import selectors
import socket
import ServerThread


class SMTPServer:
    def __init__(self, host: str, port: int):
        self.__host = host
        self.__port = port
        self.__socket = None
        self.__selector = selectors.DefaultSelector()

        self.__server_threads = []
        self.active = False

    def start_server(self) -> bool:
        server_address = (self.__host, self.__port)

        try:
            self.__socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            self.__socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
            self.__socket.bind(server_address)
            self.__socket.listen()
            self.__socket.setblocking(False)
            self.__selector.register(self.__socket, selectors.EVENT_READ, data=None)
            self.active = True

            print(f"Server Listening on {self.__host}:{self.__port}")
            result = True
        except OSError as ex:
            self.__socket.close()
            self.__socket = None
            print(f"Error opening the listener: {repr(ex)}")
            result = False

        return result

    def accept_wrapper(self, socket_in: socket):
        connection, address = socket_in.accept()
        print("Received Connection from", address)

        connection.setblocking(False)
        new_server_thread = ServerThread.ServerThread(connection, address)
        self.__server_threads.append(new_server_thread)
        new_server_thread.start()

    def open_server(self):
        try:
            while self.active:
                events = self.__selector.select(timeout=None)

                for key, mask in events:
                    if key.data is None:
                        self.accept_wrapper(key.fileobj)
                    else:
                        pass
        except KeyboardInterrupt as ex:
            print("Keyboard Exception")
            for child_thread in self.__server_threads:
                child_thread.active = False
            self.active = False
        finally:
            self.__selector.close()