#!/usr/bin/env bash
set -euo pipefail

ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
override_store_root="${STORE_ROOT:-}"
override_store_backend="${STORE_BACKEND:-}"
override_space="${SPACE:-}"
override_sock="${SOCK:-}"
override_amduatd_bin="${AMDUATD_BIN:-}"
override_asl_bin="${ASL_BIN:-}"

ENV_FILE="${ROOT_DIR}/config/env.local"
if [[ ! -f "${ENV_FILE}" ]]; then
  ENV_FILE="${ROOT_DIR}/config/env.example"
fi
# shellcheck source=/dev/null
source "${ENV_FILE}"

if [[ -n "${override_store_root}" ]]; then STORE_ROOT="${override_store_root}"; fi
if [[ -n "${override_store_backend}" ]]; then STORE_BACKEND="${override_store_backend}"; fi
if [[ -n "${override_space}" ]]; then SPACE="${override_space}"; fi
if [[ -n "${override_sock}" ]]; then SOCK="${override_sock}"; fi
if [[ -n "${override_amduatd_bin}" ]]; then AMDUATD_BIN="${override_amduatd_bin}"; fi
if [[ -n "${override_asl_bin}" ]]; then ASL_BIN="${override_asl_bin}"; fi

STORE_ROOT="${STORE_ROOT:-${ROOT_DIR}/.amduat-asl}"
STORE_BACKEND="${STORE_BACKEND:-index}"
SPACE="${SPACE:-app1}"
SOCK="${SOCK:-${ROOT_DIR}/amduatd.sock}"
INDEX_BACKEND_PROBE="${INDEX_BACKEND_PROBE:-1}"
INDEX_BACKEND_FALLBACK="${INDEX_BACKEND_FALLBACK:-fs}"
FS_FALLBACK_STORE_ROOT="${FS_FALLBACK_STORE_ROOT:-${STORE_ROOT}-fs}"

if [[ "${STORE_ROOT}" != /* ]]; then STORE_ROOT="${ROOT_DIR}/${STORE_ROOT}"; fi
if [[ "${SOCK}" != /* ]]; then SOCK="${ROOT_DIR}/${SOCK}"; fi
if [[ "${FS_FALLBACK_STORE_ROOT}" != /* ]]; then FS_FALLBACK_STORE_ROOT="${ROOT_DIR}/${FS_FALLBACK_STORE_ROOT}"; fi

# Try common local build paths first, then PATH.
AMDUATD_BIN="${AMDUATD_BIN:-}"
if [[ -z "${AMDUATD_BIN}" ]]; then
  for cand in \
    "${ROOT_DIR}/vendor/amduat-api/build/amduatd" \
    "${ROOT_DIR}/vendor/amduat-api/build-asan/amduatd"; do
    if [[ -x "${cand}" ]]; then
      AMDUATD_BIN="${cand}"
      break
    fi
  done
  if [[ -z "${AMDUATD_BIN}" ]] && command -v amduatd >/dev/null 2>&1; then
    AMDUATD_BIN="$(command -v amduatd)"
  fi
fi

ASL_BIN="${ASL_BIN:-}"
if [[ -z "${ASL_BIN}" ]]; then
  for cand in \
    "${ROOT_DIR}/vendor/amduat-api/vendor/amduat/build/amduat-asl" \
    "${ROOT_DIR}/vendor/amduat-api/build/vendor/amduat/amduat-asl"; do
    if [[ -x "${cand}" ]]; then
      ASL_BIN="${cand}"
      break
    fi
  done
  if [[ -z "${ASL_BIN}" ]] && command -v amduat-asl >/dev/null 2>&1; then
    ASL_BIN="$(command -v amduat-asl)"
  fi
fi

if [[ -z "${AMDUATD_BIN}" || ! -x "${AMDUATD_BIN}" ]]; then
  echo "missing amduatd binary; set AMDUATD_BIN" >&2
  exit 1
fi
if [[ -z "${ASL_BIN}" || ! -x "${ASL_BIN}" ]]; then
  echo "missing amduat-asl binary; set ASL_BIN" >&2
  exit 1
fi

