feat: add price impact calc to swap-estimation-by-denom (#315)

* feat: add price impact calc to swap-estimation-by-denom

* fix: lowest amount to fix

docs/static/openapi.yml

@@ -38404,6 +38404,8 @@ paths:
                   signatures required by gogoproto.
               weight_balance_ratio:
                 type: string
+              price_impact:
+                type: string
         default:
           description: An unexpected error response.
           schema:
@@ -82978,6 +82980,8 @@ definitions:
           signatures required by gogoproto.
       weight_balance_ratio:
         type: string
+      price_impact:
+        type: string
   elys.amm.QuerySwapEstimationResponse:
     type: object
     properties:

proto/elys/amm/query.proto

@@ -183,6 +183,7 @@ message QuerySwapEstimationByDenomResponse {
            string                   discount   = 6 [(gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec", (gogoproto.nullable) = false];
            cosmos.base.v1beta1.Coin available_liquidity  = 7 [(gogoproto.nullable)   = false ] ;
            string                   weight_balance_ratio = 8 [(gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec", (gogoproto.nullable) = false];
+           string price_impact = 9 [(gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec", (gogoproto.nullable) = false];
 }
 
 message QueryAMMPriceRequest {

x/amm/keeper/calc_swap_estimation_by_denom.go

@@ -5,6 +5,10 @@ import (
 	"github.com/elys-network/elys/x/amm/types"
 )
 
+const (
+	lowestAmountForInitialSpotPriceCalc = 10 // lowest amount to use for initial spot price calculation
+)
+
 // CalcSwapEstimationByDenom calculates the swap estimation by denom
 func (k Keeper) CalcSwapEstimationByDenom(
 	ctx sdk.Context,
@@ -23,34 +27,53 @@ func (k Keeper) CalcSwapEstimationByDenom(
 	discountOut sdk.Dec,
 	availableLiquidity sdk.Coin,
 	weightBonus sdk.Dec,
+	priceImpact sdk.Dec,
 	err error,
 ) {
 	// if amount denom is equal to denomIn, calculate swap estimation by denomIn
 	if amount.Denom == denomIn {
 		inRoute, err := k.CalcInRouteByDenom(ctx, denomIn, denomOut, baseCurrency)
 		if err != nil {
-			return nil, nil, sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), sdk.ZeroDec(), sdk.Coin{}, sdk.ZeroDec(), err
+			return nil, nil, sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), sdk.ZeroDec(), sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), err
+		}
+		initialSpotPrice, _, _, _, _, _, err := k.CalcInRouteSpotPrice(ctx, sdk.NewInt64Coin(amount.Denom, lowestAmountForInitialSpotPriceCalc), inRoute, discount, overrideSwapFee)
+		if err != nil {
+			return nil, nil, sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), sdk.ZeroDec(), sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), err
+		}
+		// check if initialSpotPrice is zero to avoid division by zero
+		if initialSpotPrice.IsZero() {
+			return nil, nil, sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), sdk.ZeroDec(), sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), types.ErrInitialSpotPriceIsZero
 		}
 		spotPrice, tokenOut, swapFeeOut, _, availableLiquidity, weightBonus, err := k.CalcInRouteSpotPrice(ctx, amount, inRoute, discount, overrideSwapFee)
 		if err != nil {
-			return nil, nil, sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), sdk.ZeroDec(), sdk.Coin{}, sdk.ZeroDec(), err
+			return nil, nil, sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), sdk.ZeroDec(), sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), err
 		}
-		return inRoute, nil, tokenOut, spotPrice, swapFeeOut, discount, availableLiquidity, weightBonus, nil
+		priceImpact := initialSpotPrice.Sub(spotPrice).Quo(initialSpotPrice)
+		return inRoute, nil, tokenOut, spotPrice, swapFeeOut, discount, availableLiquidity, weightBonus, priceImpact, nil
 	}
 
