#!/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 = []

def _append_task():
    cur_task = curio.current_task()
    _tasks.append(cur_task)

def _remove_task():
    cur_task = curio.current_task()
    if cur_task in _tasks:
        _tasks.remove(cur_task)

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):
    """docstring for SocketHandler"""
    def __init__(self,
            host,
            port=None,
            af_family="AF_INET",
            log_ip=False,
            max_allowed_clients=5,
            handler=None,
            handler_kwargs={},
            ):
        super(Server, self).__init__()
        self.exit_event =  False
        self.host = host
        self.port = port
        self.af_family = af_family
        self.log_ip = log_ip
        self.handler_kwargs = handler_kwargs
        self.handler = handler
        self.max_allowed_clients = max_allowed_clients
        self.socket = self.make_socket()
        self.handle_tasks = curio.TaskGroup(name="tg_handle_clients")
        self.connection_handler = []
        self.conn_to_addr = {}
        self.addr_to_conn = {}
        self.conn_to_handler ={}
        self.handler_to_conn = {}
        self.read_sockets_expected = [self.socket]
        atexit.register(self.shutdown)

    def make_socket(self):
        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):
        return self.handler(conn, addr, self, **self.handler_kwargs)

    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):
        lserver.info("setting up 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)
        # self.socket.settimeout(1)

    def shutdown(self):
        def error_handler(func,*args,log_text="error",**kwargs):
            try:
                func(*args,**kwargs)
            except Exception as exc:
                lserver.debug("error occured during "+log_text,exc_info=exc)
        # this function can be called by the user and we don't need to clean
        # up a second time when the program exits
        atexit.unregister(self.shutdown)
        lserver.info("shutting down server")
        error_handler(self.handle_tasks.cancel_remaining,log_text="handler cancel")
        if self.socket:
            error_handler(self.socket.shutdown,log_text="socket shutdown")
            error_handler(self.socket.close,log_text="socket close")
        # del self.socket
        # self.socket = None

    def start(self):
        # lserver.debug(dir(self))
        curio.run(self.run)

    async def run(self):
        self.setup()
        lserver.debug("entering main loop")
        while ( not self.exit_event ):
            lserver.debug("waiting for 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):
        # _append_task()
        while True:
        # for i in range(1):
            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")
                data = await handler.recv()
                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
                else:
                    lschat.info("Client:"+data.strip())
                    coro = handler.handle(data)
                    task = await curio.spawn(coro)
                    _tasks.append(task)
            except Exception as e:
                    lserver.error(e, exc_info=True)
                    # saver to use time.sleep
                    time.sleep(0.1)
        cur_task = await curio.current_task()
        await curio.ignore_after(0,cur_task.join)
        # _tasks.remove(cur_task)


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)
                # if os.path.exists(self.host):
                #     pass
                # 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 = 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
    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:
                        self.handle_data(data_received)
                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,connect=False):
        if connect:
            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)




























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