#!/usr/bin/ruby

require 'socket'
require 'thread'
require 'time'
require 'kconv'

CRLF = "\r\n"

def filter(str)
	return str 
end

# analyse command line option
while l = ARGV.shift
	case l
	when /^--help$/
		print "usage: #{$PROGRAM_NAME} [-p PORT] [-m /path/to/motd] [-l /path/to/log]\n"
		exit
	when /^-l$/
		$stderr = File.open(ARGV.shift, "a")
	when /^-m$/
		Motd = ARGV.shift
	when /^-p$/
		Port = ARGV.shift.to_i
	else
	end
end


# set default value
Port = 36800 unless defined? Port
Motd = "./motd" unless defined? Motd

TCPServer.open(Port) do |gs|
	q = Queue.new
	clientHash = Hash.new

	# if caught SIGINT shutdown ther server
	Signal.trap(:INT) do
		$stderr.print "[" + Time.now.to_s + "] caught SIGINT, shutting down.\n"
		exit
	end

	# if caught SIGTERM shutdown the server	
	Signal.trap(:TERM) do
		$stderr.print "[" + Time.now.to_s + "] caught SIGTERM, shutting down.\n"
		exit
	end

	# if caught SIGHUP flush all clients and queue
	Signal.trap(:HUP) do
		$stderr.print "[" + Time.now.to_s + "] caught SIGHUP, flusing all of clients.\n"
		begin
			clientHash.each_value do |cs|
				cs.close
			end
		rescue
			nil
		end
			clientHash = Hash.new
			q = Queue.new
	end

	# chat server started
	$stderr.print "[" + Time.now.to_s + "] Chat server started.\n"

	loop do
		ns = gs.accept

		Thread.start(ns) do |s|
			# initialize value
			user = nil

			# print motd to client
			s.write "+OK Welcome to MECH chat server." + CRLF
			if FileTest.exist?(Motd)
				File.open(Motd) do |f|
					while l = f.gets
						l.chomp!
						s.write Kconv.toutf8(l) + CRLF
					end
					s.write "." + CRLF
				end
			end

			# thread to push messages to client
			tpush = Thread.start do
				while str = q.pop
						clientHash.each_value do |cs|
						cs.write str
					end
				end
			end

			# command operations
			while l = s.gets
				l.chomp!
				l = Kconv.toutf8(l)
				case l
				when /^USER \w+/i
					if user == nil
						user = l.split(/ /)[1]
					else
						s.write "-ERR You have already logged in." + CRLF
						next
					end
					if clientHash.has_key?(user) != true
						clientHash.store(user, s)
						s.write "+OK Hello, " + user + "." + CRLF
						now = Time.now
						str2cli = "*INFO [" + now.to_s + "] " + user + " logged in." + CRLF
						str2log = "[" + now.to_s + "] " + user + " logged in from " + ns.peeraddr[2] + "." + "\n"
						$stderr.print str2log
						#tpush.run
						q.push str2cli
					else
						s.write "-ERR Nickname already in use." + CRLF
					end
				when /^MEMBER$/i
					num_members = clientHash.size
					s.write "+OK " + num_members.to_s + " members in the room." + CRLF
					if num_members != 0
						clientHash.each_key do |u|
							s.write u + CRLF
						end
						s.write "." + CRLF
					end
				when /^TALK .+/i
					if user == nil
						s.write "-ERR You are not logged in." + CRLF
						next
					else
						message = l.split(/ /, 2)[1]
						s.write "+OK Your message has received." + CRLF
						q.push("*MSG [" + Time.now.to_s + "] " + user + " " + filter(message) + CRLF)
					end
				when /^QUIT$/i
					s.write "+OK Have a nice day!" + CRLF
					if user != nil
						clientHash.delete(user)
						now = Time.now
						str2cli = "*INFO [" + now.to_s + "] " + user + " logged out." + CRLF
						str2log = "[" + now.to_s + "] " + user + " logged out from " + ns.peeraddr[2] + "." + "\n"
						$stderr.print str2log
						q.push str2cli
					end
					break
				when /^NOOP$/i
					s.write "+OK I'm here saying nothing." + CRLF
				else
					s.write "-ERR Invalid command." + CRLF
				end
			end
			s.close
		end
	end
end