name: Comment on issue when it is closed automatically

on:
  issues:
    types: [closed]

jobs:
  comment-on-issue-closure:
    runs-on: ubuntu-latest
    steps:
      - name: Generate GitHub App token
        id: generate-token
        uses: actions/create-github-app-token@29824e69f54612133e76f7eaac726eef6c875baf # v2
        with:
          app-id: ${{ secrets.BOT_APP_ID }}
          private-key: ${{ secrets.BOT_APP_PRIVATE_KEY }}

      - name: Find closing PR or commit
        id: find-closer
        uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8
        with:
          github-token: ${{ steps.generate-token.outputs.token }}
          script: |
            const issueNumber = context.payload.issue.number;

            // Get the issue events to find the "closed" event with commit_id
            const { data: events } = await github.rest.issues.listEvents({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: issueNumber
            });

            // Find the most recent "closed" event
            const closedEvent = events
              .filter(event => event.event === 'closed')
              .pop();
            // Find the most recent "referenced" event
            const referencedEvent = events
              .filter(event => event.event === 'referenced')
              .pop();

            const commitId = closedEvent?.commit_id ?? referencedEvent?.commit_id;

            if (commitId) {
              // Closed by a direct commit or regular merge
              console.log(`✅ Issue #${issueNumber} was closed by commit: ${commitId}`);
              core.setOutput('closed_by_code', 'true');
              core.setOutput('commit_sha', commitId);
              core.setOutput('commit_url', closedEvent.commit_url);
              return;
            }

            // No commit_id — this happens with merge queue.
            // Use GraphQL to check if a PR closed this issue.
            const query = `query($owner: String!, $repo: String!, $number: Int!) {
              repository(owner: $owner, name: $repo) {
                issue(number: $number) {
                  closedByPullRequestsReferences(first: 1) {
                    nodes { number }
                  }
                }
              }
            }`;

            const result = await github.graphql(query, {
              owner: context.repo.owner,
              repo: context.repo.repo,
              number: issueNumber,
            });

            const prNodes = result.repository.issue.closedByPullRequestsReferences.nodes;
            if (prNodes.length > 0) {
              const prNumber = prNodes[0].number;
              console.log(`✅ Issue #${issueNumber} was closed by PR #${prNumber} (via merge queue)`);
              core.setOutput('closed_by_code', 'true');
              core.setOutput('closing_pr', String(prNumber));
              return;
            }

            console.log(`ℹ️  Issue #${issueNumber} was closed manually (not by commit or PR)`);
            core.setOutput('closed_by_code', 'false');

      - name: Comment on issue
        if: steps.find-closer.outputs.closed_by_code == 'true'
        uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8
        with:
          github-token: ${{ steps.generate-token.outputs.token }}
          script: |
            const issueNumber = context.payload.issue.number;
            const closingPrNumber = '${{ steps.find-closer.outputs.closing_pr }}';
            const commitSha = '${{ steps.find-closer.outputs.commit_sha }}';
            const commitUrl = '${{ steps.find-closer.outputs.commit_url }}';

            let closedRef;

            if (closingPrNumber) {
              // Already know the PR (merge queue path or GraphQL found it)
              closedRef = `#${closingPrNumber}`;
              console.log(`Using PR #${closingPrNumber} from previous step`);
            } else if (commitSha) {
              // Have a commit SHA — try to find the PR that contains it
              const { data: prs } = await github.rest.repos.listPullRequestsAssociatedWithCommit({
                owner: context.repo.owner,
                repo: context.repo.repo,
                commit_sha: commitSha,
              });
              const mergedPR = prs.find(pr => pr.merged_at);
              if (mergedPR) {
                closedRef = `#${mergedPR.number}`;
                console.log(`Found PR #${mergedPR.number} for commit ${commitSha.substring(0, 7)}`);
              } else {
                closedRef = `[\`${commitSha.substring(0, 7)}\`](${commitUrl})`;
                console.log(`No PR found, using commit ${commitSha.substring(0, 7)}`);
              }
            }

            const comment = `This issue has been fixed in ${closedRef}, please check with the next unstable build (should be ready for deployment in ~30min, also on [the demo](https://try.vikunja.io)).`;

            await github.rest.issues.createComment({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: issueNumber,
              body: comment,
            });

            console.log(`✅ Added comment to issue #${issueNumber}: fixed in ${closedRef}`);