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

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

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

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

contract('ZRXToken', (accounts: string[]) => {
	const owner = accounts[0];
	const spender = accounts[1];
	let zeroEx: ZeroEx;

	let MAX_UINT: BigNumber;

	let zrx: ContractInstance;
	let zrxAddress: string;

	beforeEach(async () => {
		zeroEx = new ZeroEx(web3.currentProvider, {
			exchangeContractAddress: Exchange.address,
			networkId: constants.TESTRPC_NETWORK_ID,
		});
		zrx = await ZRXToken.new();
		zrxAddress = zrx.address;
		MAX_UINT = zeroEx.token.UNLIMITED_ALLOWANCE_IN_BASE_UNITS;
	});

	describe('constants', () => {
		it('should have 18 decimals', async () => {
			const decimals = new BigNumber(await zrx.decimals.call());
			const expectedDecimals = 18;
			expect(decimals).to.be.bignumber.equal(expectedDecimals);
		});

		it('should have a total supply of 1 billion tokens', async () => {
			const totalSupply = new BigNumber(await zrx.totalSupply.call());
			const expectedTotalSupply = 1000000000;
			expect(ZeroEx.toUnitAmount(totalSupply, 18)).to.be.bignumber.equal(expectedTotalSupply);
		});

		it('should be named 0x Protocol Token', async () => {
			const name = await zrx.name.call();
			const expectedName = '0x Protocol Token';
			expect(name).to.be.equal(expectedName);
		});

		it('should have the symbol ZRX', async () => {
			const symbol = await zrx.symbol.call();
			const expectedSymbol = 'ZRX';
			expect(symbol).to.be.equal(expectedSymbol);
		});
	});

	describe('constructor', () => {
		it('should initialize owner balance to totalSupply', async () => {
			const ownerBalance = await zeroEx.token.getBalanceAsync(zrxAddress, owner);
			const totalSupply = new BigNumber(await zrx.totalSupply.call());
			expect(totalSupply).to.be.bignumber.equal(ownerBalance);
		});
	});

	describe('transfer', () => {
		it('should transfer balance from sender to receiver', async () => {
			const receiver = spender;
			const initOwnerBalance = await zeroEx.token.getBalanceAsync(zrxAddress, owner);
			const amountToTransfer = new BigNumber(1);
			const txHash = await zeroEx.token.transferAsync(zrxAddress, owner, receiver, amountToTransfer);
			await zeroEx.awaitTransactionMinedAsync(txHash);
			const finalOwnerBalance = await zeroEx.token.getBalanceAsync(zrxAddress, owner);
			const finalReceiverBalance = await zeroEx.token.getBalanceAsync(zrxAddress, 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 zrx.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(zrxAddress, owner);
			const amountToTransfer = ownerBalance.plus(1);
			const txHash = await zeroEx.token.setAllowanceAsync(zrxAddress, owner, spender, amountToTransfer, {
				gasLimit: constants.MAX_TOKEN_APPROVE_GAS,
			});
			await zeroEx.awaitTransactionMinedAsync(txHash);
			const didReturnTrue = await zrx.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(zrxAddress, owner);
			const amountToTransfer = ownerBalance;

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

			const didReturnTrue = await zrx.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 zrx.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(zrxAddress, owner);
			const amountToTransfer = initOwnerBalance;
			const initSpenderAllowance = MAX_UINT;
			let txHash = await zeroEx.token.setAllowanceAsync(zrxAddress, owner, spender, initSpenderAllowance, {
				gasLimit: constants.MAX_TOKEN_APPROVE_GAS,
			});
			await zeroEx.awaitTransactionMinedAsync(txHash);
			txHash = await zeroEx.token.transferFromAsync(zrxAddress, owner, spender, spender, amountToTransfer, {
				gasLimit: constants.MAX_TOKEN_TRANSFERFROM_GAS,
			});
			await zeroEx.awaitTransactionMinedAsync(txHash);

			const newSpenderAllowance = await zeroEx.token.getAllowanceAsync(zrxAddress, 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(zrxAddress, owner);
			const initSpenderBalance = await zeroEx.token.getBalanceAsync(zrxAddress, spender);
			const amountToTransfer = initOwnerBalance;
			const initSpenderAllowance = initOwnerBalance;
			let txHash = await zeroEx.token.setAllowanceAsync(zrxAddress, owner, spender, initSpenderAllowance);
			await zeroEx.awaitTransactionMinedAsync(txHash);
			txHash = await zeroEx.token.transferFromAsync(zrxAddress, owner, spender, spender, amountToTransfer, {
				gasLimit: constants.MAX_TOKEN_TRANSFERFROM_GAS,
			});
			await zeroEx.awaitTransactionMinedAsync(txHash);

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

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

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

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