name: Coverage Comment

on:
  # The so-called dangerous workflow_run trigger is necessary for letting forks
  # gain workflow-scoped pull-requests: write permission. The only
  # user-controlled content is the content of diff-cover-report.md.
  workflow_run:  # zizmor: ignore[dangerous-triggers]
    workflows: ["Coverage Tests"]
    types:
      - completed

permissions:
  actions: read
  pull-requests: write

jobs:
  comment:
    if: >
      github.event.workflow_run.event == 'pull_request' &&
      github.event.workflow_run.conclusion == 'success' &&
      github.repository == 'django/django'
    name: Post Coverage Comment
    runs-on: ubuntu-latest
    timeout-minutes: 60
    steps:
      - name: Download coverage artifacts
        uses: actions/download-artifact@v8
        with:
          name: coverage-artifacts
          github-token: ${{ secrets.GITHUB_TOKEN }}
          run-id: ${{ github.event.workflow_run.id }}

      - name: Post/update PR comment
        uses: actions/github-script@v9
        with:
          script: |
            const fs = require('fs');
            const reportPath = 'diff-cover-report.md';
            let body = 'No coverage data available.';
            if (fs.existsSync(reportPath)) {
              body = fs.readFileSync(reportPath, 'utf8');
              const divider = '-------------';
              // Start after the second divder, where changed files are listed.
              const start = body.indexOf(divider, 1);
              body = body.substring(start);
            }
            const commentBody = (
              '#### Uncovered lines in changed files\n\n```\n' + body + '```\n' +
              '**Note:** Missing lines are warnings only. Some database-specific lines may not be measured. [More information](https://docs.djangoproject.com/en/dev/internals/contributing/writing-code/unit-tests/#code-coverage-on-pull-requests)'
            );

            const run = context.payload.workflow_run;
            const { data: prs } = await github.rest.pulls.list({
              owner: context.repo.owner,
              repo: context.repo.repo,
              state: "open",
              head: `${run.head_repository.owner.login}:${run.head_branch}`,
            });
            const pr = prs[0];
            if (!pr) {
              core.setFailed(`No PR found for commit ${run.head_sha}.`);
              return;
            }
            
            const { data: comments } = await github.rest.issues.listComments({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: pr.number,
            });
            
            for (const c of comments) {
              if ((c.body || '').includes('Uncovered lines in changed files')) {
                await github.rest.issues.deleteComment({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  comment_id: c.id,
                });
              }
            }

            await github.rest.issues.createComment({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: pr.number,
              body: commentBody,
            });