import argparse
from collections import deque
from enum import Enum
import time
import socket
import json
team_name = "HanyangFloorFunction"

class Dir(str, Enum):
    BUY = "BUY"
    SELL = "SELL"


class ExchangeConnection:
    def __init__(self, args):
        self.message_timestamps = deque(maxlen=500)
        self.exchange_hostname = args.exchange_hostname
        self.port = args.port
        exchange_socket = self._connect(add_socket_timeout=args.add_socket_timeout)
        self.reader = exchange_socket.makefile("r", 1)
        self.writer = exchange_socket

        self._write_message({"type": "hello", "team": team_name.upper()})

    def read_message(self):
        """Read a single message from the exchange"""
        message = json.loads(self.reader.readline())
        if "dir" in message:
            message["dir"] = Dir(message["dir"])
        return message

    def send_add_message(
        self, order_id: int, symbol: str, dir: Dir, price: int, size: int
    ):
        """Add a new order"""
        self._write_message(
            {
                "type": "add",
                "order_id": order_id,
                "symbol": symbol,
                "dir": dir,
                "price": price,
                "size": size,
                "tif": "DAY",
            }
        )

    def send_convert_message(self, order_id: int, symbol: str, dir: Dir, size: int):
        """Convert between related symbols"""
        self._write_message(
            {
                "type": "convert",
                "order_id": order_id,
                "symbol": symbol,
                "dir": dir,
                "size": size,
            }
        )

    def send_cancel_message(self, order_id: int):
        """Cancel an existing order"""
        self._write_message({"type": "cancel", "order_id": order_id})

    def _connect(self, add_socket_timeout):
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

        if add_socket_timeout:
            # Automatically raise an exception if no data has been recieved for
            # multiple seconds. This should not be enabled on an "empty" test
            # exchange.
            s.settimeout(5)
        s.connect((self.exchange_hostname, self.port))
        return s

    def _write_message(self, message):
        what_to_write = json.dumps(message)
        if not what_to_write.endswith("\n"):
            what_to_write = what_to_write + "\n"

        length_to_send = len(what_to_write)
        total_sent = 0
        while total_sent < length_to_send:
            sent_this_time = self.writer.send(
                what_to_write[total_sent:].encode("utf-8")
            )
            if sent_this_time == 0:
                raise Exception("Unable to send data to exchange")
            total_sent += sent_this_time

        now = time.time()
        self.message_timestamps.append(now)
        if len(
            self.message_timestamps
        ) == self.message_timestamps.maxlen and self.message_timestamps[0] > (now - 1):
            print(
                "WARNING: You are sending messages too frequently. The exchange will start ignoring your messages. Make sure you are not sending a message in response to every exchange message."
            )


def parse_arguments():
    test_exchange_port_offsets = {"prod-like": 0, "slower": 1, "empty": 2}

    parser = argparse.ArgumentParser(description="Trade on an ETC exchange!")
    exchange_address_group = parser.add_mutually_exclusive_group(required=True)
    exchange_address_group.add_argument(
        "--production", action="store_true", help="Connect to the production exchange."
    )
    exchange_address_group.add_argument(
        "--test",
        type=str,
        choices=test_exchange_port_offsets.keys(),
        help="Connect to a test exchange.",
    )

    # Connect to a specific host. This is only intended to be used for debugging.
    exchange_address_group.add_argument(
        "--specific-address", type=str, metavar="HOST:PORT", help=argparse.SUPPRESS
    )

    args = parser.parse_args()
    args.add_socket_timeout = True

    if args.production:
        args.exchange_hostname = "production"
        args.port = 25000
    elif args.test:
        args.exchange_hostname = "test-exch-" + team_name
        args.port = 22000 + test_exchange_port_offsets[args.test]
        if args.test == "empty":
            args.add_socket_timeout = False
    elif args.specific_address:
        args.exchange_hostname, port = args.specific_address.split(":")
        args.port = int(port)

    return args