import socket
from threading import Thread


class SocketClient(Thread):
    __BLOCK_SIZE, __MAX_TIMES = 1024, 1024 * 10

    def __init__(self, host: "str", port: "int"):
        super().__init__()
        self.__client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.__client.connect((host, port))
        self.__handlers, self.__running = {"BROADCAST": self.__on_broad}, False

    def __on_broad(self, msg: "str"):
        raise NotImplementedError(
            "got a broadcast msg, but there are no handler for it.\n"
            "you should bind a <BROADCAST> message handler with 'on'."
        )

    def on(self, event: "str"):
        def decorator(func):
            self.__handlers[event] = func
            return func

        return decorator

    def emit(self, event: "str", msg: "bytes"):
        self.__client.sendall(f"==EVENT:{event}==".encode("utf-8") + msg + b"==END==")

    def run(self) -> None:
        self.__running = True
        try:
            while self.__running:
                times = SocketClient.__MAX_TIMES
                cur = self.__client.recv(SocketClient.__BLOCK_SIZE)
                if cur.startswith(b"==EVENT:"):
                    _e = cur[8:].find(b"==")
                    event, cur = cur[8:_e + 8].decode("utf-8"), cur[_e + 10:]
                    data = cur
                    while not data.endswith(b"==END=="):
                        cur = self.__client.recv(SocketClient.__BLOCK_SIZE)
                        data, times = data + cur, times - 1
                        if times <= 0:
                            break
                    if data.endswith(b"==END=="):
                        if event in self.__handlers.keys():
                            self.__handlers[event](data[:-7])
                    else:
                        raise RuntimeError(f"bad ending in msg: {data[:20]}")
        finally:
            self.__client.close()

    def stop(self):
        self.__running = False