                 "\"api_contract_ref\":\"%s\""
                 "}\n",
                 cfg != NULL ? cfg->store_id : "",
                 cfg != NULL ? (unsigned int)cfg->config.encoding_profile_id
                             : 0u,
                 cfg != NULL ? (unsigned int)cfg->config.hash_id : 0u,
                 contract_hex);
  } else {
    n = snprintf(json,
                 sizeof(json),
                 "{"
                 "\"store_id\":\"%s\","
                 "\"encoding_profile_id\":\"0x%04x\","
                 "\"hash_id\":\"0x%04x\","
                 "\"api_contract_ref\":null"
                 "}\n",
                 cfg != NULL ? cfg->store_id : "",
                 cfg != NULL ? (unsigned int)cfg->config.encoding_profile_id
                             : 0u,
                 cfg != NULL ? (unsigned int)cfg->config.hash_id : 0u);
  }

  free(contract_hex);
  if (n <= 0 || (size_t)n >= sizeof(json)) {
    return amduatd_http_send_text(fd, 500, "Internal Server Error", "error\n",
                                 head_only);
  }
  return amduatd_http_send_json(fd, 200, "OK", json, head_only);
}

static bool amduatd_handle_get_contract(int fd,
                                       amduat_asl_store_t *store,
                                       const amduatd_http_req_t *req,
                                       amduat_reference_t api_contract_ref) {
  char *hex = NULL;
  char format[32];

  if (api_contract_ref.hash_id == 0 || api_contract_ref.digest.data == NULL ||
      api_contract_ref.digest.len == 0) {
    return amduatd_http_send_not_found(fd, req);
  }

  memset(format, 0, sizeof(format));
  if (req != NULL &&
      amduatd_query_param(req->path, "format", format, sizeof(format)) !=
          NULL &&
      strcmp(format, "ref") == 0) {
    char json[2048];
    int n;
    if (!amduat_asl_ref_encode_hex(api_contract_ref, &hex)) {
      return amduatd_http_send_text(fd, 500, "Internal Server Error",
                                   "encode error\n", false);
    }
    n = snprintf(json, sizeof(json), "{\"ref\":\"%s\"}\n", hex);
    free(hex);
    if (n <= 0 || (size_t)n >= sizeof(json)) {
      return amduatd_http_send_text(fd, 500, "Internal Server Error",
                                   "error\n", false);
    }
    return amduatd_http_send_json(fd, 200, "OK", json, false);
  }

  {
    amduat_artifact_t artifact;
    amduat_asl_store_error_t err;

    memset(&artifact, 0, sizeof(artifact));
    err = amduat_asl_store_get(store, api_contract_ref, &artifact);
    if (err == AMDUAT_ASL_STORE_ERR_NOT_FOUND) {
      return amduatd_http_send_not_found(fd, req);
    }
    if (err != AMDUAT_ASL_STORE_OK) {
      amduat_asl_artifact_free(&artifact);
      return amduatd_http_send_text(fd, 500, "Internal Server Error",
                                   "store error\n", false);
    }
    if (artifact.bytes.len != 0 && artifact.bytes.data == NULL) {
      amduat_asl_artifact_free(&artifact);
      return amduatd_http_send_text(fd, 500, "Internal Server Error",
                                   "store error\n", false);
    }

    if (!amduat_asl_ref_encode_hex(api_contract_ref, &hex)) {
      amduat_asl_artifact_free(&artifact);
      return amduatd_http_send_text(fd, 500, "Internal Server Error",
                                   "encode error\n", false);
    }

    {
      char hdr[600];
      int n = snprintf(hdr,
                       sizeof(hdr),
                       "HTTP/1.1 200 OK\r\n"
                       "Content-Length: %zu\r\n"
                       "Content-Type: application/json\r\n"
                       "X-Amduat-Contract-Ref: %s\r\n"
                       "Connection: close\r\n"
                       "\r\n",
                       artifact.bytes.len,
                       hex);
      free(hex);
      if (n <= 0 || (size_t)n >= sizeof(hdr)) {
        amduat_asl_artifact_free(&artifact);
        return false;
      }
      if (!amduatd_write_all(fd, (const uint8_t *)hdr, (size_t)n)) {
        amduat_asl_artifact_free(&artifact);
        return false;
      }
      if (artifact.bytes.len != 0) {
        bool ok = amduatd_write_all(fd, artifact.bytes.data, artifact.bytes.len);
        amduat_asl_artifact_free(&artifact);
        return ok;
      }
      amduat_asl_artifact_free(&artifact);
      return true;
    }
  }
}

static bool amduatd_seed_api_contract(amduat_asl_store_t *store,
                                     const amduat_asl_store_fs_config_t *cfg,
                                     amduat_reference_t *out_ref) {
  amduat_artifact_t artifact;
  amduat_asl_store_error_t err;

  if (out_ref != NULL) {
    memset(out_ref, 0, sizeof(*out_ref));
  }
  if (store == NULL || cfg == NULL || out_ref == NULL) {
    return false;
  }

  artifact = amduat_artifact(amduat_octets(k_amduatd_contract_v1_json,
                                          strlen(k_amduatd_contract_v1_json)));

  (void)amduat_asl_ref_derive(artifact,
                              cfg->config.encoding_profile_id,
                              cfg->config.hash_id,
                              out_ref,
                              NULL);
  err = amduat_asl_store_put(store, artifact, out_ref);
  if (err != AMDUAT_ASL_STORE_OK) {
    return false;
  }
  return true;
}

static bool amduatd_handle_get_artifact(int fd,
                                        amduat_asl_store_t *store,
                                        const amduatd_http_req_t *req,
                                        const char *path,
                                        bool head_only) {
  char no_query[1024];
  char format[32];
  const char *ref_text = NULL;
  amduat_reference_t ref;
  amduat_artifact_t artifact;
  amduat_asl_store_error_t err;
  bool want_artifact = false;
  bool want_info = false;

  memset(&ref, 0, sizeof(ref));
  memset(&artifact, 0, sizeof(artifact));
  amduatd_path_without_query(path, no_query, sizeof(no_query));

  if (strncmp(no_query, "/v1/artifacts/", 14) != 0) {
    (void)head_only;
    return amduatd_http_send_not_found(fd, req);
  }
  ref_text = no_query + 14;
  if (ref_text[0] == '\0') {
    return amduatd_http_send_text(fd, 400, "Bad Request", "missing ref\n",
                                 head_only);
  }

  if (!amduat_asl_ref_decode_hex(ref_text, &ref)) {
    return amduatd_http_send_text(fd, 400, "Bad Request", "invalid ref\n",
                                 head_only);
  }

  memset(format, 0, sizeof(format));
  if (amduatd_query_param(path, "format", format, sizeof(format)) != NULL) {
    if (strcmp(format, "artifact") == 0) {
      want_artifact = true;
      want_info = false;
    } else if (strcmp(format, "info") == 0) {
      want_artifact = false;
      want_info = true;
    } else if (strcmp(format, "raw") == 0 || format[0] == '\0') {
      want_artifact = false;
      want_info = false;
    } else {
      free((void *)ref.digest.data);
      return amduatd_http_send_text(fd, 400, "Bad Request",
                                   "invalid format\n", head_only);
    }
  }

  err = amduat_asl_store_get(store, ref, &artifact);
  free((void *)ref.digest.data);
  if (err == AMDUAT_ASL_STORE_ERR_NOT_FOUND) {
    if (!head_only) {
      return amduatd_http_send_not_found(fd, req);
    }
    return amduatd_http_send_text(fd, 404, "Not Found", "not found\n", true);
  }
  if (err != AMDUAT_ASL_STORE_OK) {
    amduat_asl_artifact_free(&artifact);
    return amduatd_http_send_text(fd, 500, "Internal Server Error",
                                 "store error\n", head_only);
  }

  if (!want_artifact) {
    if (want_info) {
      char json[256];
      int n;
      if (artifact.has_type_tag) {
        n = snprintf(json,
                     sizeof(json),
                     "{"
                     "\"len\":%zu,"
                     "\"has_type_tag\":true,"
                     "\"type_tag\":\"0x%08x\""
                     "}\n",
                     artifact.bytes.len,
                     (unsigned int)artifact.type_tag.tag_id);
      } else {
        n = snprintf(json,
                     sizeof(json),
                     "{"
                     "\"len\":%zu,"
                     "\"has_type_tag\":false,"
                     "\"type_tag\":null"
                     "}\n",
                     artifact.bytes.len);
      }
      amduat_asl_artifact_free(&artifact);
      if (n <= 0 || (size_t)n >= sizeof(json)) {
        return amduatd_http_send_text(fd, 500, "Internal Server Error",
                                     "error\n", head_only);
      }
      return amduatd_http_send_json(fd, 200, "OK", json, head_only);
    }
    bool ok = amduatd_http_send_status(
        fd,
        200,
        "OK",
        "application/octet-stream",
        artifact.bytes.data,
        artifact.bytes.len,
        head_only);
    amduat_asl_artifact_free(&artifact);
    return ok;
  }

