name: Changelog

on:
  push:
    branches: [ develop ]

jobs:
  generate:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v2

      - name: Check branch for new commits
        run: |
          git fetch origin
          BRANCH="${GITHUB_REF##*/}"
          if [[ $(git rev-parse "origin/$BRANCH") != $GITHUB_SHA ]]; then
            echo "BRANCH: $BRANCH"
            echo "GITHUB_SHA: $GITHUB_SHA"
            echo "$BRANCH has been updated since build started. Aborting changelog."
            exit 1
          fi
          echo "BRANCH=$BRANCH" >> $GITHUB_ENV

      - name: Prep environment variables
        run: |
          echo "BRANCH=${GITHUB_REF##*/}" >> $GITHUB_ENV
          echo "FILENAME=CHANGELOG.md" >> $GITHUB_ENV
          echo "gittag=$(git tag --sort=-creatordate | grep -Ev '(alpha|beta|rc)' | awk 'NR==1')" >> $GITHUB_ENV

      - name: Prep changelog file (clear out old lines)
        run: |
          # delete the top of the changelog up to the correct tag
          tagline=$(grep -n "^## \[\?$gittag\]\?" "$FILENAME" | awk '{print $1}' FS=':' | head -1)
          echo "tagline: ${tagline}"
          [[ ! -z $tagline ]] && sed -i "1,$(expr $tagline - 1)d" "$FILENAME"
          # delete generated line (or it will be added multiple times)
          sed -i '/This Changelog was automatically generated by/d' "$FILENAME"
          # delete trailing empty lines
          sed -i -e :a -e '/^\n*$/{$d;N;};/\n$/ba' "$FILENAME"

      - name: Generate changelog
        uses: heinrichreimer/action-github-changelog-generator@v2.1.1
        with:
          # see: https://github.com/heinrichreimer/action-github-changelog-generator
          repo: jrnl-org/jrnl
          token: ${{ secrets.GITHUB_TOKEN }}
          base: CHANGELOG.md
          addSections: '{"build":{"prefix":"**Build:**","labels":["build"]},"docs":{"prefix":"**Documentation:**","labels":["documentation"]}}'
          issues: true
          issuesWoLabels: false
          unreleased: true
          compareLink: true
          includeLabels: bug,enhancement,documentation,build,deprecated
          excludeLabels: stale,wontfix
          excludeTagsRegex: '(alpha|beta|rc)'
          sinceTag: ${{ env.gittag }}
          releaseUrl: https://pypi.org/project/jrnl/%s/
          verbose: false

      - name: Small fixes
        run: |
          # Change unreleased link to correct url
          sed -i 's!https://pypi.org/project/jrnl/HEAD/!https://github.com/jrnl-org/jrnl/!' "$FILENAME"

      - name: Consistency check
        run: |
          if [[ $(grep '^# Changelog$' "$FILENAME") != 1 ]]; then
            echo 'Something is wrong with the changelog.'
            git diff -- "$FILENAME"
            exit 1
          fi

      - name: Commit
        run: |
          git config user.email "jrnl.bot@gmail.com"
          git config user.name "Jrnl Bot"
          git add "$FILENAME"
          git commit -m "Update changelog"
          git push origin $BRANCH