#!/usr/bin/env python3.5
# Copyright 2017 Digital
#
# This file is part of DigiLib.
#
# DigiLib is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# DigiLib is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with DigiLib.  If not, see <http://www.gnu.org/licenses/>.

import atexit
import logging
import logging.handlers
import os
import queue
import select
import socket
import sys
import threading
import time
import traceback

import blinker
import curio
import digilib.misc

lclient = logging.getLogger(__name__+".client")
lserver = logging.getLogger(__name__+".server")
lschat = logging.getLogger(__name__+".server.chat")
lcchat = logging.getLogger(__name__+".client.chat")

_tasks = []

class ConnHandlerBase(object):
    def __init__(self, socket, addr, server):
        self.status = "init"
        super(ConnHandlerBase, self).__init__()
        self.socket = socket
        self.addr = addr
        self.server = server
        self.block_size = 1024
        # self.welcome_client()
        self.status="connected"

    async def welcome_client(self):
        pass

    async def handle(self, data):
        return

    async def recv(self):
        data_received = await self.socket.recv(self.block_size)
        data_decoded = data_received.decode("utf-8")
        return data_decoded

    async def send(self, msg, log_msg=False):
        msg_encoded = bytes(msg, "utf-8")
        if log_msg:
            lschat.info("server:"+log_msg)
        else:
            lschat.info("Server:"+msg)
        try:
            await self.socket.send(msg_encoded)
            return True
        except Exception as e:
            lserver.error(e, exc_info=True)
            return False

    async def close(self):
        self.status = "closed"
        try:
            await self.socket.shutdown(0)
        except:
            lserver.debug("error during socket shutdown")
        try:
            await self.socket.close()
        except:
            lserver.debug("error closing socket")


class ConnHandlerEcho(ConnHandlerBase):
    def __init__(self, socket, addr, server):
        self.status = "init"
        self.super_class = super(ConnHandlerEcho, self)
        self.super_class.__init__(socket, addr, server)
        self.server = server
    def welcome_client(self):
        self.send("welcome to the client")
    def handle(self, data):
        lschat.info("Client:"+data)
        for h in list(set(self.server.connection_handler)-{self}):
            h.send(data)

class Server(object):
    """
    Server opens either an unix or an inet connection. for every client which connects a new ClientHandler class is created.
    """
    def __init__(self,
            host,
            port=None,
            af_family="AF_INET",
            log_ip=False,
            max_allowed_clients=5,
            handler_class=None,
            handler_kwargs={},
            ):
        super(Server, self).__init__()
        # set to true when the server shuts down, for instance after a
        # fatal exception
        self.exit_event =  False
        # on which hostname or ip address the connection will be opened
        self.host = host
        # on which port the connection will be opened
        self.port = port
        # what AF_INET family to use, either AF_INET or AF_UNIX (file socket)
        self.af_family = af_family
        # whether ip addresses will be logged
        self.log_ip = log_ip
        # number of maximum client connection at a time
        self.max_allowed_clients = max_allowed_clients
        # this handler class will be used when creating a new handler
        self.handler_class = handler_class
        # the kwargs passed to the handler's __init__ function
        self.handler_kwargs = handler_kwargs
        # don't make the socket yet, we don't need right now. will be created
        # when the start method is called
        # self.socket = self.make_socket()
        self.socket = None
        # create a task group for handlers, so we can easily cancel/terminate
        # them all at once
        self.handle_tasks = curio.TaskGroup(name="tg_handle_clients")
        # list of all active connection handlers
        self.connection_handler = []
        # these aren't actually used, I will remove them soon
        # self.conn_to_addr = {}
        # self.addr_to_conn = {}
        # self.conn_to_handler ={}
        # self.handler_to_conn = {}
        # this was used for the select.select approach. we use the async approach now, let's remove it
        # self.read_sockets_expected = [self.socket]
        # register our cleanup method to be executed when the program exits.
        # the cleanup function unregisters itself, so it won't get executed twice when the user called it befor the program exites
        atexit.register(self.shutdown)

    def make_socket(self):
        """
        factory method for sockets.
        this method makes a normal socket and wraps it in a curi.io.Socket wrapper
        """
        lserver.debug("making a {} socket".format(self.af_family))
        if self.af_family == "AF_INET":
            s = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
        elif self.af_family == "AF_UNIX":
            s = socket.socket(socket.AF_UNIX,socket.SOCK_STREAM)
        else:
            raise ValueError(
                "AF_FAMILY '{}' not supported!".format(
                    self.af_family
                )
            )
        s = curio.io.Socket(s)
        return s

    def make_handler(self, conn, addr):
        """
        factory method for handlers.
        this method creates a handler object from self.handler_class and self.handler_kwargs
        """
        return self.handler_class(conn, addr, self, **self.handler_kwargs)