 	// if amount denom is equal to denomOut, calculate swap estimation by denomOut
 	if amount.Denom == denomOut {
 		outRoute, err := k.CalcOutRouteByDenom(ctx, denomOut, denomIn, baseCurrency)
 		if err != nil {
-			return nil, nil, sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), sdk.ZeroDec(), sdk.Coin{}, sdk.ZeroDec(), err
+			return nil, nil, sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), sdk.ZeroDec(), sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), err
+		}
+		initialSpotPrice, _, _, _, _, _, err := k.CalcOutRouteSpotPrice(ctx, sdk.NewInt64Coin(amount.Denom, lowestAmountForInitialSpotPriceCalc), outRoute, discount, overrideSwapFee)
+		if err != nil {
+			return nil, nil, sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), sdk.ZeroDec(), sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), err
+		}
+		// check if initialSpotPrice is zero to avoid division by zero
+		if initialSpotPrice.IsZero() {
+			return nil, nil, sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), sdk.ZeroDec(), sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), types.ErrInitialSpotPriceIsZero
 		}
 		spotPrice, tokenIn, swapFeeOut, _, availableLiquidity, weightBonus, err := k.CalcOutRouteSpotPrice(ctx, amount, outRoute, discount, overrideSwapFee)
 		if err != nil {
-			return nil, nil, sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), sdk.ZeroDec(), sdk.Coin{}, sdk.ZeroDec(), err
+			return nil, nil, sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), sdk.ZeroDec(), sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), err
 		}
-		return nil, outRoute, tokenIn, spotPrice, swapFeeOut, discount, availableLiquidity, weightBonus, nil
+		priceImpact := initialSpotPrice.Sub(spotPrice).Quo(initialSpotPrice)
+		return nil, outRoute, tokenIn, spotPrice, swapFeeOut, discount, availableLiquidity, weightBonus, priceImpact, nil
 	}
 
 	// if amount denom is neither equal to denomIn nor denomOut, return error
-	return nil, nil, sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), sdk.ZeroDec(), sdk.Coin{}, sdk.ZeroDec(), types.ErrInvalidDenom
+	return nil, nil, sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), sdk.ZeroDec(), sdk.Coin{}, sdk.ZeroDec(), sdk.ZeroDec(), types.ErrInvalidDenom
 }

x/amm/keeper/calc_swap_estimation_by_denom_test.go

@@ -92,7 +92,7 @@ func (suite *KeeperTestSuite) TestCalcSwapEstimationByDenom() {
 	suite.app.AmmKeeper.SetPool(suite.ctx, pool2)
 
 	amount := sdk.NewCoin(ptypes.Elys, sdk.NewInt(100))
-	inRoute, outRoute, tokenOut, spotPrice, _, _, _, _, err := suite.app.AmmKeeper.CalcSwapEstimationByDenom(
+	inRoute, outRoute, tokenOut, spotPrice, _, _, _, _, _, err := suite.app.AmmKeeper.CalcSwapEstimationByDenom(
 		suite.ctx,
 		amount,
 		ptypes.Elys, "uusda", ptypes.BaseCurrency,
@@ -105,7 +105,7 @@ func (suite *KeeperTestSuite) TestCalcSwapEstimationByDenom() {
 	suite.Require().NotZero(spotPrice)
 
 	amount = sdk.NewCoin("uusda", sdk.NewInt(100))
-	inRoute, outRoute, tokenOut, spotPrice, _, _, _, _, err = suite.app.AmmKeeper.CalcSwapEstimationByDenom(
+	inRoute, outRoute, tokenOut, spotPrice, _, _, _, _, _, err = suite.app.AmmKeeper.CalcSwapEstimationByDenom(
 		suite.ctx,
 		amount,
 		ptypes.Elys, "uusda", ptypes.BaseCurrency,
@@ -119,7 +119,7 @@ func (suite *KeeperTestSuite) TestCalcSwapEstimationByDenom() {
 
