import os
from datetime import tzinfo
from datetime import datetime

import bcodec

_READ_MAX_LEN = -1

class BTFormatError(BaseException):
    pass
    
class TorrentFile(object):
    
    __metainfo = {}
    __file_name = ''
    
    def read_file(self, filename):
        
        torrent_file = open(filename, '
 
rb')
        data = torrent_file.read(_READ_MAX_LEN)
        torrent_file.close()
        
        data = list(data)
        metainfo = bcodec.bdcode(data)
        if metainfo and type(metainfo) == type({}):
            self.__file_name = filename
            self.__metainfo = metainfo
        else:
            
 
raise BTFormatError()
           
    def __is_singlefile(self):
        return 'length' in self.__metainfo.keys()
    
    def __decode_text(self, text):
        encoding = 'utf-8'
        resultstr = ''
        if self.get_encoding():
            encoding = self.get_encoding()
        elif self.get_codepage():
            encoding 
 
= 'cp' + str(self.get_codepage())
        if text:
            try:
                resultstr = text.decode(encoding=encoding)
            except ValueError:
                return text
        else:
            return None
        return resultstr
    
    def __get_meta_top(self, key):
        if key in self.__metainfo.keys():
            return self.__metainfo[key]
        else:
            return None
    def __get_meta_info(self,key):
        meta_info = self.__get_meta_top('info')
        if meta_info and key in meta_info.keys():
                return meta_info[key]
        return None
    
    def get_codepage(self):
        return self.__get_meta_top('codepage')
    def get_encoding(self):
        return self.__get_meta_top('encoding')
    
    def get_announces(self):
        announces = []
        ann = self.__get_meta_top('announce')
        if ann:
            ann_list = []
            ann_list.append(ann)
            announces.append(ann_list)
        announces.append(self.__get_meta_top('announce-list'))
        return announces
    
    def get_publisher(self):
        return self.__decode_text(self.__get_meta_top('publisher'))
    def get_publisher_url(self):
        return self.__decode_text(self.__get_meta_top('publisher-url'))
    
    def get_creater(self):
        return self.__decode_text(self.__get_meta_top('created by'))
    def get_creation_date(self):
        utc_date = self.__get_meta_top('creation date')
        if utc_date is None:
            return utc_date
        creationdate = datetime.utcfromtimestamp(utc_date)
        return creationdate
    def get_comment(self):
        return self.__get_meta_top('comment')
          
    def get_nodes(self):
        return self.__get_meta_top('nodes')
    
    def get_piece_length(self):
        return self.__get_meta_info('piece length')
    
    def get_files(self):
        
        files = []
        pieces = self.__get_meta_info('pieces')
        name = self.__decode_text(self.__get_meta_info('name'))
        piece_length = self.get_piece_length()
        
        if not pieces or not name:
            return files
        
        if self.__is_singlefile():
            file_name = name
            file_length = self.__get_meta_info('length')
            if not file_length:
                return files
            
            pieces_num = file_length/piece_length
            if file_length % piece_length:
                pieces_num = int(pieces_num) + 1
            if 20*pieces_num > len(pieces):
                return  files
                           
            file_pieces = []
            i = 0
            pn = 0
            while pn < pieces_num:
                file_pieces.append(pieces[i:i+20])
                i += 20
                pn += 1
            
            files.appen({'name':[file_name], 'length':file_length, 'peaces':file_pieces})
            return files
        

        folder = name
        meta_files = self.__get_meta_info('files')
        if not meta_files:
            return files
        
        total_length = 0
        for one_file in self.__get_meta_info('files'):
            
            file_info = {}
            path_list = []
            path_list.append(folder)
                        
            if 'path' not in one_file.keys():
                break
            for path in one_file['path']:
                path_list.append(self.__decode_text(path))
            file_info['name'] = path_list
            
            if 'length' not in one_file.keys():
                break
            
            file_info['length'] =  one_file['length']
            
            piece_index = int(total_length / piece_length)
            total_length += one_file['length']
            pieces_num = int(total_length / piece_length) - piece_index
            pieces_num = int(file_info['length']/piece_length)
            
            if total_length % piece_length:
                pieces_num += 1
            
           # print  (piece_index+pieces_num)*20, len(pieces),pieces_num,file_info['length'], self.get_piece_length()
            
            if (piece_index+pieces_num)*20 > len(pieces):
                break
            
            file_info['pieces'] = []
            
            pn = 0
            while pn < pieces_num:
                file_info['pieces'].append(pieces[piece_index*20:piece_index*20+20])
                pn += 1

            files.append(file_info)
            
        return files
    
if __name__ == '__main__':
    #filename = r".\huapi2.torrent"
    #filename = r".\mh5t3tJ0EC.torrent"
    filename = r".\huapi2.1.torrent"   
    torrent = TorrentFile()

    print "begin to read file"
    try:
        torrent.read_file(filename)
    except (IOError,BTFormatError), reason:
        print "Read bittorrent file error! Error:%s" %reason
     
    print "end to read file"

    print "announces: " , torrent.get_announces() 
    print "peace length:", torrent.get_piece_length()
    print "code page:" , torrent.get_codepage()
    print "encoding:" , torrent.get_encoding()
    print "publisher:" ,torrent.get_publisher()
    print "publisher url:", torrent.get_publisher_url()
    print "creater:" , torrent.get_creater()
    print "creation date:", torrent.get_creation_date()
    print "commnent:", torrent.get_comment()
    print "nodes:", torrent.get_nodes()
    torrent.get_files()
    for one_file in torrent.get_files():
        print 'file name:', '\\'.join(one_file['name'])
        print 'file length:', one_file['length']
        print 'pieces:', list(one_file['pieces'])