#!/usr/bin/env python3

import socket
import ssl


class Connection:
    """
        Establishes a connection to the OM Application XML Interface

        :param host: Hostname or IP address of OMM
        :param port: Port of the OM Application XML plain TCP port

        Usage::
            >>> c = Connection("omm.local")
            >>> c.connect()
            >>> c.send(request)
            >>> r = c.recv()
    """

    def __init__(self, host, port=12621):
        self._host = host
        self._port = port
        self._socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self._recv_buffer = ""

    def connect(self):
        """
            Establishes the connection
        """

        self._socket.connect((self._host, self._port))

    def send(self, message):
        """
            Sends message string

            :param message: Message string
        """

        self._socket.send(message.encode("utf-8") + b"\0")

    def recv(self):
        """
            Returns one message

            Use multiple times to receive multiple messages
        """

        data = b""
        while True:
            new_data = self._socket.recv(65536)
            if new_data is not None:
                data += new_data
            else:
                break
        self._recv_buffer += data.decode("utf-8")

        if "\0" not in self._recv_buffer:
            # no new messages
            return None

        message, buffer = self._recv_buffer.split("\0", 1)
        self._recv_buffer = buffer

        return message

    def close(self):
        """
            Shout down connection
        """

        return self._socket.close()

    def __del__(self):
        self.close()


class SSLConnection(Connection):
    """
        Establishes a secure connection to the OM Application XML Interface

        Please not that this class might be useless on your system since new
        versions of OpenSSL don't ship with TLVv1.2 or lower anymore which are
        the protocols supported by OMM.

        :param host: Hostname or IP address of OMM
        :param port: Port of the OM Application XML ssl TCP port

        Usage:

        See :class:`Connection`
    """

    def __init__(self, host, port=12622):
        super().__init__(host, port)

        self._socket = ssl.wrap_socket(self._socket)