# Copyright (c) 2015, NORDUnet A/S.
# See LICENSE for licensing information.
import base64
import sys
import struct
from certtools import get_leaf_hash

def parselogrow(row):
    return base64.b16decode(row)

def get_logorder(filename):
    f = open(filename, "r")
    return [parselogrow(row.rstrip()) for row in f]

def read_chain(chainsdir, key):
    filename = base64.b16encode(key)
    path = chainsdir + "/" + filename[0:2] + "/" + filename[2:4] + "/" + filename[4:6]
    try:
        f = open(path + "/" + filename, "r")
    except IOError, e:
        f = open(chainsdir + "/" + filename, "r")
    value = f.read()
    f.close()
    return value

def unpack_entry(entry):
    pieces = []
    while len(entry):
        (length,) = struct.unpack(">I", entry[0:4])
        data = entry[4:4+length]
        entry = entry[4+length:]
        pieces.append(data)
    return pieces

def verify_entry(verifycert, entry, hash):
    unpacked = unpack_entry(entry)
    mtl = unpacked[0]
    assert hash == get_leaf_hash(mtl)
    s = struct.pack(">I", len(entry)) + entry
    try:
        verifycert.stdin.write(s)
    except IOError, e:
        sys.stderr.write("merge: unable to write to verifycert process: ")
        while 1:
            line = verifycert.stdout.readline()
            if line:
                sys.stderr.write(line)
            else:
                sys.exit(1)
    result_length_packed = verifycert.stdout.read(4)
    (result_length,) = struct.unpack(">I", result_length_packed)
    result = verifycert.stdout.read(result_length)
    assert len(result) == result_length
    (error_code,) = struct.unpack("B", result[0:1])
    if error_code != 0:
        print >>sys.stderr, result[1:]
        sys.exit(1)