comment-on-pr.yaml

name: Comment on PR

on:
  # This workflow doesn't show up in the PR, only in the actions tab. We need to use this
  # separated workflow because pull_request events from forks are not allowed to have a
  # write-token, and we need that to comment on the incoming PR. Changes to this file will
  # not take place during the PR, this workflow runs using the version of this file on the
  # default branch.
  workflow_run:
    workflows:
      - Link Checking
    types:
      - completed

jobs:
  comment-on-pr:
    runs-on: ubuntu-latest
    if: github.event.workflow_run.event == 'pull_request' && github.event.workflow_run.conclusion != 'skipped'
    permissions:
      pull-requests: write
    steps:
      - name: Download Report
        uses: actions/download-artifact@v4
        id: report
        with:
          name: report
          path: ${{ github.workspace }}/reports
          run-id: ${{ github.event.workflow_run.id }}
          github-token: ${{ secrets.GITHUB_TOKEN }}

      - name: Read PR number
        id: pr-number
        # Glob the downloaded folder for reports, should only be one in the artifact;
        # Then extract the PR number from the report name and write it to the output file.
        run: |
          reports=( "${{ steps.report.outputs.download-path }}/*.md" )
          if [ ${#reports[@]} -ne 1 ]; then
            echo "Expected 1 report, found ${#reports[@]}"
            exit 1
          fi
          echo "number=$(basename -- ${reports[0]} .md)" >> "$GITHUB_OUTPUT"

      - name: Find Comment
        uses: peter-evans/find-comment@v3
        id: fc
        if: github.event.workflow_run.event == 'pull_request'
        with:
          issue-number: ${{ steps.pr-number.outputs.number }}
          comment-author: "github-actions[bot]"
          body-includes: <!-- link-checker -->

      # An comment exists here already, and now there's no issues from the link checker
      - name: Clear report
        if: ${{ github.event.workflow_run.conclusion == 'success' && steps.fc.outputs.comment-id != '' }}
        uses: peter-evans/create-or-update-comment@v4
        with:
          comment-id: ${{ steps.fc.outputs.comment-id }}
          edit-mode: replace
          body: |
            <!-- link-checker -->
            Link checker still sees no broken links, all good! :tada:

      # No comment exists here, and link checking found no issues
      - name: No issues
        if: ${{ github.event.workflow_run.conclusion == 'success' && steps.fc.outputs.comment-id == '' }}
        uses: peter-evans/create-or-update-comment@v4
        with:
          issue-number: ${{ steps.pr-number.outputs.number }}
          body: |
            <!-- link-checker -->
            Link checker found no broken links! :sparkles:

      # No comment exists here, and the link checker has found issues
      - name: Create new report
        if: ${{ github.event.workflow_run.conclusion != 'success' && steps.fc.outputs.comment-id == '' }}
        uses: peter-evans/create-or-update-comment@v4
        with:
          issue-number: ${{ steps.pr-number.outputs.number }}
          body-path: "reports/${{ steps.pr-number.outputs.number }}.md"

      # Update existing comment with new report
      - name: Update report
        if: ${{ github.event.workflow_run.conclusion != 'success' && steps.fc.outputs.comment-id != '' }}
        uses: peter-evans/create-or-update-comment@v4
        with:
          comment-id: ${{ steps.fc.outputs.comment-id }}
          body-path: "reports/${{ steps.pr-number.outputs.number }}.md"
          edit-mode: replace