class CommandParser
  def initialize(command)
    @command_name = command
    @arg = []
    @opt_w_p = {}
    @arg_cnt = 0
    @used_args = 0
  end

  def argument(name)
    @arg[@arg_cnt] = [Proc.new, name]
    @arg_cnt += 1
  end

  def option_with_parameter(short_name, full_name, description, value = true)
    short_name = '-' << short_name
    full_name = '--' << full_name
    @opt_w_p[short_name] = [full_name, description, Proc.new, value]
    @opt_w_p[full_name] = [short_name, description, Proc.new, value]
  end

  alias_method :option, :option_with_parameter

  def parse(command_runner, argv)
    argv.each do |x|
      unless x.start_with?("-")
        @arg[@used_args][0].call(command_runner, x) && @used_args += 1 && next
      end
      name, param = x.split('=')
      @opt_w_p[name][2].call(command_runner, true) && next unless param
      @opt_w_p[name][2].call(command_runner, param)
    end
  end

  def help
    description = "Usage: #{@command_name}"
    @arg.each { |x| description << " [#{x[1]}]" }
    description <<= "\n"
    @opt_w_p.each { |value| description <<= option_definition(value) }
    description
  end

  private

  def option_definition(value)
    definition = ""
    key, option = value
    if value.first.length <= 2
      definition << "    " << value.first << ", " << @opt_w_p[key][0]
      definition << "=" << option[3] unless option[3] === true
      definition << " " << option[1].to_s << "\n"
    end
    definition
  end
end