 	// Test no routes
 	amount = sdk.NewCoin("invalid", sdk.NewInt(1000))
-	_, _, _, _, _, _, _, _, err = suite.app.AmmKeeper.CalcSwapEstimationByDenom(
+	_, _, _, _, _, _, _, _, _, err = suite.app.AmmKeeper.CalcSwapEstimationByDenom(
 		suite.ctx, amount,
 		ptypes.Elys, "uusda", ptypes.BaseCurrency,
 		sdk.ZeroDec(),

x/amm/keeper/msg_server_swap_by_denom.go

@@ -24,7 +24,7 @@ func (k msgServer) SwapByDenom(goCtx context.Context, msg *types.MsgSwapByDenom)
 	}
 	baseCurrency := entry.Denom
 
-	inRoute, outRoute, _, spotPrice, _, _, _, _, err := k.CalcSwapEstimationByDenom(ctx, msg.Amount, msg.DenomIn, msg.DenomOut, baseCurrency, msg.Discount, sdk.ZeroDec())
+	inRoute, outRoute, _, spotPrice, _, _, _, _, _, err := k.CalcSwapEstimationByDenom(ctx, msg.Amount, msg.DenomIn, msg.DenomOut, baseCurrency, msg.Discount, sdk.ZeroDec())
 	if err != nil {
 		return nil, err
 	}

x/amm/keeper/query_swap_estimation_by_denom.go

@@ -27,7 +27,7 @@ func (k Keeper) SwapEstimationByDenom(goCtx context.Context, req *types.QuerySwa
 
 	_ = baseCurrency
 
-	inRoute, outRoute, amount, spotPrice, swapFee, discount, availableLiquidity, weightBonus, err := k.CalcSwapEstimationByDenom(ctx, req.Amount, req.DenomIn, req.DenomOut, baseCurrency, req.Discount, sdk.ZeroDec())
+	inRoute, outRoute, amount, spotPrice, swapFee, discount, availableLiquidity, weightBonus, priceImpact, err := k.CalcSwapEstimationByDenom(ctx, req.Amount, req.DenomIn, req.DenomOut, baseCurrency, req.Discount, sdk.ZeroDec())
 	if err != nil {
 		return nil, err
 	}
@@ -41,5 +41,6 @@ func (k Keeper) SwapEstimationByDenom(goCtx context.Context, req *types.QuerySwa
 		Discount:           discount,
 		AvailableLiquidity: availableLiquidity,
 		WeightBalanceRatio: weightBonus,
+		PriceImpact:        priceImpact,
 	}, nil
 }

x/amm/types/errors.go

@@ -25,11 +25,12 @@ var (
 	ErrInvalidPoolId      = sdkerrors.Register(ModuleName, 91, "invalid pool id")
 	ErrInvalidSwapMsgType = sdkerrors.Register(ModuleName, 92, "unexpected swap message type")
 
-	ErrSameDenom       = sdkerrors.Register(ModuleName, 101, "denom in and denom out are the same")
-	ErrPoolNotFound    = sdkerrors.Register(ModuleName, 102, "pool not found")
-	ErrAmountTooLow    = sdkerrors.Register(ModuleName, 103, "amount too low")
-	ErrInvalidDenom    = sdkerrors.Register(ModuleName, 104, "invalid denom")
-	ErrInvalidDiscount = sdkerrors.Register(ModuleName, 105, "invalid discount")
+	ErrSameDenom              = sdkerrors.Register(ModuleName, 101, "denom in and denom out are the same")
+	ErrPoolNotFound           = sdkerrors.Register(ModuleName, 102, "pool not found")
+	ErrAmountTooLow           = sdkerrors.Register(ModuleName, 103, "amount too low")
+	ErrInvalidDenom           = sdkerrors.Register(ModuleName, 104, "invalid denom")
+	ErrInvalidDiscount        = sdkerrors.Register(ModuleName, 105, "invalid discount")
+	ErrInitialSpotPriceIsZero = sdkerrors.Register(ModuleName, 106, "initial spot price is zero")
 )
 
 const (