  {
    amduat_octets_t out = amduat_octets(NULL, 0);
    bool ok = amduat_enc_asl1_core_encode_artifact_v1(artifact, &out);
    amduat_asl_artifact_free(&artifact);
    if (!ok) {
      return amduatd_http_send_text(fd, 500, "Internal Server Error",
                                   "encode error\n", head_only);
    }
    ok = amduatd_http_send_status(fd,
                                 200,
                                 "OK",
                                 "application/vnd.amduat.asl.artifact+v1",
                                 out.data,
                                 out.len,
                                 head_only);
    free((void *)out.data);
    return ok;
  }
}

static bool amduatd_handle_head_artifact(int fd,
                                         amduat_asl_store_t *store,
                                         const amduatd_http_req_t *req,
                                         const char *path) {
  return amduatd_handle_get_artifact(fd, store, req, path, true);
}

static bool amduatd_handle_post_artifacts(int fd,
                                          amduat_asl_store_t *store,
                                          const amduatd_http_req_t *req) {
  uint8_t *body = NULL;
  bool has_type_tag = false;
  amduat_type_tag_t type_tag;
  amduat_asl_io_format_t input_format = AMDUAT_ASL_IO_RAW;
  amduat_artifact_t artifact;
  amduat_reference_t ref;
  amduat_asl_store_error_t err;
  char *ref_hex = NULL;
  char json[2048];

  memset(&artifact, 0, sizeof(artifact));
  memset(&ref, 0, sizeof(ref));
  memset(&type_tag, 0, sizeof(type_tag));

  if (req == NULL) {
    return amduatd_http_send_text(fd, 400, "Bad Request", "bad request\n",
                                 false);
  }

  if (req->content_length > (64u * 1024u * 1024u)) {
    return amduatd_http_send_text(fd, 413, "Payload Too Large",
                                 "payload too large\n", false);
  }

  if (req->content_length != 0) {
    body = (uint8_t *)malloc(req->content_length);
    if (body == NULL) {
      return amduatd_http_send_text(fd, 500, "Internal Server Error",
                                   "oom\n", false);
    }
    if (!amduatd_read_exact(fd, body, req->content_length)) {
      free(body);
      return false;
    }
  } else {
    body = NULL;
  }

  if (req->content_type[0] != '\0' &&
      strstr(req->content_type, "application/vnd.amduat.asl.artifact+v1") !=
          NULL) {
    input_format = AMDUAT_ASL_IO_ARTIFACT;
  }

  if (input_format == AMDUAT_ASL_IO_RAW) {
    if (!amduatd_parse_type_tag_hex(req->x_type_tag,
                                   &has_type_tag,
                                   &type_tag)) {
      free(body);
      return amduatd_http_send_text(fd, 400, "Bad Request",
                                   "invalid X-Amduat-Type-Tag\n", false);
    }
  }

  if (!amduat_asl_artifact_from_bytes(amduat_octets(body, req->content_length),
                                      input_format,
                                      has_type_tag,
                                      type_tag,
                                      &artifact)) {
    free(body);
    return amduatd_http_send_text(fd, 400, "Bad Request",
                                 "invalid artifact\n", false);
  }

  err = amduat_asl_store_put(store, artifact, &ref);
  amduat_asl_artifact_free(&artifact);
  if (err != AMDUAT_ASL_STORE_OK) {
    free((void *)ref.digest.data);
    return amduatd_http_send_text(fd, 500, "Internal Server Error",
                                 "store error\n", false);
  }

  if (!amduat_asl_ref_encode_hex(ref, &ref_hex)) {
    free((void *)ref.digest.data);
    return amduatd_http_send_text(fd, 500, "Internal Server Error",
                                 "encode ref error\n", false);
  }
  free((void *)ref.digest.data);

  {
    int n = snprintf(json, sizeof(json), "{\"ref\":\"%s\"}\n", ref_hex);
    free(ref_hex);
    if (n <= 0 || (size_t)n >= sizeof(json)) {
      return amduatd_http_send_text(fd, 500, "Internal Server Error",
                                   "error\n", false);
    }
    return amduatd_http_send_json(fd, 200, "OK", json, false);
  }
}

static bool amduatd_handle_post_pel_run(int fd,
                                        amduat_asl_store_t *store,
                                        const amduat_asl_store_fs_config_t *cfg,
                                        const amduatd_concepts_t *concepts,
                                        const amduatd_http_req_t *req) {
  uint8_t *body = NULL;
  const char *p = NULL;
  const char *end = NULL;
  bool have_program_ref = false;
  bool have_input_refs = false;
  bool have_scheme_ref = false;
  bool scheme_is_dag = false;
  bool has_params_ref = false;
  amduat_reference_t scheme_ref;
  amduat_reference_t program_ref;
  amduat_reference_t params_ref;
  amduat_reference_t *input_refs = NULL;
  size_t input_refs_len = 0;
  amduat_pel_run_result_t run_result;
  int status_code = 200;
  const char *status_reason = "OK";
  bool ok = false;

  memset(&scheme_ref, 0, sizeof(scheme_ref));
  memset(&program_ref, 0, sizeof(program_ref));
  memset(&params_ref, 0, sizeof(params_ref));
  memset(&run_result, 0, sizeof(run_result));

  if (store == NULL || req == NULL) {
    return amduatd_send_json_error(fd, 500, "Internal Server Error",
                                  "internal error");
  }
  if (cfg == NULL || concepts == NULL) {
    return amduatd_send_json_error(fd, 500, "Internal Server Error",
                                  "internal error");
  }

  if (req->content_length > (1u * 1024u * 1024u)) {
    return amduatd_send_json_error(fd, 413, "Payload Too Large",
                                  "payload too large");
  }

  if (req->content_length == 0) {
    return amduatd_send_json_error(fd, 400, "Bad Request", "missing body");
  }

  body = NULL;
  if (req->content_length != 0) {
    body = (uint8_t *)malloc(req->content_length);
    if (body == NULL) {
      return amduatd_send_json_error(fd, 500, "Internal Server Error", "oom");
    }
    if (!amduatd_read_exact(fd, body, req->content_length)) {
      free(body);
      return false;
    }
  }

  p = (const char *)body;
  end = (const char *)body + req->content_length;
  if (!amduatd_json_expect(&p, end, '{')) {
    ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
    goto pel_run_cleanup;
  }

  for (;;) {
    const char *key = NULL;
    size_t key_len = 0;
    const char *sv = NULL;
    size_t sv_len = 0;
    const char *cur = NULL;

    cur = amduatd_json_skip_ws(p, end);
    if (cur < end && *cur == '}') {
      p = cur + 1;
      break;
    }

    if (!amduatd_json_parse_string_noesc(&p, end, &key, &key_len)) {
      ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                  "invalid json key");
      goto pel_run_cleanup;
    }
    if (!amduatd_json_expect(&p, end, ':')) {
      ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
      goto pel_run_cleanup;
    }

