feat(perp): Add user discounts (#1594)

* add discounts

* impl genesis

* fix test

* make test more robust

* galaxy brain int encoding fix

* test and optimise

* lint

* CHANGELOG.md

* do merge

* clarify fee variable names in applyDiscountAndRebate func

* refactor dnr_test.go as per PR review

* add genesis tests

---------

Co-authored-by: unknown unknown <unknown@unknown>
Co-authored-by: godismercilex <[email protected]>
Co-authored-by: Jonathan Gimeno <[email protected]>

CHANGELOG.md

@@ -58,7 +58,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * [#1543](https://github.com/NibiruChain/nibiru/pull/1543) - epic(devgas): devgas module for incentivizing smart contract
 * [#1559](https://github.com/NibiruChain/nibiru/pull/1559) - feat: add versions to markets to allow to disable them
 * [#1585](https://github.com/NibiruChain/nibiru/pull/1585) - feat: include flag versioned in query markets to allow to query disabled markets
-
+* [#1594](https://github.com/NibiruChain/nibiru/pull/1594) - feat: add user discounts
 ### Improvements
 
 * [#1466](https://github.com/NibiruChain/nibiru/pull/1466) - refactor(perp): `PositionLiquidatedEvent`

proto/nibiru/perp/v2/genesis.proto

@@ -35,7 +35,27 @@ message GenesisState {
     ];
   }
 
-  repeated GenesisMarketLastVersion market_last_versions = 8
+  message Discount {
+    string fee = 1 [
+      (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
+      (gogoproto.nullable) = false
+    ];
+    string volume = 2 [
+      (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Int",
+      (gogoproto.nullable) = false
+    ];
+  }
+
+  repeated Discount global_discount = 8 [ (gogoproto.nullable) = false ];
+
+  repeated CustomDiscount custom_discounts = 9 [ (gogoproto.nullable) = false ];
+
+  message CustomDiscount {
+    string trader = 1;
+    Discount discount = 2;
+  }
+
+  repeated GenesisMarketLastVersion market_last_versions = 10
       [ (gogoproto.nullable) = false ];
 }
 

x/perp/v2/integration/action/dnr.go

@@ -8,7 +8,9 @@ import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 
 	"github.com/NibiruChain/nibiru/app"
+	"github.com/NibiruChain/nibiru/x/common/asset"
 	"github.com/NibiruChain/nibiru/x/common/testutil/action"
+	"github.com/NibiruChain/nibiru/x/perp/v2/types"
 )
 
 func DnREpochIs(epoch uint64) action.Action {
@@ -66,7 +68,12 @@ type expectPreviousVolumeAction struct {
 }
 
