import json
import math
import random
import re
import time

from .common import InfoExtractor
from ..utils import (
    ExtractorError,
)


class YoukuIE(InfoExtractor):
    _VALID_URL =  r'(?:http://)?v\.youku\.com/v_show/id_(?P<ID>[A-Za-z0-9]+)\.html'

    def _gen_sid(self):
        nowTime = int(time.time() * 1000)
        random1 = random.randint(1000,1998)
        random2 = random.randint(1000,9999)

        return "%d%d%d" %(nowTime,random1,random2)

    def _get_file_ID_mix_string(self, seed):
        mixed = []
        source = list("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ/\:._-1234567890")
        seed = float(seed)
        for i in range(len(source)):
            seed  =  (seed * 211 + 30031 ) % 65536
            index  =  math.floor(seed / 65536 * len(source) )
            mixed.append(source[int(index)])
            source.remove(source[int(index)])
        #return ''.join(mixed)
        return mixed

    def _get_file_id(self, fileId, seed):
        mixed = self._get_file_ID_mix_string(seed)
        ids = fileId.split('*')
        realId = []
        for ch in ids:
            if ch:
                realId.append(mixed[int(ch)])
        return ''.join(realId)

    def _real_extract(self, url):
        mobj = re.match(self._VALID_URL, url)
        if mobj is None:
            raise ExtractorError(u'Invalid URL: %s' % url)
        video_id = mobj.group('ID')

        info_url = 'http://v.youku.com/player/getPlayList/VideoIDS/' + video_id

        jsondata = self._download_webpage(info_url, video_id)

        self.report_extraction(video_id)
        try:
            config = json.loads(jsondata)

            video_title =  config['data'][0]['title']
            seed = config['data'][0]['seed']

            format = self._downloader.params.get('format', None)
            supported_format = list(config['data'][0]['streamfileids'].keys())

            if format is None or format == 'best':
                if 'hd2' in supported_format:
                    format = 'hd2'
                else:
                    format = 'flv'
                ext = u'flv'
            elif format == 'worst':
                format = 'mp4'
                ext = u'mp4'
            else:
                format = 'flv'
                ext = u'flv'


            fileid = config['data'][0]['streamfileids'][format]
            keys = [s['k'] for s in config['data'][0]['segs'][format]]
        except (UnicodeDecodeError, ValueError, KeyError):
            raise ExtractorError(u'Unable to extract info section')

        files_info=[]
        sid = self._gen_sid()
        fileid = self._get_file_id(fileid, seed)

        #column 8,9 of fileid represent the segment number
        #fileid[7:9] should be changed
        for index, key in enumerate(keys):

            temp_fileid = '%s%02X%s' % (fileid[0:8], index, fileid[10:])
            download_url = 'http://f.youku.com/player/getFlvPath/sid/%s_%02X/st/flv/fileid/%s?k=%s' % (sid, index, temp_fileid, key)

            info = {
                'id': '%s_part%02d' % (video_id, index),
                'url': download_url,
                'uploader': None,
                'upload_date': None,
                'title': video_title,
                'ext': ext,
            }
            files_info.append(info)

        return files_info