#!/usr/bin/env python3
#
# mmgen = Multi-Mode GENerator, command-line Bitcoin cold storage solution
# Copyright (C)2013-2022 The MMGen Project <mmgen@tuta.io>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

"""
protocol.py: Coin protocol base classes and initializer
"""

from collections import namedtuple

from .devtools import *
from .globalvars import g

decoded_wif = namedtuple('decoded_wif',['sec','pubkey_type','compressed'])
decoded_addr = namedtuple('decoded_addr',['bytes','ver_bytes','fmt'])
parsed_addr = namedtuple('parsed_addr',['ver_bytes','data'])

_finfo = namedtuple('fork_info',['height','hash','name','replayable'])
_nw = namedtuple('coin_networks',['mainnet','testnet','regtest'])

class CoinProtocol(MMGenObject):

	proto_info = namedtuple('proto_info',['name','trust_level']) # trust levels: see altcoin.py

	# keys are mirrored in g.core_coins:
	coins = {
		'btc': proto_info('Bitcoin',         5),
		'bch': proto_info('BitcoinCash',     5),
		'ltc': proto_info('Litecoin',        5),
		'eth': proto_info('Ethereum',        4),
		'etc': proto_info('EthereumClassic', 4),
		'zec': proto_info('Zcash',           2),
		'xmr': proto_info('Monero',          4)
	}

	class Base(MMGenObject):
		base_proto = None
		base_proto_coin  = None
		base_coin  = None
		is_fork_of = None
		networks   = ('mainnet','testnet','regtest')

		def __init__(self,coin,name,network,tokensym=None,need_amt=False):
			self.coin       = coin.upper()
			self.coin_id    = self.coin
			self.name       = name
			self.network    = network
			self.tokensym   = tokensym
			self.cls_name   = type(self).__name__
			self.testnet    = network in ('testnet','regtest')
			self.regtest    = network == 'regtest'
			self.networks   = tuple(k for k,v in self.network_names._asdict().items() if v)
			self.network_id = coin.lower() + {
				'mainnet': '',
				'testnet': '_tn',
				'regtest': '_rt',
			}[network]

			if hasattr(self,'wif_ver_num'):
				self.wif_ver_bytes = {k:bytes.fromhex(v) for k,v in self.wif_ver_num.items()}
				self.wif_ver_bytes_to_pubkey_type = {v:k for k,v in self.wif_ver_bytes.items()}
				vbs = list(self.wif_ver_bytes.values())
				self.wif_ver_bytes_len = len(vbs[0]) if len(set(len(b) for b in vbs)) == 1 else None

			if hasattr(self,'addr_ver_info'):
				self.addr_ver_bytes = {bytes.fromhex(k):v for k,v in self.addr_ver_info.items()}
				self.addr_fmt_to_ver_bytes = {v:k for k,v in self.addr_ver_bytes.items()}
				self.addr_ver_bytes_len = len(list(self.addr_ver_bytes)[0])

			if 'tx' not in self.mmcaps and g.is_txprog:
				from .util import die
				die(2,f'Command {g.prog_name!r} not supported for coin {self.coin}')

			if hasattr(self,'chain_names'):
				self.chain_name = self.chain_names[0] # first chain name is default
			else:
				self.chain_name = self.network
				self.chain_names = [self.network]

			if self.tokensym:
				assert self.name.startswith('Ethereum'), 'CoinProtocol.Base_chk1'

			if self.base_coin in ('ETH','XMR'):
				from .util2 import get_keccak
				self.keccak_256 = get_keccak()

			if need_amt:
				import mmgen.amt
				setattr( self, 'coin_amt', getattr(mmgen.amt,self.coin_amt) )
				fee = getattr(self,'max_tx_fee',None)
				setattr( self, 'max_tx_fee', (self.coin_amt(fee) if fee else None) )
			else:
				setattr( self, 'coin_amt', None )
				setattr( self, 'max_tx_fee', None )

		@property
		def dcoin(self):
			return self.coin

		@classmethod
		def chain_name_to_network(cls,coin,chain_name):
			"""
			The generic networks 'mainnet', 'testnet' and 'regtest' are required for all coins
			that support transaction operations.

			For protocols that have specific names for chains corresponding to these networks,
			the attribute 'chain_name' is used, while 'network' retains the generic name.
			For Bitcoin and Bitcoin forks, 'network' and 'chain_name' are equivalent.
			"""
			for network in ('mainnet','testnet','regtest'):
				proto = init_proto(coin,network=network)
				for proto_chain_name in proto.chain_names:
					if chain_name == proto_chain_name:
						return network
			raise ValueError(f'{chain_name}: unrecognized chain name for coin {coin}')

		@staticmethod
		def parse_network_id(network_id):
			nid = namedtuple('parsed_network_id',['coin','network'])
			if network_id.endswith('_tn'):
				return nid(network_id[:-3],'testnet')
			elif network_id.endswith('_rt'):
				return nid(network_id[:-3],'regtest')
			else:
				return nid(network_id,'mainnet')

