name: Generate check

on:
  push:
  pull_request:

jobs:
  check-changes:
    runs-on: ubuntu-latest
    outputs:
      has_gen_changes: ${{ steps.check.outputs.has_gen_changes }}
    steps:
      - name: Checkout code
        uses: actions/checkout@v3
        with:
          fetch-depth: 0

      - name: Check for generated file changes
        id: check
        run: |
          if git diff --name-only origin/${{ github.base_ref }}...HEAD | grep -E '_gen\.go$|/generate\.go$'; then
            echo "has_gen_changes=true" >> $GITHUB_OUTPUT
          else
            echo "has_gen_changes=false" >> $GITHUB_OUTPUT
          fi

  check-generate:
    runs-on: ubuntu-latest
    needs: check-changes
    if: needs.check-changes.outputs.has_gen_changes == 'true'
    steps:
      - name: Checkout code
        uses: actions/checkout@v3

      - name: Setup Go
        uses: actions/setup-go@v4
        with:
          go-version: 1.25

      - name: Save pre-generate git state
        run: git status --porcelain > pre-generate.txt

      - name: Run go generate
        run: go generate ./...

      - name: Save post-generate git state
        run: git status --porcelain > post-generate.txt

      - name: Check for changes
        run: |
          if ! diff pre-generate.txt post-generate.txt | grep .; then
            echo "No files changed by go generate"
          else
            echo "go generate produced changes; commit those first" >&2
            exit 1
          fi