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

REPO_DIR="${REPO_DIR:-$(pwd)}"
TARGET_BRANCH="${TARGET_BRANCH:-thirdparty/skill}"
MANIFEST_PATH="${MANIFEST_PATH:-.gitea/ci/thirdparty_skills.json}"
COMMIT_AUTHOR_NAME="${COMMIT_AUTHOR_NAME:-ci[bot]}"
COMMIT_AUTHOR_EMAIL="${COMMIT_AUTHOR_EMAIL:-ci-bot@local}"

retry_cmd() {
  local retries="$1"
  shift
  local delay="$1"
  shift

  local attempt=1
  while true; do
    if "$@"; then
      return 0
    fi
    if [ "$attempt" -ge "$retries" ]; then
      return 1
    fi
    echo "Retry ($attempt/$retries): $*" >&2
    sleep "$delay"
    attempt=$((attempt + 1))
  done
}

github_owner_repo() {
  case "$1" in
    https://github.com/*)
      echo "$1" | sed -E 's#^https://github.com/([^/]+/[^/.]+)(\.git)?$#\1#'
      ;;
    http://github.com/*)
      echo "$1" | sed -E 's#^http://github.com/([^/]+/[^/.]+)(\.git)?$#\1#'
      ;;
    git@github.com:*)
      echo "$1" | sed -E 's#^git@github.com:([^/]+/[^/.]+)(\.git)?$#\1#'
      ;;
    *)
      return 1
      ;;
  esac
}

resolve_latest_sha() {
  local repo="$1"
  local ref="$2"
  local tmp_json="$3"
  local gh_repo="$4"
  local sha=""

  if [ -n "$gh_repo" ]; then
    local api_url="https://api.github.com/repos/${gh_repo}/commits/${ref}"
    if retry_cmd 3 2 curl -fsSL --retry 3 --retry-delay 2 "$api_url" -o "$tmp_json"; then
      sha="$(sed -n 's/^[[:space:]]*"sha":[[:space:]]*"\([0-9a-f]\{40\}\)".*/\1/p' "$tmp_json" | head -n 1)"
      if [ -n "$sha" ]; then
        echo "$sha"
        return 0
      fi
    fi
  fi

  sha="$(retry_cmd 3 2 git -c http.version=HTTP/1.1 ls-remote "$repo" "refs/heads/$ref" | awk 'NR==1 {print $1}')"
  if [ -n "$sha" ]; then
    echo "$sha"
    return 0
  fi

  return 1
}

emit_sources_tsv() {
  python3 - "$MANIFEST_PATH" <<'PY'
import json
import sys

with open(sys.argv[1], encoding="utf-8") as fh:
    data = json.load(fh)

for entry in data["sources"]:
    print(
        "\t".join(
            [
                entry["id"],
                entry["upstream_repo"],
                entry.get("upstream_ref", "main"),
                entry["snapshot_dir"],
                entry["sync_mode"],
            ]
        )
    )
PY
}

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"

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

changed=0
while IFS=$'\t' read -r source_id upstream_repo upstream_ref snapshot_dir sync_mode; do
  [ -n "$source_id" ] || continue

  gh_repo=""
  if gh_repo="$(github_owner_repo "$upstream_repo" 2>/dev/null)"; then
    :
  fi

  latest_sha="$(resolve_latest_sha "$upstream_repo" "$upstream_ref" "$tmp_dir/${source_id}-latest.json" "$gh_repo" || true)"
  if [ -z "$latest_sha" ]; then
    echo "ERROR: failed to resolve upstream ref for ${source_id}: $upstream_repo $upstream_ref" >&2
    exit 1
  fi

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

  if [ "$latest_sha" = "$current_sha" ]; then
    echo "Third-party snapshot is up to date for ${source_id}: $latest_sha"
    continue
  fi

  rm -rf "$snapshot_dir"
  mkdir -p "$snapshot_dir"

  snapshot_loaded=0
  if [ -n "$gh_repo" ]; then
    tar_url="https://codeload.github.com/${gh_repo}/tar.gz/${latest_sha}"
    if retry_cmd 3 2 curl -fsSL --retry 3 --retry-delay 2 "$tar_url" -o "$tmp_dir/${source_id}.tar.gz"; then
      tar -xzf "$tmp_dir/${source_id}.tar.gz" -C "$snapshot_dir" --strip-components=1
      snapshot_loaded=1
    fi
  fi

  if [ "$snapshot_loaded" -eq 0 ]; then
    upstream_dir="$tmp_dir/${source_id}-upstream"
    git init "$upstream_dir" >/dev/null
    git -C "$upstream_dir" remote add origin "$upstream_repo"
    retry_cmd 3 2 git -C "$upstream_dir" fetch --depth 1 origin "$latest_sha"
    git -C "$upstream_dir" checkout --detach FETCH_HEAD
    git -C "$upstream_dir" archive --format=tar HEAD | tar -xf - -C "$snapshot_dir"
  fi

  snapshot_date="$(date -u +%Y-%m-%d)"
  cat > "$snapshot_dir/SOURCE.md" <<EOF
# Source

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

  git add -A "$snapshot_dir"
  changed=1
done < <(emit_sources_tsv)

if [ "$changed" -eq 0 ] || git diff --cached --quiet; then
  echo "All third-party snapshots are up to date."
  exit 0
fi

git commit -m ":package: deps(thirdparty): update snapshots"

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"