import os,os.path,stat,sha

tree      = None
archive   = None
slices    = []
lastslice = (0,-1)

def recurse(path):
    s = os.stat(path)
    if stat.S_ISDIR(s.st_mode):
        print path
        contents = []
        for n in os.listdir(path):
            uid = recurse(os.path.join(path,n))
            contents.append('\t'.join((n,uid)))
        contents = '\n'.join(contents)
        buf = sha.new(contents)
        uid = buf.hexdigest()
        uid = ','.join((uid,str(len(contents))))
        store(uid)
        return uid
    else:
        fd = file(path,"rb")
        contents = fd.read()
        fd.close()
        buf = sha.new(contents)
        uid = ','.join((buf.hexdigest(),str(s.st_size)))
        store(uid)
        return uid

def store(uid):
    p = archive
    if not os.path.exists(p):
        os.mkdir(p)
    for s in slices:
        p = os.path.join(p,uid[s[0]:s[1]])
        if not os.path.exists(p):
            os.mkdir(p)
    p = os.path.join(p,uid[lastslice[0]:lastslice[1]])
    fd = file(p,"wb")
    fd.close()

if __name__ == '__main__':
    import sys
    from optparse import OptionParser
    from types import IntType
    parser = OptionParser(usage="usage: %prog TREE ARCHIVE N1 ... Nk")
    (options, args) = parser.parse_args()
    if len(args) < 3:
        print sys.stderr, "expected at least 3 positional arguments"
        sys.exit(1)
    tree    = args[0]
    archive = args[1]
    prev    = 0
    for a in args[2:]:
        try:
            next = prev+int(a)
            slices.append((prev,next))
            prev = next
        except:
            print >>sys.stderr, "positional argument is not an integer:",a
            sys.exit(1)
    lastslice = (next,-1)
    recurse(tree)
    sys.exit(0)