dl

#!/usr/bin/env ruby -w

# dl: directory list.
#
# Take a collection of paths from either stdin or a collection of files.
#
# Group items by their parent directories.

require 'optparse'

class PathSet
  def initialize
    @paths = Hash.new { |hash, key| hash[key] = [] }
  end

  def add(path)
    @paths[File.dirname(path)] << File.basename(path)
  end

  def show(dirs_only = false)
    @paths.sort.each do |dir, files|
      puts dir
      unless dirs_only
        files.each do |file|
          puts "  #{file}"
        end
        puts
      end
    end
  end
end


def parse_args
  options = {}

  op = OptionParser.new do |opts|
    opts.banner = "Usage: #{opts.program_name} [option]... [argument]..."

    options[:dirs_only] = false
    opts.on("-d", "--dirs_only", "Show only the directory components.") do
      options[:dirs_only] = true
    end

  end

  op.parse!

  options
end

# ------------------

options = parse_args

pathset = PathSet.new()

ARGF.each_line do |line|
  pathset.add(line.chomp)
end

pathset.show(options[:dirs_only])