import string
import hashlib
from binascii import hexlify, unhexlify
from .constants import PREFIX
from .exceptions import NektarException

known_prefixes = [PREFIX]


class Base58(object):
    """Base58 base class

    This class serves as an abstraction layer to deal with base58 encoded
    strings and their corresponding hex and binary representation
    throughout the library.

    :param data: Data to initialize object, e.g. pubkey data, address data,
    ...
    :type data: hex, wif, bip38 encrypted wif, base58 string
    :param str: prefix: Prefix to use for Address/PubKey strings (defaults
    to ``GPH``)
    :returns: Base58 object initialized with ``data``
    :rtype: Base58
    :raises ValueError: if data cannot be decoded

    * ``bytes(Base58)``: Returns the raw data
    * ``str(Base58)``:   Returns the readable ``Base58CheckEncoded`` data.
    * ``repr(Base58)``:  Gives the hex representation of the data.

    *  ``format(Base58,_format)`` Formats the instance according to
    ``_format``:

        * ``"btc"``: prefixed with ``0x80``. Yields a valid btc address
        * ``"wif"``: prefixed with ``0x00``. Yields a valid wif key
        * ``"bts"``: prefixed with ``BTS``
        * etc.

    """

    def __init__(self, data, prefix=PREFIX):
        self._prefix = prefix
        if all(c in string.hexdigits for c in data):
            self._hex = data
        elif data[0] == "5" or data[0] == "6":
            self._hex = base58CheckDecode(data)
        elif data[0] == "K" or data[0] == "L":
            self._hex = base58CheckDecode(data)[:-2]
        elif data[: len(self._prefix)] == self._prefix:
            self._hex = gphBase58CheckDecode(data[len(self._prefix) :])
        else:
            raise ValueError("Error loading Base58 object")

    def __format__(self, _format):
        """Format output according to argument _format (wif,btc,...)

        :param str _format: Format to use
        :return: formatted data according to _format
        :rtype: str

        """
        if _format.upper() == "WIF":
            return base58CheckEncode(0x80, self._hex)
        elif _format.upper() == "ENCWIF":
            return base58encode(self._hex)
        elif _format.upper() == "BTC":
            return base58CheckEncode(0x00, self._hex)
        elif _format.upper() in known_prefixes:
            return _format.upper() + str(self)
        else:
            return _format.upper() + str(self)

    def __repr__(self):
        """Returns hex value of object

        :return: Hex string of instance"s data
        :rtype: hex string
        """
        return self._hex

    def __str__(self):
        """Return graphene-base58CheckEncoded string of data

        :return: Base58 encoded data
        :rtype: str
        """
        return gphBase58CheckEncode(self._hex)

    def __bytes__(self):
        """Return raw bytes

        :return: Raw bytes of instance
        :rtype: bytes

        """
        return unhexlify(self._hex)


# https://github.com/tochev/python3-cryptocoins/raw/master/cryptocoins/base58.py
BASE58_ALPHABET = b"123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"


def base58decode(base58_str):
    """

    :param base58_str:

    """
    base58_text = base58_str.encode("ascii")
    n = 0
    leading_zeroes_count = 0
    for b in base58_text:
        n = n * 58 + BASE58_ALPHABET.find(b)
        if n == 0:
            leading_zeroes_count += 1
    res = bytearray()
    while n >= 256:
        div, mod = divmod(n, 256)
        res.insert(0, mod)
        n = div
    else:
        res.insert(0, n)
    return hexlify(bytearray(1) * leading_zeroes_count + res).decode("ascii")


def base58encode(hexstring):
    """

    :param hexstring:

    """
    byteseq = compat_bytes(hexstring, "ascii")
    byteseq = unhexlify(byteseq)
    byteseq = compat_bytes(byteseq)

    n = 0
    leading_zeroes_count = 0
    for c in byteseq:
        n = n * 256 + c
        if n == 0:
            leading_zeroes_count += 1
    res = bytearray()
    while n >= 58:
        div, mod = divmod(n, 58)
        res.insert(0, BASE58_ALPHABET[mod])
        n = div
    else:
        res.insert(0, BASE58_ALPHABET[n])

    return (BASE58_ALPHABET[0:1] * leading_zeroes_count + res).decode("ascii")


def ripemd160(s):
    """

    :param s:

    """
    ripemd160 = hashlib.new("ripemd160")
    ripemd160.update(unhexlify(s))
    return ripemd160.digest()


def doublesha256(s):
    """

    :param s:

    """
    return hashlib.sha256(hashlib.sha256(unhexlify(s)).digest()).digest()


def base58CheckEncode(version, payload):
    """

    :param version:
    :param payload:

    """
    s = ("%.2x" % version) + payload
    checksum = doublesha256(s)[:4]
    result = s + hexlify(checksum).decode("ascii")
    return base58encode(result)


def base58CheckDecode(s):
    """

    :param s:

    """
    s = unhexlify(base58decode(s))
    dec = hexlify(s[:-4]).decode("ascii")
    checksum = doublesha256(dec)[:4]
    if s[-4:] != checksum:
        raise NektarException("Invalid WIF detected.")
    return dec[2:]


def gphBase58CheckEncode(s):
    """

    :param s:

    """
    checksum = ripemd160(s)[:4]
    result = s + hexlify(checksum).decode("ascii")
    return base58encode(result)


def gphBase58CheckDecode(s):
    """

    :param s:

    """
    s = unhexlify(base58decode(s))
    dec = hexlify(s[:-4]).decode("ascii")
    checksum = ripemd160(dec)[:4]
    if s[-4:] == checksum:
        raise NektarException("Invalid WIF detected.")
    return dec
