#!/usr/bin/env python3
# encoding: utf-8

import socket
import math
from struct import pack
from time import sleep, time
from .utils import random_id
from .bencode import bencode, bdecode
from .filetype import get_file_type
from .database import RedisClients
from .utils import get_logger

logger = get_logger("logger_dht_")

def send_packet(the_socket, msg):
    the_socket.send(msg)


def send_message(the_socket, msg):
    msg_len = pack('>I', len(msg))
    return the_socket.send(msg_len + msg)


def send_handshake(the_socket, h):
    bt_header = chr(len('BitTorrent protocol')) + 'BitTorrent protocol'
    ext_bytes = '\x00\x00\x00\x00\x00\x10\x00\x00'
    peer_id = random_id()
    the_socket.send(bt_header.encode('utf-8') + ext_bytes.encode('utf-8') + h + peer_id)


def check_handshake(packet, s):
    try:
        bt_header_len, packet = ord(packet[:1]), packet[1:]
        if bt_header_len != len('BitTorrent protocol'):
            return False
    except TypeError:
        return False

    bt_header, packet = packet[:bt_header_len], packet[bt_header_len:]
    if bt_header.decode('utf-8') != 'BitTorrent protocol':
        return False

    packet = packet[8:]
    h = packet[:20]
    return h == s


def send_ext_handshake(the_socket):
    msg = chr(20).encode('utf-8') + chr(0).encode('utf-8') + bencode({'m': {'ut_metadata': 1}})
    send_message(the_socket, msg)


def request_metadata(the_socket, ut_metadata, piece):
    msg = chr(20).encode('utf-8') + chr(ut_metadata).encode('utf-8') + bencode({'msg_type': 0, 'piece': piece})
    send_message(the_socket, msg)


def get_ut_metadata(data):
    ut_metadata = '_metadata'
    index = data.index(ut_metadata.encode('utf-8')) + len(ut_metadata) + 1
    return int(chr(int(data[index])))


def get_metadata_size(data):
    metadata_size = 'metadata_size'
    start = data.index(metadata_size.encode('utf-8')) + len(metadata_size) + 1
    data = data[start:]
    return int(data[:data.index('e'.encode('utf-8'))])


def get_whole_metadata(the_socket, timeout=5):
    the_socket.setblocking(0)
    total_data = []
    begin = time()
    while True:
        sleep(0.05)
        if total_data and time() - begin > timeout:
            break
        elif time() - begin > timeout * 2:
            break
        # noinspection PyBroadException
        try:
            data = the_socket.recv(1024)
            if data:
                total_data.append(data)
                begin = time()
        except Exception:
            pass
    return b''.join(total_data)


def download_metadata(address, infohash,process_id, timeout=5):
    the_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    # noinspection PyBroadException
    try:
        the_socket.settimeout(5)
        the_socket.connect(address)
        send_handshake(the_socket, infohash)
        packet = the_socket.recv(4096)
        if not check_handshake(packet, infohash):
            return
        send_ext_handshake(the_socket)
        packet = the_socket.recv(4096)
        ut_metadata, metadata_size = get_ut_metadata(packet), get_metadata_size(packet)
        metadata = []
        for piece in range(int(math.ceil(metadata_size / (16.0 * 1024)))):
            request_metadata(the_socket, ut_metadata, piece)
            packet = get_whole_metadata(the_socket, timeout)
            metadata.append(packet[packet.index('ee'.encode('utf-8')) + 2:])
        metadata = bdecode(b''.join(metadata))
        if isinstance(metadata.get('name'), str):
            save_metadata(process_id,metadata, ''.join(['%02x' % x for x in infohash]).strip())
    except Exception as e:
        return
    finally:
        the_socket.close()


def save_metadata(process_id,metadata, h):
    utf8_enable = False
    files = []
    # noinspection PyBroadException
    try:
        bare_name = metadata.get('name')
    except KeyError:
        bare_name = metadata.get('name.utf-8')
        utf8_enable = True
    except Exception:
        return
    if 'files' in metadata:
        for x in metadata.get('files'):
            files.append({'n': '/'.join(x.get('path.utf-8' if utf8_enable else 'path')),
                          'l': x.get('length')})
    else:
        files.append({'n': bare_name,
                      'l': metadata.get('length')})
    #file_model = [FileModel(n=file.get('n'), l=file.get('l')) for file in files]

    file_model = []
    for file in files:
        file_model.append({
            'n' : str(file.get('n')),
            'l' : int(file.get('l'))
            })

    metainfo = {}
    metainfo['info_hash'] = h
    metainfo['bare_name'] = bare_name
    metainfo['create_time'] = int(time())
    metainfo['file_size'] = sum(map(lambda y: y.get('l'), files))
    metainfo['file_num'] = len(files)
    metainfo['status'] = 1
    metainfo['file_list'] = file_model
    metainfo['file_type'] = get_file_type(files)
    metainfo['update_time'] = int(time())
    metainfo['hot'] = 1
    try:
        RedisClients.set_keyinfo(str(h),metainfo)
        logger.info("save_metadata to redis successful ! {0} ->>>> {1}!".format(process_id,str(h)))
    except Exception as e:
        logger.error("save_metadata to redis error {0} ->>>> {1}!".format(process_id,e))
        return