from random import (
    randint,
)
import re

import pytest

import eth_tester
from eth_tester import (
    EthereumTester,
    PyEVMBackend,
)
from vyper import (
    compiler,
)
from web3 import Web3
from web3.providers.eth_tester import (
    EthereumTesterProvider,
)
from .utils import (
    get_deposit_contract_code,
    get_deposit_contract_json,
)


# Constants
MIN_DEPOSIT_AMOUNT = 1000000000  # Gwei
FULL_DEPOSIT_AMOUNT = 32000000000  # Gwei
CHAIN_START_FULL_DEPOSIT_THRESHOLD = 65536  # 2**16
DEPOSIT_CONTRACT_TREE_DEPTH = 32
TWO_TO_POWER_OF_TREE_DEPTH = 2**DEPOSIT_CONTRACT_TREE_DEPTH


@pytest.fixture
def tester():
    return EthereumTester(PyEVMBackend())


@pytest.fixture
def a0(tester):
    return tester.get_accounts()[0]


@pytest.fixture
def w3(tester):
    web3 = Web3(EthereumTesterProvider(tester))
    return web3


@pytest.fixture
def registration_contract(w3, tester):
    contract_bytecode = get_deposit_contract_json()['bytecode']
    contract_abi = get_deposit_contract_json()['abi']
    registration = w3.eth.contract(
        abi=contract_abi,
        bytecode=contract_bytecode)
    tx_hash = registration.constructor().transact()
    tx_receipt = w3.eth.waitForTransactionReceipt(tx_hash)
    registration_deployed = w3.eth.contract(
        address=tx_receipt.contractAddress,
        abi=contract_abi
    )
    return registration_deployed


@pytest.fixture(scope="session")
def chain_start_full_deposit_thresholds():
    return [randint(1, 5), randint(6, 10), randint(11, 15)]


@pytest.fixture(params=[0, 1, 2])
def modified_registration_contract(
        request,
        w3,
        tester,
        chain_start_full_deposit_thresholds):
    # Set CHAIN_START_FULL_DEPOSIT_THRESHOLD to different threshold t
    registration_code = get_deposit_contract_code()
    t = str(chain_start_full_deposit_thresholds[request.param])
    modified_registration_code = re.sub(
        r'CHAIN_START_FULL_DEPOSIT_THRESHOLD: constant\(uint256\) = [0-9]+',
        'CHAIN_START_FULL_DEPOSIT_THRESHOLD: constant(uint256) = ' + t,
        registration_code,
    )
    assert modified_registration_code != registration_code
    contract_bytecode = compiler.compile_code(modified_registration_code)['bytecode']
    contract_abi = compiler.mk_full_signature(modified_registration_code)
    registration = w3.eth.contract(
        abi=contract_abi,
        bytecode=contract_bytecode)
    tx_hash = registration.constructor().transact()
    tx_receipt = w3.eth.waitForTransactionReceipt(tx_hash)
    registration_deployed = w3.eth.contract(
        address=tx_receipt.contractAddress,
        abi=contract_abi
    )
    setattr(
        registration_deployed,
        'chain_start_full_deposit_threshold',
        chain_start_full_deposit_thresholds[request.param]
    )
    return registration_deployed


@pytest.fixture
def assert_tx_failed(tester):
    def assert_tx_failed(function_to_test, exception=eth_tester.exceptions.TransactionFailed):
        snapshot_id = tester.take_snapshot()
        with pytest.raises(exception):
            function_to_test()
        tester.revert_to_snapshot(snapshot_id)
    return assert_tx_failed