# Label-gated coverage workflow (`measure code coverage`).
#
# The only trigger type is `labeled`: applying the label approves
# exactly the head commit present at that moment. Later pushes do NOT
# re-fire the workflow. The label is removed automatically at the end
# of every run, so re-applying it retriggers the workflow.

name: Code coverage

on:
  pull_request:
    branches: [main]
    types: [labeled]

concurrency:
  group: ${{ github.workflow }}-${{ github.event.pull_request.number }}
  cancel-in-progress: true

permissions:
  contents: read

env:
  CARGO_TERM_COLOR: always

jobs:
  coverage:
    name: Measure coverage
    if: ${{ github.event.label.name == 'measure code coverage' }}
    runs-on: parity-large
    timeout-minutes: 30
    outputs:
      artifact-url: ${{ steps.upload.outputs.artifact-url }}
    permissions:
      contents: read
    steps:
      - name: Checkout PR head
        uses: actions/checkout@v6
        with:
          ref: ${{ github.event.pull_request.head.sha }}
          persist-credentials: false

      - name: Set up Rust toolchain
        uses: actions-rust-lang/setup-rust-toolchain@v1
        with:
          rustflags: ""
          components: llvm-tools-preview

      - name: Install solc
        uses: ./.github/actions/get-solc

      - name: Install Geth
        run: |
          sudo add-apt-repository -y ppa:ethereum/ethereum
          sudo apt update
          sudo apt install -y ethereum

      - name: Download LLVM
        uses: ./.github/actions/get-llvm
        with:
          target: x86_64-unknown-linux-gnu

      - name: Set LLVM environment variables
        run: |
          echo "LLVM_SYS_221_PREFIX=$(pwd)/llvm-x86_64-unknown-linux-gnu" >> $GITHUB_ENV

      - name: Run coverage and generate revive HTML report
        id: coverage
        run: |
          make coverage
          echo "report_dir=coverage-reports/$(cat target/llvm-cov-target/coverage-stamp)/revive" >> "$GITHUB_OUTPUT"

      - name: Upload coverage report
        id: upload
        uses: actions/upload-artifact@v6
        with:
          name: coverage-report-pr-${{ github.event.pull_request.number }}
          path: ${{ steps.coverage.outputs.report_dir }}
          retention-days: 30

  comment:
    name: Comment coverage on PR
    needs: coverage
    # Use `always()` so the trigger label is consumed even when measurement
    # fails or is cancelled. Skipped for fork PRs since their token is
    # read-only, so commenting and label removal would fail.
    if: >-
      always() && github.event.label.name == 'measure code coverage'
      && github.event.pull_request.head.repo.full_name == github.repository
    runs-on: ubuntu-24.04
    permissions:
      pull-requests: write
    steps:
      - name: Download coverage artifact
        if: ${{ !cancelled() && needs.coverage.result == 'success' }}
        uses: actions/download-artifact@v7
        with:
          name: coverage-report-pr-${{ github.event.pull_request.number }}
          path: coverage

      - name: Comment coverage report on PR
        if: ${{ !cancelled() && needs.coverage.result == 'success' }}
        uses: actions/github-script@v7
        env:
          ARTIFACT_URL: ${{ needs.coverage.outputs.artifact-url }}
        with:
          script: |
            const fs = require('fs');
            const summary = fs.readFileSync('coverage/summary.txt', 'utf8').trim();
            const owner = context.repo.owner;
            const repo = context.repo.repo;
            const prNumber = context.issue.number;
            const sha = context.payload.pull_request.head.sha.substring(0, 8);
            const runUrl = `${context.serverUrl}/${owner}/${repo}/actions/runs/${context.runId}`;
            const artifactUrl = process.env.ARTIFACT_URL || runUrl;
            const marker = '<!-- code-coverage-bot -->';
            const body = [
              marker,
              `### Code coverage`,
              ``,
              `Report for commit \`${sha}\`: [click here to download the report](${artifactUrl}) and open \`html/index.html\` in a browser.`,
              ``,
              `<details open><summary>Summary</summary>`,
              ``,
              summary,
              ``,
              `</details>`,
              ``,
              `_Workflow run: [#${context.runId}](${runUrl})_`,
            ].join('\n');

            // Update the prior bot comment in place rather than spamming.
            // Paginate so the marker is found on PRs with >100 comments.
            const comments = await github.paginate(
              github.rest.issues.listComments,
              { owner, repo, issue_number: prNumber, per_page: 100 },
            );
            const existing = comments.find(c => c.body && c.body.includes(marker));
            if (existing) {
              await github.rest.issues.updateComment({
                owner, repo, comment_id: existing.id, body,
              });
            } else {
              await github.rest.issues.createComment({
                owner, repo, issue_number: prNumber, body,
              });
            }

      - name: Remove trigger label
        if: always()
        uses: actions/github-script@v7
        with:
          script: |
            try {
              await github.rest.issues.removeLabel({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: context.issue.number,
                name: 'measure code coverage',
              });
            } catch (error) {
              // 404: label already removed (e.g. by a human mid-run).
              if (error.status !== 404) {
                core.setFailed(`Failed to remove label: ${error.message}`);
              }
            }