coverage.yml

name: Code Coverage

on:
  pull_request:
    branches: [main]

  push:
    branches: [main]

  workflow_dispatch:

permissions:
  contents: read
  pull-requests: write
  pages: write
  id-token: write

defaults:
  run:
    shell: bash

jobs:
  coverage:
    name: Generate code coverage with cargo-llvm-cov
    runs-on: ubuntu-latest
    env:
      LAMBDA_REQUIRE_GPU_ADAPTER: "1"

    steps:
      - name: Checkout Repository
        uses: actions/checkout@v4
        with:
          # Fetch enough history for diff against base branch
          fetch-depth: 0
          lfs: true

      - name: Cache cargo builds
        uses: Swatinem/rust-cache@v2

      - name: Install Rust toolchain with llvm-tools-preview
        uses: dtolnay/rust-toolchain@stable
        with:
          components: llvm-tools-preview

      - name: Install cargo-llvm-cov
        uses: taiki-e/install-action@cargo-llvm-cov

      - name: Install Linux deps for winit/wgpu
        run: |
          sudo apt-get update
          sudo apt-get install -y \
            pkg-config libx11-dev libxcb1-dev libxcb-render0-dev \
            libxcb-shape0-dev libxcb-xfixes0-dev libxkbcommon-dev \
            libwayland-dev libudev-dev \
            libvulkan-dev libvulkan1 mesa-vulkan-drivers vulkan-tools

      - name: Install Linux deps for audio
        run: |
          sudo apt-get update
          sudo apt-get install -y libasound2-dev

      - name: Configure Vulkan (Ubuntu)
        run: |
          echo "WGPU_BACKEND=vulkan" >> "$GITHUB_ENV"
          # Prefer Mesa's software Vulkan (lavapipe) for headless availability.
          # The exact ICD filename can differ across Ubuntu images, so discover it.
          LVP_ICD="$(
            if [[ -d /usr/share/vulkan/icd.d ]]; then
              find /usr/share/vulkan/icd.d -maxdepth 1 -type f \
                \( -name '*lvp_icd*.json' -o -name '*lavapipe*.json' \) \
                -print 2>/dev/null | head -n1
            fi
          )"
          if [[ -z "$LVP_ICD" ]]; then
            echo "lavapipe Vulkan ICD not found under /usr/share/vulkan/icd.d" >&2
            ls -la /usr/share/vulkan/icd.d || true
          else
            echo "Using lavapipe ICD: $LVP_ICD"
            echo "VK_ICD_FILENAMES=$LVP_ICD" >> "$GITHUB_ENV"
          fi
          vulkaninfo --summary || true

      - name: Generate full coverage JSON
        run: |
          cargo llvm-cov --workspace \
            --exclude lambda-demos-audio \
            --exclude lambda-demos-minimal \
            --exclude lambda-demos-render \
            --features lambda-rs/with-vulkan,lambda-rs/audio-output-device \
            --json \
            --output-path coverage.json

      - name: Generate HTML coverage report
        run: |
          cargo llvm-cov --workspace \
            --exclude lambda-demos-audio \
            --exclude lambda-demos-minimal \
            --exclude lambda-demos-render \
            --features lambda-rs/with-vulkan,lambda-rs/audio-output-device \
            --html \
            --output-dir coverage-html \
            --no-run

      - name: Get changed files in PR
        if: github.event_name == 'pull_request'
        id: changed
        run: |
          # Use GitHub's provided base/head SHAs for accurate diff
          base_sha="${{ github.event.pull_request.base.sha }}"
          head_sha="${{ github.event.pull_request.head.sha }}"
          changed_files=$(git diff --name-only "$base_sha" "$head_sha" -- \
            '*.rs' \
            ':(exclude)demos/**' \
            | tr '\n' ' ')
          echo "files=$changed_files" >> "$GITHUB_OUTPUT"

      - name: Generate coverage report data
        id: cov
        run: |
          # Extract total coverage and round to 2 decimal places
          pct_raw=$(jq -r '(.data[0].totals.lines.percent // 0)' coverage.json)
          pct=$(printf "%.2f" "$pct_raw")
          covered=$(jq -r '(.data[0].totals.lines.covered // 0)' coverage.json)
          total=$(jq -r '(.data[0].totals.lines.count // 0)' coverage.json)
          echo "pct=$pct" >> "$GITHUB_OUTPUT"
          echo "covered=$covered" >> "$GITHUB_OUTPUT"
          echo "total=$total" >> "$GITHUB_OUTPUT"

          # Extract per-file coverage as JSON for changed files
          jq -r '.data[0].files[] | "\(.filename)|\(.summary.lines.percent // 0)|\(.summary.lines.covered // 0)|\(.summary.lines.count // 0)"' coverage.json > file_coverage.txt

      - name: Build PR coverage comment
        if: github.event_name == 'pull_request'
        id: comment
        env:
          CHANGED_FILES: ${{ steps.changed.outputs.files }}
          RUN_ID: ${{ github.run_id }}
          REPO: ${{ github.repository }}
          COMMIT_SHA: ${{ github.event.pull_request.head.sha }}
        run: |
          # Base URL for GitHub Pages coverage (from main branch)
          PAGES_BASE="https://lambda-sh.github.io/lambda/coverage"
          # Get current timestamp in UTC
          TIMESTAMP=$(date -u +"%Y-%m-%d %H:%M:%S UTC")
          # Short commit SHA for display
          SHORT_SHA="${COMMIT_SHA:0:7}"

