0g-chain/x/cdp/keeper/auctions.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

173 lines
6.8 KiB
Go

package keeper
import (
sdk "github.com/cosmos/cosmos-sdk/types"
"github.com/kava-labs/kava/x/cdp/types"
)
const (
// factor for setting the initial value of gov tokens to sell at debt auctions -- assuming stable token is ~1 usd, this starts the auction with a price of $0.01 KAVA
dump = 100
)
// AuctionCollateral creates auctions from the input deposits which attempt to raise the corresponding amount of debt
func (k Keeper) AuctionCollateral(ctx sdk.Context, deposits types.Deposits, collateralType string, debt sdk.Int, bidDenom string) error {
auctionSize := k.getAuctionSize(ctx, collateralType)
totalCollateral := deposits.SumCollateral()
for _, deposit := range deposits {
debtCoveredByDeposit := (sdk.NewDecFromInt(deposit.Amount.Amount).Quo(sdk.NewDecFromInt(totalCollateral))).Mul(sdk.NewDecFromInt(debt)).RoundInt()
err := k.CreateAuctionsFromDeposit(ctx, deposit.Amount, collateralType, deposit.Depositor, debtCoveredByDeposit, auctionSize, bidDenom)
if err != nil {
return err
}
}
return nil
}
// CreateAuctionsFromDeposit creates auctions from the input deposit
func (k Keeper) CreateAuctionsFromDeposit(
ctx sdk.Context, collateral sdk.Coin, collateralType string, returnAddr sdk.AccAddress, debt, auctionSize sdk.Int,
principalDenom string) error {
// number of auctions of auctionSize
numberOfAuctions := collateral.Amount.Quo(auctionSize)
debtPerAuction := debt.Mul(auctionSize).Quo(collateral.Amount)
// last auction for remaining collateral (collateral < auctionSize)
lastAuctionCollateral := collateral.Amount.Mod(auctionSize)
lastAuctionDebt := debt.Mul(lastAuctionCollateral).Quo(collateral.Amount)
// amount of debt that has not been allocated due to
// rounding error (unallocated debt is less than numberOfAuctions + 1)
unallocatedDebt := debt.Sub(numberOfAuctions.Mul(debtPerAuction).Add(lastAuctionDebt))
// rounding error for whole and last auctions in units of collateral
// higher value means a larger truncation
wholeAuctionError := debt.Mul(auctionSize).Mod(collateral.Amount)
lastAuctionError := debt.Mul(lastAuctionCollateral).Mod(collateral.Amount)
// if last auction has larger rounding error, then allocate one debt to last auction first
// follows the largest remainder method https://en.wikipedia.org/wiki/Largest_remainder_method
if lastAuctionError.GT(wholeAuctionError) {
lastAuctionDebt = lastAuctionDebt.Add(sdk.OneInt())
unallocatedDebt = unallocatedDebt.Sub(sdk.OneInt())
}
debtDenom := k.GetDebtDenom(ctx)
numAuctions := numberOfAuctions.Int64()
// create whole auctions
for i := int64(0); i < numAuctions; i++ {
debtAmount := debtPerAuction
// distribute unallocated debt left over starting with first auction created
if unallocatedDebt.IsPositive() {
debtAmount = debtAmount.Add(sdk.OneInt())
unallocatedDebt = unallocatedDebt.Sub(sdk.OneInt())
}
penalty := k.ApplyLiquidationPenalty(ctx, collateralType, debtAmount)
_, err := k.auctionKeeper.StartCollateralAuction(
ctx, types.LiquidatorMacc, sdk.NewCoin(collateral.Denom, auctionSize),
sdk.NewCoin(principalDenom, debtAmount.Add(penalty)), []sdk.AccAddress{returnAddr},
[]sdk.Int{auctionSize}, sdk.NewCoin(debtDenom, debtAmount),
)
if err != nil {
return err
}
}
// skip last auction if there is no collateral left to auction
if !lastAuctionCollateral.IsPositive() {
return nil
}
// if the last auction had a larger rounding error than whole auctions,