    if (key_len == strlen("program_ref") &&
        memcmp(key, "program_ref", key_len) == 0) {
      amduatd_ref_status_t st;
      if (have_program_ref) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                    "duplicate program_ref");
        goto pel_run_cleanup;
      }
      if (!amduatd_json_parse_string_noesc(&p, end, &sv, &sv_len)) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                    "invalid program_ref");
        goto pel_run_cleanup;
      }
      st = amduatd_decode_ref_or_name_latest(store, cfg, concepts, sv, sv_len,
                                            &program_ref);
      if (st == AMDUATD_REF_ERR_NOT_FOUND) {
        ok = amduatd_send_json_error(fd, 404, "Not Found",
                                    "program_ref not found");
        goto pel_run_cleanup;
      }
      if (st != AMDUATD_REF_OK) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                    "invalid program_ref");
        goto pel_run_cleanup;
      }
      have_program_ref = true;
    } else if (key_len == strlen("scheme_ref") &&
               memcmp(key, "scheme_ref", key_len) == 0) {
      if (have_scheme_ref) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                    "duplicate scheme_ref");
        goto pel_run_cleanup;
      }
      if (!amduatd_json_parse_string_noesc(&p, end, &sv, &sv_len)) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                    "invalid scheme_ref");
        goto pel_run_cleanup;
      }
      if (sv_len == 3 && memcmp(sv, "dag", 3) == 0) {
        scheme_ref = amduat_pel_program_dag_scheme_ref();
        scheme_is_dag = true;
      } else if (!amduatd_decode_ref_hex_str(sv, sv_len, &scheme_ref)) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                    "invalid scheme_ref");
        goto pel_run_cleanup;
      }
      have_scheme_ref = true;
    } else if (key_len == strlen("params_ref") &&
               memcmp(key, "params_ref", key_len) == 0) {
      amduatd_ref_status_t st;
      if (has_params_ref) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                    "duplicate params_ref");
        goto pel_run_cleanup;
      }
      if (!amduatd_json_parse_string_noesc(&p, end, &sv, &sv_len)) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                    "invalid params_ref");
        goto pel_run_cleanup;
      }
      st = amduatd_decode_ref_or_name_latest(store, cfg, concepts, sv, sv_len,
                                            &params_ref);
      if (st == AMDUATD_REF_ERR_NOT_FOUND) {
        ok = amduatd_send_json_error(fd, 404, "Not Found",
                                    "params_ref not found");
        goto pel_run_cleanup;
      }
      if (st != AMDUATD_REF_OK) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                    "invalid params_ref");
        goto pel_run_cleanup;
      }
      has_params_ref = true;
    } else if (key_len == strlen("input_refs") &&
               memcmp(key, "input_refs", key_len) == 0) {
      size_t cap = 0;
      if (have_input_refs) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                    "duplicate input_refs");
        goto pel_run_cleanup;
      }
      if (!amduatd_json_expect(&p, end, '[')) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                    "invalid input_refs");
        goto pel_run_cleanup;
      }
      cur = amduatd_json_skip_ws(p, end);
      if (cur < end && *cur == ']') {
        p = cur + 1;
        have_input_refs = true;
      } else {
        for (;;) {
          amduat_reference_t ref;
          memset(&ref, 0, sizeof(ref));
          if (!amduatd_json_parse_string_noesc(&p, end, &sv, &sv_len)) {
            ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                        "invalid input_ref");
            goto pel_run_cleanup;
          }
          {
            amduatd_ref_status_t st = amduatd_decode_ref_or_name_latest(
                store, cfg, concepts, sv, sv_len, &ref);
            if (st == AMDUATD_REF_ERR_NOT_FOUND) {
              ok = amduatd_send_json_error(fd, 404, "Not Found",
                                          "input_ref not found");
              goto pel_run_cleanup;
            }
            if (st != AMDUATD_REF_OK) {
              ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                          "invalid input_ref");
              goto pel_run_cleanup;
            }
          }
          if (input_refs_len == cap) {
            size_t next_cap = cap != 0 ? cap * 2u : 4u;
            amduat_reference_t *next;
            if (next_cap > (SIZE_MAX / sizeof(*input_refs))) {
              amduat_reference_free(&ref);
              ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                          "too many input_refs");
              goto pel_run_cleanup;
            }
            next = (amduat_reference_t *)realloc(
                input_refs, next_cap * sizeof(*input_refs));
            if (next == NULL) {
              amduat_reference_free(&ref);
              ok = amduatd_send_json_error(fd, 500, "Internal Server Error",
                                          "oom");
              goto pel_run_cleanup;
            }
            input_refs = next;
            cap = next_cap;
          }
          input_refs[input_refs_len++] = ref;

          cur = amduatd_json_skip_ws(p, end);
          if (cur >= end) {
            ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                        "invalid input_refs");
            goto pel_run_cleanup;
          }
          if (*cur == ',') {
            p = cur + 1;
            continue;
          }
          if (*cur == ']') {
            p = cur + 1;
            have_input_refs = true;
            break;
          }
          ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                      "invalid input_refs");
          goto pel_run_cleanup;
        }
      }
    } else {
      if (!amduatd_json_skip_value(&p, end, 0)) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
        goto pel_run_cleanup;
      }
    }

    cur = amduatd_json_skip_ws(p, end);
    if (cur >= end) {
      ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
      goto pel_run_cleanup;
    }
    if (*cur == ',') {
      p = cur + 1;
      continue;
    }
    if (*cur == '}') {
      p = cur + 1;
      break;
    }
    ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
    goto pel_run_cleanup;
  }

  p = amduatd_json_skip_ws(p, end);
  if (p != end) {
    ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
    goto pel_run_cleanup;
  }
  free(body);
  body = NULL;

  if (!have_program_ref) {
    ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                "missing program_ref");
    goto pel_run_cleanup;
  }
  if (!have_input_refs) {
    ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                "missing input_refs");
    goto pel_run_cleanup;
  }
  if (!have_scheme_ref) {
    scheme_ref = amduat_pel_program_dag_scheme_ref();
    scheme_is_dag = true;
  }

  if (!amduat_pel_surf_run_with_result(store,
                                       scheme_ref,
                                       program_ref,
                                       input_refs,
                                       input_refs_len,
                                       has_params_ref,
                                       params_ref,
                                       &run_result)) {
    ok = amduatd_send_json_error(fd, 500, "Internal Server Error",
                                "pel run failed");
    goto pel_run_cleanup;
  }

  if (run_result.has_result_value && run_result.result_value.has_store_failure) {
    if (run_result.result_value.store_failure.error_code ==
        AMDUAT_PEL_STORE_ERROR_NOT_FOUND) {
      status_code = 404;
      status_reason = "Not Found";
    } else {
      status_code = 500;
      status_reason = "Internal Server Error";
    }
  }

  {
    amduatd_strbuf_t resp;
    char *result_hex = NULL;
    char *trace_hex = NULL;
    const char *status = "UNKNOWN";
    size_t i;

    memset(&resp, 0, sizeof(resp));

    if (!amduat_asl_ref_encode_hex(run_result.result_ref, &result_hex)) {
      amduatd_strbuf_free(&resp);
      ok = amduatd_send_json_error(fd, 500, "Internal Server Error",
                                  "encode error");
      goto pel_run_cleanup;
    }

    if (run_result.has_result_value) {
      status = amduat_format_pel_status_name(
          run_result.result_value.core_result.status);
      if (run_result.result_value.has_trace_ref) {
        if (!amduat_asl_ref_encode_hex(run_result.result_value.trace_ref,
                                       &trace_hex)) {
          free(result_hex);
          amduatd_strbuf_free(&resp);
          ok = amduatd_send_json_error(fd, 500, "Internal Server Error",
                                      "encode error");
          goto pel_run_cleanup;
        }
      }
    }

    if (!amduatd_strbuf_append_cstr(&resp, "{\"result_ref\":\"") ||
        !amduatd_strbuf_append_cstr(&resp, result_hex) ||
        !amduatd_strbuf_append_cstr(&resp, "\"")) {
      free(result_hex);
      free(trace_hex);
      amduatd_strbuf_free(&resp);
      ok = amduatd_send_json_error(fd, 500, "Internal Server Error", "oom");
      goto pel_run_cleanup;
    }
    free(result_hex);

    if (trace_hex != NULL) {
      if (!amduatd_strbuf_append_cstr(&resp, ",\"trace_ref\":\"") ||
          !amduatd_strbuf_append_cstr(&resp, trace_hex) ||
          !amduatd_strbuf_append_cstr(&resp, "\"")) {
        free(trace_hex);
        amduatd_strbuf_free(&resp);
        ok = amduatd_send_json_error(fd, 500, "Internal Server Error", "oom");
        goto pel_run_cleanup;
      }
      free(trace_hex);
    }

    if (!amduatd_strbuf_append_cstr(&resp, ",\"output_refs\":[")) {
      amduatd_strbuf_free(&resp);
      ok = amduatd_send_json_error(fd, 500, "Internal Server Error", "oom");
      goto pel_run_cleanup;
    }

    for (i = 0; i < run_result.output_refs_len; ++i) {
      char *out_hex = NULL;
      if (!amduat_asl_ref_encode_hex(run_result.output_refs[i], &out_hex)) {
        amduatd_strbuf_free(&resp);
        ok = amduatd_send_json_error(fd, 500, "Internal Server Error",
                                    "encode error");
        goto pel_run_cleanup;
      }
      if (i != 0) {
        if (!amduatd_strbuf_append_char(&resp, ',')) {
          free(out_hex);
          amduatd_strbuf_free(&resp);
          ok = amduatd_send_json_error(fd, 500, "Internal Server Error", "oom");
          goto pel_run_cleanup;
        }
      }
      if (!amduatd_strbuf_append_cstr(&resp, "\"") ||
          !amduatd_strbuf_append_cstr(&resp, out_hex) ||
          !amduatd_strbuf_append_cstr(&resp, "\"")) {
        free(out_hex);
        amduatd_strbuf_free(&resp);
        ok = amduatd_send_json_error(fd, 500, "Internal Server Error", "oom");
        goto pel_run_cleanup;
      }
      free(out_hex);
    }

    if (!amduatd_strbuf_append_cstr(&resp, "],\"status\":\"") ||
        !amduatd_strbuf_append_cstr(&resp, status) ||
        !amduatd_strbuf_append_cstr(&resp, "\"}\n")) {
      amduatd_strbuf_free(&resp);
      ok = amduatd_send_json_error(fd, 500, "Internal Server Error", "oom");
      goto pel_run_cleanup;
    }

