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

# Claude Project Knowledge sync tool.
# Keeps .claude-sync/ aligned with documents listed in .claude-sync.conf
# so the bundle can be uploaded to Claude Chat Project Knowledge.

err() { printf '%s\n' "$*" >&2; }

REPO_ROOT="$(git rev-parse --show-toplevel 2>/dev/null || true)"
if [ -z "${REPO_ROOT}" ]; then
  err "❌ Not inside a git repository."
  exit 1
fi
cd "${REPO_ROOT}"

CONF_FILE=".claude-sync.conf"
OUT_DIR=".claude-sync"
MANIFEST="${OUT_DIR}/SYNC_MANIFEST.md"

sha256() {
  if command -v shasum >/dev/null 2>&1; then
    shasum -a 256 "$1" | awk '{print $1}'
  elif command -v sha256sum >/dev/null 2>&1; then
    sha256sum "$1" | awk '{print $1}'
  else
    err "❌ Neither shasum nor sha256sum is available."
    exit 1
  fi
}

iso_now() {
  # ISO-8601 with timezone offset; portable across macOS (BSD) and Linux (GNU).
  date +"%Y-%m-%dT%H:%M:%S%z"
}

file_mtime() {
  # Returns "YYYY-MM-DD HH:MM:SS" for the given file.
  local f="$1"
  if stat -f "%Sm" -t "%Y-%m-%d %H:%M:%S" "$f" >/dev/null 2>&1; then
    stat -f "%Sm" -t "%Y-%m-%d %H:%M:%S" "$f"
  else
    stat -c "%y" "$f" | cut -d'.' -f1
  fi
}

read_conf_paths() {
  # Emits configured paths, skipping blank lines and # comments; trims whitespace.
  if [ ! -f "${CONF_FILE}" ]; then
    err "❌ Config file not found: ${CONF_FILE}"
    exit 1
  fi
  awk '
    {
      sub(/#.*/, "")
      gsub(/^[[:space:]]+|[[:space:]]+$/, "")
      if (length($0) > 0) print
    }
  ' "${CONF_FILE}"
}

cmd_sync() {
  local paths=()
  while IFS= read -r line; do
    paths+=("${line}")
  done < <(read_conf_paths)

  if [ ${#paths[@]} -eq 0 ]; then
    err "❌ No paths configured in ${CONF_FILE}."
    exit 1
  fi

  # Verify every listed file exists.
  local missing=()
  local p
  for p in "${paths[@]}"; do
    if [ ! -f "${p}" ]; then
      missing+=("${p}")
    fi
  done
  if [ ${#missing[@]} -gt 0 ]; then
    err "❌ Missing source files listed in ${CONF_FILE}:"
    for p in "${missing[@]}"; do
      err "     ${p}"
    done
    exit 1
  fi

  # Detect filename collisions (e.g. two README.md under different folders).
  local seen_basenames=""
  for p in "${paths[@]}"; do
    local bn
    bn="$(basename "${p}")"
    # Find any prior path with the same basename.
    local other=""
    local q
    for q in "${paths[@]}"; do
      if [ "${q}" = "${p}" ]; then continue; fi
      if [ "$(basename "${q}")" = "${bn}" ]; then
        other="${q}"
        break
      fi
    done
    if [ -n "${other}" ]; then
      case "${seen_basenames}" in
        *"|${bn}|"*) ;;
        *)
          err "❌ Filename collision in ${CONF_FILE}: basename '${bn}' used by:"
          err "     ${p}"
          err "     ${other}"
          exit 1
          ;;
      esac
      seen_basenames="${seen_basenames}|${bn}|"
    fi
  done

  rm -rf "${OUT_DIR}"
  mkdir -p "${OUT_DIR}"

  local git_full_sha git_short_sha branch synced_at
  git_full_sha="$(git rev-parse HEAD)"
  git_short_sha="$(git rev-parse --short HEAD)"
  branch="$(git rev-parse --abbrev-ref HEAD)"
  synced_at="$(iso_now)"

  # Build manifest rows as we go.
  local manifest_rows=""
  local count=0

  for p in "${paths[@]}"; do
    local bn hash mtime dest
    bn="$(basename "${p}")"
    hash="$(sha256 "${p}")"
    mtime="$(file_mtime "${p}")"
    dest="${OUT_DIR}/${bn}"

    {
      printf '%s\n' "<!-- CREWLI-SYNC"
      printf 'source: %s\n' "${p}"
      printf 'sha256: %s\n' "${hash}"
      printf 'git-sha: %s\n' "${git_short_sha}"
      printf 'synced-at: %s\n' "${synced_at}"
      printf '%s\n' "-->"
      printf '\n'
    } > "${dest}"
    cat "${p}" >> "${dest}"

    manifest_rows="${manifest_rows}| ${bn} | ${p} | ${hash} | ${mtime} |"$'\n'
    count=$((count + 1))
  done

