#!/usr/bin/env python3
# -*- coding: utf-8 -*-

"""
Author: freezed <freezed@users.noreply.github.com> 2018-03-06
Version: 0.1
Licence: `GNU GPL v3` GNU GPL v3: http://www.gnu.org/licenses/

This file is part or roboc project. View `readme.md`
"""
import socket
import select


class ConnectSocket:
    """
    ConnectSocket
    =======

    Provide network connection and management methods

    :Example:
    >>> c0 = ConnectSocket()
    Server is running, listening on port 5555

    >>> c0.list_sockets(False, False)
    []

    >>> c0.list_sockets()
    ''

    >>> c0.count_clients()
    0

    >>> c0.close()
    Server stop
    """
    # default connection parameters
    _HOST = 'localhost'
    _PORT = 5555
    _BUFFER = 1024
    _MAIN_CONNECT = "MAIN_CONNECT"

    # Template messages
    _BROADCAST_MSG = "{}~ {}\n"
    _MSG_DISCONNECTED = "<gone away to infinity, and beyond>"
    _MSG_SALUTE = "Hi, {}, wait for other players\n"
    _MSG_SERVER_STOP = "Server stop"
    _MSG_START_SERVER = "Server is running, listening on port {}"
    _MSG_USER_IN = "<entered the network>"
    _MSG_WELCOME = "Welcome. First do something usefull and type your name: "
    _MSG_UNWELCOME = "Sorry, no more place here.\n"
    _MSG_UNSUPPORTED = "Unsupported data:«{}»{}"
    _SERVER_LOG = "{}:{}|{name}|{msg}"

    # Others const
    _MAX_CLIENT_NAME_LEN = 8
    _MIN_CLIENT_NAME_LEN = 3
    _MAX_CLIENT_NB = 5

    def __init__(self, host=_HOST, port=_PORT):
        """
        Set up the server connection using a socket object

        :param str _HOST: domain or IPV4 address
        :param int _PORT: port number
        :return obj: socket
        """

        # Setting up the connection
        self._main_sckt = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self._main_sckt.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        self._main_sckt.bind((host, port))
        self._main_sckt.listen(5)

        # Init connection list
        self._inputs = []
        self._inputs.append(self._main_sckt)

        # Init username list, to keep match between inputs & name lists
        self._user_name = []
        self._user_name.append(self._MAIN_CONNECT)

        # Logging server's activity
        self.server_log(self._MSG_START_SERVER.format(port))

    def broadcast(self, sender, message):
        """
        Send a message to all named-clients but the sender

        TODO should replace sckt.send() too

        :param obj sender: sender socket (or 'server' str() for server)
        :param str message: message to send
        """
        # Define senders name
        if sender == 'server':
            name = 'server'.upper()
        else:
            idx = self._inputs.index(sender)
            name = self._user_name[idx].upper()

        message = self._BROADCAST_MSG.format(name, message)
        recipients = self.list_sockets(False, False)

        for sckt in recipients:
            if sckt != sender:
                sckt.send(message.encode())
                # NOTE I remove a `try/except` here because I do not
                # encountered any Error, I cannot choose the correct
                # exception type
                # sckt.close() \ self._inputs.remove(sckt)

    def close(self):
        """ Cleanly closes each socket (clients) of the network """
        self._main_sckt = self._inputs.pop(0)
        i = 1
        for sckt in self._inputs:
            self.server_log(self._SERVER_LOG.format(
                *sckt.getpeername(),
                name=self._user_name[i],
                msg="closed client socket")
                           )
            sckt.close()
            i += 1
        self._inputs.clear()
        self._main_sckt.close()
        self.server_log(self._MSG_SERVER_STOP)

    def count_clients(self):
        """
        Count connected and named clients

        (to avoid playing with a unamed player)
        """
        return len(self.list_sockets(False, False))

    def data_filter(self, data, s_idx):
        """
        Filters the data basically:

        - Alphanumeric char only
        - non-alphanum char replaced by 'x'
        - 'xxx' for string < MIN
        - Troncated after the MAX char
        - trailed with index number if same name exists
        """
        # alphanumeric
        if str(data).isalnum() is False:
            f_data = ''
            for char in data:
                if char.isalnum():
                    f_data += char
                else:
                    f_data += 'x'
            data = f_data

        # minimum length
        if len(data) < self._MIN_CLIENT_NAME_LEN:
            data += 'xxx'

        # maximum length
        data = data[0:self._MAX_CLIENT_NAME_LEN]

        # name already used
        if data in self._user_name:
            data += str(s_idx)

        return data

    def list_sockets(self, print_string=True, user_name=True):
        """
        List connected sockets