    ok = amduatd_http_send_json(fd, status_code, status_reason, resp.data, false);
    amduatd_strbuf_free(&resp);
  }

pel_run_cleanup:
  if (body != NULL) {
    free(body);
  }
  if (run_result.has_result_value) {
    amduat_enc_pel1_result_free(&run_result.result_value);
  }
  if (run_result.output_refs != NULL) {
    amduat_pel_surf_free_refs(run_result.output_refs, run_result.output_refs_len);
  }
  amduat_pel_surf_free_ref(&run_result.result_ref);

  if (input_refs != NULL) {
    size_t i;
    for (i = 0; i < input_refs_len; ++i) {
      amduat_reference_free(&input_refs[i]);
    }
    free(input_refs);
  }
  if (has_params_ref) {
    amduat_reference_free(&params_ref);
  }
  if (have_program_ref) {
    amduat_reference_free(&program_ref);
  }
  if (have_scheme_ref && !scheme_is_dag) {
    amduat_reference_free(&scheme_ref);
  }
  return ok;
}

typedef struct {
  amduat_pel_node_t *nodes;
  size_t nodes_len;
  amduat_pel_root_ref_t *roots;
  size_t roots_len;
} amduatd_pel_program_tmp_t;

static void amduatd_pel_program_tmp_free(amduatd_pel_program_tmp_t *tmp) {
  size_t i;

  if (tmp == NULL) {
    return;
  }
  if (tmp->nodes != NULL) {
    for (i = 0; i < tmp->nodes_len; ++i) {
      free(tmp->nodes[i].inputs);
      tmp->nodes[i].inputs = NULL;
      tmp->nodes[i].inputs_len = 0;
      free((void *)tmp->nodes[i].params.data);
      tmp->nodes[i].params.data = NULL;
      tmp->nodes[i].params.len = 0;
    }
  }
  free(tmp->nodes);
  tmp->nodes = NULL;
  tmp->nodes_len = 0;
  free(tmp->roots);
  tmp->roots = NULL;
  tmp->roots_len = 0;
}

static bool amduatd_parse_params_hex(const char *s,
                                    size_t len,
                                    amduat_octets_t *out) {
  char *tmp = NULL;
  uint8_t *bytes = NULL;
  size_t out_len = 0;

  if (out != NULL) {
    *out = amduat_octets(NULL, 0);
  }
  if (s == NULL || out == NULL) {
    return false;
  }
  if (!amduatd_copy_json_str(s, len, &tmp)) {
    return false;
  }
  if (tmp[0] == '\0') {
    free(tmp);
    *out = amduat_octets(NULL, 0);
    return true;
  }
  if (!amduat_hex_decode_alloc(tmp, &bytes, &out_len)) {
    free(tmp);
    return false;
  }
  free(tmp);
  *out = amduat_octets(bytes, out_len);
  return true;
}

static bool amduatd_handle_post_pel_programs(int fd,
                                             amduat_asl_store_t *store,
                                             const amduatd_http_req_t *req) {
  uint8_t *body = NULL;
  const char *p = NULL;
  const char *end = NULL;
  amduatd_pel_program_tmp_t tmp;
  amduat_pel_program_t program;
  amduat_octets_t program_bytes;
  amduat_artifact_t artifact;
  amduat_reference_t program_ref;
  char *ref_hex = NULL;
  char json[2048];
  bool ok = false;

  memset(&tmp, 0, sizeof(tmp));
  memset(&program, 0, sizeof(program));
  program_bytes = amduat_octets(NULL, 0);
  memset(&artifact, 0, sizeof(artifact));
  memset(&program_ref, 0, sizeof(program_ref));

  if (store == NULL || req == NULL) {
    return amduatd_send_json_error(fd, 500, "Internal Server Error",
                                  "internal error");
  }
  if (req->content_length == 0) {
    return amduatd_send_json_error(fd, 400, "Bad Request", "missing body");
  }
  if (req->content_length > (2u * 1024u * 1024u)) {
    return amduatd_send_json_error(fd, 413, "Payload Too Large",
                                  "payload too large");
  }

  body = (uint8_t *)malloc(req->content_length);
  if (body == NULL) {
    return amduatd_send_json_error(fd, 500, "Internal Server Error", "oom");
  }
  if (!amduatd_read_exact(fd, body, req->content_length)) {
    free(body);
    return false;
  }

  p = (const char *)body;
  end = (const char *)body + req->content_length;
  if (!amduatd_json_expect(&p, end, '{')) {
    ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
    goto pel_programs_cleanup;
  }

  {
    bool have_nodes = false;
    bool have_roots = false;

    for (;;) {
      const char *key = NULL;
      size_t key_len = 0;
      const char *cur = NULL;

      cur = amduatd_json_skip_ws(p, end);
      if (cur < end && *cur == '}') {
        p = cur + 1;
        break;
      }

      if (!amduatd_json_parse_string_noesc(&p, end, &key, &key_len) ||
          !amduatd_json_expect(&p, end, ':')) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
        goto pel_programs_cleanup;
      }

      if (key_len == strlen("nodes") && memcmp(key, "nodes", key_len) == 0) {
        size_t cap = 0;
        if (have_nodes) {
          ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                      "duplicate nodes");
          goto pel_programs_cleanup;
        }
        if (!amduatd_json_expect(&p, end, '[')) {
          ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                      "invalid nodes");
          goto pel_programs_cleanup;
        }
        cur = amduatd_json_skip_ws(p, end);
        if (cur < end && *cur == ']') {
          p = cur + 1;
          have_nodes = true;
        } else {
          for (;;) {
            amduat_pel_node_t node;
            bool have_id = false;
            bool have_op = false;
            bool have_inputs = false;
            bool have_params_hex = false;
            amduat_octets_t op_name = amduat_octets(NULL, 0);
            uint32_t op_ver = 0;

            memset(&node, 0, sizeof(node));

            if (!amduatd_json_expect(&p, end, '{')) {
              ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                          "invalid node");
              goto pel_programs_cleanup;
            }
            for (;;) {
              const char *nk = NULL;
              size_t nk_len = 0;
              const char *sv = NULL;
              size_t sv_len = 0;

              cur = amduatd_json_skip_ws(p, end);
              if (cur < end && *cur == '}') {
                p = cur + 1;
                break;
              }
              if (!amduatd_json_parse_string_noesc(&p, end, &nk, &nk_len) ||
                  !amduatd_json_expect(&p, end, ':')) {
                ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                            "invalid node");
                goto pel_programs_cleanup;
              }

