name: pr-examples
on:
  pull_request:
    paths:
      - '_examples/**/*'

jobs:
  detect-changed-examples:
    runs-on: ubuntu-latest
    outputs:
      examples: ${{ steps.set.outputs.examples }}
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0
      - id: set
        env:
          BASE_SHA: ${{ github.event.pull_request.base.sha }}
          HEAD_SHA: ${{ github.event.pull_request.head.sha }}
        run: |
          changed=$(git diff --name-only "$BASE_SHA"..."$HEAD_SHA")
          example_dirs=$(find _examples -name '.validate_example*.yml' -exec dirname {} \; | sort -u)
          examples=()
          while IFS= read -r dir; do
            if printf '%s\n' "$changed" | grep -q "^${dir}/"; then
              examples+=("${dir#_examples/}")
            fi
          done <<< "$example_dirs"
          if [ ${#examples[@]} -eq 0 ]; then
            json='[]'
          else
            json=$(jq -c -n '$ARGS.positional' --args "${examples[@]}")
          fi
          echo "examples=$json" >> "$GITHUB_OUTPUT"
          echo "Detected changed examples: $json"

  validate:
    needs: detect-changed-examples
    if: needs.detect-changed-examples.outputs.examples != '[]'
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        example: ${{ fromJSON(needs.detect-changed-examples.outputs.examples) }}
    timeout-minutes: 15
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-go@v5
        with:
          go-version: '^1.26'
      - name: Validate ${{ matrix.example }}
        run: cd dev/validate-examples && go run main.go "${{ matrix.example }}"