from ethereum import utils

def mk_forwarder(address):
    code = b'\x36\x60\x00\x60\x00\x37' # CALLDATACOPY 0 0 (CALLDATASIZE)
    code += b'\x61\x20\x00\x60\x00\x36\x60\x00' # 8192 0 CALLDATASIZE 0
    code += b'\x73' + utils.normalize_address(address) + b'\x5a' # address gas
    code += b'\xf4' # delegatecall
    code += b'\x61\x20\x00\x60\x00\xf3' # 8192 0 RETURN
    return code

def mk_wrapper(code):
    lencodepush = b'\x60' + utils.encode_int(len(code)) # length of code
    returner = lencodepush +  b'\x60\x0c\x60\x00' # start from 12 in code, 0 in memory
    returner += b'\x39' # CODECOPY
    returner += lencodepush + b'\x60\x00' + b'\xf3' # return code
    assert len(returner) == 12
    return returner + code

kode = """
moose: num
def increment_moose(i: num) -> num:
    self.moose += i
    return self.moose
"""

def test():
    from ethereum.tools import tester2
    c = tester2.Chain()
    x = c.contract(kode, language='viper')
    fwdcode = mk_forwarder(x.address)
    initcode = mk_wrapper(fwdcode)
    y = c.contract(initcode, language='evm')
    assert c.head_state.get_code(y) == fwdcode
    z = tester2.ABIContract(c, x.translator, y)
    assert z.increment_moose(3) == 3
    assert z.increment_moose(5) == 8

if __name__ == '__main__':
    test()