// then unallocatedDebt will be zero since we will have already distributed
// all of the unallocated debt
if unallocatedDebt.IsPositive() {
lastAuctionDebt = lastAuctionDebt.Add(sdk.OneInt())
unallocatedDebt = unallocatedDebt.Sub(sdk.OneInt())
}
penalty := k.ApplyLiquidationPenalty(ctx, collateralType, lastAuctionDebt)
_, err := k.auctionKeeper.StartCollateralAuction(
ctx, types.LiquidatorMacc, sdk.NewCoin(collateral.Denom, lastAuctionCollateral),
sdk.NewCoin(principalDenom, lastAuctionDebt.Add(penalty)), []sdk.AccAddress{returnAddr},
[]sdk.Int{lastAuctionCollateral}, sdk.NewCoin(debtDenom, lastAuctionDebt),
)
return err
}
// NetSurplusAndDebt burns surplus and debt coins equal to the minimum of surplus and debt balances held by the liquidator module account
// for example, if there is 1000 debt and 100 surplus, 100 surplus and 100 debt are burned, netting to 900 debt
func (k Keeper) NetSurplusAndDebt(ctx sdk.Context) error {
totalSurplus := k.GetTotalSurplus(ctx, types.LiquidatorMacc)
debt := k.GetTotalDebt(ctx, types.LiquidatorMacc)
netAmount := sdk.MinInt(totalSurplus, debt)
if netAmount.IsZero() {
return nil
}
// burn debt coins equal to netAmount
err := k.supplyKeeper.BurnCoins(ctx, types.LiquidatorMacc, sdk.NewCoins(sdk.NewCoin(k.GetDebtDenom(ctx), netAmount)))
if err != nil {
return err
}
// burn stable coins equal to min(balance, netAmount)
dp := k.GetParams(ctx).DebtParam
balance := k.supplyKeeper.GetModuleAccount(ctx, types.LiquidatorMacc).GetCoins().AmountOf(dp.Denom)
burnAmount := sdk.MinInt(balance, netAmount)
return k.supplyKeeper.BurnCoins(ctx, types.LiquidatorMacc, sdk.NewCoins(sdk.NewCoin(dp.Denom, burnAmount)))
}
// GetTotalSurplus returns the total amount of surplus tokens held by the liquidator module account
func (k Keeper) GetTotalSurplus(ctx sdk.Context, accountName string) sdk.Int {
acc := k.supplyKeeper.GetModuleAccount(ctx, accountName)
dp := k.GetParams(ctx).DebtParam
return acc.GetCoins().AmountOf(dp.Denom)
}
// GetTotalDebt returns the total amount of debt tokens held by the liquidator module account
func (k Keeper) GetTotalDebt(ctx sdk.Context, accountName string) sdk.Int {
acc := k.supplyKeeper.GetModuleAccount(ctx, accountName)
return acc.GetCoins().AmountOf(k.GetDebtDenom(ctx))
}
// RunSurplusAndDebtAuctions nets the surplus and debt balances and then creates surplus or debt auctions if the remaining balance is above the auction threshold parameter
func (k Keeper) RunSurplusAndDebtAuctions(ctx sdk.Context) error {
if err := k.NetSurplusAndDebt(ctx); err != nil {
return err
}
remainingDebt := k.GetTotalDebt(ctx, types.LiquidatorMacc)
params := k.GetParams(ctx)
if remainingDebt.GTE(params.DebtAuctionThreshold) {
debtLot := sdk.NewCoin(k.GetDebtDenom(ctx), params.DebtAuctionLot)
bidCoin := sdk.NewCoin(params.DebtParam.Denom, debtLot.Amount)
initialLot := sdk.NewCoin(k.GetGovDenom(ctx), debtLot.Amount.Mul(sdk.NewInt(dump)))
_, err := k.auctionKeeper.StartDebtAuction(ctx, types.LiquidatorMacc, bidCoin, initialLot, debtLot)
if err != nil {
return err
}
}
surplus := k.supplyKeeper.GetModuleAccount(ctx, types.LiquidatorMacc).GetCoins().AmountOf(params.DebtParam.Denom)
if !surplus.GTE(params.SurplusAuctionThreshold) {
return nil
}
surplusLot := sdk.NewCoin(params.DebtParam.Denom, sdk.MinInt(params.SurplusAuctionLot, surplus))
_, err := k.auctionKeeper.StartSurplusAuction(ctx, types.LiquidatorMacc, surplusLot, k.GetGovDenom(ctx))
return err
}