from binascii import unhexlify

from lbry.crypto.hash import hash160, double_sha256
from lbry.crypto.base58 import Base58
from lbry.conf import Config
from lbry.schema.url import URL
from .header import Headers, UnvalidatedHeaders
from .checkpoints import HASHES


class Ledger:
    name = 'LBRY Credits'
    symbol = 'LBC'
    network_name = 'mainnet'

    headers_class = Headers

    secret_prefix = bytes((0x1c,))
    pubkey_address_prefix = bytes((0x55,))
    script_address_prefix = bytes((0x7a,))
    extended_public_key_prefix = unhexlify('0488b21e')
    extended_private_key_prefix = unhexlify('0488ade4')

    max_target = 0x0000ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
    genesis_hash = '9c89283ba0f3227f6c03b70216b9f665f0118d5e0fa729cedf4fb34d6a34f463'
    genesis_bits = 0x1f00ffff
    target_timespan = 150

    fee_per_byte = 50
    fee_per_name_char = 200000

    checkpoints = HASHES

    def __init__(self, conf: Config = None):
        self.conf = conf or Config.with_same_dir('/dev/null')
        self.coin_selection_strategy = None

    @classmethod
    def get_id(cls):
        return '{}_{}'.format(cls.symbol.lower(), cls.network_name.lower())

    @classmethod
    def hash160_to_address(cls, h160):
        raw_address = cls.pubkey_address_prefix + h160
        return Base58.encode(bytearray(raw_address + double_sha256(raw_address)[0:4]))

    @staticmethod
    def address_to_hash160(address):
        return Base58.decode(address)[1:21]

    @classmethod
    def is_valid_address(cls, address):
        decoded = Base58.decode_check(address)
        return decoded[0] == cls.pubkey_address_prefix[0]

    @classmethod
    def valid_address_or_error(cls, address):
        try:
            assert cls.is_valid_address(address)
        except:
            raise Exception(f"'{address}' is not a valid address")

    @classmethod
    def valid_channel_name_or_error(cls, name):
        try:
            if not name:
                raise Exception(
                    "Channel name cannot be blank."
                )
            parsed = URL.parse(name)
            if not parsed.has_channel:
                raise Exception("Channel names must start with '@' symbol.")
            if parsed.channel.name != name:
                raise Exception("Channel name has invalid character")
        except (TypeError, ValueError):
            raise Exception("Invalid channel name.")

    @classmethod
    def public_key_to_address(cls, public_key):
        return cls.hash160_to_address(hash160(public_key))

    @staticmethod
    def private_key_to_wif(private_key):
        return b'\x1c' + private_key + b'\x01'


class TestNetLedger(Ledger):
    network_name = 'testnet'
    pubkey_address_prefix = bytes((111,))
    script_address_prefix = bytes((196,))
    extended_public_key_prefix = unhexlify('043587cf')
    extended_private_key_prefix = unhexlify('04358394')
    checkpoints = {}


class RegTestLedger(Ledger):
    network_name = 'regtest'
    headers_class = UnvalidatedHeaders
    pubkey_address_prefix = bytes((111,))
    script_address_prefix = bytes((196,))
    extended_public_key_prefix = unhexlify('043587cf')
    extended_private_key_prefix = unhexlify('04358394')

    max_target = 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
    genesis_hash = '6e3fcf1299d4ec5d79c3a4c91d624a4acf9e2e173d95a1a0504f677669687556'
    genesis_bits = 0x207fffff
    target_timespan = 1
    checkpoints = {}