#include "amduatd_fed_push_plan.h"

#include "amduat/asl/log_store.h"
#include "amduat/asl/artifact_io.h"
#include "amduat/asl/ref_text.h"
#include "amduat/asl/store.h"
#include "amduat/enc/fer1_receipt.h"
#include "amduat/enc/tgk1_edge.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef struct {
  char *data;
  size_t len;
  size_t cap;
} amduatd_fed_push_plan_strbuf_t;

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

static bool amduatd_fed_push_plan_strbuf_reserve(
    amduatd_fed_push_plan_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_fed_push_plan_strbuf_append(
    amduatd_fed_push_plan_strbuf_t *b,
    const char *s,
    size_t n) {
  if (b == NULL) {
    return false;
  }
  if (n == 0u) {
    return true;
  }
  if (s == NULL) {
    return false;
  }
  if (!amduatd_fed_push_plan_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_fed_push_plan_strbuf_append_cstr(
    amduatd_fed_push_plan_strbuf_t *b,
    const char *s) {
  return amduatd_fed_push_plan_strbuf_append(
      b, s != NULL ? s : "", s != NULL ? strlen(s) : 0u);
}

static const char *amduatd_fed_push_plan_record_type_name(
    amduat_fed_record_type_t type) {
  switch (type) {
    case AMDUAT_FED_REC_ARTIFACT:
      return "artifact";
    case AMDUAT_FED_REC_PER:
      return "per";
    case AMDUAT_FED_REC_TGK_EDGE:
      return "tgk_edge";
    case AMDUAT_FED_REC_TOMBSTONE:
      return "tombstone";
    default:
      return "unknown";
  }
}

void amduatd_fed_push_plan_candidate_init(
    amduatd_fed_push_cursor_candidate_t *candidate) {
  if (candidate == NULL) {
    return;
  }
  memset(candidate, 0, sizeof(*candidate));
  candidate->ref = amduat_reference(0u, amduat_octets(NULL, 0u));
}

void amduatd_fed_push_plan_candidate_free(
    amduatd_fed_push_cursor_candidate_t *candidate) {
  if (candidate == NULL) {
    return;
  }
  if (candidate->has_ref) {
    amduat_reference_free(&candidate->ref);
  }
  memset(candidate, 0, sizeof(*candidate));
}

bool amduatd_fed_push_plan_next_cursor_candidate(
    const amduatd_fed_cursor_record_t *cursor,
    const amduat_fed_record_t *records,
    size_t record_count,
    amduatd_fed_push_cursor_candidate_t *out_candidate) {
  if (out_candidate == NULL) {
    return false;
  }
  amduatd_fed_push_plan_candidate_init(out_candidate);

  if (record_count > 0u && records != NULL) {
    const amduat_fed_record_t *last = &records[record_count - 1u];
    out_candidate->has_logseq = true;
    out_candidate->logseq = last->logseq;
    out_candidate->has_ref = true;
    if (!amduat_reference_clone(last->id.ref, &out_candidate->ref)) {
      amduatd_fed_push_plan_candidate_free(out_candidate);
      return false;
    }
    return true;
  }
  (void)cursor;
  return true;
}

amduatd_fed_push_plan_status_t amduatd_fed_push_plan_check(
    const amduatd_fed_cfg_t *cfg,
    const amduat_asl_store_t *store) {
  if (cfg == NULL || store == NULL) {
    return AMDUATD_FED_PUSH_PLAN_ERR_INVALID;
  }
  if (!cfg->enabled) {
    return AMDUATD_FED_PUSH_PLAN_ERR_DISABLED;
  }
  if (store->ops.log_scan == NULL || store->ops.current_state == NULL) {
    return AMDUATD_FED_PUSH_PLAN_ERR_UNSUPPORTED;
  }
  return AMDUATD_FED_PUSH_PLAN_OK;
}

static void amduatd_fed_push_plan_records_free(amduat_fed_record_t *records,
                                               size_t record_count) {
  size_t i;
  if (records == NULL) {
    return;
  }
  for (i = 0; i < record_count; ++i) {
    amduat_reference_free(&records[i].id.ref);
  }
  free(records);
}

