name: Performance Benchmarks

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]
  workflow_dispatch:
    inputs:
      baseline:
        description: 'Git ref to use as baseline (default: main)'
        required: false
        default: 'main'

env:
  CARGO_TERM_COLOR: always

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

    - uses: dtolnay/rust-toolchain@stable

    - uses: Swatinem/rust-cache@v2
      with:
        cache-on-failure: true

    - name: Install criterion helpers
      run: cargo install critcmp || true

    - name: Run benchmarks on current code
      run: |
        cargo bench --workspace -- --save-baseline current 2>/dev/null || \
        cargo bench -p rtx-tensor -- --save-baseline current 2>/dev/null || \
        echo "No benchmarks found or benchmark failed"
      continue-on-error: true

    - name: Checkout baseline (main)
      if: gitea.event_name == 'pull_request'
      run: |
        git stash || true
        git checkout ${{ gitea.base_ref || 'main' }}

    - name: Run benchmarks on baseline
      if: gitea.event_name == 'pull_request'
      run: |
        cargo bench --workspace -- --save-baseline baseline 2>/dev/null || true
      continue-on-error: true

    - name: Compare benchmarks
      if: gitea.event_name == 'pull_request'
      run: |
        critcmp baseline current || echo "No comparison available"
      continue-on-error: true

    - name: Upload benchmark results
      uses: actions/upload-artifact@v4
      with:
        name: benchmark-results
        path: target/criterion/
        retention-days: 14