              if (nk_len == strlen("id") && memcmp(nk, "id", nk_len) == 0) {
                uint32_t id = 0;
                if (have_id || !amduatd_json_parse_u32(&p, end, &id)) {
                  ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                              "invalid node id");
                  goto pel_programs_cleanup;
                }
                node.id = (amduat_pel_node_id_t)id;
                have_id = true;
              } else if (nk_len == strlen("op") &&
                         memcmp(nk, "op", nk_len) == 0) {
                bool have_name = false;
                bool have_version = false;
                if (have_op || !amduatd_json_expect(&p, end, '{')) {
                  ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                              "invalid op");
                  goto pel_programs_cleanup;
                }
                for (;;) {
                  const char *okey = NULL;
                  size_t okey_len = 0;
                  cur = amduatd_json_skip_ws(p, end);
                  if (cur < end && *cur == '}') {
                    p = cur + 1;
                    break;
                  }
                  if (!amduatd_json_parse_string_noesc(&p, end, &okey,
                                                      &okey_len) ||
                      !amduatd_json_expect(&p, end, ':')) {
                    ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                                "invalid op");
                    goto pel_programs_cleanup;
                  }
                  if (okey_len == strlen("name") &&
                      memcmp(okey, "name", okey_len) == 0) {
                    if (have_name ||
                        !amduatd_json_parse_string_noesc(&p, end, &sv, &sv_len)) {
                      ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                                  "invalid op name");
                      goto pel_programs_cleanup;
                    }
                    op_name = amduat_octets(sv, sv_len);
                    have_name = true;
                  } else if (okey_len == strlen("version") &&
                             memcmp(okey, "version", okey_len) == 0) {
                    if (have_version ||
                        !amduatd_json_parse_u32(&p, end, &op_ver)) {
                      ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                                  "invalid op version");
                      goto pel_programs_cleanup;
                    }
                    have_version = true;
                  } else {
                    if (!amduatd_json_skip_value(&p, end, 0)) {
                      ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                                  "invalid op");
                      goto pel_programs_cleanup;
                    }
                  }
                  cur = amduatd_json_skip_ws(p, end);
                  if (cur < end && *cur == ',') {
                    p = cur + 1;
                    continue;
                  }
                  if (cur < end && *cur == '}') {
                    p = cur + 1;
                    break;
                  }
                  ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                              "invalid op");
                  goto pel_programs_cleanup;
                }
                if (!have_name || !have_version) {
                  ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                              "missing op fields");
                  goto pel_programs_cleanup;
                }
                node.op.name = op_name;
                node.op.version = op_ver;
                have_op = true;
              } else if (nk_len == strlen("inputs") &&
                         memcmp(nk, "inputs", nk_len) == 0) {
                size_t icap = 0;
                if (have_inputs || !amduatd_json_expect(&p, end, '[')) {
                  ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                              "invalid inputs");
                  goto pel_programs_cleanup;
                }
                cur = amduatd_json_skip_ws(p, end);
                if (cur < end && *cur == ']') {
                  p = cur + 1;
                  have_inputs = true;
                } else {
                  for (;;) {
                    amduat_pel_dag_input_t in;
                    memset(&in, 0, sizeof(in));
                    if (!amduatd_json_expect(&p, end, '{')) {
                      ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                                  "invalid input");
                      goto pel_programs_cleanup;
                    }
                    {
                      const char *ik = NULL;
                      size_t ik_len = 0;
                      if (!amduatd_json_parse_string_noesc(&p, end, &ik,
                                                          &ik_len) ||
                          !amduatd_json_expect(&p, end, ':') ||
                          !amduatd_json_expect(&p, end, '{')) {
                        ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                                    "invalid input");
                        goto pel_programs_cleanup;
                      }
                      if (ik_len == strlen("external") &&
                          memcmp(ik, "external", ik_len) == 0) {
                        uint32_t idx = 0;
                        const char *k2 = NULL;
                        size_t k2_len = 0;
                        if (!amduatd_json_parse_string_noesc(&p, end, &k2,
                                                            &k2_len) ||
                            k2_len != strlen("input_index") ||
                            memcmp(k2, "input_index", k2_len) != 0 ||
                            !amduatd_json_expect(&p, end, ':') ||
                            !amduatd_json_parse_u32(&p, end, &idx) ||
                            !amduatd_json_expect(&p, end, '}')) {
                          ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                                      "invalid external input");
                          goto pel_programs_cleanup;
                        }
                        in.kind = AMDUAT_PEL_DAG_INPUT_EXTERNAL;
                        in.value.external.input_index = idx;
                      } else if (ik_len == strlen("node") &&
                                 memcmp(ik, "node", ik_len) == 0) {
                        bool have_node_id = false;
                        bool have_output_index = false;
                        uint32_t nid = 0;
                        uint32_t oidx = 0;
                        for (;;) {
                          const char *k2 = NULL;
                          size_t k2_len = 0;
                          cur = amduatd_json_skip_ws(p, end);
                          if (cur < end && *cur == '}') {
                            p = cur + 1;
                            break;
                          }
                          if (!amduatd_json_parse_string_noesc(&p, end, &k2,
                                                              &k2_len) ||
                              !amduatd_json_expect(&p, end, ':')) {
                            ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                                        "invalid node input");
                            goto pel_programs_cleanup;
                          }
                          if (k2_len == strlen("node_id") &&
                              memcmp(k2, "node_id", k2_len) == 0) {
                            if (have_node_id ||
                                !amduatd_json_parse_u32(&p, end, &nid)) {
                              ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                                          "invalid node_id");
                              goto pel_programs_cleanup;
                            }
                            have_node_id = true;
                          } else if (k2_len == strlen("output_index") &&
                                     memcmp(k2, "output_index", k2_len) == 0) {
                            if (have_output_index ||
                                !amduatd_json_parse_u32(&p, end, &oidx)) {
                              ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                                          "invalid output_index");
                              goto pel_programs_cleanup;
                            }
                            have_output_index = true;
                          } else {
                            if (!amduatd_json_skip_value(&p, end, 0)) {
                              ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                                          "invalid node input");
                              goto pel_programs_cleanup;
                            }
                          }
                          cur = amduatd_json_skip_ws(p, end);
                          if (cur < end && *cur == ',') {
                            p = cur + 1;
                            continue;
                          }
                          if (cur < end && *cur == '}') {
                            p = cur + 1;
                            break;
                          }
                          ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                                      "invalid node input");
                          goto pel_programs_cleanup;
                        }
                        if (!have_node_id || !have_output_index) {
                          ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                                      "missing node input fields");
                          goto pel_programs_cleanup;
                        }
                        in.kind = AMDUAT_PEL_DAG_INPUT_NODE;
                        in.value.node.node_id = (amduat_pel_node_id_t)nid;
                        in.value.node.output_index = oidx;
                      } else {
                        ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                                    "invalid input kind");
                        goto pel_programs_cleanup;
                      }
                      if (!amduatd_json_expect(&p, end, '}')) {
                        ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                                    "invalid input");
                        goto pel_programs_cleanup;
                      }
                    }

                    if (node.inputs_len == icap) {
                      size_t next_cap = icap != 0 ? icap * 2u : 4u;
                      amduat_pel_dag_input_t *next =
                          (amduat_pel_dag_input_t *)realloc(
                              node.inputs, next_cap * sizeof(*node.inputs));
                      if (next == NULL) {
                        ok = amduatd_send_json_error(fd, 500,
                                                    "Internal Server Error",
                                                    "oom");
                        goto pel_programs_cleanup;
                      }
                      node.inputs = next;
                      icap = next_cap;
                    }
                    node.inputs[node.inputs_len++] = in;

                    cur = amduatd_json_skip_ws(p, end);
                    if (cur < end && *cur == ',') {
                      p = cur + 1;
                      continue;
                    }
                    if (cur < end && *cur == ']') {
                      p = cur + 1;
                      have_inputs = true;
                      break;
                    }
                    ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                                "invalid inputs");
                    goto pel_programs_cleanup;
                  }
                }
              } else if (nk_len == strlen("params_hex") &&
                         memcmp(nk, "params_hex", nk_len) == 0) {
                if (have_params_hex ||
                    !amduatd_json_parse_string_noesc(&p, end, &sv, &sv_len) ||
                    !amduatd_parse_params_hex(sv, sv_len, &node.params)) {
                  ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                              "invalid params_hex");
                  goto pel_programs_cleanup;
                }
                have_params_hex = true;
              } else {
                if (!amduatd_json_skip_value(&p, end, 0)) {
                  ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                              "invalid node");
                  goto pel_programs_cleanup;
                }
              }

              cur = amduatd_json_skip_ws(p, end);
              if (cur < end && *cur == ',') {
                p = cur + 1;
                continue;
              }
              if (cur < end && *cur == '}') {
                p = cur + 1;
                break;
              }
            }

            if (!have_id || !have_op || !have_inputs || !have_params_hex) {
              free(node.inputs);
              free((void *)node.params.data);
              ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                          "missing node fields");
              goto pel_programs_cleanup;
            }
            if (amduat_pel_kernel_op_lookup(node.op.name, node.op.version) ==
                NULL) {
              free(node.inputs);
              free((void *)node.params.data);
              ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                          "unknown op");
              goto pel_programs_cleanup;
            }

            if (tmp.nodes_len == cap) {
              size_t next_cap = cap != 0 ? cap * 2u : 4u;
              amduat_pel_node_t *next =
                  (amduat_pel_node_t *)realloc(tmp.nodes,
                                               next_cap * sizeof(*tmp.nodes));
              if (next == NULL) {
                free(node.inputs);
                free((void *)node.params.data);
                ok = amduatd_send_json_error(fd, 500, "Internal Server Error",
                                            "oom");
                goto pel_programs_cleanup;
              }
              tmp.nodes = next;
              cap = next_cap;
            }
            tmp.nodes[tmp.nodes_len++] = node;

            cur = amduatd_json_skip_ws(p, end);
            if (cur < end && *cur == ',') {
              p = cur + 1;
              continue;
            }
            if (cur < end && *cur == ']') {
              p = cur + 1;
              have_nodes = true;
              break;
            }
            ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                        "invalid nodes");
            goto pel_programs_cleanup;
          }
        }
      } else if (key_len == strlen("roots") &&
                 memcmp(key, "roots", key_len) == 0) {
        size_t cap = 0;
        if (have_roots) {
          ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                      "duplicate roots");
          goto pel_programs_cleanup;
        }
        if (!amduatd_json_expect(&p, end, '[')) {
          ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                      "invalid roots");
          goto pel_programs_cleanup;
        }
        cur = amduatd_json_skip_ws(p, end);
        if (cur < end && *cur == ']') {
          p = cur + 1;
          have_roots = true;
        } else {
          for (;;) {
            amduat_pel_root_ref_t root;
            bool have_node_id = false;
            bool have_output_index = false;

            memset(&root, 0, sizeof(root));
            if (!amduatd_json_expect(&p, end, '{')) {
              ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                          "invalid root");
              goto pel_programs_cleanup;
            }
            for (;;) {
              const char *rk = NULL;
              size_t rk_len = 0;
              uint32_t v = 0;

