# angular_init (short-name: ngi)
# Copyright 2015 Joshua Beam
# github.com/joshbeam/angular_init
# MIT License

# Similar to Ruby's OptionParser
# However, this is customized for angular_init
class CommandParser
  attr_reader :args
  attr_accessor :banner, :version, :separator, :name

  def initialize
    # TODO: to "Usage #{file_name}", etc.
    @name = '<CLI>'
    @banner = "Usage: #{@name} <command>"
    @version = '0.0.0'
    @separator = '===================='
    @listeners = []

    # automatically register some listeners
    register_help
    register_version

    # be able to pass in a block for setup
    yield(self) if block_given?
  end

  def name=(name)
    # need to also replace the name in the banner
    @banner = @banner.gsub(@name, name)

    @name = name
  end

  # register the listeners
  def on(options, description = '', &block)
    listener = {}

    # be able to pass in a single argument, or an array of arguments
    options = *options unless options.is_a? Array

    listener[:options] = options.map do |opt|
      opt.strip.split(' ')
    end

    listener[:block] = block
    listener[:description] = description

    @listeners << listener
  end

  def parse(args)
    # puts @listeners
    matched_listener = {
      options: nil,
      block: nil
    }

    @listeners.each do |listener|
      listener[:options].each do |opt_arr|
        if opt_arr == args
          matched_listener[:options] = opt_arr
          matched_listener[:block] = listener[:block]
          break
        end
      end
    end

    if !matched_listener[:options].nil?
      # matched_listener[:options] should always be an array
      # when we call, we can each member of that array to be
      # passed separately
      matched_listener[:block].call(*matched_listener[:options])
    else
      # if there was no match, show the help menu
      parse(['-h'])
    end
  end

  def register_help
    # automaticaly register this listener
    on(['-h', '--help'], 'Show the help menu') do
      puts @separator
      puts @banner

      @listeners.each_with_index do |listener, i|
        desc = "\n" << "(#{i + 1}) #{listener[:description]}: "
        desc << "#{listener[:options].join(', ')}"
        puts desc
      end
      puts @separator
    end
  end

  def register_version
    # automaticaly register this listener
    on(['-v', '--version'], 'Show the version') do
      puts "#{@name} #{@version}"
    end
  end
end