ci.yml

on:
  workflow_dispatch:
  pull_request:
  push:
    branches:
      - main
  schedule:
    - cron: '23 14 * * 2'
  release:

name: build

jobs:
  lint:
    name: "Run hlint"
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v4

    - name: Set up HLint
      uses: haskell-actions/hlint-setup@v2

    - name: Run HLint
      uses: haskell-actions/hlint-run@v2
      with:
        fail-on: warning

  fourmolu:
    name: "Run fourmolu"
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v4
    - uses: haskell-actions/run-fourmolu@v11
      with:
        version: "0.14.0.0"

  generateMatrix:
    name: "Generate matrix from cabal"
    runs-on: ubuntu-latest
    outputs:
      matrix: ${{ steps.set-matrix.outputs.matrix }}
    steps:
      - name: Checkout base repo
        uses: actions/checkout@v4
      - name: Extract the tested GHC versions
        id: set-matrix
        run: |
          wget https://github.com/Kleidukos/get-tested/releases/download/v0.1.5.0/get-tested-0.1.5.0-linux-amd64 -O get-tested
          chmod +x get-tested
          ./get-tested --ubuntu rhine-koans.cabal >> $GITHUB_OUTPUT

  build-cabal:
    runs-on: ubuntu-latest
    needs: generateMatrix
    strategy:
      matrix: ${{ fromJSON(needs.generateMatrix.outputs.matrix) }}
    name: Haskell GHC ${{ matrix.ghc }} cabal
    steps:
      - uses: actions/checkout@v4
      - uses: haskell-actions/setup@v2
        id: setup
        with:
          ghc-version: ${{ matrix.ghc }}

      - name: Install system dependencies
        run: |
          sudo apt-get update
          sudo apt-get install -y libgl1-mesa-dev libglu1-mesa-dev freeglut3-dev

      - name: Configure the build
        run: |
          cabal configure --enable-tests --enable-benchmarks --disable-documentation
          cabal build all --dry-run
        # The last step generates dist-newstyle/cache/plan.json for the cache key.

      - name: Restore cached dependencies
        uses: actions/cache/restore@v4
        id: cache
        env:
          key: ${{ runner.os }}-ghc-${{ steps.setup.outputs.ghc-version }}-cabal-${{ steps.setup.outputs.cabal-version }}
        with:
          path: ${{ steps.setup.outputs.cabal-store }}
          key: ${{ env.key }}-plan-${{ hashFiles('**/plan.json') }}
          restore-keys: |
            ${{ env.key }}-

      - name: Install dependencies
        # If we had an exact cache hit, the dependencies will be up to date.
        if: steps.cache.outputs.cache-hit != 'true'
        run: cabal build all --only-dependencies

      # Cache dependencies already here, so that we do not have to rebuild them should the subsequent steps fail.
      - name: Save cached dependencies
        uses: actions/cache/save@v4
        # If we had an exact cache hit, trying to save the cache would error because of key clash.
        if: steps.cache.outputs.cache-hit != 'true'
        with:
          path: ${{ steps.setup.outputs.cabal-store }}
          key: ${{ steps.cache.outputs.cache-primary-key }}

      - name: Cabal build dependencies
        run: cabal build all --enable-tests --only-dependencies

      - name: Cabal build solutions
        run: cabal build all --enable-tests -fdev -fsolution

      - name: Cabal test solutions
        run: cabal test all --enable-tests --test-show-details=Always -fsolution

  build-flake:
    name: Nix Flake
    runs-on:
      - ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Free disk space
        run: |
          sudo rm -rf /usr/local/* /usr/share/* /opt/*
          docker rmi $(docker image ls -aq)
      - uses: cachix/install-nix-action@v30
      - uses: DeterminateSystems/magic-nix-cache-action@v8
      - uses: cachix/cachix-action@v15
        with:
          name: rhine-koans
          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
      - name: Check whether .nix files are formatted
        run: |
          nix fmt
          git diff --exit-code
      - name: Build executables
        run: nix build .#rhine-koans-all --accept-flake-config
      - name: Run tests
        run: |
          nix develop --accept-flake-config -c cabal update
          nix develop --accept-flake-config -c cabal test all -fsolution

  presentation:
    name: Build presentation
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: cachix/install-nix-action@v30
      - uses: DeterminateSystems/magic-nix-cache-action@v8
      - uses: cachix/cachix-action@v15
        with:
          name: rhine-koans
          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
      - name: Build presentation
        run: nix build --accept-flake-config
      - name: Install pdftotext
        run: nix profile install nixpkgs#poppler_utils
      - name: Compare presentation to checked in version
        run: diff <(pdftotext -layout presentation/presentation.pdf /dev/stdout) <(pdftotext -layout result/presentation.pdf /dev/stdout)

  diffs:
    name: Check whether diffs between solution and problem have changed
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Check diffs
        run: ./check_diffs.sh

  success:
    name: All GHCs built successfully
    runs-on: ubuntu-latest
    needs:
      - build-cabal
      - build-flake
    steps:
      - name: Success
        run: echo "Success"