              cur = amduatd_json_skip_ws(p, end);
              if (cur < end && *cur == '}') {
                p = cur + 1;
                break;
              }
              if (!amduatd_json_parse_string_noesc(&p, end, &rk, &rk_len) ||
                  !amduatd_json_expect(&p, end, ':')) {
                ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                            "invalid root");
                goto pel_programs_cleanup;
              }
              if (rk_len == strlen("node_id") &&
                  memcmp(rk, "node_id", rk_len) == 0) {
                if (have_node_id || !amduatd_json_parse_u32(&p, end, &v)) {
                  ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                              "invalid root node_id");
                  goto pel_programs_cleanup;
                }
                root.node_id = (amduat_pel_node_id_t)v;
                have_node_id = true;
              } else if (rk_len == strlen("output_index") &&
                         memcmp(rk, "output_index", rk_len) == 0) {
                if (have_output_index || !amduatd_json_parse_u32(&p, end, &v)) {
                  ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                              "invalid root output_index");
                  goto pel_programs_cleanup;
                }
                root.output_index = v;
                have_output_index = true;
              } else {
                if (!amduatd_json_skip_value(&p, end, 0)) {
                  ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                              "invalid root");
                  goto pel_programs_cleanup;
                }
              }

              cur = amduatd_json_skip_ws(p, end);
              if (cur < end && *cur == ',') {
                p = cur + 1;
                continue;
              }
              if (cur < end && *cur == '}') {
                p = cur + 1;
                break;
              }
              ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                          "invalid root");
              goto pel_programs_cleanup;
            }
            if (!have_node_id || !have_output_index) {
              ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                          "missing root fields");
              goto pel_programs_cleanup;
            }
            if (tmp.roots_len == cap) {
              size_t next_cap = cap != 0 ? cap * 2u : 2u;
              amduat_pel_root_ref_t *next =
                  (amduat_pel_root_ref_t *)realloc(
                      tmp.roots, next_cap * sizeof(*tmp.roots));
              if (next == NULL) {
                ok = amduatd_send_json_error(fd, 500, "Internal Server Error",
                                            "oom");
                goto pel_programs_cleanup;
              }
              tmp.roots = next;
              cap = next_cap;
            }
            tmp.roots[tmp.roots_len++] = root;

            cur = amduatd_json_skip_ws(p, end);
            if (cur < end && *cur == ',') {
              p = cur + 1;
              continue;
            }
            if (cur < end && *cur == ']') {
              p = cur + 1;
              have_roots = true;
              break;
            }
            ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                        "invalid roots");
            goto pel_programs_cleanup;
          }
        }
      } else {
        if (!amduatd_json_skip_value(&p, end, 0)) {
          ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
          goto pel_programs_cleanup;
        }
      }

      cur = amduatd_json_skip_ws(p, end);
      if (cur < end && *cur == ',') {
        p = cur + 1;
        continue;
      }
      if (cur < end && *cur == '}') {
        p = cur + 1;
        break;
      }
      ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
      goto pel_programs_cleanup;
    }

    p = amduatd_json_skip_ws(p, end);
    if (p != end) {
      ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
      goto pel_programs_cleanup;
    }
    if (!have_nodes || !have_roots) {
      ok = amduatd_send_json_error(fd, 400, "Bad Request",
                                  "missing nodes/roots");
      goto pel_programs_cleanup;
    }
  }

  program.nodes = tmp.nodes;
  program.nodes_len = tmp.nodes_len;
  program.roots = tmp.roots;
  program.roots_len = tmp.roots_len;
  if (!amduat_pel_program_dag_validate(&program)) {
    ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid program");
    goto pel_programs_cleanup;
  }

  if (!amduat_enc_pel_program_dag_encode_v1(&program, &program_bytes)) {
    ok = amduatd_send_json_error(fd, 500, "Internal Server Error",
                                "encode error");
    goto pel_programs_cleanup;
  }

  artifact = amduat_artifact_with_type(program_bytes,
                                       amduat_type_tag(AMDUAT_PEL_TYPE_TAG_PROGRAM_DAG_1));
  if (amduat_asl_store_put(store, artifact, &program_ref) != AMDUAT_ASL_STORE_OK) {
    ok = amduatd_send_json_error(fd, 500, "Internal Server Error",
                                "store error");
    goto pel_programs_cleanup;
  }

  if (!amduat_asl_ref_encode_hex(program_ref, &ref_hex)) {
    ok = amduatd_send_json_error(fd, 500, "Internal Server Error",
                                "encode ref error");
    goto pel_programs_cleanup;
  }
  {
    int n = snprintf(json, sizeof(json), "{\"program_ref\":\"%s\"}\n", ref_hex);
    free(ref_hex);
    if (n <= 0 || (size_t)n >= sizeof(json)) {
      ok = amduatd_send_json_error(fd, 500, "Internal Server Error", "error");
      goto pel_programs_cleanup;
    }
    ok = amduatd_http_send_json(fd, 200, "OK", json, false);
    goto pel_programs_cleanup;
  }

pel_programs_cleanup:
  free(body);
  free((void *)program_bytes.data);
  amduat_reference_free(&program_ref);
  amduatd_pel_program_tmp_free(&tmp);
  return ok;
}

static bool amduatd_handle_get_ui(int fd) {
  return amduatd_http_send_status(fd,
                                 200,
                                 "OK",
                                 "text/html; charset=utf-8",
                                 (const uint8_t *)k_amduatd_ui_html,
                                 strlen(k_amduatd_ui_html),
                                 false);
}

static bool amduatd_handle_post_concepts(int fd,
                                        amduat_asl_store_t *store,
                                        const amduat_asl_store_fs_config_t *cfg,
                                        amduatd_concepts_t *concepts,
                                        const amduatd_http_req_t *req) {
  uint8_t *body = NULL;
  const char *p = NULL;
  const char *end = NULL;
  char *name = NULL;
  bool have_name = false;
  bool have_ref = false;
  amduat_reference_t target_ref;
  amduat_reference_t name_ref;
  amduat_reference_t concept_ref;
  amduat_reference_t edge_ref;
  char *concept_hex = NULL;
  char json[4096];
  bool ok = false;

  memset(&target_ref, 0, sizeof(target_ref));
  memset(&name_ref, 0, sizeof(name_ref));
  memset(&concept_ref, 0, sizeof(concept_ref));
  memset(&edge_ref, 0, sizeof(edge_ref));

  if (store == NULL || cfg == NULL || concepts == NULL || req == NULL) {
    return amduatd_send_json_error(fd, 500, "Internal Server Error",
                                  "internal error");
  }
  if (req->content_length == 0) {
    return amduatd_send_json_error(fd, 400, "Bad Request", "missing body");
  }
  if (req->content_length > (256u * 1024u)) {
    return amduatd_send_json_error(fd, 413, "Payload Too Large",
                                  "payload too large");
  }
  body = (uint8_t *)malloc(req->content_length);
  if (body == NULL) {
    return amduatd_send_json_error(fd, 500, "Internal Server Error", "oom");
  }
  if (!amduatd_read_exact(fd, body, req->content_length)) {
    free(body);
    return false;
  }
  p = (const char *)body;
  end = (const char *)body + req->content_length;
  if (!amduatd_json_expect(&p, end, '{')) {
    ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
    goto concepts_cleanup;
  }

  for (;;) {
    const char *key = NULL;
    size_t key_len = 0;
    const char *sv = NULL;
    size_t sv_len = 0;
    const char *cur = NULL;

    cur = amduatd_json_skip_ws(p, end);
    if (cur < end && *cur == '}') {
      p = cur + 1;
      break;
    }
    if (!amduatd_json_parse_string_noesc(&p, end, &key, &key_len) ||
        !amduatd_json_expect(&p, end, ':')) {
      ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
      goto concepts_cleanup;
    }

    if (key_len == strlen("name") && memcmp(key, "name", key_len) == 0) {
      if (have_name || !amduatd_json_parse_string_noesc(&p, end, &sv, &sv_len) ||
          !amduatd_copy_json_str(sv, sv_len, &name)) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid name");
        goto concepts_cleanup;
      }
      if (!amduatd_name_valid(name)) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid name");
        goto concepts_cleanup;
      }
      have_name = true;
    } else if (key_len == strlen("ref") && memcmp(key, "ref", key_len) == 0) {
      if (have_ref || !amduatd_json_parse_string_noesc(&p, end, &sv, &sv_len) ||
          !amduatd_decode_ref_hex_str(sv, sv_len, &target_ref)) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid ref");
        goto concepts_cleanup;
      }
      have_ref = true;
    } else {
      if (!amduatd_json_skip_value(&p, end, 0)) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
        goto concepts_cleanup;
      }
    }

    cur = amduatd_json_skip_ws(p, end);
    if (cur < end && *cur == ',') {
      p = cur + 1;
      continue;
    }
    if (cur < end && *cur == '}') {
      p = cur + 1;
      break;
    }
    ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
    goto concepts_cleanup;
  }

  if (!have_name) {
    ok = amduatd_send_json_error(fd, 400, "Bad Request", "missing name");
    goto concepts_cleanup;
  }

  if (!amduatd_concepts_put_name_artifact(store, name, &name_ref)) {
    ok = amduatd_send_json_error(fd, 500, "Internal Server Error",
                                "store error");
    goto concepts_cleanup;
  }

