<h1 align="center">How to Transfer ONT/ONG in Smart Contract</h1>
<p align="center" class="version">Version 0.1</p>

1. How to transfer ONT/ONG

state is used for building transfer structure.
Invoke is used for invoke native contract.

from ontology.interop.System.Runtime import Notify, CheckWitness
from ontology.interop.Ontology.Runtime import Base58ToAddress
from ontology.interop.Ontology.Native import Invoke
from ontology.builtins import state, bytearray

# contract address 
contract_address_ONT = bytearray(b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01')
contract_address_ONG = bytearray(b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02')

def Main(operation, args):
    if operation == 'transfer':
        from_acct = args[0]
        to_acct = args[1]
        ont_amount = args[2]
        ong_amount = args[3]
        return transfer(from_acct,to_acct,ont_amount,ong_amount)
    
    return False


def transfer(from_acct, to_acct, ont_amount, ong_amount):
    # transfer base58 address to address in the form of byte array 
    from_acct=Base58ToAddress(from_acct)
    to_acct=Base58ToAddress(to_acct)
    # check whether the sender is the payer
    if CheckWitness(from_acct):
        # transfer ONT
        param = state(from_acct, to_acct, ont_amount)
        res = Invoke(1, contract_address_ONT, 'transfer', [param])
        if res and res == b'\x01':
            Notify('transfer succeed')
        else:
            Notify('transfer failed')
        # transfer ONG
        param = state(from_acct, to_acct, ong_amount)
        res = Invoke(1, contract_address_ONG, 'transfer', [param])
        if res and res == b'\x01':
            Notify('transfer succeed')
        else:
            Notify('transfer failed')
    else:
        Notify('CheckWitness failed')

2. How to transfer ONG to self contract

from ontology.interop.System.Runtime import Notify, CheckWitness
from ontology.interop.Ontology.Runtime import Base58ToAddress
from ontology.interop.Ontology.Native import Invoke
from ontology.builtins import state, bytearray
from ontology.interop.System.ExecutionEngine import GetExecutingScriptHash

# contract address 
contract_address_ONT = bytearray(b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01')
contract_address_ONG = bytearray(b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02')
self_contract_address = GetExecutingScriptHash()

def Main(operation, args):
    if operation == 'transfer_ONG_to_contract':
        from_acct = args[0]
        ong_amount = args[1]
        return transfer_ONG_to_contract(from_acct, ong_amount)
    
    return False


def transfer_ONG_to_contract(from_acct, ong_amount):
    param = state(from_acct, self_contract_address, ong_amount)
    res = Invoke(0, contract_address_ONG, 'transfer', [param])
    if res and res == b'\x01':
        Notify('transfer ONG to contract successfully')
    else:
        Notify('transfer ONG failed')

3. Check ONG balance of a contract

from ontology.interop.System.Runtime import Notify, CheckWitness
from ontology.interop.Ontology.Runtime import Base58ToAddress
from ontology.interop.Ontology.Native import Invoke
from ontology.builtins import state, bytearray
from ontology.interop.System.ExecutionEngine import GetExecutingScriptHash

# contract address 
contract_address_ONT = bytearray(b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01')
contract_address_ONG = bytearray(b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02')
self_contract_address = GetExecutingScriptHash()

def Main(operation, args):
    if operation == 'check_self_contract_ONG_amount':
        return check_self_contract_ONG_amount()
    
    return False


def check_self_contract_ONG_amount():
    param = state(self_contract_address)
    # do not use [param]
    res = Invoke(0, contract_address_ONG, 'balanceOf', param)
    return res