#!/usr/bin/env bash

set -euo pipefail

SCRIPT_DIR=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)
ROOT_DIR=$(cd -- "${SCRIPT_DIR}/.." && pwd)
DIST_ENV="${ROOT_DIR}/dist/package-info.env"
MESA_SRC_DIR="${ROOT_DIR}/work/mesa"

if [[ ! -f "${DIST_ENV}" ]]; then
  echo "missing dist metadata: ${DIST_ENV}" >&2
  exit 1
fi

if [[ ! -d "${MESA_SRC_DIR}/.git" ]]; then
  echo "missing mesa source checkout: ${MESA_SRC_DIR}" >&2
  exit 1
fi

# shellcheck disable=SC1090
source "${DIST_ENV}"

require_env() {
  local name
  for name in "$@"; do
    if [[ -z "${!name:-}" ]]; then
      echo "missing environment variable: ${name}" >&2
      exit 1
    fi
  done
}

require_env GITEA_SERVER_URL GITEA_REPOSITORY GITEA_TOKEN RELEASE_TAG

RELEASES_JSON="$(curl -fsS \
  -H "Authorization: token ${GITEA_TOKEN}" \
  "${GITEA_SERVER_URL}/api/v1/repos/${GITEA_REPOSITORY}/releases?limit=20")"

PREVIOUS_SHA="$(
  python3 - "${RELEASES_JSON}" "${RELEASE_TAG}" "${PACKAGE_NAME}" <<'PY'
import json
import re
import sys

releases = json.loads(sys.argv[1])
current_tag = sys.argv[2]
package_name = sys.argv[3]
pattern = re.compile(rf"^{re.escape(package_name)}-.*\+git([0-9a-f]{{12}})-")

for release in releases:
    tag = release.get("tag_name", "")
    if tag == current_tag:
        continue
    match = pattern.match(tag)
    if match:
        print(match.group(1))
        break
PY
)"

COMMITS_TRUNCATED=0
COMMIT_LIMIT=50

if [[ -n "${PREVIOUS_SHA}" ]] && git -C "${MESA_SRC_DIR}" rev-parse --verify --quiet "${PREVIOUS_SHA}^{commit}" >/dev/null; then
  COMPARE_RANGE="${PREVIOUS_SHA}..${UPSTREAM_GIT_SHA}"
  mapfile -t COMMITS < <(git -C "${MESA_SRC_DIR}" log --no-merges --format='- %h %s' "${COMPARE_RANGE}")
  RANGE_LABEL="Changes since \`${PREVIOUS_SHA}\`"
else
  COMPARE_RANGE="${UPSTREAM_GIT_SHA}"
  mapfile -t COMMITS < <(git -C "${MESA_SRC_DIR}" log --no-merges -n "${COMMIT_LIMIT}" --format='- %h %s' "${COMPARE_RANGE}")
  RANGE_LABEL="Recent upstream commits"
fi

if (( ${#COMMITS[@]} > COMMIT_LIMIT )); then
  COMMITS=( "${COMMITS[@]:0:${COMMIT_LIMIT}}" )
  COMMITS_TRUNCATED=1
fi

{
  printf '## Mesa Upstream\n\n'
  printf -- '- Upstream: `%s`\n' "${UPSTREAM_GIT_URL}"
  printf -- '- Ref: `%s`\n' "${UPSTREAM_GIT_REF}"
  printf -- '- Commit: `%s`\n' "${UPSTREAM_GIT_SHA_SHORT}"
  printf -- '- Package: `%s`\n\n' "${PACKAGE_FILE}"
  printf '## %s\n\n' "${RANGE_LABEL}"

  if (( ${#COMMITS[@]} == 0 )); then
    printf -- '- No new upstream commits found for this release.\n'
  else
    printf '%s\n' "${COMMITS[@]}"
  fi

  if (( COMMITS_TRUNCATED == 1 )); then
    printf '\n_Release notes truncated to the first %d commits._\n' "${COMMIT_LIMIT}"
  fi
} > "${ROOT_DIR}/dist/release-notes.md"