name: Lint

on: [pull_request]

jobs:
  lint:
    runs-on: ubuntu-latest
    env:
      TARGET_BRANCH: ${{ github.event.pull_request.base.ref }}
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Fetch Target Branch
        run: git fetch origin $TARGET_BRANCH --depth=1

      - name: Install Ruff
        run: pip install ruff

      - name: Get Changed Python Files
        id: changed-files
        run: |
          merge_base=$(git merge-base origin/"$TARGET_BRANCH" HEAD)
          changed_files=$(git diff --name-only --diff-filter=ACMRTUB "$merge_base" | grep '\.py$' || true)
          echo "files<<EOF" >> $GITHUB_OUTPUT
          echo "$changed_files" >> $GITHUB_OUTPUT
          echo "EOF" >> $GITHUB_OUTPUT

      - name: Run Ruff on Changed Files
        if: ${{ steps.changed-files.outputs.files != '' }}
        run: |
          echo "${{ steps.changed-files.outputs.files }}" | tr " " "\n" | xargs -I{} ruff check "{}"