  {
    amduat_reference_t existing;
    memset(&existing, 0, sizeof(existing));
    if (amduatd_concepts_lookup_alias(store, cfg, concepts, name, &existing)) {
      amduat_reference_free(&existing);
      ok = amduatd_send_json_error(fd, 409, "Conflict", "name exists");
      goto concepts_cleanup;
    }
  }

  if (!amduatd_concepts_put_concept_id(store, cfg, &concept_ref)) {
    ok = amduatd_send_json_error(fd, 500, "Internal Server Error",
                                "store error");
    goto concepts_cleanup;
  }

  if (!amduatd_concepts_put_edge(store,
                                concepts,
                                name_ref,
                                concept_ref,
                                concepts->rel_aliases_ref,
                                &edge_ref)) {
    ok = amduatd_send_json_error(fd, 500, "Internal Server Error",
                                "store error");
    goto concepts_cleanup;
  }

  if (have_ref) {
    if (!amduatd_concepts_put_edge(store,
                                  concepts,
                                  concept_ref,
                                  target_ref,
                                  concepts->rel_materializes_ref,
                                  &edge_ref)) {
      ok = amduatd_send_json_error(fd, 500, "Internal Server Error",
                                  "store error");
      goto concepts_cleanup;
    }
  }

  if (!amduat_asl_ref_encode_hex(concept_ref, &concept_hex)) {
    ok = amduatd_send_json_error(fd, 500, "Internal Server Error",
                                "encode error");
    goto concepts_cleanup;
  }

  {
    int n = snprintf(json,
                     sizeof(json),
                     "{"
                     "\"name\":\"%s\","
                     "\"concept_ref\":\"%s\""
                     "}\n",
                     name,
                     concept_hex);
    free(concept_hex);
    if (n <= 0 || (size_t)n >= sizeof(json)) {
      ok = amduatd_send_json_error(fd, 500, "Internal Server Error", "error");
      goto concepts_cleanup;
    }
    ok = amduatd_http_send_json(fd, 200, "OK", json, false);
  }

concepts_cleanup:
  free(body);
  free(name);
  amduat_reference_free(&target_ref);
  amduat_reference_free(&name_ref);
  amduat_reference_free(&concept_ref);
  amduat_reference_free(&edge_ref);
  return ok;
}

static bool amduatd_path_extract_name(const char *path,
                                     const char *prefix,
                                     char *out,
                                     size_t cap) {
  size_t plen;
  const char *p;
  size_t len;

  if (out != NULL && cap != 0) {
    out[0] = '\0';
  }
  if (path == NULL || prefix == NULL || out == NULL || cap == 0) {
    return false;
  }
  plen = strlen(prefix);
  if (strncmp(path, prefix, plen) != 0) {
    return false;
  }
  p = path + plen;
  if (*p == '\0') {
    return false;
  }
  len = strlen(p);
  if (len >= cap) {
    len = cap - 1;
  }
  memcpy(out, p, len);
  out[len] = '\0';
  return true;
}

static bool amduatd_handle_post_concept_publish(int fd,
                                                amduat_asl_store_t *store,
                                                const amduat_asl_store_fs_config_t *cfg,
                                                amduatd_concepts_t *concepts,
                                                const char *name,
                                                const amduatd_http_req_t *req) {
  uint8_t *body = NULL;
  const char *p = NULL;
  const char *end = NULL;
  amduat_reference_t target_ref;
  amduat_reference_t concept_ref;
  amduat_reference_t edge_ref;
  bool have_ref = false;
  bool ok = false;

  memset(&target_ref, 0, sizeof(target_ref));
  memset(&concept_ref, 0, sizeof(concept_ref));
  memset(&edge_ref, 0, sizeof(edge_ref));

  if (store == NULL || cfg == NULL || concepts == NULL || name == NULL ||
      req == NULL) {
    return amduatd_send_json_error(fd, 500, "Internal Server Error",
                                  "internal error");
  }
  if (!amduatd_name_valid(name)) {
    return amduatd_send_json_error(fd, 400, "Bad Request", "invalid name");
  }
  if (req->content_length == 0) {
    return amduatd_send_json_error(fd, 400, "Bad Request", "missing body");
  }
  if (req->content_length > (256u * 1024u)) {
    return amduatd_send_json_error(fd, 413, "Payload Too Large",
                                  "payload too large");
  }

  if (!amduatd_concepts_lookup_alias(store, cfg, concepts, name, &concept_ref)) {
    return amduatd_send_json_error(fd, 404, "Not Found", "unknown concept");
  }

  body = (uint8_t *)malloc(req->content_length);
  if (body == NULL) {
    ok = amduatd_send_json_error(fd, 500, "Internal Server Error", "oom");
    goto publish_cleanup;
  }
  if (!amduatd_read_exact(fd, body, req->content_length)) {
    free(body);
    amduat_reference_free(&concept_ref);
    return false;
  }

  p = (const char *)body;
  end = (const char *)body + req->content_length;
  if (!amduatd_json_expect(&p, end, '{')) {
    ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
    goto publish_cleanup;
  }
  for (;;) {
    const char *key = NULL;
    size_t key_len = 0;
    const char *sv = NULL;
    size_t sv_len = 0;
    const char *cur = NULL;

    cur = amduatd_json_skip_ws(p, end);
    if (cur < end && *cur == '}') {
      p = cur + 1;
      break;
    }
    if (!amduatd_json_parse_string_noesc(&p, end, &key, &key_len) ||
        !amduatd_json_expect(&p, end, ':')) {
      ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
      goto publish_cleanup;
    }
    if (key_len == strlen("ref") && memcmp(key, "ref", key_len) == 0) {
      if (have_ref || !amduatd_json_parse_string_noesc(&p, end, &sv, &sv_len) ||
          !amduatd_decode_ref_hex_str(sv, sv_len, &target_ref)) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid ref");
        goto publish_cleanup;
      }
      have_ref = true;
    } else {
      if (!amduatd_json_skip_value(&p, end, 0)) {
        ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
        goto publish_cleanup;
      }
    }
    cur = amduatd_json_skip_ws(p, end);
    if (cur < end && *cur == ',') {
      p = cur + 1;
      continue;
    }
    if (cur < end && *cur == '}') {
      p = cur + 1;
      break;
    }
    ok = amduatd_send_json_error(fd, 400, "Bad Request", "invalid json");
    goto publish_cleanup;
  }
  if (!have_ref) {
    ok = amduatd_send_json_error(fd, 400, "Bad Request", "missing ref");
    goto publish_cleanup;
  }

  if (!amduatd_concepts_put_edge(store,
                                concepts,
                                concept_ref,
                                target_ref,
                                concepts->rel_materializes_ref,
                                &edge_ref)) {
    ok = amduatd_send_json_error(fd, 500, "Internal Server Error",
                                "store error");
    goto publish_cleanup;
  }

  ok = amduatd_http_send_json(fd, 200, "OK", "{\"ok\":true}\n", false);

publish_cleanup:
  free(body);
  amduat_reference_free(&target_ref);
  amduat_reference_free(&concept_ref);
  amduat_reference_free(&edge_ref);
  return ok;
}

static bool amduatd_handle_get_resolve(int fd,
                                      amduat_asl_store_t *store,
                                      const amduat_asl_store_fs_config_t *cfg,
                                      const amduatd_concepts_t *concepts,
                                      const char *name) {
  amduat_reference_t concept_ref;
  amduat_reference_t latest_ref;
  char *hex = NULL;
  char json[2048];
  int n;

  memset(&concept_ref, 0, sizeof(concept_ref));
  memset(&latest_ref, 0, sizeof(latest_ref));

  if (store == NULL || cfg == NULL || concepts == NULL || name == NULL) {
    return amduatd_send_json_error(fd, 500, "Internal Server Error",
                                  "internal error");
  }
  if (!amduatd_name_valid(name)) {
    return amduatd_send_json_error(fd, 400, "Bad Request", "invalid name");
  }
  if (!amduatd_concepts_lookup_alias(store, cfg, concepts, name, &concept_ref)) {
    return amduatd_send_json_error(fd, 404, "Not Found", "unknown concept");
  }
  if (!amduatd_concepts_resolve_latest(store, concepts, concept_ref,
                                      &latest_ref)) {
    amduat_reference_free(&concept_ref);
    return amduatd_send_json_error(fd, 404, "Not Found", "no versions");
  }
  amduat_reference_free(&concept_ref);

