require "option_parser"
require "ipc"
require "socket"
require "./colors"

class WrappedTCPFileDescriptor < TCPSocket
	# do not close the connection when garbage collected!!
	def finalize
		# puts "WrappedTCPFileDescriptor garbage collection!!"
		# super
	end
end

service_name = "tcp"
port_to_listen = 1234

OptionParser.parse do |parser|
	parser.on "-p port", "--port port", "Port to listen on." do |port|
		port_to_listen = port.to_u16
	end

	parser.on "-s service-name", "--service-name service-name", "Service name." do |name|
		service_name = name
	end

	parser.on "-h", "--help", "Show this help" do
		puts parser
		exit 0
	end
end


fdlist_client = [] of TCPSocket
fdlist = [] of TCPSocket

server = TCPServer.new("localhost", port_to_listen)
service = IPC::SwitchingService.new service_name
service << server.fd

service.loop do |event|
	# TODO: remove closed tcp connections
	fdlist_client.select do |x| ! x.closed? end
	case event
	when IPC::Event::Connection
		puts "#{CBLUE}IPC::Event::Connection#{CRESET}"
	when IPC::Event::Disconnection
		puts "#{CBLUE}IPC::Event::Disconnection#{CRESET}"
	when IPC::Event::ExtraSocket
		puts "#{CBLUE}IPC::Event::ExtraSocket#{CRESET}"

		if server.fd == event.connection.fd
			client = server.accept
			fdlist << client
			service << client.fd
			puts "#{CBLUE}new client: #{client.fd}#{CRESET}"
			next
		end

		# since it's an external communication
		# we have to read the message here, it's not handled by default in libipc
		client = WrappedTCPFileDescriptor.new(fd: event.connection.fd, family: Socket::Family::INET)
		message = client.gets
		if message.nil?
			# disconnection
			puts "#{CBLUE}disconnection of client #{event.connection.fd}#{CRESET}"
			service.remove_fd event.connection.fd
			fdlist.select do |x| x.fd != event.connection.fd end
			client.close
		else
			message.chomp
			puts "#{CORANGE}message from client #{client.fd} (#{message.size} bytes): #{message}#{CRESET}"
			begin
				requested_service = message
				newservice = IPC::Connection.new requested_service
				service << newservice.fd
				service.switch.add event.connection.fd, newservice.fd
				client << "OK\n"
			rescue e
				puts "#{CRED}Exception during connection to the service: #{e}#{CRESET}"
			end
			# client << message
		end
	when IPC::Event::Switch
		puts "\033[36mIPC::Event::Switch#{CRESET}: from fd #{event.connection.fd}"

	# IPC::Event::Message has to be the last entry
	# because ExtraSocket and Switch inherit from Message class
	when IPC::Event::Message
		puts "#{CBLUE}IPC::Event::Message#{CRESET}: #{event.connection.fd}"
		puts "\033[33mconnection to the service: #{String.new event.message.payload}\033[00m"

		begin
			# should be in the format: service-name IP port
			payload = String.new event.message.payload
			uri = URI.parse payload.chomp
			host = uri.host
			port = uri.port
			host ||= "localhost"
			port ||= 9000

			requested_service = uri.path.lchop

			newservice = TCPSocket.new(host, port)
			puts "sending the requested service to the remote tcpd: #{requested_service}"
			newservice << "#{requested_service}\n"

			puts "waiting for a response from the remote tcpd"
			response = newservice.gets
			if response.nil?
				raise "#{CRED}No response from the tcpd server#{CRESET}"
			end
			response.chomp
			puts "#{CGREEN}response from the remote tcpd: #{CRESET}#{response}"

			# TODO: when to remove this? This has to happen, memory leak otherwise
			# XXX: hint, check after a select for all dead connections
			fdlist_client << newservice

			# newservice = IPC::Connection.new requested_service
			service << newservice.fd
			service.switch.add event.connection.fd, newservice.fd
			# service.switch.print
			event.connection.send 1.to_u8, "OK"
		rescue e
			puts "\033[31mException: #{e}"
			event.connection.close
		end
	end
end