import {ZeroEx} from '0x.js';
import {BigNumber} from 'bignumber.js';
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 {DummyTokenV2} = new Artifacts(artifacts);
const web3: Web3 = (global as any).web3;
chaiSetup.configure();
const expect = chai.expect;

contract('ERC20Token', (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 DummyTokenV2.new({from: owner});
        await token.mint(MAX_MINT_VALUE, {from: owner});
        tokenAddress = token.address;
    });

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

        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 throw 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);
            return expect(token.transferFrom.call(owner, spender, amountToTransfer, {from: spender}))
                .to.be.rejectedWith(constants.REVERT);
        });

        it('should throw 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();

            return expect(token.transferFrom.call(owner, spender, amountToTransfer, {from: spender}))
                .to.be.rejectedWith(constants.REVERT);
        });

        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);

            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);

            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);

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