static bool amduatd_fed_push_entry_record_type(
    amduat_asl_store_t *store,
    const amduat_asl_log_entry_t *entry,
    amduat_fed_record_type_t *out_type) {
  amduat_fed_record_type_t rec_type = AMDUAT_FED_REC_ARTIFACT;
  if (store == NULL || entry == NULL || out_type == NULL) {
    return false;
  }
  if (entry->kind == AMDUATD_FED_LOG_KIND_ARTIFACT) {
    amduat_artifact_t artifact;
    amduat_asl_store_error_t store_err;
    memset(&artifact, 0, sizeof(artifact));
    store_err = amduat_asl_store_get(store, entry->payload_ref, &artifact);
    if (store_err == AMDUAT_ASL_STORE_OK && artifact.has_type_tag) {
      if (artifact.type_tag.tag_id == AMDUAT_TYPE_TAG_TGK1_EDGE_V1) {
        rec_type = AMDUAT_FED_REC_TGK_EDGE;
      } else if (artifact.type_tag.tag_id == AMDUAT_TYPE_TAG_FER1_RECEIPT_1) {
        rec_type = AMDUAT_FED_REC_PER;
      }
    }
    if (store_err == AMDUAT_ASL_STORE_OK) {
      amduat_asl_artifact_free(&artifact);
    }
  } else if (entry->kind == AMDUATD_FED_LOG_KIND_TOMBSTONE) {
    rec_type = AMDUAT_FED_REC_TOMBSTONE;
  } else {
    return false;
  }
  *out_type = rec_type;
  return true;
}

void amduatd_fed_push_plan_scan_init(amduatd_fed_push_plan_scan_t *scan) {
  if (scan == NULL) {
    return;
  }
  memset(scan, 0, sizeof(*scan));
  amduatd_fed_cursor_record_init(&scan->cursor);
  scan->cursor_ref = amduat_reference(0u, amduat_octets(NULL, 0u));
}

void amduatd_fed_push_plan_scan_free(amduatd_fed_push_plan_scan_t *scan) {
  if (scan == NULL) {
    return;
  }
  if (scan->cursor_present) {
    amduatd_fed_cursor_record_free(&scan->cursor);
    amduat_reference_free(&scan->cursor_ref);
  }
  amduatd_fed_push_plan_records_free(scan->records, scan->record_count);
  memset(scan, 0, sizeof(*scan));
}

amduatd_fed_push_plan_status_t amduatd_fed_push_plan_scan(
    amduat_asl_store_t *store,
    amduat_asl_pointer_store_t *pointer_store,
    const amduatd_space_t *effective_space,
    const char *peer_key,
    uint64_t limit,
    const char *root_path,
    amduatd_fed_push_plan_scan_t *out_scan) {
  amduat_asl_log_store_t log_store;
  amduat_asl_log_entry_t *entries = NULL;
  size_t entry_count = 0u;
  uint64_t next_offset = 0u;
  bool end = false;
  amduat_octets_t log_name = amduat_octets(NULL, 0u);
  uint64_t from_logseq = 0u;

  if (store == NULL || pointer_store == NULL || peer_key == NULL ||
      root_path == NULL || out_scan == NULL) {
    return AMDUATD_FED_PUSH_PLAN_ERR_INVALID;
  }
  amduatd_fed_push_plan_scan_init(out_scan);

  {
    amduatd_fed_cursor_status_t cursor_status;
    cursor_status = amduatd_fed_push_cursor_get(store,
                                                pointer_store,
                                                effective_space,
                                                peer_key,
                                                &out_scan->cursor,
                                                &out_scan->cursor_ref);
    if (cursor_status == AMDUATD_FED_CURSOR_ERR_NOT_FOUND) {
      out_scan->cursor_present = false;
    } else if (cursor_status == AMDUATD_FED_CURSOR_OK) {
      out_scan->cursor_present = true;
      if (out_scan->cursor.has_logseq) {
        if (out_scan->cursor.last_logseq == UINT64_MAX) {
          amduatd_fed_push_plan_scan_free(out_scan);
          return AMDUATD_FED_PUSH_PLAN_ERR_INVALID;
        }
        from_logseq = out_scan->cursor.last_logseq + 1u;
      }
    } else {
      amduatd_fed_push_plan_scan_free(out_scan);
      return AMDUATD_FED_PUSH_PLAN_ERR_INVALID;
    }
  }