 func (e expectPreviousVolumeAction) Do(app *app.NibiruApp, ctx sdk.Context) (outCtx sdk.Context, err error, isMandatory bool) {
-	v := app.PerpKeeperV2.GetUserVolumeLastEpoch(ctx, e.User)
+	currentEpoch, err := app.PerpKeeperV2.DnREpoch.Get(ctx)
+	if err != nil {
+		return ctx, err, true
+	}
+
+	v := app.PerpKeeperV2.GetTraderVolumeLastEpoch(ctx, currentEpoch, e.User)
 	if !v.Equal(e.Volume) {
 		return ctx, fmt.Errorf("unexpected user dnr volume, wanted %s, got %s", e.Volume, v), true
 	}
@@ -92,3 +99,111 @@ func (e expectVolumeNotExistAction) Do(app *app.NibiruApp, ctx sdk.Context) (out
 	}
 	return ctx, nil, true
 }
+
+type marketOrderFeeIs struct {
+	fee sdk.Dec
+	*openPositionAction
+}
+
+func MarketOrderFeeIs(
+	fee sdk.Dec,
+	trader sdk.AccAddress,
+	pair asset.Pair,
+	dir types.Direction,
+	margin math.Int,
+	leverage sdk.Dec,
+	baseAssetLimit sdk.Dec,
+	responseCheckers ...MarketOrderResponseChecker,
+) action.Action {
+	o := openPositionAction{
+		trader:           trader,
+		pair:             pair,
+		dir:              dir,
+		margin:           margin,
+		leverage:         leverage,
+		baseAssetLimit:   baseAssetLimit,
+		responseCheckers: responseCheckers,
+	}
+	return &marketOrderFeeIs{
+		fee:                fee,
+		openPositionAction: &o,
+	}
+}
+
+func (o *marketOrderFeeIs) Do(app *app.NibiruApp, ctx sdk.Context) (sdk.Context, error, bool) {
+	balanceBefore := app.BankKeeper.GetBalance(ctx, o.trader, o.pair.QuoteDenom()).Amount
+	resp, err := app.PerpKeeperV2.MarketOrder(
+		ctx, o.pair, o.dir, o.trader,
+		o.margin, o.leverage, o.baseAssetLimit,
+	)
+	if err != nil {
+		return ctx, err, true
+	}
+
+	balanceBefore = balanceBefore.Sub(resp.MarginToVault.TruncateInt())
+
+	expectedFee := math.LegacyNewDecFromInt(o.margin).Mul(o.fee.Add(sdk.MustNewDecFromStr("0.001"))) // we add the ecosystem fund fee
+	balanceAfter := app.BankKeeper.GetBalance(ctx, o.trader, o.pair.QuoteDenom()).Amount
+	paidFees := balanceBefore.Sub(balanceAfter)
+	if !paidFees.Equal(expectedFee.TruncateInt()) {
+		return ctx, fmt.Errorf("unexpected fee, wanted %s, got %s", expectedFee, paidFees), true
+	}
+	return ctx, nil, true
+}
+
+func SetPreviousEpochUserVolume(user sdk.AccAddress, volume math.Int) action.Action {
+	return &setPreviousEpochUserVolumeAction{
+		user:   user,
+		volume: volume,
+	}
+}
+
+type setPreviousEpochUserVolumeAction struct {
+	user   sdk.AccAddress
+	volume math.Int
+}
+
+func (s setPreviousEpochUserVolumeAction) Do(app *app.NibiruApp, ctx sdk.Context) (outCtx sdk.Context, err error, isMandatory bool) {
+	currentEpoch, err := app.PerpKeeperV2.DnREpoch.Get(ctx)
+	if err != nil {
+		return ctx, err, true
+	}
+	app.PerpKeeperV2.TraderVolumes.Insert(ctx, collections.Join(s.user, currentEpoch-1), s.volume)
+	return ctx, nil, true
+}
+
+func SetGlobalDiscount(fee sdk.Dec, volume math.Int) action.Action {
+	return &setGlobalDiscountAction{
+		fee:    fee,
+		volume: volume,
+	}
+}
+
+type setGlobalDiscountAction struct {
+	fee    sdk.Dec
+	volume math.Int
+}
+
+func (s setGlobalDiscountAction) Do(app *app.NibiruApp, ctx sdk.Context) (outCtx sdk.Context, err error, isMandatory bool) {
+	app.PerpKeeperV2.GlobalDiscounts.Insert(ctx, s.volume, s.fee)
+	return ctx, nil, true
+}
+
+func SetCustomDiscount(user sdk.AccAddress, fee sdk.Dec, volume math.Int) action.Action {
+	return &setCustomDiscountAction{
+		fee:    fee,
+		volume: volume,
+		user:   user,
+	}
+}
+
+type setCustomDiscountAction struct {
+	fee    sdk.Dec
+	volume math.Int
+	user   sdk.AccAddress
+}
+
+func (s *setCustomDiscountAction) Do(app *app.NibiruApp, ctx sdk.Context) (outCtx sdk.Context, err error, isMandatory bool) {
+	app.PerpKeeperV2.TraderDiscounts.Insert(ctx, collections.Join(s.user, s.volume), s.fee)
+	return ctx, nil, true
+}

