name: Benchmark

on:
  push:
    branches: [main]
    paths:
      - 'examples/scipix/**'
  pull_request:
    paths:
      - 'examples/scipix/**'
  workflow_dispatch:

env:
  CARGO_TERM_COLOR: always

jobs:
  benchmark:
    name: Run Benchmarks
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Setup Rust toolchain
        uses: dtolnay/rust-toolchain@stable

      - name: Cache dependencies
        uses: actions/cache@v4
        with:
          path: |
            ~/.cargo/registry
            ~/.cargo/git
            target
          key: ${{ runner.os }}-cargo-bench-${{ hashFiles('**/Cargo.lock') }}

      - name: Install critcmp
        run: cargo install critcmp

      - name: Download baseline
        if: github.event_name == 'pull_request'
        run: |
          mkdir -p target/criterion
          gh release download baseline --pattern 'benchmark-baseline.tar.gz' --dir target/criterion || true
          cd target/criterion && tar -xzf benchmark-baseline.tar.gz || true
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

      - name: Run benchmarks
        run: |
          cd examples/scipix
          cargo bench --all-features -- --save-baseline current

      - name: Compare benchmarks
        if: github.event_name == 'pull_request'
        id: compare
        run: |
          cd examples/scipix
          critcmp baseline current > benchmark-comparison.txt || echo "No baseline found"
          cat benchmark-comparison.txt

      - name: Comment PR with results
        if: github.event_name == 'pull_request'
        uses: actions/github-script@v7
        with:
          script: |
            const fs = require('fs');
            const comparison = fs.readFileSync('examples/scipix/benchmark-comparison.txt', 'utf8');

            const body = `## Benchmark Results

            \`\`\`
            ${comparison}
            \`\`\`

            <details>
            <summary>Benchmark Details</summary>

            - **Event**: ${{ github.event_name }}
            - **Branch**: ${{ github.head_ref }}
            - **Commit**: ${{ github.sha }}

            </details>`;

            github.rest.issues.createComment({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
              body: body
            });

      - name: Store baseline (main branch only)
        if: github.ref == 'refs/heads/main'
        run: |
          cd target/criterion
          tar -czf benchmark-baseline.tar.gz */*/base

      - name: Upload baseline
        if: github.ref == 'refs/heads/main'
        run: |
          gh release create baseline \
            --title "Benchmark Baseline" \
            --notes "Automatically generated benchmark baseline" \
            target/criterion/benchmark-baseline.tar.gz \
            --clobber
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

      - name: Upload benchmark results
        uses: actions/upload-artifact@v4
        with:
          name: benchmark-results
          path: |
            examples/scipix/target/criterion
            examples/scipix/benchmark-comparison.txt

  performance-regression:
    name: Check Performance Regression
    runs-on: ubuntu-latest
    if: github.event_name == 'pull_request'
    needs: benchmark
    steps:
      - name: Download benchmark results
        uses: actions/download-artifact@v4
        with:
          name: benchmark-results

      - name: Check for regressions
        id: check
        run: |
          # Parse benchmark results and check for >10% regression
          if grep -q "regressed" benchmark-comparison.txt; then
            echo "regression=true" >> $GITHUB_OUTPUT
            echo "REGRESSION DETECTED!"
          else
            echo "regression=false" >> $GITHUB_OUTPUT
          fi

      - name: Fail if regression
        if: steps.check.outputs.regression == 'true'
        run: |
          echo "::error::Performance regression detected. Please optimize before merging."
          exit 1

  memory-profiling:
    name: Memory Profiling
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Setup Rust toolchain
        uses: dtolnay/rust-toolchain@stable

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

      - name: Build with debug symbols
        run: |
          cd examples/scipix
          cargo build --profile bench

      - name: Run memory profiling
        run: |
          cd examples/scipix
          valgrind --tool=massif --massif-out-file=massif.out \
            target/release/scipix-benchmark

      - name: Analyze memory usage
        run: |
          cd examples/scipix
          ms_print massif.out > memory-profile.txt
          cat memory-profile.txt

      - name: Upload memory profile
        uses: actions/upload-artifact@v4
        with:
          name: memory-profile
          path: examples/scipix/memory-profile.txt

  flamegraph:
    name: Generate Flamegraph
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Setup Rust toolchain
        uses: dtolnay/rust-toolchain@stable

      - name: Install cargo-flamegraph
        run: cargo install flamegraph

      - name: Install perf
        run: sudo apt-get update && sudo apt-get install -y linux-tools-common linux-tools-generic

      - name: Generate flamegraph
        run: |
          cd examples/scipix
          sudo cargo flamegraph --bench scipix_benchmark -- --bench

      - name: Upload flamegraph
        uses: actions/upload-artifact@v4
        with:
          name: flamegraph
          path: examples/scipix/flamegraph.svg