          # Build the comment body
          {
            echo "### ✅ Coverage Report"
            echo ""
            echo "📊 [View Full HTML Report](https://github.com/${REPO}/actions/runs/${RUN_ID}) (download artifact)"
            echo ""
            echo "#### Overall Coverage"
            echo ""
            echo "| Metric | Value |"
            echo "|--------|-------|"
            echo "| **Total Line Coverage** | ${{ steps.cov.outputs.pct }}% |"
            echo "| **Lines Covered** | ${{ steps.cov.outputs.covered }} / ${{ steps.cov.outputs.total }} |"
            echo ""

            # Calculate coverage for changed files
            if [ -n "$CHANGED_FILES" ]; then
              echo "#### Changed Files in This PR"
              echo ""
              echo "| File | Coverage | Lines |"
              echo "|------|----------|-------|"

              pr_covered=0
              pr_total=0

              for file in $CHANGED_FILES; do
                # Find this file in coverage data (match by filename ending)
                match=$(grep -E "/${file}\|" file_coverage.txt || grep -E "^${file}\|" file_coverage.txt || true)
                if [ -n "$match" ]; then
                  file_pct=$(echo "$match" | cut -d'|' -f2)
                  file_covered=$(echo "$match" | cut -d'|' -f3)
                  file_total=$(echo "$match" | cut -d'|' -f4)
                  # Format percentage to 2 decimal places
                  file_pct_fmt=$(printf "%.2f" "$file_pct")
                  # Create HTML filename (replace / with path structure, add .html)
                  html_file=$(echo "$file" | sed 's|/|/|g').html
                  echo "| [\`${file}\`](${PAGES_BASE}/${html_file}) | ${file_pct_fmt}% | ${file_covered}/${file_total} |"
                  pr_covered=$((pr_covered + file_covered))
                  pr_total=$((pr_total + file_total))
                else
                  echo "| \`${file}\` | N/A | (no coverage data) |"
                fi
              done

              echo ""
              if [ "$pr_total" -gt 0 ]; then
                pr_pct=$(echo "scale=2; $pr_covered * 100 / $pr_total" | bc)
                echo "**PR Files Coverage:** ${pr_pct}% (${pr_covered}/${pr_total} lines)"
              fi
            else
              echo "*No Rust files changed in this PR.*"
            fi

            echo ""
            echo "---"
            echo "*Generated by [cargo-llvm-cov](https://github.com/taiki-e/cargo-llvm-cov) · [Latest main coverage](${PAGES_BASE})*"
            echo ""
            echo "<sub>Last updated: ${TIMESTAMP} · Commit: [\`${SHORT_SHA}\`](https://github.com/${REPO}/commit/${COMMIT_SHA})</sub>"
          } > comment_body.md

          # Store as output (handle multiline)
          {
            echo "body<<EOF"
            cat comment_body.md
            echo "EOF"
          } >> "$GITHUB_OUTPUT"

      - name: Find existing coverage comment
        if: github.event_name == 'pull_request'
        id: find_comment
        uses: actions/github-script@v7
        with:
          script: |
            const { owner, repo } = context.repo;
            const issue_number = context.issue.number;

            const comments = await github.rest.issues.listComments({
              owner,
              repo,
              issue_number,
            });

            const botComment = comments.data.find(comment =>
              comment.user.type === 'Bot' &&
              comment.body.includes('### ✅ Coverage Report')
            );

            return botComment ? botComment.id : null;
          result-encoding: string

      - name: Create or update PR comment
        if: github.event_name == 'pull_request'
        uses: actions/github-script@v7
        with:
          script: |
            const fs = require('fs');
            const body = fs.readFileSync('comment_body.md', 'utf8');
            const { owner, repo } = context.repo;
            const issue_number = context.issue.number;
            const existingCommentId = ${{ steps.find_comment.outputs.result }};

            if (existingCommentId) {
              await github.rest.issues.updateComment({
                owner,
                repo,
                comment_id: existingCommentId,
                body,
              });
              console.log(`Updated existing comment ${existingCommentId}`);
            } else {
              await github.rest.issues.createComment({
                owner,
                repo,
                issue_number,
                body,
              });
              console.log('Created new coverage comment');
            }

      - name: Upload coverage HTML as artifact
        uses: actions/upload-artifact@v4
        with:
          name: coverage-html-report
          path: coverage-html/
          retention-days: 30

      - name: Upload coverage JSON as artifact
        uses: actions/upload-artifact@v4
        with:
          name: coverage-json
          path: coverage.json
          retention-days: 30

  # Deploy HTML report to GitHub Pages on pushes to main
  deploy-coverage:
    name: Deploy coverage to GitHub Pages
    needs: coverage
    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
    runs-on: ubuntu-latest

    environment:
      name: github-pages
      url: ${{ steps.deployment.outputs.page_url }}

    steps:
      - name: Download coverage HTML artifact
        uses: actions/download-artifact@v4
        with:
          name: coverage-html-report
          path: coverage-html

      - name: Setup Pages
        uses: actions/configure-pages@v4

      - name: Upload to GitHub Pages
        uses: actions/upload-pages-artifact@v3
        with:
          path: coverage-html

      - name: Deploy to GitHub Pages
        id: deployment
        uses: actions/deploy-pages@v4