1 files changed, 140 insertions, 0 deletions
diff --git a/packages/order-utils/src/order_state_utils.ts b/packages/order-utils/src/order_state_utils.ts
new file mode 100644
index 000000000..36171f526
--- /dev/null
+++ b/packages/order-utils/src/order_state_utils.ts
@@ -0,0 +1,140 @@
+import {
+    ExchangeContractErrs,
+    OrderRelevantState,
+    OrderState,
+    OrderStateInvalid,
+    OrderStateValid,
+    SignedOrder,
+} from '@0xproject/types';
+import { BigNumber } from '@0xproject/utils';
+import * as _ from 'lodash';
+
+import { AbstractBalanceAndProxyAllowanceFetcher } from './abstract/abstract_balance_and_proxy_allowance_fetcher';
+import { AbstractOrderFilledCancelledFetcher } from './abstract/abstract_order_filled_cancelled_fetcher';
+import { getOrderHashHex } from './order_hash';
+import { RemainingFillableCalculator } from './remaining_fillable_calculator';
+
+const ACCEPTABLE_RELATIVE_ROUNDING_ERROR = 0.0001;
+
+export class OrderStateUtils {
+    private _balanceAndProxyAllowanceFetcher: AbstractBalanceAndProxyAllowanceFetcher;
+    private _orderFilledCancelledFetcher: AbstractOrderFilledCancelledFetcher;
+    private static _validateIfOrderIsValid(signedOrder: SignedOrder, orderRelevantState: OrderRelevantState): void {
+        const unavailableTakerTokenAmount = orderRelevantState.cancelledTakerTokenAmount.add(
+            orderRelevantState.filledTakerTokenAmount,
+        );
+        const availableTakerTokenAmount = signedOrder.takerTokenAmount.minus(unavailableTakerTokenAmount);
+        if (availableTakerTokenAmount.eq(0)) {
+            throw new Error(ExchangeContractErrs.OrderRemainingFillAmountZero);
+        }
+
+        if (orderRelevantState.makerBalance.eq(0)) {
+            throw new Error(ExchangeContractErrs.InsufficientMakerBalance);
+        }
+        if (orderRelevantState.makerProxyAllowance.eq(0)) {
+            throw new Error(ExchangeContractErrs.InsufficientMakerAllowance);
+        }
+        if (!signedOrder.makerFee.eq(0)) {
+            if (orderRelevantState.makerFeeBalance.eq(0)) {
+                throw new Error(ExchangeContractErrs.InsufficientMakerFeeBalance);
+            }
+            if (orderRelevantState.makerFeeProxyAllowance.eq(0)) {
+                throw new Error(ExchangeContractErrs.InsufficientMakerFeeAllowance);
+            }
+        }
+        const minFillableTakerTokenAmountWithinNoRoundingErrorRange = signedOrder.takerTokenAmount
+            .dividedBy(ACCEPTABLE_RELATIVE_ROUNDING_ERROR)
+            .dividedBy(signedOrder.makerTokenAmount);
+        if (
+            orderRelevantState.remainingFillableTakerTokenAmount.lessThan(
+                minFillableTakerTokenAmountWithinNoRoundingErrorRange,
+            )
+        ) {
+            throw new Error(ExchangeContractErrs.OrderFillRoundingError);
+        }
+    }
+    constructor(
+        balanceAndProxyAllowanceFetcher: AbstractBalanceAndProxyAllowanceFetcher,
+        orderFilledCancelledFetcher: AbstractOrderFilledCancelledFetcher,
+    ) {
+        this._balanceAndProxyAllowanceFetcher = balanceAndProxyAllowanceFetcher;
+        this._orderFilledCancelledFetcher = orderFilledCancelledFetcher;
+    }
+    public async getOrderStateAsync(signedOrder: SignedOrder): Promise<OrderState> {
+        const orderRelevantState = await this.getOrderRelevantStateAsync(signedOrder);
+        const orderHash = getOrderHashHex(signedOrder);
+        try {
+            OrderStateUtils._validateIfOrderIsValid(signedOrder, orderRelevantState);
+            const orderState: OrderStateValid = {
+                isValid: true,
+                orderHash,
+                orderRelevantState,
+            };
+            return orderState;
+        } catch (err) {
+            const orderState: OrderStateInvalid = {
+                isValid: false,
+                orderHash,
+                error: err.message,
+            };
+            return orderState;
+        }
+    }
+    public async getOrderRelevantStateAsync(signedOrder: SignedOrder): Promise<OrderRelevantState> {
+        const zrxTokenAddress = this._orderFilledCancelledFetcher.getZRXTokenAddress();
+        const orderHash = getOrderHashHex(signedOrder);
+        const makerBalance = await this._balanceAndProxyAllowanceFetcher.getBalanceAsync(
+            signedOrder.makerTokenAddress,
+            signedOrder.maker,
+        );
+        const makerProxyAllowance = await this._balanceAndProxyAllowanceFetcher.getProxyAllowanceAsync(
+            signedOrder.makerTokenAddress,
+            signedOrder.maker,
+        );
+        const makerFeeBalance = await this._balanceAndProxyAllowanceFetcher.getBalanceAsync(
+            zrxTokenAddress,
+            signedOrder.maker,
+        );
+        const makerFeeProxyAllowance = await this._balanceAndProxyAllowanceFetcher.getProxyAllowanceAsync(
+            zrxTokenAddress,
+            signedOrder.maker,
+        );
+        const filledTakerTokenAmount = await this._orderFilledCancelledFetcher.getFilledTakerAmountAsync(orderHash);
+        const cancelledTakerTokenAmount = await this._orderFilledCancelledFetcher.getCancelledTakerAmountAsync(
+            orderHash,
+        );
+        const unavailableTakerTokenAmount = await this._orderFilledCancelledFetcher.getUnavailableTakerAmountAsync(
+            orderHash,
+        );
+        const totalMakerTokenAmount = signedOrder.makerTokenAmount;
+        const totalTakerTokenAmount = signedOrder.takerTokenAmount;
+        const remainingTakerTokenAmount = totalTakerTokenAmount.minus(unavailableTakerTokenAmount);
+        const remainingMakerTokenAmount = remainingTakerTokenAmount
+            .times(totalMakerTokenAmount)
+            .dividedToIntegerBy(totalTakerTokenAmount);
+        const transferrableMakerTokenAmount = BigNumber.min([makerProxyAllowance, makerBalance]);
+        const transferrableFeeTokenAmount = BigNumber.min([makerFeeProxyAllowance, makerFeeBalance]);
+
+        const isMakerTokenZRX = signedOrder.makerTokenAddress === zrxTokenAddress;
+        const remainingFillableCalculator = new RemainingFillableCalculator(
+            signedOrder,
+            isMakerTokenZRX,
+            transferrableMakerTokenAmount,
+            transferrableFeeTokenAmount,
+            remainingMakerTokenAmount,
+        );
+        const remainingFillableMakerTokenAmount = remainingFillableCalculator.computeRemainingMakerFillable();
+        const remainingFillableTakerTokenAmount = remainingFillableCalculator.computeRemainingTakerFillable();
+        const orderRelevantState = {
+            makerBalance,
+            makerProxyAllowance,
+            makerFeeBalance,
+            makerFeeProxyAllowance,
+            filledTakerTokenAmount,
+            cancelledTakerTokenAmount,
+            remainingFillableMakerTokenAmount,
+            remainingFillableTakerTokenAmount,
+        };
+        return orderRelevantState;
+    }
+}