name: Release

"on":
  push:
    tags:
      - "**"

permissions:
  contents: read
  releases: write

jobs:
  release:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Build changelog
        id: changelog
        shell: bash
        run: |
          set -euo pipefail

          current_tag="${GITHUB_REF_NAME}"
          previous_tag=""

          if previous_tag="$(git describe --tags --abbrev=0 "${current_tag}^" 2>/dev/null)"; then
            range="${previous_tag}..${current_tag}"
            {
              printf '## Changelog\n\n'
              printf 'Changes since `%s`.\n\n' "${previous_tag}"
              git log --reverse --pretty=format:'- %h %s' "${range}"
              printf '\n'
            } >CHANGELOG.md
          else
            {
              printf '## Changelog\n\n'
              printf 'Initial release.\n\n'
              git log --reverse --pretty=format:'- %h %s' "${current_tag}"
              printf '\n'
            } >CHANGELOG.md
          fi

      - name: Create or update release
        env:
          GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
        shell: bash
        run: |
          set -euo pipefail

          current_tag="${GITHUB_REF_NAME}"
          api_url="${GITHUB_API_URL}/repos/${GITHUB_REPOSITORY}/releases"
          release_by_tag_url="${api_url}/tags/${current_tag}"

          json_escape() {
            sed ':a;N;$!ba;s/\\/\\\\/g;s/"/\\"/g;s/\t/\\t/g;s/\r//g;s/\n/\\n/g'
          }

          body="$(json_escape < CHANGELOG.md)"
          payload="$(printf '{"tag_name":"%s","name":"%s","body":"%s","draft":false,"prerelease":false}' \
            "${current_tag}" \
            "${current_tag}" \
            "${body}")"

          http_code="$(
            curl --silent --show-error --output release.json --write-out '%{http_code}' \
              --header "Authorization: token ${GITEA_TOKEN}" \
              --header 'Accept: application/json' \
              "${release_by_tag_url}"
          )"

          case "${http_code}" in
            200)
              release_id="$(
                tr '{,' '\n' < release.json |
                  sed -n 's/^[[:space:]]*"id":[[:space:]]*\([0-9][0-9]*\)$/\1/p' |
                  head -n1
              )"

              if [ -z "${release_id}" ]; then
                echo "failed to parse release id from existing release response" >&2
                exit 1
              fi

              curl --silent --show-error --fail \
                --request PATCH \
                --header "Authorization: token ${GITEA_TOKEN}" \
                --header 'Accept: application/json' \
                --header 'Content-Type: application/json' \
                --data "${payload}" \
                "${api_url}/${release_id}" >/dev/null
              ;;
            404)
              curl --silent --show-error --fail \
                --request POST \
                --header "Authorization: token ${GITEA_TOKEN}" \
                --header 'Accept: application/json' \
                --header 'Content-Type: application/json' \
                --data "${payload}" \
                "${api_url}" >/dev/null
              ;;
            *)
              echo "unexpected status code while looking up release: ${http_code}" >&2
              cat release.json >&2
              exit 1
              ;;
          esac