name: Tutorial CI

on:
  push:
    branches: [ master ]
    paths:
      - 'tutorial/**'
      - 'src/**'
      - 'CMakeLists.txt'
      - 'tutorial/CMakeLists.txt'
  pull_request:
    paths:
      - 'tutorial/**'
      - 'src/**'
      - 'CMakeLists.txt'
      - 'tutorial/CMakeLists.txt'
  workflow_dispatch:

permissions:
  contents: read

concurrency:
  group: tutorial-${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
  cancel-in-progress: true

env:
  NIX_CONFIG: |
    experimental-features = nix-command flakes

jobs:
  compile-check:
    name: Compile and Smoke check (${{ matrix.name }})
    runs-on: ${{ matrix.runner }}
    timeout-minutes: 30

    strategy:
      fail-fast: false
      matrix:
        include:
          - name: Linux (x86_64-linux)
            runner: ubuntu-latest
            system: x86_64-linux

          - name: macOS (aarch64-darwin)
            runner: macos-latest
            system: aarch64-darwin

    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          persist-credentials: false

      - name: Install Nix
        uses: DeterminateSystems/nix-installer-action@v12

      - name: Setup Nix Cache
        uses: DeterminateSystems/magic-nix-cache-action@v5
        with:
          use-flakehub: false

      - name: Build tutorials inside Nix dev shell
        run: |
          nix develop --command ./tutorial/build_tutorials.sh

      # Run tutorials after compilation as a simple check that the tutorial code is also correct.
      - name: Run tutorial examples inside Nix dev shell
        run: |
          nix develop --command bash -c '
            set -euo pipefail
            shopt -s nullglob

            tutorial_binaries=(./build/tutorial/tutorial_*)
            if [[ ${#tutorial_binaries[@]} -eq 0 ]]; then
              echo "No tutorial binaries found in ./build/tutorial/"
              exit 1
            fi

            ran_any=0
            for tutorial_binary in "${tutorial_binaries[@]}"; do
              if [[ ! -f "${tutorial_binary}" || ! -x "${tutorial_binary}" ]]; then
                continue
              fi

              echo "Running ${tutorial_binary}"
              "${tutorial_binary}"
              ran_any=1
            done

            if [[ "${ran_any}" -eq 0 ]]; then
              echo "No executable tutorial binaries found in ./build/tutorial/"
              exit 1
            fi
          '

  markdown-check:
    name: Markdown freshness check
    runs-on: ubuntu-latest
    timeout-minutes: 15

    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          persist-credentials: false

      - name: Generate markdown from tutorial sources
        run: |
          chmod +x ./tutorial/generate_markdown.sh
          rm -rf ./tutorial/docs
          ./tutorial/generate_markdown.sh

      - name: Check git diff (no changes expected)
        run: |
          if ! git diff --quiet -- ./tutorial/docs/; then
            echo "❌ Generated markdown does not match committed version."
            echo ""
            echo "Differences found:"
            git diff -- ./tutorial/docs/
            echo ""
            echo "Run './tutorial/generate_markdown.sh' locally and commit the updated docs/"
            exit 1
          fi
          echo "✅ Generated markdown matches committed version."