name: 'CI'

on:
  push:
    branches: [main]
  pull_request: {}
  workflow_call: {}

jobs:
  prepare:
    name: Prepare 🚀
    runs-on: ubuntu-latest
    outputs:
      tests: ${{ steps.tests.outputs.tests }}
      checks: ${{ steps.checks.outputs.checks }}
      version: ${{ steps.version.outputs.version }}
    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Install nix ❄️
        uses: cachix/install-nix-action@6a9a9e84a173d90b3ffb42c5ddaf9ea033fad011 # v23
        with:
          extra_nix_config: 'access-tokens = github.com=${{ github.token }}'

      - name: Find tests 🔍
        id: tests
        run: |
          find tests -name '*.Tests.ps1' -print0 | perl -pe 's|(.*?)\x0|"\1",|g;s|,$||;s|(.*)|tests=[\1]|' >> $GITHUB_OUTPUT

      - name: Find checks 🔍
        id: checks
        run: |
          nix-instantiate --json --eval --strict -E 'with builtins; attrNames (getFlake (toString ./.)).checks.${currentSystem}' | perl -pe 's|(.*)|checks=\1|' >>$GITHUB_OUTPUT

      - name: Generate Version 🏷️
        id: version
        run: |
          TAG_COUNT=$(git rev-list --tags --no-walk --count)                                                                 # Count all tags
          COMMIT_COUNT=$(git rev-list --use-bitmap-index --count $(git rev-list --tags --no-walk --max-count=1)..HEAD)       # Count all commits since the last tag
          NIXOS_VERSION=$(nix-instantiate --eval -E '(import ./.).inputs.nixpkgs.lib.version' | sed -E 's/"(.+\...).*"/\1/') # Get NixOS version from nixpkgs
          NIXOS_VERSION_MS=$(echo $NIXOS_VERSION | sed -E 's/\.0*(.+)/\.\1/')                                                # Remove the leading 0 from the minor version (if it exists)
          NIXOS_WSL_VERSION=${NIXOS_VERSION_MS}.${TAG_COUNT}.${COMMIT_COUNT}                                                 # Compose the NixOS-WSL version number
          echo "version=$NIXOS_WSL_VERSION" >> $GITHUB_OUTPUT

  build:
    name: Build 🛠️
    needs:
      - prepare
    runs-on: ubuntu-latest
    strategy:
      matrix:
        config:
          - modern
          - legacy
          - test
    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Install nix ❄️
        uses: cachix/install-nix-action@6a9a9e84a173d90b3ffb42c5ddaf9ea033fad011 # v23
        with:
          extra_nix_config: 'access-tokens = github.com=${{ github.token }}'

      - name: Set version 🏷️
        run: |
          echo ${{ needs.prepare.outputs.version }} > ./VERSION
          echo $(git rev-parse HEAD) >> ./VERSION

      - name: Build tarballs 🛠️
        # We can't just nix run here because nix is not on root's PATH in the container
        run: |
          nix build .#nixosConfigurations.${{ matrix.config }}.config.system.build.tarballBuilder
          sudo ./result/bin/nixos-wsl-tarball-builder nixos-wsl.tar.gz

      - name: Upload tarball 📤
        uses: actions/upload-artifact@v3
        with:
          name: tarball-${{ matrix.config }}
          path: nixos-wsl.tar.gz

  checks:
    name: Flake Check 📋
    needs:
      - prepare
    strategy:
      fail-fast: false
      matrix:
        check: ${{ fromJSON(needs.prepare.outputs.checks) }}
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Install nix ❄️
        uses: cachix/install-nix-action@6a9a9e84a173d90b3ffb42c5ddaf9ea033fad011 # v23
        with:
          extra_nix_config: 'access-tokens = github.com=${{ github.token }}'

      - name: Run check 📋
        run: |
          nix build -L --impure --expr "with builtins; (getFlake (toString ./.)).checks.\${currentSystem}.${{ matrix.check }}"

  tests:
    name: Test 🧪
    needs:
      - prepare
      - build
    strategy:
      fail-fast: false
      matrix:
        test: ${{ fromJSON(needs.prepare.outputs.tests) }}
        os:
          - ubuntu-20.04
          # - windows-latest # doesn't work due to lack of nested virtualization on the runners, hopefully this will work one day
    runs-on: ${{ matrix.os }}
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Download tarball 📥
        uses: actions/download-artifact@v3
        with:
          name: tarball-test

      - name: Execute test 🧪
        shell: pwsh
        run: |
          Invoke-Pester -Output Detailed ${{ matrix.test }}