    # DEPRECATED
    # def register_conn(self, conn, addr):
    #     # if self.log_ip:
    #     #     lserver.info("New connection from {} on port {}".format(*addr))
    #     self.read_sockets_expected.append(conn)
    #     if addr:
    #         self.conn_to_addr[conn] = addr
    #         self.addr_to_conn[addr] = conn
    #
    # def unregister_conn(self, conn):
    #     self.read_sockets_expected.remove(conn)
    #     addr = self.conn_to_addr.get(conn, False)
    #     if addr:
    #         del self.addr_to_conn[addr]
    #         del self.conn_to_addr[conn]
    #
    # def register_handler(self, handler, conn):
    #     self.connection_handler.append(handler)
    #     self.conn_to_handler[conn] = handler
    #     self.handler_to_conn[handler] = conn
    #
    # def unregister_handler(self, handler, conn):
    #     self.connection_handler.remove(handler)
    #     del self.conn_to_handler[conn]
    #     del self.handler_to_conn[handler]

    def setup(self):
        """
        creates a scoket, opens the connection and starts listening for
        clients. this method does not block, it returns after starting to
        listen.
        """
        lserver.info("setting up server")
        self.socket = self.make_socket()
        if self.af_family == "AF_INET":
            self.socket.bind((self.host, self.port))
        elif self.af_family == "AF_UNIX":
            if os.path.exists(self.host):
                lserver.debug("file already exists")
                lserver.debug("attempting to remove it")
                os.remove(self.host)
            self.socket.bind(self.host)
        self.socket.listen(self.max_allowed_clients)

    def shutdown(self):
        """
        This method properly shuts down the sockets and closes them.
        it unregisters itself from atexit, so it doesn't get executed twice
        when it was manually called before to program exits.
        """
        def error_handler(func,*args,log_text="error",async_=False,**kwargs):
            try:
                if async_:
                    coro = func(*args,**kwargs)
                    lserver.debug("{} {}".format(func,coro))
                else:
                    func(*args,**kwargs)
            except Exception as exc:
                lserver.debug("error occured during "+log_text,exc_info=exc)
        atexit.unregister(self.shutdown)
        lserver.info("shutting down server")
        error_handler(
            self.handle_tasks.cancel_remaining,log_text="handler cancel",async_=True)
        # check if there is actually a socket. if the shutdown method is
        # executed before the start method, there is no socket.
        if self.socket:
            error_handler(self.socket.shutdown,log_text="socket shutdown")
            error_handler(self.socket.close,log_text="socket close")

    def start(self):
        """
        this method starts the server. it is blocking.
        """
        self.setup()
        curio.run(self.run)

    async def run(self):
        """
        this method is the main loop of the Server. it waits for new client
        connections and creates a handle task for each of them. it does not
        receive or send anything.
        """
        lserver.debug("entering main loop")
        while ( not self.exit_event ):
            lserver.debug("waiting for client to connect")
            # wait for a client to connect
            conn,addr = await self.socket.accept()
            if self.log_ip:
                lserver.info(
                    "new client connection, {}:{}!".format(*addr))
            else:
                lserver.info("a new client connected, let's handle it")
            handler = self.make_handler(conn, addr)
            # self.register_conn(conn, addr)
            # self.register_handler(handler, conn)
            await self.handle_tasks.spawn(self.handle_client(conn,handler))

    async def handle_client(self,socket,handler):
        """
        This method waits for the client to send something and calls the
        ClientHandler's handle method. there is a handle_client method running for each client connected.
        """
        while True:
            try:
                if self.log_ip:
                    lserver.debug("waiting for {} to send something"
                        .format(socket.getsockname()))
                else:
                    lserver.debug("waiting for the client to send something")
                # wait for the client to send something
                data = await handler.recv()
                # if there is no data the client disconnected. this is a
                # tcp protocoll specification.
                if not data:
                    if self.log_ip:
                        lserver.info("the connection to {} was closed"
                            .format(socket.getsockname()))
                    else:
                        lserver.info("the connection to the client was closed")
                    # self.unregister_handler(handler, socket)
                    # self.unregister_conn(socket)
                    await handler.close()
                    # break out of the loop. don't return because we need to
                    # do cleanup
                    break
                else:
                    # don't strip the data of its whitespaces, since they may
                    # be important.
                    lschat.info("Client:"+data.rstrip())
                    coro = handler.handle(data)
                    task = await curio.spawn(coro)
            except Exception as e:
                    lserver.error(e, exc_info=True)
                    # let's sleep a bit, in case something is broken and the
                    # loop throws an exception every time
                    await curio.sleep(0.01)
        # if a task exits and hasn't been joined, curio prints a warning.
        # we don't want the warning, so let's join the current task for 0
        # seconds. instead of task.join() we use task.wait(). the only
        # difference is that wait doesn't throw a exception if the task was
        # stopped or crashed
        cur_task = await curio.current_task()
        await curio.ignore_after(0,cur_task.wait)