  if (!amduat_asl_log_store_init(&log_store, root_path, store,
                                pointer_store)) {
    amduatd_fed_push_plan_scan_free(out_scan);
    return AMDUATD_FED_PUSH_PLAN_ERR_INVALID;
  }
  if (!amduatd_space_scope_name(effective_space, "fed/records", &log_name)) {
    amduatd_fed_push_plan_scan_free(out_scan);
    return AMDUATD_FED_PUSH_PLAN_ERR_INVALID;
  }

  {
    amduat_asl_store_error_t read_err =
        amduat_asl_log_read(&log_store,
                            (const char *)log_name.data,
                            from_logseq,
                            (size_t)limit,
                            &entries,
                            &entry_count,
                            &next_offset,
                            &end);
    amduat_octets_free(&log_name);
    if (read_err != AMDUAT_ASL_STORE_OK) {
      amduatd_fed_push_plan_scan_free(out_scan);
      return AMDUATD_FED_PUSH_PLAN_ERR_INVALID;
    }
  }
  (void)next_offset;
  (void)end;

  if (entry_count != 0u) {
    out_scan->records =
        (amduat_fed_record_t *)calloc(entry_count, sizeof(*out_scan->records));
    if (out_scan->records == NULL) {
      amduat_asl_log_entries_free(entries, entry_count);
      amduatd_fed_push_plan_scan_free(out_scan);
      return AMDUATD_FED_PUSH_PLAN_ERR_OOM;
    }
  }

  {
    size_t i;
    for (i = 0; i < entry_count; ++i) {
      const amduat_asl_log_entry_t *entry = &entries[i];
      amduat_fed_record_type_t rec_type = AMDUAT_FED_REC_ARTIFACT;
      uint64_t logseq;

      if (entry->payload_ref.digest.data == NULL ||
          entry->payload_ref.digest.len == 0u) {
        continue;
      }
      if (from_logseq > UINT64_MAX - (uint64_t)i) {
        amduat_asl_log_entries_free(entries, entry_count);
        amduatd_fed_push_plan_scan_free(out_scan);
        return AMDUATD_FED_PUSH_PLAN_ERR_INVALID;
      }
      logseq = from_logseq + (uint64_t)i;
      if (!amduatd_fed_push_entry_record_type(store, entry, &rec_type)) {
        continue;
      }
      memset(&out_scan->records[out_scan->record_count], 0,
             sizeof(out_scan->records[out_scan->record_count]));
      out_scan->records[out_scan->record_count].id.type = rec_type;
      out_scan->records[out_scan->record_count].logseq = logseq;
      if (!amduat_reference_clone(entry->payload_ref,
                                  &out_scan->records[out_scan->record_count]
                                       .id.ref)) {
        amduat_asl_log_entries_free(entries, entry_count);
        amduatd_fed_push_plan_scan_free(out_scan);
        return AMDUATD_FED_PUSH_PLAN_ERR_OOM;
      }
      out_scan->record_count++;
    }
  }

  amduat_asl_log_entries_free(entries, entry_count);
  return AMDUATD_FED_PUSH_PLAN_OK;
}

amduatd_fed_push_plan_status_t amduatd_fed_push_plan_json(
    const amduatd_fed_push_plan_input_t *input,
    char **out_json) {
  amduatd_fed_push_plan_strbuf_t b;
  size_t i;
  const amduat_fed_record_t *first = NULL;
  const amduat_fed_record_t *last = NULL;
  amduatd_fed_push_cursor_candidate_t candidate;
  char *ref_hex = NULL;
  char *cursor_ref_hex = NULL;
  char tmp[64];

  if (out_json != NULL) {
    *out_json = NULL;
  }
  if (input == NULL || out_json == NULL || input->peer_key == NULL) {
    return AMDUATD_FED_PUSH_PLAN_ERR_INVALID;
  }
  if (input->record_count > 0u && input->records == NULL) {
    return AMDUATD_FED_PUSH_PLAN_ERR_INVALID;
  }
  if (input->cursor_present && input->cursor == NULL) {
    return AMDUATD_FED_PUSH_PLAN_ERR_INVALID;
  }

