name: Backend diagnostics (comment)

on:
  workflow_run:
    types: [completed]
    workflows:
      - Backend diagnostics (inspect) # backend-diagnostics.inspect.yml

jobs:
  compare-memory:
    runs-on: ubuntu-latest
    if: ${{ github.event.workflow_run.conclusion == 'success' }}
    permissions:
      actions: read
      contents: read
      pull-requests: write

    steps:
      - name: Checkout
        uses: actions/checkout@v6.0.3

      - name: Download artifacts
        uses: actions/download-artifact@v8
        with:
          pattern: memory-artifact-*
          path: artifacts
          merge-multiple: true
          github-token: ${{ github.token }}
          repository: ${{ github.repository }}
          run-id: ${{ github.event.workflow_run.id }}
      - name: Check artifacts
        run: ls -lh artifacts/
      - name: Load PR Number
        id: load-pr-num
        run: echo "pr-number=$(cat artifacts/pr_number)" >> "$GITHUB_OUTPUT"
      - name: Find heap snapshot artifacts
        id: find-heap-snapshot-artifacts
        uses: actions/github-script@v9
        with:
          script: |
            const { owner, repo } = context.repo;
            const run_id = context.payload.workflow_run.id;
            const artifacts = await github.paginate(github.rest.actions.listWorkflowRunArtifacts, {
              owner,
              repo,
              run_id,
            });
            const artifactNames = {
              base: 'base-heap-snapshot.heapsnapshot',
              head: 'head-heap-snapshot.heapsnapshot',
            };
            for (const [label, artifactName] of Object.entries(artifactNames)) {
              const artifact = artifacts.find(artifact => artifact.name === artifactName);
              if (artifact == null) throw new Error(`Artifact not found: ${artifactName}`);
              core.setOutput(`${label}-url`, `https://github.com/${owner}/${repo}/actions/runs/${run_id}/artifacts/${artifact.id}`);
            }

      - id: build-comment
        name: Build memory comment
        env:
          MK_MEMORY_HEAP_SNAPSHOT_ARTIFACT_URL_BASE: ${{ steps.find-heap-snapshot-artifacts.outputs.base-url }}
          MK_MEMORY_HEAP_SNAPSHOT_ARTIFACT_URL_HEAD: ${{ steps.find-heap-snapshot-artifacts.outputs.head-url }}
        run: node .github/scripts/backend-diagnostics.render-md.mts ./artifacts/memory-base.json ./artifacts/memory-head.json ./output.md
      - uses: thollander/actions-comment-pull-request@v3
        with:
          pr-number: ${{ steps.load-pr-num.outputs.pr-number }}
          comment-tag: show_memory_diff
          file-path: ./output.md
      - name: Tell error to PR
        uses: thollander/actions-comment-pull-request@v3
        if: failure() && steps.load-pr-num.outputs.pr-number
        with:
          pr-number: ${{ steps.load-pr-num.outputs.pr-number }}
          comment-tag: show_memory_diff_error
          message: |
            An error occurred while comparing backend memory usage. See [workflow logs](https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}) for details.