from binascii import hexlify, unhexlify
import struct
from sha3 import keccak_256

from . import base58

class Address(object):
    _valid_netbytes = (18, 53)
    # NOTE: _valid_netbytes order is (real, testnet)

    def __init__(self, address):
        address = str(address)
        if len(address) != 95:
            raise ValueError("Address must be 95 characters long, is %d" % len(address))
        self._decode(address)

    def _decode(self, address):
        self._decoded = bytearray(unhexlify(base58.decode(address)))
        checksum = self._decoded[-4:]
        if checksum != keccak_256(self._decoded[:-4]).digest()[:4]:
            raise ValueError("Invalid checksum")
        if self._decoded[0] not in self._valid_netbytes:
            raise ValueError("Invalid address netbyte {nb}. Allowed values are: {allowed}".format(
                nb=hexlify(bytes(self._decoded[0])),
                allowed=", ".join(map(lambda b: '%02x' % b, self._valid_netbytes))))

    def is_testnet(self):
        return self._decoded[0] == self._valid_netbytes[1]

    def get_view_key(self):
        return hexlify(self._decoded[33:65]).decode()

    def get_spend_key(self):
        return hexlify(self._decoded[1:33]).decode()

    def with_payment_id(self, payment_id=0):
        if isinstance(payment_id, (bytes, str)):
            payment_id = int(payment_id, 16)
        elif not isinstance(payment_id, int):
            raise TypeError("payment_id must be either int or hexadecimal str or bytes")
        prefix = 54 if self.is_testnet() else 19
        data = bytearray([prefix]) + self._decoded[1:65] + struct.pack('>Q', payment_id)
        checksum = bytearray(keccak_256(data).digest()[:4])
        return IntegratedAddress(base58.encode(hexlify(data + checksum)))

    def __repr__(self):
        return base58.encode(hexlify(self._decoded))

    def __eq__(self, other):
        if isinstance(other, Address):
            return str(self) == str(other)
        if isinstance(other, str):
            return str(self) == other
        return super()


class SubAddress(Address):
    _valid_netbytes = (42, 63)

    def with_payment_id(self):
        raise TypeError("SubAddress cannot be merged with payment ID into IntegratedAddress")


class IntegratedAddress(Address):
    _valid_netbytes = (19, 54)

    def __init__(self, address):
        address = str(address)
        if len(address) != 106:
            raise ValueError("Integrated address must be 106 characters long, is %d" % len(address))
        self._decode(address)

    def get_payment_id(self):
        return hexlify(self._decoded[65:-4]).decode()

    def get_base_address(self):
        prefix = 53 if self.is_testnet() else 18
        data = bytearray([prefix]) + self._decoded[1:65]
        checksum = keccak_256(data).digest()[:4]
        return Address(base58.encode(hexlify(data + checksum)))


def address(addr):
    addr = str(addr)
    if len(addr) == 95:
        netbyte = bytearray(unhexlify(base58.decode(addr)))[0]
        if netbyte in Address._valid_netbytes:
            return Address(addr)
        elif netbyte in SubAddress._valid_netbytes:
            return SubAddress(addr)
        raise ValueError("Invalid address netbyte {nb}. Allowed values are: {allowed}".format(
            nb=hexlify(chr(netbyte)),
            allowed=", ".join(map(
                lambda b: '%02x' % b,
                sorted(Address._valid_netbytes + SubAddress._valid_netbytes)))))
    elif len(addr) == 106:
        return IntegratedAddress(addr)
    raise ValueError("Address must be either 95 or 106 characters long")