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

REPO_DIR="${REPO_DIR:-$(pwd)}"
TARGET_BRANCH="${TARGET_BRANCH:-thirdparty/skill}"
SNAPSHOT_DIR="${SNAPSHOT_DIR:-superpowers}"
SOURCE_FILE="${SOURCE_FILE:-${SNAPSHOT_DIR}/SOURCE.md}"
UPSTREAM_REPO="${UPSTREAM_REPO:-https://github.com/obra/superpowers.git}"
UPSTREAM_REF="${UPSTREAM_REF:-main}"
COMMIT_AUTHOR_NAME="${COMMIT_AUTHOR_NAME:-playbook-bot}"
COMMIT_AUTHOR_EMAIL="${COMMIT_AUTHOR_EMAIL:-playbook-bot@local}"

cd "$REPO_DIR"

git config user.name "$COMMIT_AUTHOR_NAME"
git config user.email "$COMMIT_AUTHOR_EMAIL"

git fetch origin "$TARGET_BRANCH"
git checkout -B "$TARGET_BRANCH" "origin/$TARGET_BRANCH"

latest_sha="$(git ls-remote "$UPSTREAM_REPO" "refs/heads/$UPSTREAM_REF" | awk 'NR==1 {print $1}')"
if [ -z "$latest_sha" ]; then
  echo "ERROR: failed to resolve upstream ref: $UPSTREAM_REPO $UPSTREAM_REF" >&2
  exit 1
fi

current_sha=""
if [ -f "$SOURCE_FILE" ]; then
  current_sha="$(sed -n 's/^- Ref:[[:space:]]*//p' "$SOURCE_FILE" | head -n 1)"
fi

if [ "$latest_sha" = "$current_sha" ]; then
  echo "Third-party snapshot is up to date: $latest_sha"
  exit 0
fi

tmp_dir="$(mktemp -d)"
cleanup() {
  rm -rf "$tmp_dir"
}
trap cleanup EXIT

upstream_dir="$tmp_dir/upstream"
git init "$upstream_dir" >/dev/null
git -C "$upstream_dir" remote add origin "$UPSTREAM_REPO"
git -C "$upstream_dir" fetch --depth 1 origin "$latest_sha"
git -C "$upstream_dir" checkout --detach FETCH_HEAD

rm -rf "$SNAPSHOT_DIR"
mkdir -p "$SNAPSHOT_DIR"
git -C "$upstream_dir" archive --format=tar HEAD | tar -xf - -C "$SNAPSHOT_DIR"

snapshot_date="$(date -u +%Y-%m-%d)"
cat > "$SOURCE_FILE" <<EOF
# Source

- Repo: ${UPSTREAM_REPO%".git"}
- Ref: $latest_sha
- Snapshot: $snapshot_date
- Notes: vendored into playbook branch $TARGET_BRANCH
EOF

git add "$SNAPSHOT_DIR"

if git diff --cached --quiet; then
  echo "No changes detected after snapshot refresh."
  exit 0
fi

git commit -m ":package: deps(superpowers): vendor snapshot"

TOKEN="${WORKFLOW:-}"
if [ -n "$TOKEN" ] && [ -n "${GITHUB_SERVER_URL:-}" ] && [ -n "${GITHUB_REPOSITORY:-}" ]; then
  git remote set-url origin "https://oauth2:${TOKEN}@${GITHUB_SERVER_URL#https://}/${GITHUB_REPOSITORY}.git"
fi

git push origin "$TARGET_BRANCH"