x/perp/v2/keeper/clearing_house.go

@@ -554,13 +554,6 @@ func (k Keeper) afterPositionUpdate(
 		}
 	}
 
-	// update user volume
-	dnrEpoch, err := k.DnREpoch.Get(ctx)
-	if err != nil {
-		return err
-	}
-	k.IncreaseTraderVolume(ctx, dnrEpoch, traderAddr, positionResp.ExchangedNotionalValue.Abs().TruncateInt())
-
 	transferredFee, err := k.transferFee(ctx, market.Pair, traderAddr, positionResp.ExchangedNotionalValue,
 		market.ExchangeFeeRatio, market.EcosystemFundFeeRatio,
 	)
@@ -644,6 +637,10 @@ func (k Keeper) transferFee(
 	exchangeFeeRatio sdk.Dec,
 	ecosystemFundFeeRatio sdk.Dec,
 ) (fees sdkmath.Int, err error) {
+	exchangeFeeRatio, err = k.applyDiscountAndRebate(ctx, pair, trader, positionNotional, exchangeFeeRatio)
+	if err != nil {
+		return sdkmath.Int{}, err
+	}
 	feeToExchangeFeePool := exchangeFeeRatio.Mul(positionNotional).RoundInt()
 	if feeToExchangeFeePool.IsPositive() {
 		if err = k.BankKeeper.SendCoinsFromAccountToModule(

x/perp/v2/keeper/dnr.go

@@ -1,45 +1,74 @@
 package keeper
 
 import (
+	"math/big"
+
 	"cosmossdk.io/math"
 	"github.com/NibiruChain/collections"
 	sdk "github.com/cosmos/cosmos-sdk/types"
+
+	"github.com/NibiruChain/nibiru/x/common/asset"
 )
 
 // DnRGCFrequency is the frequency at which the DnR garbage collector runs.
 const DnRGCFrequency = 1000
 
-// IntValueEncoder instructs collections on how to encode a math.Int.
+// IntValueEncoder instructs collections on how to encode a math.Int as a value.
 // TODO: move to collections.
 var IntValueEncoder collections.ValueEncoder[math.Int] = intValueEncoder{}
 
+// IntKeyEncoder instructs collections on how to encode a math.Int as a key.
+// NOTE: unsafe to use as the first part of a composite key.
+var IntKeyEncoder collections.KeyEncoder[math.Int] = intKeyEncoder{}
+
 type intValueEncoder struct{}
 
-func (i intValueEncoder) Encode(value math.Int) []byte {
-	v, err := value.Marshal()
-	if err != nil {
-		panic(err)
-	}
-	return v
+func (intValueEncoder) Encode(value math.Int) []byte {
+	return IntKeyEncoder.Encode(value)
 }
 
-func (i intValueEncoder) Decode(b []byte) math.Int {
-	var v math.Int
-	err := v.Unmarshal(b)
-	if err != nil {
-		panic(err)
-	}
-	return v
+func (intValueEncoder) Decode(b []byte) math.Int {
+	_, got := IntKeyEncoder.Decode(b)
+	return got
 }
 
-func (i intValueEncoder) Stringify(value math.Int) string {
-	return value.String()
+func (intValueEncoder) Stringify(value math.Int) string {
+	return IntKeyEncoder.Stringify(value)
 }
 
-func (i intValueEncoder) Name() string {
+func (intValueEncoder) Name() string {
 	return "math.Int"
 }
 
+type intKeyEncoder struct{}
+
+const maxIntKeyLen = math.MaxBitLen / 8
+
+func (intKeyEncoder) Encode(key math.Int) []byte {
+	if key.IsNil() {
+		panic("cannot encode invalid math.Int")
+	}
+	if key.IsNegative() {
+		panic("cannot encode negative math.Int")
+	}
+	i := key.BigInt()
+
+	be := i.Bytes()
+	padded := make([]byte, maxIntKeyLen)
+	copy(padded[maxIntKeyLen-len(be):], be)
+	return padded
+}
+
+func (intKeyEncoder) Decode(b []byte) (int, math.Int) {
+	if len(b) != maxIntKeyLen {
+		panic("invalid key length")
+	}
+	i := new(big.Int).SetBytes(b)
+	return maxIntKeyLen, math.NewIntFromBigInt(i)
+}
+
+func (intKeyEncoder) Stringify(key math.Int) string { return key.String() }
+
 // IncreaseTraderVolume adds the volume to the user's volume for the current epoch.
 func (k Keeper) IncreaseTraderVolume(ctx sdk.Context, currentEpoch uint64, user sdk.AccAddress, volume math.Int) {
 	currentVolume := k.TraderVolumes.GetOr(ctx, collections.Join(user, currentEpoch), math.ZeroInt())
@@ -68,18 +97,78 @@ func (k Keeper) gcUserVolume(ctx sdk.Context, user sdk.AccAddress, currentEpoch
 	}
 }
 
