import getopt
import sys
import struct
import os
import zlib
import hashlib

class MypException(Exception):
    pass

def main():
    try:
        opts,args=getopt.getopt(sys.argv[1:],"d:",["directory="])
    except getopt.GetoptError,err:
        print str(err) # will print something like "option -a not recognized"
        #usage()
        sys.exit(2)
    directory=None
    for o,a in opts:
        if o in ("-d","--directory"):
            directory=a
        else:
            raise MypException('unhandled option')
    if directory==None:
        raise MypException('no directory specified')
    files=os.listdir(directory)
    for filename in files:
        if '.tor' not in filename: continue
        print '%s...'%(filename)
        f=open(directory+os.sep+filename,'rb')
        signature,version,endianness,tableOffset,_,_,_,_,_,_=struct.unpack('<LLLQLLLHHL',f.read(40)) #getbasicfileinfo
        #print '0x%08x %d 0x%08x'%(signature,version,endianness)
        if signature!=0x0050594d or endianness!=0xfd23ec43:
            raise MypException('invalid file signature or endianness')
        if version!=5:
            raise MypException('invalid version')
        while tableOffset!=0:
            f.seek(tableOffset,os.SEEK_SET)
            n,tableOffset=struct.unpack('<LQ',f.read(12))
            #print '%d 0x%016x'%(n,tableOffset)
            while n!=0:
                streamOffset,h,compressedSize,uncompressedSize,qwordHash,X,isCompressed=struct.unpack('<QLLLQLH',f.read(34))
                if streamOffset==0:
                    break #no need to continue
                if isCompressed==0 and compressedSize!=uncompressedSize:
                    raise MypException('compression discrepency')
                currentOffset=f.tell()
                #print '0x%016x %d 0x%08x 0x%08x 0x%016x 0x%08x %d'%(streamOffset,h,compressedSize,uncompressedSize,qwordHash,X,isCompressed)
                f.seek(streamOffset,os.SEEK_SET)
                hashType,hashSize=struct.unpack('<HH',f.read(4)) #2 is sha256?
                if hashType!=2:
                    raise MypException('unknown hash type')
                streamHash=f.read(hashSize)
                #print '%d %d %s'%(hashType,hashSize,streamHash.encode('hex'))
                buffer=f.read(compressedSize)
                if isCompressed==1: buffer=zlib.decompress(buffer)
                h=hashlib.new('sha256')
                h.update(buffer)
                computedHash=h.digest()
                if computedHash!=streamHash:
                    #print '%s!=%s'%(computedHash.encode('hex'),streamHash.encode('hex'))
                    #raise MypException('sha256 discrepency')
                    pass
                if len(buffer)!=uncompressedSize:
                    raise MypException('size discrepency')

                #XXX: DO SOMETHING HERE

                f.seek(currentOffset,os.SEEK_SET)
                n-=1
        f.close()

if __name__=="__main__":
    main()