name: CI
on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

jobs:
  detect-changes:
    name: Check for changed packages
    runs-on: ubuntu-latest
    outputs:
      packages: ${{ steps.changes.outputs.packages }}
    steps:
    - uses: actions/checkout@v6
      with:
        fetch-depth: 0

    - name: Detect changed packages
      id: changes
      run: |
        if [[ "${{ github.event_name }}" == "pull_request" ]]; then
          CHANGED_FILES=$(git diff --name-only "origin/${{ github.base_ref }}"...HEAD)
        else
          CHANGED_FILES=$(git diff --name-only HEAD~1)
        fi

        PACKAGES=$(echo "$CHANGED_FILES" | ./tools/changed_packages.sh)

        echo "packages=$PACKAGES" >> "$GITHUB_OUTPUT"
        echo "Changed packages: $PACKAGES"

  build:
    name: Build package
    needs: detect-changes
    runs-on: ubuntu-latest
    if: needs.detect-changes.outputs.packages != '{"include":[]}'
    strategy:
      matrix: ${{ fromJson(needs.detect-changes.outputs.packages) }}
    steps:
    - uses: actions/checkout@v6
    - uses: cachix/install-nix-action@v31
      with:
        github_access_token: ${{ secrets.GITHUB_TOKEN }}

    - uses: cachix/cachix-action@v16
      with:
        name: scenics
        authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
        skipPush: true
        useDaemon: true

    - name: Build ${{ matrix.package }}
      run: nix build .#${{ matrix.package }}

  buildall:
    name: Build Packages
    needs: build
    runs-on: ubuntu-latest
    if: failure() || cancelled()
    steps:
    - name: Fail on purpose
      run: exit 1