1 files changed, 44 insertions, 0 deletions
diff --git a/packages/contracts/src/utils/order_info_utils.ts b/packages/contracts/src/utils/order_info_utils.ts
new file mode 100644
index 000000000..9df627da3
--- /dev/null
+++ b/packages/contracts/src/utils/order_info_utils.ts
@@ -0,0 +1,44 @@
+import { assetProxyUtils, OrderStateUtils } from '@0xproject/order-utils';
+import { SignedOrder } from '@0xproject/types';
+import { BigNumber } from '@0xproject/utils';
+
+import { ExchangeContract } from '../contract_wrappers/generated/exchange';
+
+import { constants } from './constants';
+import { ERC20Wrapper } from './erc20_wrapper';
+import { SimpleERC20BalanceAndProxyAllowanceFetcher } from './simple_erc20_balance_and_allowance_fetcher';
+import { SimpleOrderFilledCancelledFetcher } from './simple_filled_cancelled_fetcher';
+
+export class OrderInfoUtils {
+    private _orderStateUtils: OrderStateUtils;
+    private _erc20Wrapper: ERC20Wrapper;
+    constructor(exchangeContract: ExchangeContract, erc20Wrapper: ERC20Wrapper, zrxAddress: string) {
+        this._erc20Wrapper = erc20Wrapper;
+        const simpleOrderFilledCancelledFetcher = new SimpleOrderFilledCancelledFetcher(exchangeContract, zrxAddress);
+        const simpleERC20BalanceAndProxyAllowanceFetcher = new SimpleERC20BalanceAndProxyAllowanceFetcher(erc20Wrapper);
+        this._orderStateUtils = new OrderStateUtils(
+            simpleERC20BalanceAndProxyAllowanceFetcher,
+            simpleOrderFilledCancelledFetcher,
+        );
+    }
+    public async getFillableTakerAssetAmountAsync(signedOrder: SignedOrder, takerAddress: string): Promise<BigNumber> {
+        const orderRelevantState = await this._orderStateUtils.getOrderRelevantStateAsync(signedOrder);
+        console.log('orderRelevantState', orderRelevantState);
+        if (takerAddress === constants.NULL_ADDRESS) {
+            return orderRelevantState.remainingFillableTakerAssetAmount;
+        }
+        const takerAssetData = assetProxyUtils.decodeERC20ProxyData(signedOrder.takerAssetData);
+        const takerBalance = await this._erc20Wrapper.getBalanceAsync(takerAddress, takerAssetData.tokenAddress);
+        const takerAllowance = await this._erc20Wrapper.getProxyAllowanceAsync(
+            takerAddress,
+            takerAssetData.tokenAddress,
+        );
+        // TODO: We also need to make sure taker has sufficient ZRX for fees...
+        const fillableTakerAssetAmount = BigNumber.min([
+            takerBalance,
+            takerAllowance,
+            orderRelevantState.remainingFillableTakerAssetAmount,
+        ]);
+        return fillableTakerAssetAmount;
+    }
+}