Implement partial close on leveragelp (#270)

* implement partial close on leveragelp

* implement ForceCloseLongPartial

proto/elys/leveragelp/tx.proto

@@ -41,6 +41,10 @@ message MsgOpenResponse {}
 message MsgClose {
   string creator = 1;
   uint64 id = 2;
+  string lp_amount = 3 [
+    (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Int",
+    (gogoproto.nullable) = false
+  ];
 }
 
 message MsgCloseResponse {}

x/leveragelp/keeper/begin_blocker.go

@@ -61,7 +61,7 @@ func (k Keeper) LiquidatePositionIfUnhealthy(ctx sdk.Context, position *types.Po
 		return
 	}
 
-	repayAmount, err := k.ForceCloseLong(ctx, *position, pool)
+	repayAmount, err := k.ForceCloseLong(ctx, *position, pool, position.LeveragedLpAmount)
 	if err == nil {
 		ctx.EventManager().EmitEvent(sdk.NewEvent(types.EventClose,
 			sdk.NewAttribute("id", strconv.FormatInt(int64(position.Id), 10)),

x/leveragelp/keeper/position_close.go

@@ -6,16 +6,20 @@ import (
 	"github.com/elys-network/elys/x/leveragelp/types"
 )
 
-func (k Keeper) ForceCloseLong(ctx sdk.Context, position types.Position, pool types.Pool) (sdk.Int, error) {
+func (k Keeper) ForceCloseLong(ctx sdk.Context, position types.Position, pool types.Pool, lpAmount sdk.Int) (sdk.Int, error) {
+	if lpAmount.GT(position.LeveragedLpAmount) || lpAmount.IsNegative() {
+		return sdk.ZeroInt(), types.ErrInvalidCloseSize
+	}
+
 	// Exit liquidity with collateral token
-	exitCoins, err := k.amm.ExitPool(ctx, position.GetPositionAddress(), position.AmmPoolId, position.LeveragedLpAmount, sdk.Coins{}, position.Collateral.Denom)
+	exitCoins, err := k.amm.ExitPool(ctx, position.GetPositionAddress(), position.AmmPoolId, lpAmount, sdk.Coins{}, position.Collateral.Denom)
 	if err != nil {
 		return sdk.ZeroInt(), err
 	}
 
 	// Repay with interest
 	debt := k.stableKeeper.UpdateInterestStackedByAddress(ctx, position.GetPositionAddress())
-	repayAmount := debt.Borrowed.Add(debt.InterestStacked).Sub(debt.InterestPaid)
+	repayAmount := debt.Borrowed.Add(debt.InterestStacked).Sub(debt.InterestPaid).Mul(lpAmount).Quo(position.LeveragedLpAmount)
 	if err != nil {
 		return sdk.ZeroInt(), err
 	}
@@ -32,12 +36,17 @@ func (k Keeper) ForceCloseLong(ctx sdk.Context, position types.Position, pool ty
 		return sdk.ZeroInt(), err
 	}
 
-	err = k.DestroyPosition(ctx, position.Address, position.Id)
-	if err != nil {
-		return sdk.ZeroInt(), err
+	position.LeveragedLpAmount = position.LeveragedLpAmount.Sub(lpAmount)
+	if position.LeveragedLpAmount.IsZero() {
+		err = k.DestroyPosition(ctx, position.Address, position.Id)
+		if err != nil {
+			return sdk.ZeroInt(), err
+		}
+	} else {
+		k.SetPosition(ctx, &position)
 	}
 
-	pool.LeveragedLpAmount = pool.LeveragedLpAmount.Sub(position.LeveragedLpAmount)
+	pool.LeveragedLpAmount = pool.LeveragedLpAmount.Sub(lpAmount)
 	k.UpdatePoolHealth(ctx, &pool)
 
 	// Hooks after leveragelp position closed
@@ -60,6 +69,12 @@ func (k Keeper) CloseLong(ctx sdk.Context, msg *types.MsgClose) (*types.Position
 		return nil, sdk.ZeroInt(), sdkerrors.Wrap(types.ErrInvalidBorrowingAsset, "invalid pool id")
 	}
 
-	repayAmount, err := k.ForceCloseLong(ctx, position, pool)
+	// If lpAmount is lower than zero, close full amount
+	lpAmount := msg.LpAmount
+	if lpAmount.LTE(sdk.ZeroInt()) {
+		lpAmount = position.LeveragedLpAmount
+	}
+
+	repayAmount, err := k.ForceCloseLong(ctx, position, pool, lpAmount)
 	return &position, repayAmount, err
 }

x/leveragelp/keeper/position_close_test.go

@@ -103,8 +103,9 @@ func (suite KeeperTestSuite) TestCloseLong() {
 
 	var (
 		msg = &types.MsgClose{
-			Creator: addr.String(),
-			Id:      1,
+			Creator:  addr.String(),
+			Id:       1,
+			LpAmount: sdk.ZeroInt(),
 		}
 		repayAmount = math.NewInt(0)
 	)
@@ -121,11 +122,24 @@ func (suite KeeperTestSuite) TestForceCloseLong() {
 	repayAmount := math.NewInt(4000)
 
 	suite.ctx = suite.ctx.WithBlockTime(suite.ctx.BlockTime().Add(time.Hour))
-	repayAmountOut, err := k.ForceCloseLong(suite.ctx, *position, pool)
+	repayAmountOut, err := k.ForceCloseLong(suite.ctx, *position, pool, position.LeveragedLpAmount)
 	suite.Require().NoError(err)
 	suite.Require().Equal(repayAmount.String(), repayAmountOut.String())
 }
 
+func (suite KeeperTestSuite) TestForceCloseLongPartial() {
+	k := suite.app.LeveragelpKeeper
+	addr := sdk.AccAddress(ed25519.GenPrivKey().PubKey().Address())
+	position, pool := suite.OpenPosition(addr)
+	repayAmount := math.NewInt(4000)
+
+	suite.ctx = suite.ctx.WithBlockTime(suite.ctx.BlockTime().Add(time.Hour))
+	// close 50%
+	repayAmountOut, err := k.ForceCloseLong(suite.ctx, *position, pool, position.LeveragedLpAmount.Quo(sdk.NewInt(2)))
+	suite.Require().NoError(err)
+	suite.Require().Equal(repayAmount.Quo(sdk.NewInt(2)).String(), repayAmountOut.String())
+}
+
 func (suite KeeperTestSuite) TestHealthDecreaseForInterest() {
 	k := suite.app.LeveragelpKeeper
 	addr := sdk.AccAddress(ed25519.GenPrivKey().PubKey().Address())

x/leveragelp/types/errors.go

@@ -27,4 +27,5 @@ var (
 	ErrAmmPoolNotFound         = sdkerrors.Register(ModuleName, 34, "amm pool not found")
 	ErrOnlyBaseCurrencyAllowed = sdkerrors.Register(ModuleName, 35, "only base currency is allowed for leverage lp")
 	ErrInsufficientUsdcAfterOp = sdkerrors.Register(ModuleName, 36, "insufficient amount of usdc after the operation for leveragelp withdrawal")
+	ErrInvalidCloseSize        = sdkerrors.Register(ModuleName, 37, "invalid close size")
 )