package main

import (
  "fmt"
  "io/fs"
  "path/filepath"
  "flag"
)

func main() {
	var recurse bool

	flag.BoolVar(&recurse, "R", false, "recursive listing")
	flag.Parse()

	paths := flag.Args()

	if len(paths) == 0 {
		paths = append(paths, ".")
	}

	for _, what := range paths {
		if flag.NArg() > 1 {
			fmt.Printf("\n%s:\n", what)
		}

		filepath.WalkDir(what, func (path string, d fs.DirEntry, err error) error {
			if path == what { return nil }

			if d.IsDir() && recurse {
				fmt.Printf("\n%s:\n", path)
			} else if d.IsDir() {
				fmt.Printf("%s\n", filepath.Base(path))
				return fs.SkipDir
			} else {
				fmt.Printf("%s\n", filepath.Base(path))
			}

			return nil
		})
	}
}