#!/usr/bin/env python
# -*- coding: UTF-8 -*-

"""
tcp_socket (TCP Socket)
=======================

**Author:**

* Dirk Alders <sudo-dirk@mount-mockery.de>

**Description:**

    This Module supports a client/ server tcp socket connection.

**Submodules:**

* :class:`tcp_socket.tcp_client`
* :class:`tcp_socket.tcp_client_stp`
* :class:`tcp_socket.tcp_server`
* :class:`tcp_socket.tcp_server_stp`

**Unittest:**

        See also the :download:`unittest <../../tcp_socket/_testresults_/unittest.pdf>` documentation.
"""
__DEPENDENCIES__ = ['stringtools', 'task', ]

import stringtools
import task

import logging
import socket
import time

try:
    from config import APP_NAME as ROOT_LOGGER_NAME
except ImportError:
    ROOT_LOGGER_NAME = 'root'

logger = logging.getLogger(ROOT_LOGGER_NAME).getChild(__name__)


class tcp_base(object):
    """
    :param host: The host IP for the TCP socket functionality
    :type host: str
    :param port: The port for the TCP socket functionality
    :type port: int
    :param rx_log_lvl: The log level to log incomming RX-data
    :type rx_log_lvl: int

    This is the base class for other classes in this module.

    .. note:: This class is not designed for direct usage.
    """
    LOG_PREFIX = 'TCP_IP:'
    RX_LENGTH = 0xff
    COM_TIMEOUT = 0.5
    IS_CLIENT = False

    def __init__(self, host, port, rx_log_lvl=logging.INFO):
        self.host = host
        self.port = port
        self.__socket__ = None
        self.__data_available_callback__ = None
        self.__supress_data_available_callback__ = False
        self.__connect_callback__ = None
        self.__disconnect_callback__ = None
        self.__clean_receive_buffer__()
        self.__connection__ = None
        self.__listening_message_displayed__ = False
        self.__client_address__ = None
        self.__queue__ = task.threaded_queue()
        self.__queue__.enqueue(5, self.__receive_task__, rx_log_lvl)
        self.__queue__.run()

    def is_connected(self):
        return self.__connection__ is not None

    def client_address(self):
        """
        :return: The client address.
        :rtype: str

        This method returns the address of the connected client.
        """
        return self.__client_address__[0]

    def receive(self, timeout=1, num=None):
        """
        :param timeout: The timeout for receiving data (at least after the timeout the method returns data or None).
        :type timeout: float
        :param num: the number of bytes to receive (use None to get all available data).
        :type num: int
        :return: The received data.
        :rtype: str

        This method returns data received via the initiated communication channel.
        """
        rv = None
        if self.__connection__ is not None:
            tm = time.time()
            while (num is not None and len(self.__receive_buffer__) < num) or (num is None and len(self.__receive_buffer__) < 1):
                if self.__connection__ is None:
                    return None
                if time.time() > tm + timeout:
                    logger.warning('%s TIMEOUT (%ss): Not enough data in buffer. Requested %s and buffer size is %d.', self.LOG_PREFIX, repr(timeout), repr(num or 'all'), len(self.__receive_buffer__))
                    return None
                time.sleep(0.05)
            if num is None:
                rv = self.__receive_buffer__
                self.__clean_receive_buffer__()
            else:
                rv = self.__receive_buffer__[:num]
                self.__receive_buffer__ = self.__receive_buffer__[num:]
        return rv

    def send(self, data, timeout=1, log_lvl=logging.INFO):
        """
        :param data: The data to be send over the communication channel.
        :type data: str
        :param timeout: The timeout for sending data (e.g. time to establish new connection).
        :type timeout: float
        :param rx_log_lvl: The log level to log outgoing TX-data
        :type rx_log_lvl: int
        :return: True if data had been sent, otherwise False.
        :rtype: bool

        This method sends data via the initiated communication channel.
        """
        cnt = 0
        while self.__connection__ is None and cnt < int(10 * timeout):
            time.sleep(.1)  # give some time to establish the connection
            cnt += 1
        if self.__connection__ is not None:
            self.__connection__.sendall(data)
            logger.log(log_lvl, '%s TX -> "%s"', self.LOG_PREFIX, stringtools.hexlify(data))
            return True
        else:
            logger.warning('%s Cound NOT send -> "%s"', self.LOG_PREFIX, stringtools.hexlify(data))
            return False

    def register_callback(self, callback):
        """
        :param callback: The callback which will be executed, when data is available.
        :type callback: function

        This method sets the callback which is executed, if data is available. You need to execute :func:`receive` of the instance
        given with the first argument.