init_store() {
  local backend="$1"
  local root="$2"
  mkdir -p "${root}"
  if [[ "${backend}" == "index" ]]; then
    if ! "${ASL_BIN}" index state --root "${root}" >/dev/null 2>&1; then
      echo "initializing index-backed ASL store at ${root}" >&2
      "${ASL_BIN}" index init --root "${root}"
    fi
  else
    if ! "${ASL_BIN}" log inspect --root "${root}" >/dev/null 2>&1; then
      echo "initializing ASL store at ${root}" >&2
      "${ASL_BIN}" init --root "${root}"
    fi
  fi
}

wait_ready() {
  local sock="$1"
  for _ in $(seq 1 80); do
    if [[ -S "${sock}" ]] && curl --globoff --silent --show-error --unix-socket "${sock}" "http://localhost/v2/readyz" >/dev/null 2>&1; then
      return 0
    fi
    sleep 0.1
  done
  return 1
}

probe_index_write_path() {
  local sock="$1"
  local space="$2"
  local run_id
  run_id="$(date +%s)"
  local doc="probe-doc-${run_id}"
  local topic="probe-topic-${run_id}"
  local payload
  payload="$(cat <<JSON
{"idempotency_key":"probe-${run_id}","mode":"continue_on_error","nodes":[{"name":"${doc}"},{"name":"${topic}"}],"edges":[{"subject":"${doc}","predicate":"ms.within_domain","object":"${topic}","provenance":{"source_uri":"urn:probe","extractor":"dev-start","observed_at":1,"ingested_at":2,"trace_id":"probe-${run_id}"}}]}
JSON
)"
  local out
  out="$(curl --globoff --silent --show-error --unix-socket "${sock}" \
    -H "Content-Type: application/json" \
    -H "X-Amduat-Space: ${space}" \
    -X POST --data-binary "${payload}" \
    "http://localhost/v2/graph/batch")" || return 1
  if [[ "${out}" == *'"ok":true'* ]]; then
    return 0
  fi
  echo "index probe response: ${out}" >&2
  return 1
}

run_daemon_foreground() {
  local backend="$1"
  local root="$2"
  echo "starting amduatd: root=${root} sock=${SOCK} backend=${backend} space=${SPACE}" >&2
  exec "${AMDUATD_BIN}" --root "${root}" --sock "${SOCK}" --store-backend "${backend}" --space "${SPACE}"
}

init_store "${STORE_BACKEND}" "${STORE_ROOT}"

if [[ "${STORE_BACKEND}" != "index" || "${INDEX_BACKEND_PROBE}" != "1" ]]; then
  run_daemon_foreground "${STORE_BACKEND}" "${STORE_ROOT}"
fi

echo "starting amduatd (probe mode): root=${STORE_ROOT} sock=${SOCK} backend=${STORE_BACKEND} space=${SPACE}" >&2
"${AMDUATD_BIN}" --root "${STORE_ROOT}" --sock "${SOCK}" --store-backend "${STORE_BACKEND}" --space "${SPACE}" &
daemon_pid=$!
cleanup_probe() {
  kill "${daemon_pid}" >/dev/null 2>&1 || true
}
trap cleanup_probe EXIT

fallback_to_fs=0
if ! wait_ready "${SOCK}"; then
  echo "index backend startup/readiness failed" >&2
  fallback_to_fs=1
elif ! probe_index_write_path "${SOCK}" "${SPACE}"; then
  echo "index backend write probe failed" >&2
  fallback_to_fs=1
fi

if [[ "${fallback_to_fs}" == "0" ]]; then
  trap - EXIT
  wait "${daemon_pid}"
  exit $?
fi

kill "${daemon_pid}" >/dev/null 2>&1 || true
wait "${daemon_pid}" >/dev/null 2>&1 || true
trap - EXIT

if [[ "${INDEX_BACKEND_FALLBACK}" != "fs" ]]; then
  echo "set INDEX_BACKEND_FALLBACK=fs to auto-fallback, or INDEX_BACKEND_PROBE=0 to disable probe" >&2
  exit 1
fi

echo "falling back to fs backend: root=${FS_FALLBACK_STORE_ROOT}" >&2
init_store "fs" "${FS_FALLBACK_STORE_ROOT}"
run_daemon_foreground "fs" "${FS_FALLBACK_STORE_ROOT}"