0g-chain/x/cdp/keeper/seize.go
Kevin Davis daa1b2bb83
Add collateral type to cdp (#629)
* add collateral type field to cdp and collateral  param

* fix upstream tests

* fix simulations

* fix validation logic

* update incentive to use collateral type instead of denom

* use collateral type instead of denom in cdp

* remove unused code

* address review comments
2020-08-21 15:42:46 -04:00

100 lines
3.6 KiB
Go

package keeper
import (
"fmt"
sdk "github.com/cosmos/cosmos-sdk/types"
"github.com/kava-labs/kava/x/cdp/types"
)
// SeizeCollateral liquidates the collateral in the input cdp.
// the following operations are performed:
// 1. Collateral for all deposits is sent from the cdp module to the liquidator module account
// 2. The liquidation penalty is applied
// 3. Debt coins are sent from the cdp module to the liquidator module account
// 4. The total amount of principal outstanding for that collateral type is decremented
// (this is the equivalent of saying that fees are no longer accumulated by a cdp once it gets liquidated)
func (k Keeper) SeizeCollateral(ctx sdk.Context, cdp types.CDP) error {
// Calculate the previous collateral ratio
oldCollateralToDebtRatio := k.CalculateCollateralToDebtRatio(ctx, cdp.Collateral, cdp.Type, cdp.GetTotalPrincipal())
// Move debt coins from cdp to liquidator account
deposits := k.GetDeposits(ctx, cdp.ID)
debt := cdp.GetTotalPrincipal().Amount
modAccountDebt := k.getModAccountDebt(ctx, types.ModuleName)
debt = sdk.MinInt(debt, modAccountDebt)
debtCoin := sdk.NewCoin(k.GetDebtDenom(ctx), debt)
err := k.supplyKeeper.SendCoinsFromModuleToModule(ctx, types.ModuleName, types.LiquidatorMacc, sdk.NewCoins(debtCoin))
if err != nil {
return err
}
// liquidate deposits and send collateral from cdp to liquidator
for _, dep := range deposits {
err := k.supplyKeeper.SendCoinsFromModuleToModule(ctx, types.ModuleName, types.LiquidatorMacc, sdk.NewCoins(dep.Amount))
if err != nil {
return err
}
k.DeleteDeposit(ctx, dep.CdpID, dep.Depositor)
ctx.EventManager().EmitEvent(
sdk.NewEvent(
types.EventTypeCdpLiquidation,
sdk.NewAttribute(sdk.AttributeKeyModule, types.AttributeValueCategory),
sdk.NewAttribute(types.AttributeKeyCdpID, fmt.Sprintf("%d", cdp.ID)),
sdk.NewAttribute(types.AttributeKeyDeposit, dep.String()),
),
)
}
err = k.AuctionCollateral(ctx, deposits, cdp.Type, debt, cdp.Principal.Denom)
if err != nil {
return err
}
// Decrement total principal for this collateral type
coinsToDecrement := cdp.GetTotalPrincipal()
k.DecrementTotalPrincipal(ctx, cdp.Type, coinsToDecrement)
// Delete CDP from state
k.RemoveCdpOwnerIndex(ctx, cdp)
k.RemoveCdpCollateralRatioIndex(ctx, cdp.Type, cdp.ID, oldCollateralToDebtRatio)
return k.DeleteCDP(ctx, cdp)
}
// LiquidateCdps seizes collateral from all CDPs below the input liquidation ratio
func (k Keeper) LiquidateCdps(ctx sdk.Context, marketID string, collateralType string, liquidationRatio sdk.Dec) error {
price, err := k.pricefeedKeeper.GetCurrentPrice(ctx, marketID)
if err != nil {
return err
}
priceDivLiqRatio := price.Price.Quo(liquidationRatio)
if priceDivLiqRatio.IsZero() {
priceDivLiqRatio = sdk.SmallestDec()
}
// price = $0.5
// liquidation ratio = 1.5
// normalizedRatio = (1/(0.5/1.5)) = 3
normalizedRatio := sdk.OneDec().Quo(priceDivLiqRatio)
cdpsToLiquidate := k.GetAllCdpsByCollateralTypeAndRatio(ctx, collateralType, normalizedRatio)
for _, c := range cdpsToLiquidate {
err := k.SeizeCollateral(ctx, c)
if err != nil {
return err
}
}
return nil
}
// ApplyLiquidationPenalty multiplies the input debt amount by the liquidation penalty
func (k Keeper) ApplyLiquidationPenalty(ctx sdk.Context, collateralType string, debt sdk.Int) sdk.Int {
penalty := k.getLiquidationPenalty(ctx, collateralType)
return sdk.NewDecFromInt(debt).Mul(penalty).RoundInt()
}
func (k Keeper) getModAccountDebt(ctx sdk.Context, accountName string) sdk.Int {
macc := k.supplyKeeper.GetModuleAccount(ctx, accountName)
return macc.GetCoins().AmountOf(k.GetDebtDenom(ctx))
}