class Client(threading.Thread):
    """docstring for Client"""
    is_connecting = False
    is_connected = False
    status = "uninitialized"
    def __init__(self,
                host,
                port=None,
                af_family="AF_INET",
                handle_data_func=None,
                error_handler=None,
                block_size=1024,
                ):
        self.super_class = super(Client, self)
        self.super_class.__init__()
        self.name = "Client"
        self.exit_event = False
        self.host = host
        self.port = port
        self.af_family = af_family
        self.block_size = block_size
        self.handle_data_func = handle_data_func
        self.is_connected = False
        self.error_handler = error_handler
        # self.socket = self.make_socket()
        self.socket = None
        self.status = "disconnected"
    def connect(self):
        self.status = "connecting"
        self.socket = self.make_socket()
        lclient.info(
            "connecting to socket '{}' of type {}".format(
                self.host,
                self.af_family
            )
        )
        try:
            if self.af_family == "AF_INET":
                self.socket.connect((self.host, self.port))
            elif self.af_family == "AF_UNIX":
                if os.path.exists(self.host):
                    self.socket.connect(self.host)
                else:
                    lclient.warn("File not found. Aborting.")
                    return
            self.is_connected = True
            self.status = "connected"
            lclient.info("connected")
            return True
        except Exception as e:
            lclient.debug(e, exc_info=True)
            if type(e) is ConnectionRefusedError:
                lclient.info("failed to connect to socket '{}'".format(self.host))
                self.disconnect()
                return False
    def disconnect(self):
        lclient.info("disconnecting from socket '{}'".format(self.host))
        self.is_connected = False
        self.status = "disconnected"
        if self.socket:
            try:
                self.socket.shutdown(socket.SHUT_RDWR)
            except Exception as e:
                lclient.error(e)
            try:
                self.socket.close()
            except Exception as e:
                lclient.error("error occured while closing the socket, " +
                    "maybe it is already closed",exc_info=e)
        del self.socket
        self.socket = None
    def handle_data(self, data_received):
        data_decoded = data_received.decode("utf-8")
        lcchat.info("Server: "+data_decoded)
        if self.handle_data_func:
            try:
                self.handle_data_func(data_decoded)
            except Exception as e:
                lclient.error(e, exc_info=True)
    def is_running(self):
        return (self in threading.enumerate())
    def make_socket(self):
        lclient.info("creating a {} socket".format(self.af_family))
        if self.af_family == "AF_INET":
            s = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
        elif self.af_family == "AF_UNIX":
            s = socket.socket(socket.AF_UNIX,socket.SOCK_STREAM)
        else:
            raise ValueError(
                "AF_FAMILY '{}' not supported!".format(
                    self.af_family
                )
            )
        return s
    def main_loop(self):
        lclient.debug("starting main loop")
        while ( not self.exit_event ):
            if not self.status in ["connected"]:
                time.sleep(0.1)
                continue
            # print(0)
            read_confirmed, write_confirmed, exc_confirmed \
            = select.select(
                [self.socket],
                [],
                [self.socket],
                1
            )
            if self.socket in exc_confirmed:
                self.is_connected = False
                lclient.warning("socket is expected to corrupt, exiting")
                self.disconnect()
               # self.stop()
                break
            elif self.socket in read_confirmed:
                try:
                    data_received = self.read_from_socket()
                    if data_received == b'':
                        lclient.info("connection is broken, closing socket exiting")
                        self.disconnect()
                        # self.stop()
                        # break
                    else:
                        try:
                            self.handle_data(data_received)
                        except Exception as e:
                            lserver.error(
                                "Error while handling data",
                                exc_info=e
                            )
                except Exception as e:
                    lclient.error(e, exc_info=True)
                    if type(e) is OSError:
                        self.is_connected = False
                        lclient.warn("connection broken, exiting")
                        self.disconnect()
                        # self.stop()
                        # break
                    else:
                        raise
            else:
                time.sleep(0.1)
    def read_from_socket(self):
        data_received = self.socket.recv(self.block_size)
        return data_received
    def run(self):
        # self.connect()
        if self.error_handler:
            self.error_handler(self.main_loop)
        else:
            self.main_loop()
    def send(self, msg):
        msg = msg.rstrip()
        msg_encoded = bytes(msg+"\r\n", "utf-8")
        try:
            lcchat.info("Client: "+msg)
            self.socket.send(msg_encoded)
        except Exception as e:
            self.is_connected = False
            lclient.error(e, exc_info=True)
            self.status = "shutdown"
    def setup(self):
        pass
    def stop(self,reason=None):
        self.disconnect()
        self.exit_event = True
        if reason:
            print(reason)