        .. note:: The :func:`callback` is executed with these arguments:

            :param self: This communication instance
        """
        self.__data_available_callback__ = callback

    def register_connect_callback(self, callback):
        """
        :param callback: The callback which will be executed, when a connect is identified.
        :type callback: function

        This method sets the callback which is executed, if a connect is identified.
        """
        self.__connect_callback__ = callback

    def register_disconnect_callback(self, callback):
        """
        :param callback: The callback which will be executed, when a disconnect is identified.
        :type callback: function

        This method sets the callback which is executed, if a disconnect is identified.
        """
        self.__disconnect_callback__ = callback

    def __receive_task__(self, queue_inst, rx_log_lvl):
        if self.__connection__ is not None:
            try:
                data = self.__connection__.recv(self.RX_LENGTH)
            except socket.error as e:
                if e.errno != 11:
                    raise
                else:
                    time.sleep(.05)
            else:
                if len(data) > 0:
                    logger.log(rx_log_lvl, '%s RX <- "%s"', self.LOG_PREFIX, stringtools.hexlify(data))
                    self.__receive_buffer__ += data
                else:
                    self.__connection_lost__()
            self.__call_data_available_callback__()
        else:
            self.__connect__()
        queue_inst.enqueue(5, self.__receive_task__, rx_log_lvl)

    def __call_data_available_callback__(self):
        if len(self.__receive_buffer__) > 0 and not self.__supress_data_available_callback__ and self.__data_available_callback__ is not None:
            self.__supress_data_available_callback__ = True
            self.__data_available_callback__(self)
            self.__supress_data_available_callback__ = False

    def __connection_lost__(self):
        self.__listening_message_displayed__ = False
        self.__connection__.close()
        self.__connection__ = None
        self.__client_address__ = None
        logger.info('%s Connection lost...', self.LOG_PREFIX)
        if self.__disconnect_callback__ is not None:
            self.__disconnect_callback__()

    def __clean_receive_buffer__(self):
        logger.debug("%s Cleaning up receive-buffer", self.LOG_PREFIX)
        self.__receive_buffer__ = ""

    def close(self):
        """
        This method closes the active communication channel, if channel exists.
        """
        self.__queue__.stop()
        self.__queue__.join()
        if self.__connection__ is not None:
            self.__connection_lost__()
        if self.__socket__ is not None:
            self.__socket__.close()

    def __del__(self):
        self.close()


class tcp_server(tcp_base):
    """
    :param host: The host IP for the TCP socket functionality
    :type host: str
    :param port: The port for the TCP socket functionality
    :type port: int
    :param rx_log_lvl: The log level to log incomming RX-data
    :type rx_log_lvl: int

    This class supports a tcp-server transfering a serial stream of bytes (characters).

    .. note:: You need a :class:`tcp_client` to communicate with the server.

    **Example:**

    .. literalinclude:: ../../tcp_socket/_examples_/tcp_socket__tcp_server.py

    .. literalinclude:: ../../tcp_socket/_examples_/tcp_socket__tcp_server.log
    """
    def __connect__(self):
        if self.__socket__ is None:
            # Create a TCP/IP socket
            self.__socket__ = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            # Bind the socket to the port
            server_address = (self.host, self.port)
            self.__socket__.bind(server_address)
            # Listen for incoming connections
            self.__socket__.listen(1)
            self.__socket__.settimeout(self.COM_TIMEOUT)
            self.__socket__.setblocking(False)
        if not self.__listening_message_displayed__:
            logger.info('%s Server listening to %s:%d', self.LOG_PREFIX, self.host, self.port)
            self.__listening_message_displayed__ = True
        try:
            self.__connection__, self.__client_address__ = self.__socket__.accept()
        except socket.error as e:
            if e.errno != 11:
                raise
            else:
                time.sleep(.05)
        else:
            logger.info('%s Connection established... (from %s)', self.LOG_PREFIX, self.client_address())
            self.__clean_receive_buffer__()
            self.__connection__.setblocking(False)
            if self.__connect_callback__ is not None:
                self.__connect_callback__()


class tcp_client(tcp_base):
    """
    :param host: The host IP for the TCP socket functionality
    :type host: str
    :param port: The port for the TCP socket functionality
    :type port: int
    :param rx_log_lvl: The log level to log incomming RX-data
    :type rx_log_lvl: int

    This class supports a tcp-client transfering a serial stream of bytes (characters).

    .. note:: You need a running :class:`tcp_server` listening at the given IP and port to communicate.

