calculate best taking amount fusion order (#177)

* calculate best taking amount fusion order

* fix wrong amount

Author: ngocthanh1389

pkg/oneinch/auctioncalculator/amount_calculator.go

@@ -63,6 +63,15 @@ func (c AmountCalculator) GetRequiredTakingAmount(
 	return c.getAuctionBumpedAmount(withFee, ts, blockBaseFee)
 }
 
+func (c AmountCalculator) GetBestRequiredTakingAmount(
+	takingAmount *big.Int,
+	ts *big.Int,
+	blockBaseFee *big.Int,
+) *big.Int {
+	withFee := c.feeCalculator.GetTakingAmountWhitelist(takingAmount)
+	return c.getAuctionBumpedAmount(withFee, ts, blockBaseFee)
+}
+
 func (c AmountCalculator) GetRequiredMakingAmount(
 	taker common.Address,
 	makingAmount *big.Int,

pkg/oneinch/fusionorder/fusion_order.go

@@ -37,6 +37,15 @@ func (o FusionOrder) CalcTakingAmount(
 	return o.amountCalculator.GetRequiredTakingAmount(taker, takingAmount, blockTime, baseFee)
 }
 
+func (o FusionOrder) CalcBestTakingAmount(
+	makingAmount *big.Int,
+	blockTime,
+	baseFee *big.Int,
+) *big.Int {
+	takingAmount := util.CalcTakingAmount(makingAmount, o.LimitOrder.MakingAmount, o.LimitOrder.TakingAmount)
+	return o.amountCalculator.GetBestRequiredTakingAmount(takingAmount, blockTime, baseFee)
+}
+
 func (o FusionOrder) CalcMakingAmount(
 	taker common.Address,
 	takingAmount *big.Int,

pkg/oneinch/limitorder/fee_calculator.go

@@ -112,11 +112,20 @@ func (c FeeCalculator) getFee(taker common.Address) *big.Int {
 	return new(big.Int).SetInt64(Base10000 + resolverFee + integratorFee)
 }
 
+func (c FeeCalculator) getWhitelistFee() *big.Int {
+	resolverFee, integratorFee := c.GetWhitelistFees()
+	return new(big.Int).SetInt64(Base10000 + resolverFee + integratorFee)
+}
+
 // GetTakingAmount https://github.com/1inch/limit-order-sdk/blob/1793d32bd36c6cfea909caafbc15e8023a033249/src/limit-order/extensions/fee-taker/fee-calculator.ts#L13
 func (c FeeCalculator) GetTakingAmount(taker common.Address, orderTakingAmount *big.Int) *big.Int {
 	return util.MulDiv(orderTakingAmount, c.getFee(taker), big.NewInt(Base10000), util.Ceil)
 }
 
+func (c FeeCalculator) GetTakingAmountWhitelist(orderTakingAmount *big.Int) *big.Int {
+	return util.MulDiv(orderTakingAmount, c.getWhitelistFee(), big.NewInt(Base10000), util.Ceil)
+}
+
 // GetMakingAmount https://github.com/1inch/limit-order-sdk/blob/1793d32bd36c6cfea909caafbc15e8023a033249/src/limit-order/extensions/fee-taker/fee-calculator.ts#L23
 func (c FeeCalculator) GetMakingAmount(taker common.Address, orderMakingAmount *big.Int) *big.Int {
 	return util.MulDiv(orderMakingAmount, big.NewInt(Base10000), c.getFee(taker), util.Floor)
@@ -134,6 +143,13 @@ func (c FeeCalculator) GetFeesForTaker(taker common.Address) (int64, int64) {
 	return resolverFee, int64(c.fees.Integrator.Fee)
 }
 
+func (c FeeCalculator) GetWhitelistFees() (int64, int64) {
+	discountNumerator := Base10000 - c.fees.Resolver.WhitelistDiscount
+	resolverFee := int64(discountNumerator) * int64(c.fees.Resolver.Fee) / Base10000
+
+	return resolverFee, int64(c.fees.Integrator.Fee)
+}
+
 // GetResolverFee which resolver pays to resolver fee receiver
 func (c FeeCalculator) GetResolverFee(taker common.Address, orderTakingAmount *big.Int) *big.Int {
 	takingAmount := c.GetTakingAmount(taker, orderTakingAmount)