#!/usr/bin/env python
# coding=utf-8
#
# This file is part of aDBa.
#
# aDBa 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.
#
# aDBa 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 aDBa.  If not, see <http://www.gnu.org/licenses/>.

import logging
import socket
import sys
import threading
import zlib
from time import time, sleep

from .aniDBerrors import *
from .aniDBresponses import ResponseResolver

logger = logging.getLogger('adba')
logger.addHandler(logging.NullHandler())


class AniDBLink(threading.Thread):
    def __init__(self, server, port, myport, delay=2, timeout=20):
        super(AniDBLink, self).__init__()
        self.server = server
        self.port = port
        self.target = (server, port)
        self.timeout = timeout

        self.myport = 0
        self.bound = self.connectSocket(myport, self.timeout)

        self.cmd_queue = {None: None}
        self.resp_tagged_queue = {}
        self.resp_untagged_queue = []
        self.tags = []
        self.lastpacket = time()
        self.delay = delay
        self.session = None
        self.banned = False
        self.crypt = None

        self._stop = threading.Event()
        self._quiting = False

        self.QuitProcessed = False

        self.daemon = True
        self.start()

    def connectSocket(self, myport, timeout):
        self.sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        self.sock.settimeout(timeout)
        portlist = [myport] + [7654]
        for port in portlist:
            try:
                self.sock.bind(('', port))
            except:
                continue
            else:
                self.myport = port
                return True
        else:
            return False

    def disconnectSocket(self):
        self.sock.shutdown(socket.SHUT_RD)
        # close is not called as the garbage collection from python will handle this for us.  Calling close can also cause issues with the threaded code.
        # self.sock.close()

    def stop(self):
        logger.info("Releasing socket and stopping link thread")
        self._quiting = True
        self.disconnectSocket()
        self._stop.set()

    def stopped(self):
        return self._stop.isSet()

    def print_log_dummy(self, data):
        pass

    def run(self):
        while not self._quiting:
            try:
                data = self.sock.recv(8192)
            except socket.timeout:
                self._handle_timeouts()
                continue
            except OSError as error:
                logger.exception('Exception: %s' % error)
                break
            logger.debug("NetIO < %r" % data)
            try:
                for i in range(2):
                    try:
                        tmp = data
                        resp = None
                        if tmp[:2] == b'\x00\x00':
                            tmp = zlib.decompressobj().decompress(tmp[2:])
                            logger.debug("UnZip | %r" % tmp)
                        resp = ResponseResolver(tmp)
                    except Exception as e:
                        logger.exception('Exception: %s' % e)
                        sys.excepthook(*sys.exc_info())
                        self.crypt = None
                        self.session = None
                    else:
                        break
                if not resp:
                    raise AniDBPacketCorruptedError("Either decrypting, decompressing or parsing the packet failed")
                cmd = self._cmd_dequeue(resp)
                resp = resp.resolve(cmd)
                resp.parse()
                if resp.rescode in ('200', '201'):
                    self.session = resp.attrs['sesskey']
                if resp.rescode in ('209',):
                    logger.error("sorry encryption is not supported")
                    raise AniDBError()
                    # self.crypt=aes(md5(resp.req.apipassword+resp.attrs['salt']).digest())
                if resp.rescode in ('203', '403', '500', '501', '503', '506'):
                    self.session = None
                    self.crypt = None
                if resp.rescode in ('504', '555'):
                    self.banned = True
                    logger.critical(("AniDB API informs that user or client is banned:", resp.resstr))
                resp.handle()
                if not cmd or not cmd.mode:
                    self._resp_queue(resp)
                else:
                    self.tags.remove(resp.restag)
            except:
                sys.excepthook(*sys.exc_info())
                logger.error("Avoiding flood by paranoidly panicing: Aborting link thread, killing connection, releasing waiters and quiting")
                self.sock.close()
                try:
                    cmd.waiter.release()
                except:
                    pass
                for tag, cmd in self.cmd_queue.items():
                    try:
                        cmd.waiter.release()
                    except:
                        pass
                sys.exit()
        if self._quiting:
            self.QuitProcessed = True

    def _handle_timeouts(self):
        willpop = []
        for tag, cmd in self.cmd_queue.items():
            if not tag:
                continue
            if time() - cmd.started > self.timeout:
                self.tags.remove(cmd.tag)
                willpop.append(cmd.tag)
                cmd.waiter.release()

        for tag in willpop:
            self.cmd_queue.pop(tag)

    def _resp_queue(self, response):
        if response.restag:
            self.resp_tagged_queue[response.restag] = response
        else:
            self.resp_untagged_queue.append(response)

    def getresponse(self, command):
        if command:
            resp = self.resp_tagged_queue.pop(command.tag)
        else:
            resp = self.resp_untagged_queue.pop()
        self.tags.remove(resp.restag)
        return resp

    def _cmd_queue(self, command):
        self.cmd_queue[command.tag] = command
        self.tags.append(command.tag)

    def _cmd_dequeue(self, resp):
        if not resp.restag:
            return None
        else:
            return self.cmd_queue.pop(resp.restag)

    def _delay(self):
        return self.delay < 2.1 and 2.1 or self.delay

    def _do_delay(self):
        age = time() - self.lastpacket
        delay = self._delay()
        if age <= delay:
            sleep(delay - age)

    def _send(self, command):
        if self.banned:
            logger.debug("NetIO | BANNED")
            raise AniDBBannedError("Not sending, banned")
        self._do_delay()
        self.lastpacket = time()
        command.started = time()
        data = command.raw_data()

        # Encode data to bytes if needed
        try:
            data = data.encode("ASCII")
        except AttributeError:  # On Python 3: 'bytes' object has no attribute 'encode'
            pass

        self.sock.sendto(data, self.target)
        if command.command == 'AUTH':
            logger.debug("NetIO > sensitive data is not logged!")

    def new_tag(self):
        if not len(self.tags):
            maxtag = "T000"
        else:
            maxtag = max(self.tags)
        newtag = "T%03d" % (int(maxtag[1:]) + 1)
        return newtag

    def request(self, command):
        if not (self.session and command.session) and command.command not in ('AUTH', 'PING', 'ENCRYPT'):
            raise AniDBMustAuthError("You must be authed to execute commands besides AUTH and PING")
        command.started = time()
        self._cmd_queue(command)
        self._send(command)
