name: Check Changelog

on:
  pull_request_target:
    types: [opened, synchronize, reopened, ready_for_review]


concurrency:
  group: "${{ github.workflow }}-${{ github.ref }}"
  cancel-in-progress: true

permissions:
  contents: read
  pull-requests: write
  issues: write

jobs:
  check-changelog:
    name: Check for changelog
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@v6
        with:
          ref: ${{ github.event.pull_request.head.sha }}
          fetch-depth: 0
          persist-credentials: false
          sparse-checkout: .

      - name: Check for changelog entry
        id: check_files
        run: |
          git fetch origin ${GITHUB_BASE_REF}

          # Check for Added (A) or Modified (M) files in changelog.d
          CHANGELOG_CHANGES=$(git diff --name-status origin/${GITHUB_BASE_REF} HEAD -- changelog.d/)

          SRC_CHANGES=$(git diff --name-status origin/${GITHUB_BASE_REF} HEAD -- src/)

          echo "Changes in changelog.d/:"
          echo "$CHANGELOG_CHANGES"
          echo "Changes in src/:"
          echo "$SRC_CHANGES"

          if echo "$CHANGELOG_CHANGES" | grep -q "^[AM]"; then
            echo "has_changelog=true" >> $GITHUB_OUTPUT
          else
            echo "has_changelog=false" >> $GITHUB_OUTPUT
          fi

          if [ -n "$SRC_CHANGES" ]; then
            echo "src_changed=true" >> $GITHUB_OUTPUT
          else
            echo "src_changed=false" >> $GITHUB_OUTPUT
          fi

      - name: Manage PR Comment
        uses: https://github.com/actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9
        env:
          HAS_CHANGELOG: ${{ steps.check_files.outputs.has_changelog }}
          SRC_CHANGED: ${{ steps.check_files.outputs.src_changed }}
        with:
          script: |
            const hasChangelog = process.env.HAS_CHANGELOG === 'true';
            const srcChanged = process.env.SRC_CHANGED === 'true';
            const commentSignature = '<!-- changelog-check-action -->';
            const commentBody = `${commentSignature}\nPlease add a changelog fragment to \`changelog.d/\` describing your changes.`;

            const { data: currentUser } = await github.rest.users.getAuthenticated();

            const { data: comments } = await github.rest.issues.listComments({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: context.issue.number,
            });

            const botComment = comments.find(comment =>
              comment.user.id === currentUser.id &&
              comment.body.includes(commentSignature)
            );

            const shouldWarn = srcChanged && !hasChangelog;

            if (!shouldWarn) {
              if (botComment) {
                console.log('Changelog found or not required. Deleting existing warning comment.');
                await github.rest.issues.deleteComment({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  comment_id: botComment.id,
                });
              }
            } else {
              if (!botComment) {
                console.log('Changelog missing and required. Creating warning comment.');
                await github.rest.issues.createComment({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  issue_number: context.issue.number,
                  body: commentBody,
                });
              }
            }