require 'socket'

require 'dmorrill10-utils/process_runner'

module AcpcDealer
  class DealerRunner

    # @return [Array<Symbol>] The format of the dealer command. The symbols in this
    # => array should correspond to those in the +dealer_arguments+ of ::start.
    # => (see ::start)
    DEALER_COMMAND_FORMAT = [
      # @note The name of the match to start.
      :match_name,
      # @note The path of the game definition to use.
      :game_def_file_name,
      # @note The number of hands to play.
      :hands,
      # @note The random seed to use.
      :random_seed,
      # @note The names of the players in the game. Should be specified as a space delimited string of names.
      :player_names,
      # @note Should be specified as an option string that the dealer will understand.
      :options
    ]

    # @param [Array] dealer_arguments Arguments to the new dealer instance.
    # @param [String] log_directory The directory in which logs will be placed.
    # => Defaults to +<dealer_arguments[:match_name]>.logs+.
    # @param [Array] port_numbers The port numbers to which each player will connect.
    # => Defaults to random.
    # @return [Hash] The process ID of the started dealer (key +:pid+) and the array of ports that players may
    # => use to connect to the new dealer instance (key +:port_numbers+).
    # @raise (see ProcessRunner::go)
    # @raise (see FileUtils::mkdir_p)
    def self.start(dealer_arguments, log_directory=nil, port_numbers=nil)
      dealer_start_command = DEALER_COMMAND_FORMAT.inject([AcpcDealer::DEALER_PATH]) do |command, parameter|
        command << dealer_arguments[parameter].to_s
      end
      dealer_start_command << "-p #{port_numbers.join(',')}" if port_numbers

      unless log_directory
        log_directory = File.expand_path("../#{dealer_arguments[:match_name]}.logs", __FILE__)
      end

      FileUtils.mkdir_p log_directory unless Dir.exist?(log_directory)

      IO.pipe do |read_io, write_io|
        pid = ProcessRunner.go(
          dealer_start_command,
          err: [
            File.join(log_directory, "#{dealer_arguments[:match_name]}.actions.log"),
            File::CREAT|File::WRONLY
          ],
          out: write_io,
          chdir: log_directory
        )

        {pid: pid, port_numbers: read_io.gets.split, log_directory: log_directory}
      end
    end

    # @todo How could ports be reserved without starting a server? Would +::ports_for_players+ even want to do this?

    # @return [Array<Integer>] List of random open ports. Does NOT reserve the ports though,
    # => so it's possible that the ports will come into use between calling this method and
    # => using them.
    def self.ports_for_players(number_of_players)
      number_of_players.times.inject([]) do |ports, i|
        ports << TCPServer.open('localhost', 0) { |s| s.addr[1] }
      end
    end
  end
end