name: release

on:
  push:
    branches:
      - '**'
    tags:
      - '*.*.*'

jobs:
  release-notes:
    name: Generate Release Notes
    runs-on: ubuntu-latest
    outputs:
      release_branch: ${{ steps.prep.outputs.release_branch }}
    steps:
      -
        name: Checkout code
        uses: actions/checkout@v3
        with:
          fetch-depth: 0
      -
        name: Determine remote default branch
        uses: actions/github-script@v6.2.0
        id: remote_default_branch
        with:
          github-token: ${{secrets.GITHUB_TOKEN}}
          result-encoding: string
          script: |
            repo = await github.rest.repos.get({
                owner: context.repo.owner,
                repo: context.repo.repo,
            })
            return repo.data.default_branch
      -
        name: Prepare
        id: prep
        run: |
          set -eu -o pipefail

          echo "max-issues=200" >> .github_changelog_generator
          # cache requests to reduce load on API
          echo "cache-file=.github_changelog_generator_cache" >> .github_changelog_generator

          # only apply this section if triggered by a tag event
          if [[ ${GITHUB_REF} == refs/tags/* ]]
          then
            # exclude unreleased in case re-running workflow
              echo "unreleased=false" >> .github_changelog_generator
              # in case we've tagged subsequently ensure consistent run
              NEXT_TAG_SHA1="$(git rev-list --tags --skip=0 --no-walk | grep -B 1 ${{ github.sha }} || true)"
              if [[ "${NEXT_TAG_SHA1:-}" != "${{ github.sha }}" ]]
              then
                  NEXT_TAG=$(git describe --tags --abbrev=0 ${NEXT_TAG_SHA1})
                  echo "due-tag=${NEXT_TAG}" >> .github_changelog_generator
              fi
          fi

          # limit list to next tag if any
          LAST_TAG=$(git describe --tags --abbrev=0 HEAD~1 2>/dev/null || true)

          # to ensure that releases continue to get 'x commits since release'
          # need to pass the branch name in addition to the tag to the create
          # release. Work out which branch the current tag is on
          DEFAULT_BRANCH=origin/${{ steps.remote_default_branch.outputs.result }}
          if git merge-base --is-ancestor ${{ github.ref }} ${DEFAULT_BRANCH}
          then
              # if the tag is in the history of the default remote branch
              BRANCH=${DEFAULT_BRANCH}
          else
              # otherwise take the first match and hope for the best
              BRANCH=$(git branch -r --format="%(refname:short)" --contains ${{ github.ref }} | head -n1)
          fi
          BRANCH=${BRANCH#origin/}

          # set outputs for usage
          echo ::set-output name=previous_version::${LAST_TAG}
          echo ::set-output name=release_branch::${BRANCH}
      -
        name: Cache Github API requests
        id: cache-changelog-api-requests
        uses: actions/cache@v3
        with:
          key: github-changelog-cache
          path: .github_changelog_generator_cache
      -
        name: Changelog Generation
        uses: CharMixer/auto-changelog-action@v1.4
        with:
          release_branch: ${{ steps.prep.outputs.release_branch }}
          token: ${{ secrets.GITHUB_TOKEN }}
          since_tag: ${{ steps.prep.outputs.previous_version }}
          output: release_notes.md
      -
        uses: actions/upload-artifact@v2
        with:
          name: release-notes
          path: release_notes.md

  publish-release:
    name: Create Release
    needs: release-notes
    if: startsWith(github.ref, 'refs/tags/')
    runs-on: ubuntu-latest
    steps:
      -
        uses: actions/download-artifact@v3
        with:
          name: release-notes
      -
        name: Create Release
        id: create_release
        uses: actions/create-release@v1
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        with:
          tag_name: ${{ github.ref }}
          commitish: ${{ needs.release-notes.outputs.release_branch }}
          release_name: Release ${{ github.ref }}
          body_path: release_notes.md