name: regression

on:
  pull_request:
  push:
    branches:
      - main

jobs:
  changes:
    name: Detect changes
    runs-on: ubuntu-latest
    timeout-minutes: 2
    outputs:
      code: ${{ steps.filter.outputs.code }}
    steps:
      - uses: actions/checkout@v4
      - uses: dorny/paths-filter@v3
        id: filter
        with:
          filters: |
            code:
              - "packages/core/**"
              - "packages/producer/**"
              - "packages/engine/**"
              - "scripts/**"
              - "Dockerfile*"

  regression-shards:
    needs: changes
    if: needs.changes.outputs.code == 'true'
    runs-on: ubuntu-latest
    timeout-minutes: 40
    strategy:
      fail-fast: false
      matrix:
        include:
          - shard: fast
            args: "--sequential --exclude-tags slow"
          - shard: styles-a
            args: "style-1-prod style-2-prod style-3-prod"
          - shard: styles-b
            args: "style-4-prod style-5-prod style-6-prod"
          - shard: styles-c
            args: "style-7-prod style-8-prod style-9-prod"
          - shard: styles-d
            args: "style-10-prod style-11-prod style-12-prod"
          - shard: styles-e
            args: "style-13-prod style-15-prod style-16-prod"
          - shard: styles-f
            args: "style-17-prod style-18-prod"
          - shard: styles-g
            args: "overlay-montage-prod"
    steps:
      - name: Checkout (with LFS)
        uses: actions/checkout@v4
        with:
          lfs: true

      - name: Validate LFS files
        run: |
          echo "Checking golden baseline MP4s are real files (not LFS pointers)..."
          for mp4 in packages/producer/tests/*/output/output.mp4; do
            if [ -f "$mp4" ]; then
              size=$(stat --format=%s "$mp4")
              if [ "$size" -lt 1000 ]; then
                echo "ERROR: $mp4 appears to be an LFS pointer ($size bytes)"
                exit 1
              fi
              echo "OK: $mp4 ($size bytes)"
            fi
          done

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Build test Docker image (cached)
        uses: docker/build-push-action@v6
        with:
          context: .
          file: Dockerfile.test
          load: true
          tags: hyperframes-producer:test
          cache-from: type=gha,scope=regression-test-image
          cache-to: type=gha,mode=max,scope=regression-test-image

      - name: "Run regression shard: ${{ matrix.shard }}"
        run: |
          echo "Shard: ${{ matrix.shard }}"
          echo "Args: ${{ matrix.args }}"
          docker run --rm \
            --security-opt seccomp=unconfined \
            --shm-size=4g \
            -v ${{ github.workspace }}/packages/producer/tests:/app/packages/producer/tests \
            hyperframes-producer:test \
            ${{ matrix.args }}

      - name: Upload failure artifacts
        if: failure()
        uses: actions/upload-artifact@v4
        with:
          name: regression-failures-${{ matrix.shard }}
          path: packages/producer/tests/*/failures/
          if-no-files-found: ignore

  # Summary job — matches the required check name in branch protection
  regression:
    runs-on: ubuntu-latest
    needs: [changes, regression-shards]
    if: always()
    steps:
      - name: Check results
        run: |
          if [ "${{ needs.changes.outputs.code }}" != "true" ]; then
            echo "No code changes — skipping regression (auto-pass)"
            exit 0
          fi
          if [ "${{ needs.regression-shards.result }}" != "success" ]; then
            echo "One or more regression shards failed"
            exit 1
          fi