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

# Auto-sync Claude Project Knowledge when a commit touched any configured doc.

REPO_ROOT="$(git rev-parse --show-toplevel 2>/dev/null || true)"
if [ -z "${REPO_ROOT}" ]; then
  exit 0
fi
cd "${REPO_ROOT}"

CONF_FILE=".claude-sync.conf"
SYNC_SCRIPT="scripts/sync-claude-docs.sh"

if [ ! -f "${CONF_FILE}" ] || [ ! -f "${SYNC_SCRIPT}" ]; then
  exit 0
fi

# Files changed in the commit we just made.
# Merge commits: `git diff-tree HEAD` without a range returns the
# combined-condensed diff (empty for clean, no-conflict merges),
# which would skip regen on merges that bring in watched files via
# the merged branch. Use a range against the first parent when HEAD
# has two parents; plain HEAD for regular commits.
if git rev-parse --verify HEAD^2 >/dev/null 2>&1; then
  changed="$(git diff-tree --no-commit-id --name-only -r HEAD^1 HEAD 2>/dev/null || true)"
else
  changed="$(git diff-tree --no-commit-id --name-only -r HEAD 2>/dev/null || true)"
fi
if [ -z "${changed}" ]; then
  exit 0
fi

# Configured paths (strip # comments and blanks).
configured="$(awk '
  {
    sub(/#.*/, "")
    gsub(/^[[:space:]]+|[[:space:]]+$/, "")
    if (length($0) > 0) print
  }
' "${CONF_FILE}")"

match=0
while IFS= read -r cfile; do
  [ -z "${cfile}" ] && continue
  case "${cfile}" in .claude-sync.conf|scripts/sync-claude-docs.sh|.githooks/*) match=1; break ;; esac
  while IFS= read -r conf_path; do
    [ -z "${conf_path}" ] && continue
    if [ "${cfile}" = "${conf_path}" ]; then
      match=1
      break 2
    fi
  done <<EOF
${configured}
EOF
done <<EOF
${changed}
EOF

if [ "${match}" -eq 1 ]; then
  bash "${SYNC_SCRIPT}" sync
fi

exit 0