import sys
from amqplib import client_0_8 as amqp

# Modelling a global chat publisher
class Chat:

    GLOBAL_EXCHANGE = "global_chat"
    PRIVATE_EXCHANGE = "private_chat"
    GLOBAL_ROUTING_KEY = "global_message"

    def __init__(self, username):
        self.conn = amqp.Connection(host="192.168.24.131:5672 ", userid="guest", password="guest", virtual_host="/", insist=False)
        self.chan = self.conn.channel()
        self.username = username
        self.GLOBAL_QUEUE = "global_chat_%s" % self.username
        self.PRIVATE_QUEUE = "user_%s" % self.username
        self.PRIVATE_ROUTING_KEY = "private_%s"
        self.declare_amqp_components()

    def declare_amqp_components(self):
        # Declare the single chat exchange
        self.chan.exchange_declare(exchange=self.GLOBAL_EXCHANGE, type="fanout", durable=True, auto_delete=False)
        self.chan.exchange_declare(exchange=self.PRIVATE_EXCHANGE, type="direct", durable=True, auto_delete=False)

        # Declare 2 queues: one global, and one private for the user
        self.chan.queue_declare(queue=self.GLOBAL_QUEUE, durable=True, exclusive=False, auto_delete=False)
        self.chan.queue_declare(queue="user_%s" % self.username, durable=True, exclusive=False, auto_delete=False)

        # Bind both queues to the chat exchange, with different routing keys
        self.chan.queue_bind(queue=self.GLOBAL_QUEUE, exchange=self.GLOBAL_EXCHANGE, routing_key=self.GLOBAL_ROUTING_KEY)
        self.chan.queue_bind(queue=self.PRIVATE_QUEUE, exchange=self.PRIVATE_EXCHANGE, routing_key=self.PRIVATE_ROUTING_KEY % self.username)

    def shout(self, message):
        msg = amqp.Message(message)
        msg.properties["delivery_mode"] = 2 # Persistent
        self.chan.basic_publish(msg, exchange=self.GLOBAL_EXCHANGE, routing_key=self.GLOBAL_ROUTING_KEY)

    def whisper(self, target_username, message):
        msg = amqp.Message(message)
        msg.properties["delivery_mode"] = 2 # Persistent
        self.chan.basic_publish(msg, exchange=self.PRIVATE_EXCHANGE, routing_key=self.PRIVATE_ROUTING_KEY % target_username)

    def listen(self):
        self.chan.basic_consume(queue=self.GLOBAL_QUEUE, no_ack=True, callback=self._receive_global_message, consumer_tag="global_chat_receiver")
        self.chan.basic_consume(queue=self.PRIVATE_QUEUE, no_ack=True, callback=self._receive_private_message, consumer_tag="private_chat_receiver")
        while True:
            self.chan.wait()
        self.chan.basic_cancel("chat_receiver")

    def _receive_global_message(self, message):
        print "<SHOUT>: %s" % message.body

    def _receive_private_message(self, message):
        print "<PRIVATE>: %s" % message.body


# Command line client/listener

if len(sys.argv) < 2:
    print "Usage: "
    print "    python chat_client.py <your_username> whisper <target_username> \"Psst, keep this a secret!\""
    print "    python chat_client.py <your_username> shout \"Hey everybody!\""
    sys.exit(0)

user, command = sys.argv[1], sys.argv[2]

g = Chat(user)
if command == "listen":
    g.listen()

if command == "shout":
    g.shout(message=sys.argv[3])

if command == "whisper":
    g.whisper(target_username=sys.argv[3], message=sys.argv[4])