import datetime

from . import *


__encTable = "0123456789ABCDEFGHIJKLMNOPQRSTUV"


def data_to_string(data):
    data = bytearray(data)
    size = len(data)
    bits = 0
    rpos = 0
    vbit = 0
    ret = ""
    while rpos < size:
        while rpos < size and vbit < 5:
            bits = (bits << 8) | data[rpos]
            rpos += 1
            vbit += 8
        while vbit >= 5:
            vbit -= 5
            ret += __encTable[(bits >> vbit) & 31]
    if vbit > 0:
        ret += __encTable[(bits << (5 - vbit)) & 31]
    return ret


def string_to_data(s):
    s = str(s)
    size = len(s)
    bits = 0
    rpos = 0
    vbit = 0
    ret = bytearray([])
    try:
        while rpos < size:
            while rpos < size and vbit < 8:
                bits = (bits << 5) | int(s[rpos], 32)
                rpos += 1
                vbit += 5
            while vbit >= 8:
                vbit -= 8
                ret.append((bits >> vbit) & 255)
        if vbit > 0:
            if bits & ((1 << vbit) - 1) != 0:
                raise ValueError("")
    except ValueError:
        raise ValueError("'" + s + "' is not a valid data-encoding string")
    return ret


def absolute_time_to_string(t):
    return t.strftime("%a %b %d %H:%M:%S %Y")

def string_to_absolute_time(s):
    if s == "end of time":
        return None
    for fmt in (
            "%a %b %d %H:%M:%S %Y",
            "%c",
            "%Ec",
            "%Y-%m-%d %H:%M:%S",
            "%Y-%m-%d %H:%M",
            "%x",
            "%Ex",
            "%Y-%m-%d",
            "%Y-%m",
            "%Y"):
        try:
            return datetime.datetime.strptime(s, fmt)
        except ValueError:
            pass
    raise ValueError("%s is not a properly formatted time string" % s)