		@staticmethod
		def create_network_id(coin,network):
			return coin.lower() + { 'mainnet':'', 'testnet':'_tn', 'regtest':'_rt' }[network]

		def cap(self,s):
			return s in self.caps

		def get_addr_len(self,addr_fmt):
			return self.addr_len

		def decode_addr_bytes(self,addr_bytes):
			vlen = self.addr_ver_bytes_len
			return decoded_addr(
				addr_bytes[vlen:],
				addr_bytes[:vlen],
				self.addr_ver_bytes[addr_bytes[:vlen]] )

		def coin_addr(self,addr):
			from .addr import CoinAddr
			return CoinAddr( proto=self, addr=addr )

		def addr_type(self,id_str):
			from .addr import MMGenAddrType
			return MMGenAddrType( proto=self, id_str=id_str )

		def viewkey(self,viewkey_str):
			raise NotImplementedError(f'{self.name} protocol does not support view keys')

		def base_proto_subclass(self,cls,subdir,modname,sub_clsname=None):
			"""
			magic module loading and class selection
			"""
			modpath = 'mmgen.proto.{}.{}{}'.format(
				self.base_proto_coin.lower(),
				subdir + '.' if subdir else '',
				modname )

			clsname = (
				self.mod_clsname
				+ ('Token' if self.tokensym else '')
				+ cls.__name__ )

			import importlib
			if sub_clsname:
				return getattr(getattr(importlib.import_module(modpath),clsname),sub_clsname)
			else:
				return getattr(importlib.import_module(modpath),clsname)


	class Secp256k1(Base):
		"""
		Bitcoin and Ethereum protocols inherit from this class
		"""
		secp256k1_ge = 0xfffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141
		privkey_len  = 32
		pubkey_types = ('std',)

		def parse_addr(self,ver_bytes,addr_bytes,fmt):
			return parsed_addr(
				ver_bytes  = ver_bytes,
				data       = addr_bytes,
			)

		def preprocess_key(self,sec,pubkey_type):
			# Key must be non-zero and less than group order of secp256k1 curve
			if 0 < int.from_bytes(sec,'big') < self.secp256k1_ge:
				return sec
			else: # chance of this is less than 1 in 2^127
				from .util import die,ymsg
				pk = int.from_bytes(sec,'big')
				if pk == 0: # chance of this is 1 in 2^256
					die(4,'Private key is zero!')
				elif pk == self.secp256k1_ge: # ditto
					die(4,'Private key == secp256k1_ge!')
				else:
					if not g.test_suite:
						ymsg(f'Warning: private key is greater than secp256k1 group order!:\n  {hexpriv}')
					return (pk % self.secp256k1_ge).to_bytes(self.privkey_len,'big')

	class DummyWIF:
		"""
		Ethereum and Monero protocols inherit from this class
		"""
		def encode_wif(self,privbytes,pubkey_type,compressed):
			assert pubkey_type == self.pubkey_type, f'{pubkey_type}: invalid pubkey_type for {self.name} protocol!'
			assert compressed == False, f'{self.name} protocol does not support compressed pubkeys!'
			return privbytes.hex()

		def decode_wif(self,wif):
			return decoded_wif(
				sec         = bytes.fromhex(wif),
				pubkey_type = self.pubkey_type,
				compressed  = False )

def init_proto(coin=None,testnet=False,regtest=False,network=None,network_id=None,tokensym=None,need_amt=False):

	assert type(testnet) == bool, 'init_proto_chk1'
	assert type(regtest) == bool, 'init_proto_chk2'
	assert coin or network_id, 'init_proto_chk3'
	assert not (coin and network_id), 'init_proto_chk4'

	if network_id:
		coin,network = CoinProtocol.Base.parse_network_id(network_id)
	elif network:
		assert network in CoinProtocol.Base.networks, f'init_proto_chk5 - {network!r}: invalid network'
		assert testnet == False, 'init_proto_chk6'
		assert regtest == False, 'init_proto_chk7'
	else:
		network = 'regtest' if regtest else 'testnet' if testnet else 'mainnet'

	coin = coin.lower()

	if coin not in CoinProtocol.coins:
		from .altcoin import init_genonly_altcoins
		init_genonly_altcoins( coin, testnet=testnet ) # raises exception on failure

	name = CoinProtocol.coins[coin].name
	proto_name = name + ('' if network == 'mainnet' else network.capitalize())

	if not hasattr(CoinProtocol,proto_name):
		import importlib
		setattr(
			CoinProtocol,
			proto_name,
			getattr(importlib.import_module(f'mmgen.proto.{coin}.params'),network)
		)

	return getattr(CoinProtocol,proto_name)(
		coin      = coin,
		name      = name,
		network   = network,
		tokensym  = tokensym,
		need_amt  = need_amt )

def init_proto_from_opts(need_amt=False):
	return init_proto(
		coin      = g.coin,
		testnet   = g.testnet,
		regtest   = g.regtest,
		tokensym  = g.token,
		need_amt  = need_amt )

def warn_trustlevel(coinsym):

	if coinsym.lower() in CoinProtocol.coins:
		trust_level = CoinProtocol.coins[coinsym.lower()].trust_level
	else:
		from .altcoin import CoinInfo
		e = CoinInfo.get_entry(coinsym,'mainnet')
		trust_level = e.trust_level if e else None
		if trust_level in (None,-1):
			from .util import die
			die(1,f'Coin {coinsym} is not supported by {g.proj_name}')

	if trust_level > 3:
		return

	m = """
		Support for coin {c!r} is EXPERIMENTAL.  The {p} project
		assumes no responsibility for any loss of funds you may incur.
		This coin’s {p} testing status: {t}
		Are you sure you want to continue?
	"""

	from .util import qmsg,fmt
	from .color import red,yellow,green

	warning = fmt(m).strip().format(
		c = coinsym.upper(),
		t = {
			0: red('COMPLETELY UNTESTED'),
			1: red('LOW'),
			2: yellow('MEDIUM'),
			3: green('OK'),
		}[trust_level],
		p = g.proj_name )

	if g.test_suite:
		qmsg(warning)
		return

	from .ui import keypress_confirm
	if not keypress_confirm(warning,default_yes=True):
		import sys
		sys.exit(0)