  if (!amduat_asl_ref_encode_hex(latest_ref, &hex)) {
    amduat_reference_free(&latest_ref);
    return amduatd_send_json_error(fd, 500, "Internal Server Error",
                                  "encode error");
  }
  amduat_reference_free(&latest_ref);
  n = snprintf(json, sizeof(json), "{\"ref\":\"%s\"}\n", hex);
  free(hex);
  if (n <= 0 || (size_t)n >= sizeof(json)) {
    return amduatd_send_json_error(fd, 500, "Internal Server Error", "error");
  }
  return amduatd_http_send_json(fd, 200, "OK", json, false);
}

static bool amduatd_handle_conn(int fd,
                                amduat_asl_store_t *store,
                                const amduat_asl_store_fs_config_t *cfg,
                                amduat_reference_t api_contract_ref,
                                amduatd_concepts_t *concepts) {
  amduatd_http_req_t req;
  char no_query[1024];

  if (!amduatd_http_parse_request(fd, &req)) {
    return false;
  }

  amduatd_path_without_query(req.path, no_query, sizeof(no_query));

  if (strcmp(req.method, "GET") == 0 && strcmp(no_query, "/v1/ui") == 0) {
    return amduatd_handle_get_ui(fd);
  }

  if (strcmp(req.method, "GET") == 0 && strcmp(no_query, "/v1/meta") == 0) {
    return amduatd_handle_meta(fd, cfg, api_contract_ref, false);
  }
  if (strcmp(req.method, "HEAD") == 0 && strcmp(no_query, "/v1/meta") == 0) {
    return amduatd_handle_meta(fd, cfg, api_contract_ref, true);
  }
  if (strcmp(req.method, "GET") == 0 && strcmp(no_query, "/v1/contract") == 0) {
    return amduatd_handle_get_contract(fd, store, &req, api_contract_ref);
  }

  if (strcmp(req.method, "POST") == 0 && strcmp(no_query, "/v1/artifacts") == 0) {
    return amduatd_handle_post_artifacts(fd, store, &req);
  }
  if (strcmp(req.method, "POST") == 0 && strcmp(no_query, "/v1/pel/run") == 0) {
    return amduatd_handle_post_pel_run(fd, store, cfg, concepts, &req);
  }
  if (strcmp(req.method, "POST") == 0 &&
      strcmp(no_query, "/v1/pel/programs") == 0) {
    return amduatd_handle_post_pel_programs(fd, store, &req);
  }
  if (strcmp(req.method, "POST") == 0 && strcmp(no_query, "/v1/concepts") == 0) {
    return amduatd_handle_post_concepts(fd, store, cfg, concepts, &req);
  }
  if (strcmp(req.method, "GET") == 0 && strcmp(no_query, "/v1/concepts") == 0) {
    return amduatd_handle_get_concepts(fd, store, concepts);
  }
  if (strcmp(req.method, "GET") == 0 && strncmp(no_query, "/v1/concepts/", 13) == 0) {
    const char *name = no_query + 13;
    if (name[0] == '\0') {
      return amduatd_send_json_error(fd, 400, "Bad Request", "missing name");
    }
    return amduatd_handle_get_concept(fd, store, cfg, concepts, name);
  }
  if (strcmp(req.method, "POST") == 0 &&
      strncmp(no_query, "/v1/concepts/", 13) == 0 &&
      strstr(no_query, "/publish") != NULL) {
    char name[256];
    char *slash;
    if (!amduatd_path_extract_name(no_query, "/v1/concepts/", name,
                                  sizeof(name))) {
      return amduatd_send_json_error(fd, 400, "Bad Request", "invalid path");
    }
    slash = strstr(name, "/publish");
    if (slash == NULL || strcmp(slash, "/publish") != 0) {
      return amduatd_send_json_error(fd, 400, "Bad Request", "invalid path");
    }
    *slash = '\0';
    return amduatd_handle_post_concept_publish(fd, store, cfg, concepts, name,
                                               &req);
  }
  if (strcmp(req.method, "GET") == 0 && strncmp(no_query, "/v1/resolve/", 12) == 0) {
    const char *name = no_query + 12;
    if (name[0] == '\0') {
      return amduatd_send_json_error(fd, 400, "Bad Request", "missing name");
    }
    return amduatd_handle_get_resolve(fd, store, cfg, concepts, name);
  }
  if (strcmp(req.method, "GET") == 0 &&
      strncmp(no_query, "/v1/artifacts/", 14) == 0) {
    return amduatd_handle_get_artifact(fd, store, &req, req.path, false);
  }
  if (strcmp(req.method, "HEAD") == 0 &&
      strncmp(no_query, "/v1/artifacts/", 14) == 0) {
    return amduatd_handle_head_artifact(fd, store, &req, req.path);
  }

  return amduatd_http_send_not_found(fd, &req);
}

static void amduatd_print_usage(FILE *stream) {
  fprintf(stream,
          "usage:\n"
          "  amduatd [--root PATH] [--sock PATH]\n"
          "\n"
          "defaults:\n"
          "  --root %s\n"
          "  --sock %s\n",
          AMDUATD_DEFAULT_ROOT,
          AMDUATD_DEFAULT_SOCK);
}

int main(int argc, char **argv) {
  const char *root = AMDUATD_DEFAULT_ROOT;
  const char *sock_path = AMDUATD_DEFAULT_SOCK;
  amduat_asl_store_fs_config_t cfg;
  amduat_asl_store_fs_t fs;
  amduat_asl_store_t store;
  amduat_reference_t api_contract_ref;
  amduatd_concepts_t concepts;
  int i;
  int sfd = -1;

  memset(&api_contract_ref, 0, sizeof(api_contract_ref));
  memset(&concepts, 0, sizeof(concepts));

  for (i = 1; i < argc; ++i) {
    if (strcmp(argv[i], "--root") == 0) {
      if (i + 1 >= argc) {
        fprintf(stderr, "error: --root requires a path\n");
        return 2;
      }
      root = argv[++i];
    } else if (strcmp(argv[i], "--sock") == 0) {
      if (i + 1 >= argc) {
        fprintf(stderr, "error: --sock requires a path\n");
        return 2;
      }
      sock_path = argv[++i];
    } else if (strcmp(argv[i], "--help") == 0 || strcmp(argv[i], "-h") == 0) {
      amduatd_print_usage(stdout);
      return 0;
    } else {
      fprintf(stderr, "error: unknown option: %s\n", argv[i]);
      return 2;
    }
  }

  memset(&cfg, 0, sizeof(cfg));
  if (!amduat_asl_store_fs_load_config(root, &cfg)) {
    fprintf(stderr, "error: failed to load store config: %s\n", root);
    return 8;
  }

  memset(&fs, 0, sizeof(fs));
  if (!amduat_asl_store_fs_init(&fs, cfg.config, root)) {
    fprintf(stderr, "error: failed to initialize store: %s\n", root);
    return 8;
  }
  amduat_asl_store_init(&store, cfg.config, amduat_asl_store_fs_ops(), &fs);

  if (!amduatd_seed_api_contract(&store, &cfg, &api_contract_ref)) {
    fprintf(stderr, "error: failed to seed api contract\n");
    return 8;
  }
  if (!amduatd_concepts_init(&concepts, &store, &cfg, root)) {
    fprintf(stderr, "error: failed to init concept edges\n");
    return 8;
  }

  signal(SIGINT, amduatd_on_signal);
  signal(SIGTERM, amduatd_on_signal);

  sfd = socket(AF_UNIX, SOCK_STREAM, 0);
  if (sfd < 0) {
    perror("socket");
    return 8;
  }

  {
    struct sockaddr_un addr;
    memset(&addr, 0, sizeof(addr));
    addr.sun_family = AF_UNIX;
    if (strlen(sock_path) >= sizeof(addr.sun_path)) {
      fprintf(stderr, "error: socket path too long\n");
      close(sfd);
      return 2;
    }
    strncpy(addr.sun_path, sock_path, sizeof(addr.sun_path) - 1);

    (void)unlink(sock_path);

    if (bind(sfd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
      perror("bind");
      close(sfd);
      return 8;
    }
    (void)chmod(sock_path, 0660);

    if (listen(sfd, 16) < 0) {
      perror("listen");
      (void)unlink(sock_path);
      close(sfd);
      return 8;
    }
  }

  fprintf(stderr, "amduatd: root=%s sock=%s\n", root, sock_path);

  while (!amduatd_should_exit) {
    int cfd = accept(sfd, NULL, NULL);
    if (cfd < 0) {
      if (errno == EINTR) {
        continue;
      }
      perror("accept");
      break;
    }

    (void)amduatd_handle_conn(cfd, &store, &cfg, api_contract_ref, &concepts);
    (void)close(cfd);
  }

  amduat_reference_free(&api_contract_ref);
  amduatd_concepts_free(&concepts);
  (void)unlink(sock_path);
  (void)close(sfd);
  return 0;
}