name: Build & deploy website

on:
  push:
    branches: [main]
    paths:
      - 'docs/**'
      - 'CHANGELOG.md'
      - '**.lock'
      - '**.nix'
  pull_request:
    paths:
      - 'docs/**'
      - 'CHANGELOG.md'
      - '**.lock'
      - '**.nix'
  workflow_dispatch:

jobs:
  build:
    name: Build site

    runs-on: ubuntu-latest

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

      - name: Install Nix
        uses: cachix/install-nix-action@V27

      - name: Setup cache
        uses: DeterminateSystems/magic-nix-cache-action@v8

      - name: Run build
        run: |
          nix build \
            --print-build-logs \
            --show-trace \
            './dev#site'

      - name: Get artifact directory
        id: find-path
        run: |
          # exit if no `result` from `nix build`
          [ ! -L result ] && exit 1
          echo "path=$(readlink -f result)" >> "$GITHUB_OUTPUT"

      - name: Upload Pages artifact
        uses: actions/upload-pages-artifact@v3
        with:
          path: ${{ steps.find-path.outputs.path }}

  deploy:
    name: Deploy website

    if: github.event_name == 'push' || github.event_name == 'workflow_dispatch'
    needs: build

    runs-on: ubuntu-latest

    environment:
      name: github-pages
      url: ${{ steps.deploy.outputs.page_url }}

    permissions:
      id-token: write
      pages: write

    steps:
      - name: Deploy to GitHub Pages
        id: deploy
        uses: actions/deploy-pages@v4
