name: Nix aarch64 builds

on:
  workflow_dispatch: # allows manual triggering
  push:
    branches:
      - master
    paths: ['.github/workflows/**', '**/CMakeLists.txt', '**/Makefile', '**/*.h', '**/*.hpp', '**/*.c', '**/*.cpp', '**/*.cu', '**/*.swift', '**/*.m', '**/*.sh', '**/*.py', '**/*.nix']
  pull_request:
    types: [opened, synchronize, reopened]
    paths: ['**/CMakeLists.txt', '**/Makefile', '**/*.h', '**/*.hpp', '**/*.c', '**/*.cpp', '**/*.cu', '**/*.swift', '**/*.m', '**/*.sh', '**/*.py', '**/*.nix']

jobs:
  nix-build-aarch64:
    if: ${{ vars.CACHIX_NAME != '' }}
    runs-on: ubuntu-latest
    steps:
    - name: Checkout repository
      uses: actions/checkout@v4
    - name: Install QEMU
      # Copy-paste from https://github.com/orgs/community/discussions/8305#discussioncomment-5888654
      run: |
        sudo apt-get update
        sudo apt-get install -y qemu-user-static qemu-system-aarch64
        sudo usermod -a -G kvm $USER
    - name: Install Nix
      uses: DeterminateSystems/nix-installer-action@v9
      with:
        github-token: ${{ secrets.GITHUB_TOKEN }}
        extra-conf: |
          extra-platforms = aarch64-linux
          extra-system-features = nixos-test kvm
          extra-substituters = https://${{ vars.CACHIX_NAME }}.cachix.org https://cuda-maintainers.cachix.org
          extra-trusted-public-keys = ${{ vars.CACHIX_PUBLIC_KEY }} cuda-maintainers.cachix.org-1:0dq3bujKpuEPMCX6U4WylrUDZ9JyUG0VpVZa7CNfq5E=
    - uses: DeterminateSystems/magic-nix-cache-action@v2
      with:
        upstream-cache: https://${{ matrix.cachixName }}.cachix.org
    - name: Set-up cachix to push the results to
      uses: cachix/cachix-action@v13
      with:
        authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
        name: ${{ vars.CACHIX_NAME }}
    - name: Show all output paths
      run: >
          nix run github:nix-community/nix-eval-jobs
          -- --gc-roots-dir gcroot
          --flake
          ".#packages.aarch64-linux"
    - name: Build
      run: >
          nix run github:Mic92/nix-fast-build
          -- --skip-cached --no-nom
          --systems aarch64-linux
          --flake
          ".#checks.aarch64-linux"