name: Profiling

on:
  pull_request:
    branches: [master]

env:
  CARGO_TERM_COLOR: always

jobs:
  profile:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
        with:
          fetch-depth: 0

      - name: Install Rust
        uses: actions-rs/toolchain@v1
        with:
          profile: minimal
          toolchain: stable

      - name: Install Valgrind
        run: |
          sudo apt-get update
          sudo apt-get install -y valgrind

      - name: Cache dependencies
        uses: actions/cache@v3
        with:
          path: |
            ~/.cargo/registry
            ~/.cargo/git
            target
          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}

      - name: Install iai-callgrind
        run: |
          cargo install iai-callgrind-runner@0.12.3

      - name: Checkout master branch
        run: |
          git fetch origin master:master
          git checkout master

      - name: Run baseline benchmarks
        run: |
          cargo bench --bench compile_demo_art --features=iai -- --save-baseline=master

      - name: Checkout PR branch
        run: |
          git checkout ${{ github.event.pull_request.head.sha }}

      - name: Run PR benchmarks
        id: benchmark
        run: |
          BENCH_OUTPUT=$(cargo bench --bench compile_demo_art --features=iai -- --baseline=master --output-format=json  | jq -sc | sed 's/\\"//g')
          echo "BENCHMARK_OUTPUT<<EOF" >> $GITHUB_OUTPUT
          echo "$BENCH_OUTPUT" >> $GITHUB_OUTPUT
          echo "EOF" >> $GITHUB_OUTPUT

      - name: Comment PR
        uses: actions/github-script@v6
        with:
          github-token: ${{secrets.GITHUB_TOKEN}}
          script: |
            const benchmarkOutput = JSON.parse(`${{ steps.benchmark.outputs.BENCHMARK_OUTPUT }}`);

            let significantChanges = false;
            let commentBody = "#### Performance Benchmark Results\n\n";

            for (const benchmark of benchmarkOutput) {
              if (benchmark.callgrind_summary && benchmark.callgrind_summary.summaries) {
                for (const summary of benchmark.callgrind_summary.summaries) {
                  for (const [eventKind, costsDiff] of Object.entries(summary.events)) {
                    if (costsDiff.diff_pct !== null && Math.abs(costsDiff.diff_pct) > 5) {
                      significantChanges = true;
                      const changeDirection = costsDiff.diff_pct > 0 ? "Increase" : "Decrease";
                      const color = costsDiff.diff_pct > 0 ? "red" : "lime";
                      commentBody += `\`${benchmark.module_path}\` - ${eventKind}:\n`;
                      commentBody += `${changeDirection} of $$\\color{${color}}${Math.abs(costsDiff.diff_pct).toFixed(2)}\\\\%$$\n`;
                      commentBody += `Old: ${costsDiff.old}, New: ${costsDiff.new}\n\n`;
                    }
                  }
                }
              }
            }

            if (significantChanges) {
              github.rest.issues.createComment({
                issue_number: context.issue.number,
                owner: context.repo.owner,
                repo: context.repo.repo,
                body: commentBody
              });
            } else {
              console.log("No significant performance changes detected. Skipping comment.");
              console.log(commentBody);
            }