ci.yml

name: Nix CI

on:
  push:
    branches:
      - main
  pull_request:
  # Trigger manually to optionally include heavier/unstable targets
  workflow_dispatch:
    inputs:
      include_optional:
        description: 'Include optional targets (SDL2, Intel Mac)'
        type: boolean
        default: false

jobs:
  # 1. Job to generate the matrix dynamically based on inputs
  setup:
    runs-on: ubuntu-latest
    outputs:
      os: ${{ steps.set-matrix.outputs.os }}
      backend: ${{ steps.set-matrix.outputs.backend }}
    steps:
      - name: Generate Matrix JSON
        id: set-matrix
        uses: actions/github-script@v7
        with:
          script: |
            // Default configuration (Stable & Lightweight targets)
            let osList = ["ubuntu-24.04", "ubuntu-24.04-arm", "macos-15"];
            let backendList = ["lem-ncurses", "lem-webview"];

            // Check if optional targets should be included
            // (Only strictly when triggered via workflow_dispatch with the flag set to true)
            if (context.payload.inputs && context.payload.inputs.include_optional === 'true') {
              console.log("Adding optional targets (SDL2, Intel Mac)...");
              osList.push("macos-15-intel");
              backendList.push("lem-sdl2");
            }

            // Set outputs for the next job to consume
            core.setOutput('os', JSON.stringify(osList));
            core.setOutput('backend', JSON.stringify(backendList));

  # 2. Build job using the dynamically generated matrix
  build:
    needs: setup
    name: builds ${{ matrix.backend }} on ${{ matrix.os }}
    # The 'runs-on' key also uses the dynamic matrix
    runs-on: ${{ matrix.os }}
    # FlakeHub Cache authenticates via GitHub OIDC, which needs id-token: write.
    permissions:
      id-token: write
      contents: read
    strategy:
      fail-fast: false
      matrix:
        # Parse JSON strings from the setup job outputs
        os: ${{ fromJson(needs.setup.outputs.os) }}
        backend: ${{ fromJson(needs.setup.outputs.backend) }}

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Install Nix
        uses: DeterminateSystems/nix-installer-action@v16

      # magic-nix-cache-action was sunset 2025-02-01 and now rate-limits /
      # 418s, causing intermittent "no substituter" failures. FlakeHub Cache
      # is its supported successor (auth via the OIDC token above).
      - name: Setup FlakeHub Cache
        uses: DeterminateSystems/flakehub-cache-action@main

      - name: Check flake
        run: nix flake check --all-systems --no-build

      - name: Build ${{ matrix.backend }}
        run: nix build .#${{ matrix.backend }} --print-build-logs