    **Example:**

    .. literalinclude:: ../../tcp_socket/_examples_/tcp_socket__tcp_client.py

    .. literalinclude:: ../../tcp_socket/_examples_/tcp_socket__tcp_client.log
    """
    IS_CLIENT = True

    def __connect__(self):
        if self.__socket__ is None:
            # Create a TCP/IP socket
            self.__socket__ = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            self.__socket__.setblocking(False)
        # Connect the socket to the port where the server is listening
        try:
            self.__socket__.connect((self.host, self.port))
        except socket.error as e:
            if e.errno == 9:
                self.__socket__.close()
            elif e.errno != 115 and e.errno != 111 and e.errno != 114:
                raise
            else:
                self.__connection__ = None
                time.sleep(.05)
        else:
            logger.info('%s Connection to %s:%s established', self.LOG_PREFIX, self.host, self.port)
            self.__clean_receive_buffer__()
            self.__connection__ = self.__socket__
            if self.__connect_callback__ is not None:
                self.__connect_callback__()

    def __connection_lost__(self):
        self.__socket__ = None
        tcp_base.__connection_lost__(self)

    def reconnect(self):
        self.__connect__()


class tcp_base_stp(tcp_base):
    """
    :param host: The host IP for the TCP socket functionality
    :type host: str
    :param port: The port for the TCP socket functionality
    :type port: int
    :param rx_log_lvl: The log level to log incomming RX-data
    :type rx_log_lvl: int

    This is the base class for other classes in this module.

    .. note:: This class is not designed for direct usage.
    """

    def __init__(self, host, port, rx_log_lvl=logging.INFO):
        tcp_base.__init__(self, host, port, rx_log_lvl=rx_log_lvl)
        self.__stp__ = stringtools.stp.stp()

    def __clean_receive_buffer__(self):
        logger.debug("%s Cleaning up receive-buffer", self.LOG_PREFIX)
        self.__receive_buffer__ = []

    def receive(self, timeout=1):
        """
        :param timeout: The timeout for receiving data (at least after the timeout the method returns data or None).
        :type timeout: float
        :return: The received data.
        :rtype: str

        This method returns one received messages via the initiated communication channel.
        """
        try:
            return tcp_base.receive(self, timeout=timeout, num=1)[0]
        except TypeError:
            return None

    def send(self, data, timeout=1, log_lvl=logging.INFO):
        """
        :param data: The message to be send over the communication channel.
        :type data: str
        :param timeout: The timeout for sending data (e.g. time to establish new connection).
        :type timeout: float
        :param rx_log_lvl: The log level to log outgoing TX-data
        :type rx_log_lvl: int
        :return: True if data had been sent, otherwise False.
        :rtype: bool

        This method sends one message via the initiated communication channel.
        """
        if tcp_base.send(self, stringtools.stp.build_frame(data), timeout=timeout, log_lvl=logging.DEBUG):
            logger.log(log_lvl, '%s TX -> "%s"', self.LOG_PREFIX, stringtools.hexlify(data))
            return True
        else:
            return False

    def __receive_task__(self, queue_inst, rx_log_lvl):
        if self.__connection__ is not None:
            try:
                data = self.__connection__.recv(self.RX_LENGTH)
            except socket.error as e:
                if e.errno == 104:
                    self.__connection_lost__()
                elif e.errno != 11:
                    raise
                else:
                    time.sleep(.05)
            else:
                if len(data) > 0:
                    logger.debug('%s -- <- "%s"', self.LOG_PREFIX, stringtools.hexlify(data))
                    content = self.__stp__.process(data)
                    for msg in content:
                        logger.log(rx_log_lvl, '%s RX  <- "%s"', self.LOG_PREFIX, stringtools.hexlify(msg))
                        self.__receive_buffer__.append(msg)
                else:
                    self.__connection_lost__()
            self.__call_data_available_callback__()
        else:
            self.__connect__()
        queue_inst.enqueue(5, self.__receive_task__, rx_log_lvl)


class tcp_server_stp(tcp_server, tcp_base_stp):
    """
    :param host: The host IP for the TCP socket functionality
    :type host: str
    :param port: The port for the TCP socket functionality
    :type port: int
    :param rx_log_lvl: The log level to log incomming RX-data
    :type rx_log_lvl: int

    This class supports a tcp-server transfering a string. The string will be packed on send and unpacked on receive.
    See :mod:`stp` for more information on packing and unpacking.

    .. note:: You need a :class:`tcp_client_stp` to communicate with the server.

    **Example:**

    .. literalinclude:: ../../tcp_socket/_examples_/tcp_socket__tcp_server_stp.py

    .. literalinclude:: ../../tcp_socket/_examples_/tcp_socket__tcp_server_stp.log
    """
    pass


class tcp_client_stp(tcp_client, tcp_base_stp):
    """
    :param host: The host IP for the TCP socket functionality
    :type host: str
    :param port: The port for the TCP socket functionality
    :type port: int

    This class supports a tcp-server transfering a string. The string will be packed on send and unpacked on receive.
    See :mod:`stp` for more information on packing and unpacking.

    .. note:: You need a running :class:`tcp_server_stp` listening at the given IP and port to communicate.

    **Example:**

    .. literalinclude:: ../../tcp_socket/_examples_/tcp_socket__tcp_server_stp.py

    .. literalinclude:: ../../tcp_socket/_examples_/tcp_socket__tcp_server_stp.log
    """
    pass