name: Check for Newline at End of Files

on:
  pull_request:
    types:
      - opened
      - synchronize
      - reopened

jobs:
  check-newlines:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout repository
        uses: actions/checkout@v2

      - name: Check for missing newlines
        run: |
          files=$(git ls-files)

          newline_error=0

          for file in $files; do
            if file --mime "$file" | grep -q "binary"; then
              #echo "Skipping binary file: $file"
              continue
            fi

            last_char=$(tail -c 1 "$file" | xxd -p)
            if [[ "$last_char" != "0a" ]]; then
              echo "File $file does not end with a newline!"
              newline_error=1
            fi
          done

          if [[ $newline_error -eq 1 ]]; then
            echo "One or more files do not end with a newline."
            exit 1
          else
            echo "All files end with a newline."
          fi