  if (input->record_count > 0u && input->records != NULL) {
    first = &input->records[0];
    last = &input->records[input->record_count - 1u];
  }
  if (!amduatd_fed_push_plan_next_cursor_candidate(
          input->cursor_present ? input->cursor : NULL,
          input->records,
          input->record_count,
          &candidate)) {
    return AMDUATD_FED_PUSH_PLAN_ERR_OOM;
  }

  if (input->cursor_present &&
      input->cursor_ref != NULL &&
      input->cursor_ref->digest.data != NULL) {
    if (!amduat_asl_ref_encode_hex(*input->cursor_ref, &cursor_ref_hex)) {
      amduatd_fed_push_plan_candidate_free(&candidate);
      return AMDUATD_FED_PUSH_PLAN_ERR_OOM;
    }
  }

  memset(&b, 0, sizeof(b));
  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "{")) {
    goto plan_oom;
  }

  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"peer\":\"") ||
      !amduatd_fed_push_plan_strbuf_append_cstr(&b, input->peer_key) ||
      !amduatd_fed_push_plan_strbuf_append_cstr(&b, "\",")) {
    goto plan_oom;
  }

  snprintf(tmp, sizeof(tmp), "%u", (unsigned int)input->domain_id);
  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"domain_id\":") ||
      !amduatd_fed_push_plan_strbuf_append_cstr(&b, tmp) ||
      !amduatd_fed_push_plan_strbuf_append_cstr(&b, ",")) {
    goto plan_oom;
  }

  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"effective_space\":{")) {
    goto plan_oom;
  }
  if (input->effective_space != NULL &&
      input->effective_space->enabled &&
      input->effective_space->space_id.data != NULL) {
    const char *space_id = (const char *)input->effective_space->space_id.data;
    if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"mode\":\"scoped\",") ||
        !amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"space_id\":\"") ||
        !amduatd_fed_push_plan_strbuf_append_cstr(&b, space_id) ||
        !amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"")) {
      goto plan_oom;
    }
  } else {
    if (!amduatd_fed_push_plan_strbuf_append_cstr(
            &b, "\"mode\":\"unscoped\",") ||
        !amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"space_id\":null")) {
      goto plan_oom;
    }
  }
  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "},")) {
    goto plan_oom;
  }

  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"cursor\":{")) {
    goto plan_oom;
  }
  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"present\":") ||
      !amduatd_fed_push_plan_strbuf_append_cstr(&b,
                                                input->cursor_present ? "true"
                                                                      : "false")) {
    goto plan_oom;
  }
  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, ",\"last_logseq\":")) {
    goto plan_oom;
  }
  if (input->cursor_present && input->cursor != NULL &&
      input->cursor->has_logseq) {
    snprintf(tmp, sizeof(tmp), "%llu",
             (unsigned long long)input->cursor->last_logseq);
    if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, tmp)) {
      goto plan_oom;
    }
  } else {
    if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "null")) {
      goto plan_oom;
    }
  }
  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, ",\"ref\":")) {
    goto plan_oom;
  }
  if (cursor_ref_hex != NULL) {
    if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"") ||
        !amduatd_fed_push_plan_strbuf_append_cstr(&b, cursor_ref_hex) ||
        !amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"")) {
      goto plan_oom;
    }
  } else {
    if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "null")) {
      goto plan_oom;
    }
  }
  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "},")) {
    goto plan_oom;
  }

  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"scan\":{")) {
    goto plan_oom;
  }
  snprintf(tmp, sizeof(tmp), "%zu", input->record_count);
  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"record_count\":") ||
      !amduatd_fed_push_plan_strbuf_append_cstr(&b, tmp)) {
    goto plan_oom;
  }
  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, ",\"first_logseq\":")) {
    goto plan_oom;
  }
  if (first != NULL) {
    snprintf(tmp, sizeof(tmp), "%llu", (unsigned long long)first->logseq);
    if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, tmp)) {
      goto plan_oom;
    }
  } else {
    if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "null")) {
      goto plan_oom;
    }
  }
  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, ",\"last_logseq\":")) {
    goto plan_oom;
  }
  if (last != NULL) {
    snprintf(tmp, sizeof(tmp), "%llu", (unsigned long long)last->logseq);
    if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, tmp)) {
      goto plan_oom;
    }
  } else {
    if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "null")) {
      goto plan_oom;
    }
  }
  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "},")) {
    goto plan_oom;
  }