class AsyncClient(object):
    """docstring for Client"""
    is_connecting = False
    is_connected = False
    status = "uninitialized"
    def __init__(self,
                host,
                port=None,
                af_family="AF_INET",
                handle_data_func=None,
                error_handler=None,
                block_size=1024,
                ):
        self.super_class = super(AsyncClient, self)
        self.super_class.__init__()
        self.name = "Client"
        self.exit_event = False
        self.host = host
        self.port = port
        self.af_family = af_family
        self.block_size = block_size
        self.handle_data_func = handle_data_func
        self.is_connected = False
        self.error_handler = error_handler
        self.socket = None
        self.status = "disconnected"

    def connect(self):
        self.status = "connecting"
        self.socket = self.make_socket()
        lclient.info("connecting to socket '{}' of type {}".format(
                self.host,self.af_family))
        try:
            if self.af_family == "AF_INET":
                self.socket.connect((self.host, self.port))
            elif self.af_family == "AF_UNIX":
                self.socket.connect(self.host)
            self.is_connected = True
            self.status = "connected"
            lclient.info("connected")
            return True
        except Exception as e:
            lclient.debug(e, exc_info=True)
            if type(e) is ConnectionRefusedError:
                lclient.info("failed to connect to socket '{}'".format(self.host))
                self.disconnect()
                return False

    def disconnect(self):
        lclient.info("disconnecting from socket '{}'".format(self.host))
        self.is_connected = False
        self.status = "disconnected"
        if self.socket:
            try:
                self.socket.shutdown(socket.SHUT_RDWR)
            except Exception as e:
                lclient.error(e)
            try:
                self.socket.close()
            except Exception as e:
                lclient.error("error occured while closing the socket, " +
                    "maybe it is already closed",exc_info=e)
        del self.socket
        self.socket = None

    def handle_data(self, data_received):
        data_decoded = data_received.decode("utf-8")
        lcchat.info("Server: "+data_decoded)
        if self.handle_data_func:
            try:
                self.handle_data_func(data_decoded)
            except Exception as e:
                lclient.error(e, exc_info=True)

    def is_running(self):
        return (self in threading.enumerate())

    def make_socket(self):
        lclient.info("creating a {} socket".format(self.af_family))
        if self.af_family == "AF_INET":
            s = trio.socket.socket(socket.AF_INET,socket.SOCK_STREAM)
        elif self.af_family == "AF_UNIX":
            s = trio.socket.socket(socket.AF_UNIX,socket.SOCK_STREAM)
        else:
            raise ValueError(
                "AF_FAMILY '{}' not supported!".format(
                    self.af_family
                )
            )
        return s

    async def read_from_socket(self):
        data_received = await self.socket.recv(self.block_size)
        return data_received

    async def recv(self):
        data_received = await self.socket.recv(self.block_size)
        data_decoded = data_received.decode("utf-8")
        return data_decoded

    async def run(self):
        lclient.debug("starting main loop")
        while ( not self.exit_event ):
            if not self.status in ["connected"]:
                time.sleep(0.1)
                continue
            # if self.socket in exc_confirmed:
            #     self.is_connected = False
            #     lclient.warning("socket is expected to corrupt, exiting")
            #     self.disconnect()
            #    # self.stop()
            #     break
            # elif self.socket in read_confirmed:
            try:
                data = await self.read_from_socket()
                if not data:
                    lclient.info("connection closed")
                    self.disconnect()
                else:
                    self.handle_data(data)
            except Exception as e:
                lclient.error(e, exc_info=True)
                if type(e) is OSError:
                    self.is_connected = False
                    lclient.warn("connection broken, exiting")
                    self.disconnect()
                else:
                    raise

    async def start(self,connect=False):
        if connect:
            self.connect()
        if self.error_handler:
            self.error_handler(self.run)
        else:
            self.run()

    def send(self, msg):
        msg = msg.rstrip()
        msg_encoded = bytes(msg+"\r\n", "utf-8")
        try:
            lcchat.info("Client: "+msg)
            self.socket.send(msg_encoded)
        except Exception as e:
            self.is_connected = False
            lclient.error(e, exc_info=True)
            self.disconnect()
            # self.exit_event = True
            # self.status = "shutdown"

    def setup(self):
        pass

    def stop(self,reason=None):
        self.disconnect()
        self.exit_event = True
        if reason:
            print(reason)




























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