  {
    printf '%s\n' "# Crewli Project Knowledge Sync Manifest"
    printf '\n'
    printf '**Generated:** %s\n' "${synced_at}"
    printf '**Git SHA:** %s (short: %s)\n' "${git_full_sha}" "${git_short_sha}"
    printf '**Branch:** %s\n' "${branch}"
    printf '**Files synced:** %d\n' "${count}"
    printf '\n'
    printf '%s\n' "## Upload instructions"
    printf '\n'
    printf '%s\n' "Upload every file in \`.claude-sync/\` — including this manifest — to the"
    printf '%s\n' "Crewli Claude Project Knowledge, replacing existing versions. The manifest"
    printf '%s\n' "is what Claude Chat uses for drift detection against the current HEAD."
    printf '\n'
    printf '%s\n' "## Drift-detection rule"
    printf '\n'
    printf '%s\n' "Re-sync is required when:"
    printf '%s\n' "1. Current git HEAD SHA differs from this manifest's git SHA, AND"
    printf '%s\n' "2. Any listed file's current SHA256 differs from the hash recorded below."
    printf '\n'
    printf '%s\n' "## File manifest"
    printf '\n'
    printf '%s\n' "| File | Source path | SHA256 | Source mtime |"
    printf '%s\n' "|------|-------------|--------|--------------|"
    printf '%s' "${manifest_rows}"
    printf '\n'
    printf '%s\n' "## Workflow note for Claude Chat"
    printf '\n'
    printf '%s\n' "When the user reports work that touched any listed file, verify the"
    printf '%s\n' "manifest SHA above matches the latest HEAD they reference. If not,"
    printf '%s\n' "require a re-sync before generating new prompts."
  } > "${MANIFEST}"

  err "✅ Claude sync complete — ${count} files ready in ${OUT_DIR}/"
  err "📤 Upload to Claude Project Knowledge (replace existing):"
  for p in "${paths[@]}"; do
    err "     ${OUT_DIR}/$(basename "${p}")"
  done
  err "     ${MANIFEST}"
}

cmd_check() {
  if [ ! -f "${MANIFEST}" ]; then
    err "❌ No sync manifest found. Run: bash scripts/sync-claude-docs.sh sync"
    exit 1
  fi

  local paths=()
  while IFS= read -r line; do
    paths+=("${line}")
  done < <(read_conf_paths)

  local drift=()
  local missing=()
  local p
  for p in "${paths[@]}"; do
    if [ ! -f "${p}" ]; then
      missing+=("${p}")
      continue
    fi
    # Extract recorded SHA from manifest row whose "Source path" column matches p.
    local recorded
    recorded="$(awk -F' *\\| *' -v src="${p}" '
      $0 ~ /^\|/ && $3 == src { print $4; exit }
    ' "${MANIFEST}")"
    if [ -z "${recorded}" ]; then
      drift+=("${p} (not recorded in manifest)")
      continue
    fi
    local current
    current="$(sha256 "${p}")"
    if [ "${current}" != "${recorded}" ]; then
      drift+=("${p} (source changed since last sync)")
    fi
  done

  if [ ${#missing[@]} -gt 0 ]; then
    err "⚠️  Out of sync:"
    for p in "${missing[@]}"; do
      err "     ${p} (source file missing)"
    done
  fi

  if [ ${#drift[@]} -gt 0 ]; then
    if [ ${#missing[@]} -eq 0 ]; then
      err "⚠️  Out of sync:"
    fi
    for p in "${drift[@]}"; do
      err "     ${p}"
    done
    err "Run: bash scripts/sync-claude-docs.sh sync"
    exit 1
  fi

  if [ ${#missing[@]} -gt 0 ]; then
    err "Run: bash scripts/sync-claude-docs.sh sync"
    exit 1
  fi

  printf '%s\n' "✅ .claude-sync/ matches current dev-docs"
}

cmd_list() {
  local paths=()
  while IFS= read -r line; do
    paths+=("${line}")
  done < <(read_conf_paths)

  local p marker
  for p in "${paths[@]}"; do
    if [ -f "${p}" ]; then
      marker="✓"
    else
      marker="✗"
    fi
    printf '  %s  %s\n' "${marker}" "${p}"
  done
}

cmd_help() {
  cat <<'EOF'
sync-claude-docs.sh — Crewli → Claude Project Knowledge sync

Usage:
  bash scripts/sync-claude-docs.sh [subcommand]

Subcommands:
  sync    (default) Rebuild .claude-sync/ from .claude-sync.conf and write SYNC_MANIFEST.md
  check   Verify .claude-sync/ matches current source files; non-zero exit on drift
  list    Print configured source paths with existence markers (✓ / ✗)
  help    Show this help text

Examples:
  bash scripts/sync-claude-docs.sh
  bash scripts/sync-claude-docs.sh sync
  bash scripts/sync-claude-docs.sh check
  bash scripts/sync-claude-docs.sh list

Config: .claude-sync.conf (one path per line; # comments and blank lines OK)
Output: .claude-sync/ (git-ignored; regenerated on each sync)
EOF
}

sub="${1:-sync}"
case "${sub}" in
  sync)  cmd_sync ;;
  check) cmd_check ;;
  list)  cmd_list ;;
  help|-h|--help) cmd_help ;;
  *)
    err "❌ Unknown subcommand: ${sub}"
    err ""
    cmd_help >&2
    exit 1
    ;;
esac