  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"records\":[")) {
    goto plan_oom;
  }
  for (i = 0; i < input->record_count; ++i) {
    const amduat_fed_record_t *rec = &input->records[i];
    const char *type_name = amduatd_fed_push_plan_record_type_name(rec->id.type);
    if (i > 0) {
      if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, ",")) {
        goto plan_oom;
      }
    }
    if (!amduat_asl_ref_encode_hex(rec->id.ref, &ref_hex)) {
      goto plan_oom;
    }
    if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "{\"logseq\":")) {
      goto plan_oom;
    }
    snprintf(tmp, sizeof(tmp), "%llu", (unsigned long long)rec->logseq);
    if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, tmp) ||
        !amduatd_fed_push_plan_strbuf_append_cstr(&b, ",\"record_type\":\"") ||
        !amduatd_fed_push_plan_strbuf_append_cstr(&b, type_name) ||
        !amduatd_fed_push_plan_strbuf_append_cstr(&b, "\",\"ref\":\"") ||
        !amduatd_fed_push_plan_strbuf_append_cstr(&b, ref_hex) ||
        !amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"}")) {
      goto plan_oom;
    }
    free(ref_hex);
    ref_hex = NULL;
  }
  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "],")) {
    goto plan_oom;
  }

  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b,
                                                "\"required_artifacts\":[")) {
    goto plan_oom;
  }
  {
    bool first_artifact = true;
    for (i = 0; i < input->record_count; ++i) {
      const amduat_fed_record_t *rec = &input->records[i];
      if (rec->id.type == AMDUAT_FED_REC_TOMBSTONE) {
        continue;
      }
      if (!amduat_asl_ref_encode_hex(rec->id.ref, &ref_hex)) {
        goto plan_oom;
      }
      if (!first_artifact) {
        if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, ",")) {
          goto plan_oom;
        }
      }
      if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"") ||
          !amduatd_fed_push_plan_strbuf_append_cstr(&b, ref_hex) ||
          !amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"")) {
        goto plan_oom;
      }
      first_artifact = false;
      free(ref_hex);
      ref_hex = NULL;
    }
  }
  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "],")) {
    goto plan_oom;
  }

  if (!amduatd_fed_push_plan_strbuf_append_cstr(
          &b, "\"next_cursor_candidate\":{")) {
    goto plan_oom;
  }
  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"last_logseq\":")) {
    goto plan_oom;
  }
  if (candidate.has_logseq) {
    snprintf(tmp, sizeof(tmp), "%llu", (unsigned long long)candidate.logseq);
    if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, tmp)) {
      goto plan_oom;
    }
  } else {
    if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "null")) {
      goto plan_oom;
    }
  }
  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, ",\"ref\":")) {
    goto plan_oom;
  }
  if (candidate.has_ref) {
    if (!amduat_asl_ref_encode_hex(candidate.ref, &ref_hex)) {
      goto plan_oom;
    }
    if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"") ||
        !amduatd_fed_push_plan_strbuf_append_cstr(&b, ref_hex) ||
        !amduatd_fed_push_plan_strbuf_append_cstr(&b, "\"")) {
      goto plan_oom;
    }
    free(ref_hex);
    ref_hex = NULL;
  } else {
    if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "null")) {
      goto plan_oom;
    }
  }
  if (!amduatd_fed_push_plan_strbuf_append_cstr(&b, "}}\n")) {
    goto plan_oom;
  }

  amduatd_fed_push_plan_candidate_free(&candidate);
  free(cursor_ref_hex);
  *out_json = b.data;
  return AMDUATD_FED_PUSH_PLAN_OK;

plan_oom:
  free(ref_hex);
  amduatd_fed_push_plan_candidate_free(&candidate);
  free(cursor_ref_hex);
  amduatd_fed_push_plan_strbuf_free(&b);
  return AMDUATD_FED_PUSH_PLAN_ERR_OOM;
}