name: 'Initialize CI Environment and Repository for Flake Builds'
description: 'Initialize a CI environment with nix (and also checkout the repository recursively with LFS)'
inputs:
  token:
    description: 'OAUTH token to access repositories'
    required: false
    default: ${{ github.token }}
  lfs:
    description: Whether to enable lfs. Note that nix flakes don't support LFS currently.
    required: false
    default: true
runs:
  using: "composite"
  steps:
    - name: Setup NIX CI Environment
      run: |
        mkdir -p ~/.config/nix
        echo "substituters = https://nixpkgs-cache.qo.is?priority=39" >> ~/.config/nix/nix.conf
        echo "trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=" >> ~/.config/nix/nix.conf
        nix profile install nixpkgs#git-lfs nixpkgs#gnused

    - name: Checkout Repository
      shell: "nix shell nixpkgs#git-lfs nixpkgs#gnused --command {0}"
      run: |
        if [ "${{ inputs.lfs }}" == "true" ]; then git lfs install; fi
        GIT_SERVER=`echo -n "$GITHUB_SERVER_URL" | sed "s%https://%%"`
        echo -e "machine $GIT_SERVER\nlogin oauth2\npassword ${{ inputs.token }}" > ~/.netrc
        # Disable clone protection to pull LFS as well
        GIT_CLONE_PROTECTION_ACTIVE=false git clone --branch $GITHUB_REF_NAME --recurse-submodules $GITHUB_SERVER_URL/$GITHUB_REPOSITORY .
        git submodule update --init --recursive

    - name: Prefetch git submodules in nix store
      shell: "nix shell nixpkgs#nixVersions.nix_2_26 nixpkgs#git-lfs --command {0}"
      run: git submodule foreach --recursive 'nix flake prefetch'