#!/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="${ROOT_DIR}/work/mesa"
REPO_SRC_DIR="${ROOT_DIR}"

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

if [[ ! -d "${REPO_SRC_DIR}/.git" ]]; then
  echo "missing repo checkout: ${REPO_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_VALUES="$(
  python3 - "${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))
        print(release.get("target_commitish", ""))
        break
PY
)"

PREVIOUS_MESA_SHA="$(printf '%s\n' "${PREVIOUS_VALUES}" | sed -n '1p')"
PREVIOUS_REPO_SHA="$(printf '%s\n' "${PREVIOUS_VALUES}" | sed -n '2p')"

CURRENT_REPO_SHA="$(git -C "${REPO_SRC_DIR}" rev-parse HEAD)"
REPO_COMMITS_TRUNCATED=0
REPO_COMMIT_LIMIT=20
MESA_COMMITS_TRUNCATED=0
MESA_COMMIT_LIMIT=50

if [[ -n "${PREVIOUS_REPO_SHA}" ]] && git -C "${REPO_SRC_DIR}" rev-parse --verify --quiet "${PREVIOUS_REPO_SHA}^{commit}" >/dev/null; then
  REPO_COMPARE_RANGE="${PREVIOUS_REPO_SHA}..${CURRENT_REPO_SHA}"
  mapfile -t REPO_COMMITS < <(git -C "${REPO_SRC_DIR}" log --no-merges --format='- %h %s' "${REPO_COMPARE_RANGE}")
  REPO_RANGE_LABEL="Repo changes since \`${PREVIOUS_REPO_SHA}\`"
else
  REPO_COMPARE_RANGE="${CURRENT_REPO_SHA}"
  mapfile -t REPO_COMMITS < <(git -C "${REPO_SRC_DIR}" log --no-merges -n "${REPO_COMMIT_LIMIT}" --format='- %h %s' "${REPO_COMPARE_RANGE}")
  REPO_RANGE_LABEL="Recent repo commits"
fi

if (( ${#REPO_COMMITS[@]} > REPO_COMMIT_LIMIT )); then
  REPO_COMMITS=( "${REPO_COMMITS[@]:0:${REPO_COMMIT_LIMIT}}" )
  REPO_COMMITS_TRUNCATED=1
fi

if [[ -n "${PREVIOUS_MESA_SHA}" ]] && git -C "${MESA_SRC_DIR}" rev-parse --verify --quiet "${PREVIOUS_MESA_SHA}^{commit}" >/dev/null; then
  MESA_COMPARE_RANGE="${PREVIOUS_MESA_SHA}..${UPSTREAM_GIT_SHA}"
  mapfile -t MESA_COMMITS < <(git -C "${MESA_SRC_DIR}" log --no-merges --format='- %h %s' "${MESA_COMPARE_RANGE}")
  MESA_RANGE_LABEL="Mesa upstream changes since \`${PREVIOUS_MESA_SHA}\`"
else
  MESA_COMPARE_RANGE="${UPSTREAM_GIT_SHA}"
  mapfile -t MESA_COMMITS < <(git -C "${MESA_SRC_DIR}" log --no-merges -n "${MESA_COMMIT_LIMIT}" --format='- %h %s' "${MESA_COMPARE_RANGE}")
  MESA_RANGE_LABEL="Recent Mesa upstream commits"
fi

if (( ${#MESA_COMMITS[@]} > MESA_COMMIT_LIMIT )); then
  MESA_COMMITS=( "${MESA_COMMITS[@]:0:${MESA_COMMIT_LIMIT}}" )
  MESA_COMMITS_TRUNCATED=1
fi

{
  printf '## Repo Changes\n\n'
  printf -- '- Repo commit: `%s`\n' "${CURRENT_REPO_SHA}"
  printf -- '- Release tag: `%s`\n\n' "${RELEASE_TAG}"
  printf '### %s\n\n' "${REPO_RANGE_LABEL}"

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

  if (( REPO_COMMITS_TRUNCATED == 1 )); then
    printf '\n_Repo changes truncated to the first %d commits._\n' "${REPO_COMMIT_LIMIT}"
  fi

  printf '\n## 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' "${MESA_RANGE_LABEL}"

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

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