import { ZeroEx } from '0x.js';
import { BigNumber } from '@0xproject/utils';
import * as chai from 'chai';
import * as Web3 from 'web3';

import { Artifacts } from '../../util/artifacts';
import { constants } from '../../util/constants';
import { ContractInstance } from '../../util/types';

import { chaiSetup } from './utils/chai_setup';

const { DummyToken } = new Artifacts(artifacts);
const web3: Web3 = (global as any).web3;
chaiSetup.configure();
const expect = chai.expect;

contract('UnlimitedAllowanceToken', (accounts: string[]) => {
	const config = {
		networkId: constants.TESTRPC_NETWORK_ID,
	};
	const zeroEx = new ZeroEx(web3.currentProvider, config);
	const owner = accounts[0];
	const spender = accounts[1];

	const MAX_MINT_VALUE = new BigNumber(100000000000000000000);
	let tokenAddress: string;
	let token: ContractInstance;

	beforeEach(async () => {
		token = await DummyToken.new({ from: owner });
		await token.mint(MAX_MINT_VALUE, { from: owner });
		tokenAddress = token.address;
	});

	describe('transfer', () => {
		it('should transfer balance from sender to receiver', async () => {
			const receiver = spender;
			const initOwnerBalance = await zeroEx.token.getBalanceAsync(tokenAddress, owner);
			const amountToTransfer = new BigNumber(1);
			await zeroEx.token.transferAsync(tokenAddress, owner, receiver, amountToTransfer);
			const finalOwnerBalance = await zeroEx.token.getBalanceAsync(tokenAddress, owner);
			const finalReceiverBalance = await zeroEx.token.getBalanceAsync(tokenAddress, receiver);

			const expectedFinalOwnerBalance = initOwnerBalance.minus(amountToTransfer);
			const expectedFinalReceiverBalance = amountToTransfer;
			expect(finalOwnerBalance).to.be.bignumber.equal(expectedFinalOwnerBalance);
			expect(finalReceiverBalance).to.be.bignumber.equal(expectedFinalReceiverBalance);
		});

		it('should return true on a 0 value transfer', async () => {
			const didReturnTrue = await token.transfer.call(spender, 0, {
				from: owner,
			});
			expect(didReturnTrue).to.be.true();
		});
	});

	describe('transferFrom', () => {
		it('should return false if owner has insufficient balance', async () => {
			const ownerBalance = await zeroEx.token.getBalanceAsync(tokenAddress, owner);
			const amountToTransfer = ownerBalance.plus(1);
			await zeroEx.token.setAllowanceAsync(tokenAddress, owner, spender, amountToTransfer);
			const didReturnTrue = await token.transferFrom.call(owner, spender, amountToTransfer, { from: spender });
			expect(didReturnTrue).to.be.false();
		});

		it('should return false if spender has insufficient allowance', async () => {
			const ownerBalance = await zeroEx.token.getBalanceAsync(tokenAddress, owner);
			const amountToTransfer = ownerBalance;

			const spenderAllowance = await zeroEx.token.getAllowanceAsync(tokenAddress, owner, spender);
			const spenderAllowanceIsInsufficient = spenderAllowance.cmp(amountToTransfer) < 0;
			expect(spenderAllowanceIsInsufficient).to.be.true();

			const didReturnTrue = await token.transferFrom.call(owner, spender, amountToTransfer, { from: spender });
			expect(didReturnTrue).to.be.false();
		});

		it('should return true on a 0 value transfer', async () => {
			const amountToTransfer = 0;
			const didReturnTrue = await token.transferFrom.call(owner, spender, amountToTransfer, { from: spender });
			expect(didReturnTrue).to.be.true();
		});

		it('should not modify spender allowance if spender allowance is 2^256 - 1', async () => {
			const initOwnerBalance = await zeroEx.token.getBalanceAsync(tokenAddress, owner);
			const amountToTransfer = initOwnerBalance;
			const initSpenderAllowance = zeroEx.token.UNLIMITED_ALLOWANCE_IN_BASE_UNITS;
			await zeroEx.token.setAllowanceAsync(tokenAddress, owner, spender, initSpenderAllowance);
			await zeroEx.token.transferFromAsync(tokenAddress, owner, spender, spender, amountToTransfer, {
				gasLimit: constants.MAX_TOKEN_TRANSFERFROM_GAS,
			});

			const newSpenderAllowance = await zeroEx.token.getAllowanceAsync(tokenAddress, owner, spender);
			expect(initSpenderAllowance).to.be.bignumber.equal(newSpenderAllowance);
		});

		it('should transfer the correct balances if spender has sufficient allowance', async () => {
			const initOwnerBalance = await zeroEx.token.getBalanceAsync(tokenAddress, owner);
			const amountToTransfer = initOwnerBalance;
			const initSpenderAllowance = initOwnerBalance;
			await zeroEx.token.setAllowanceAsync(tokenAddress, owner, spender, initSpenderAllowance);
			await zeroEx.token.transferFromAsync(tokenAddress, owner, spender, spender, amountToTransfer, {
				gasLimit: constants.MAX_TOKEN_TRANSFERFROM_GAS,
			});

			const newOwnerBalance = await zeroEx.token.getBalanceAsync(tokenAddress, owner);
			const newSpenderBalance = await zeroEx.token.getBalanceAsync(tokenAddress, spender);

			expect(newOwnerBalance).to.be.bignumber.equal(0);
			expect(newSpenderBalance).to.be.bignumber.equal(initOwnerBalance);
		});

		it('should modify allowance if spender has sufficient allowance less than 2^256 - 1', async () => {
			const initOwnerBalance = await zeroEx.token.getBalanceAsync(tokenAddress, owner);
			const amountToTransfer = initOwnerBalance;
			const initSpenderAllowance = initOwnerBalance;
			await zeroEx.token.setAllowanceAsync(tokenAddress, owner, spender, initSpenderAllowance);
			await zeroEx.token.transferFromAsync(tokenAddress, owner, spender, spender, amountToTransfer, {
				gasLimit: constants.MAX_TOKEN_TRANSFERFROM_GAS,
			});

			const newSpenderAllowance = await zeroEx.token.getAllowanceAsync(tokenAddress, owner, spender);
			expect(newSpenderAllowance).to.be.bignumber.equal(0);
		});
	});
});