-// GetUserVolumeLastEpoch returns the user's volume for the last epoch.
+// GetTraderVolumeLastEpoch returns the user's volume for the last epoch.
 // Returns zero if the user has no volume for the last epoch.
-func (k Keeper) GetUserVolumeLastEpoch(ctx sdk.Context, user sdk.AccAddress) math.Int {
-	currentEpoch, err := k.DnREpoch.Get(ctx)
-	if err != nil {
-		// a DnR epoch should always exist, otherwise it means the chain was not initialized properly.
-		panic(err)
-	}
+func (k Keeper) GetTraderVolumeLastEpoch(ctx sdk.Context, currentEpoch uint64, user sdk.AccAddress) math.Int {
 	// if it's the first epoch, we do not have any user volume.
 	if currentEpoch == 0 {
 		return math.ZeroInt()
 	}
 	// return the user's volume for the last epoch, or zero.
 	return k.TraderVolumes.GetOr(ctx, collections.Join(user, currentEpoch-1), math.ZeroInt())
 }
+
+// GetTraderDiscount will check if the trader has a custom discount for the given volume.
+// If it does not have a custom discount, it will return the global discount for the given volume.
+// The discount is the nearest left entry of the trader volume.
+func (k Keeper) GetTraderDiscount(ctx sdk.Context, trader sdk.AccAddress, volume math.Int) (math.LegacyDec, bool) {
+	// we try to see if the trader has a custom discount.
+	customDiscountRng := collections.PairRange[sdk.AccAddress, math.Int]{}.
+		Prefix(trader).
+		EndInclusive(volume).
+		Descending()
+
+	customDiscount := k.TraderDiscounts.Iterate(ctx, customDiscountRng)
+	defer customDiscount.Close()
+
+	if customDiscount.Valid() {
+		return customDiscount.Value(), true
+	}
+
+	// if it does not have a custom discount we try with global ones
+	globalDiscountRng := collections.Range[math.Int]{}.
+		EndInclusive(volume).
+		Descending()
+
+	globalDiscounts := k.GlobalDiscounts.Iterate(ctx, globalDiscountRng)
+	defer globalDiscounts.Close()
+
+	if globalDiscounts.Valid() {
+		return globalDiscounts.Value(), true
+	}
+	return math.LegacyZeroDec(), false
+}
+
+// applyDiscountAndRebate applies the discount and rebate to the given exchange fee ratio.
+// It updates the current epoch trader volume.
+// It returns the new exchange fee ratio.
+func (k Keeper) applyDiscountAndRebate(
+	ctx sdk.Context,
+	_ asset.Pair,
+	trader sdk.AccAddress,
+	positionNotional math.LegacyDec,
+	feeRatio sdk.Dec,
+) (sdk.Dec, error) {
+	// update user volume
+	dnrEpoch, err := k.DnREpoch.Get(ctx)
+	if err != nil {
+		return feeRatio, err
+	}
+	k.IncreaseTraderVolume(ctx, dnrEpoch, trader, positionNotional.Abs().TruncateInt())
+
+	// get past epoch volume
+	pastVolume := k.GetTraderVolumeLastEpoch(ctx, dnrEpoch, trader)
+	// if the trader has no volume for the last epoch, we return the provided fee ratios.
+	if pastVolume.IsZero() {
+		return feeRatio, nil
+	}
+
+	// try to apply discount
+	discountedFeeRatio, hasDiscount := k.GetTraderDiscount(ctx, trader, pastVolume)
+	// if the trader does not have any discount, we return the provided fee ratios.
+	if !hasDiscount {
+		return feeRatio, nil
+	}
+	// return discounted fee ratios
+	return discountedFeeRatio, nil
+}