        :param bool print_string: return txt formated socket list
        :param bool user_name: return user_name
        """
        if user_name:
            client_list = [
                name for name in self._user_name
                if name != self._MAIN_CONNECT and name is not False
            ]
        else:
            client_list = [
                sckt for (idx, sckt) in enumerate(self._inputs)
                if sckt != self._main_sckt
                and self._user_name[idx] is not False
            ]

        # NOTE maybe there is a better way for the next condition: when
        # client connects it has not yet his name filled in the
        # _user_name attribut, then this method returns only clients
        # with a filled name
        if print_string and len(client_list) == 0:
            client_list = ""
        elif print_string:
            client_list = ", ".join(client_list)

        return client_list

    def listen(self):
        """
        Listen sockets activity

        Get the list of sockets which are ready to be read and apply:
        - connect a new client
        - return data sended by client

        This object only processes data specific to network connections,
        other data (username and message sent) are stored in `u_name` &
        `message` attributes to be used by parent script

        :return str, str: user_name, data
        """
        self.u_name = ""
        self.message = ""

        # listennig…
        rlist, [], [] = select.select(self._inputs, [], [], 0.05)
        for sckt in rlist:

            # logging, broadcasting & sending (LBS) params
            logging = True
            broadcasting = True
            sending = True

            # Listen for new client connection
            if sckt == self._main_sckt:
                sckt_object, sckt_addr = sckt.accept()

                # Maximum connection number is not reached: accepting
                if len(self._inputs) <= self._MAX_CLIENT_NB:
                    self._inputs.append(sckt_object)
                    self._user_name.append(False)

                    # LBS params override
                    log_msg = self._SERVER_LOG.format(
                        *sckt_addr, name="unknown", msg="connected"
                    )

                    sckt_object.send(self._MSG_WELCOME.encode())
                    broadcasting = False
                    sending = False

                # Refusing
                else:
                    sckt_object.send(self._MSG_UNWELCOME.encode())
                    self.server_log(self._SERVER_LOG.format(
                        *sckt_addr, name="unknow", msg="rejected"
                    ))
                    sckt_object.close()
                    break

            else:  # receiving data
                data = sckt.recv(self._BUFFER).decode().strip()
                s_idx = self._inputs.index(sckt)

                if self._user_name[s_idx] is False:  # setting username

                    # saving name
                    self._user_name[s_idx] = self.data_filter(data, s_idx)

                    # LBS params override
                    log_msg = self._SERVER_LOG.format(
                        *sckt.getpeername(),
                        name=self._user_name[s_idx],
                        msg="set user name"
                    )

                    bdcst_msg = self._MSG_USER_IN

                    send_msg = self._MSG_SALUTE.format(self._user_name[s_idx])

                elif data.upper() == "QUIT":  # client quit network

                    # LBS params override
                    log_msg = self._SERVER_LOG.format(
                        *sckt.getpeername(),
                        name=self._user_name[s_idx],
                        msg="disconnected"
                    )

                    # broadcasting params
                    bdcst_msg = self._MSG_DISCONNECTED
                    self.broadcast(sckt, bdcst_msg)

                    broadcasting = False
                    sending = False

                    self._inputs.remove(sckt)
                    self._user_name.pop(s_idx)
                    sckt.close()

                elif data:
                    self.u_name, self.message = self._user_name[s_idx], data

                    # LBS params override
                    log_msg = self._SERVER_LOG.format(
                        *sckt.getpeername(),
                        name=self._user_name[s_idx],
                        msg=data
                    )
                    broadcasting = False
                    sending = False

                else:

                    # LBS params override
                    log_msg = self._SERVER_LOG.format(
                        *sckt.getpeername(),
                        name=self._user_name[s_idx],
                        msg=self._MSG_UNSUPPORTED.format(data)
                    )

                    send_msg = self._MSG_UNSUPPORTED.format(data, "\n")

                    broadcasting = False

            if logging:
                self.server_log(log_msg)

            if broadcasting:
                self.broadcast(sckt, bdcst_msg)

            if sending:
                sckt.send(send_msg.encode())

    @staticmethod
    def server_log(msg):
        """ Log activity on server-side"""
        print(msg)
        # writes in a logfile here TODO19
        # adds a timestamp TODO20


if __name__ == "__main__":
    """ Starting doctests """

    import doctest
    doctest.testmod()