package keeper import ( sdk "github.com/cosmos/cosmos-sdk/types" cdptypes "github.com/kava-labs/kava/x/cdp/types" "github.com/kava-labs/kava/x/kavadist/types" ) // MintPeriodInflation mints new tokens according to the inflation schedule specified in the parameters func (k Keeper) MintPeriodInflation(ctx sdk.Context) error { params := k.GetParams(ctx) if !params.Active { ctx.EventManager().EmitEvent( sdk.NewEvent( types.EventTypeKavaDist, sdk.NewAttribute(types.AttributeKeyStatus, types.AttributeValueInactive), ), ) return nil } previousBlockTime, found := k.GetPreviousBlockTime(ctx) if !found { previousBlockTime = ctx.BlockTime() k.SetPreviousBlockTime(ctx, previousBlockTime) return nil } for _, period := range params.Periods { // Case 1 - period is fully expired if period.End.Before(previousBlockTime) { continue } // Case 2 - period has ended since the previous block time if period.End.After(previousBlockTime) && period.End.Before(ctx.BlockTime()) { // calculate time elapsed relative to the periods end time timeElapsed := sdk.NewInt(period.End.Unix() - previousBlockTime.Unix()) err := k.mintInflationaryCoins(ctx, period.Inflation, timeElapsed, types.GovDenom) if err != nil { return err } // update the value of previousBlockTime so that the next period starts from the end of the last // period and not the original value of previousBlockTime previousBlockTime = period.End } // Case 3 - period is ongoing if (period.Start.Before(previousBlockTime) || period.Start.Equal(previousBlockTime)) && period.End.After(ctx.BlockTime()) { // calculate time elapsed relative to the current block time timeElapsed := sdk.NewInt(ctx.BlockTime().Unix() - previousBlockTime.Unix()) err := k.mintInflationaryCoins(ctx, period.Inflation, timeElapsed, types.GovDenom) if err != nil { return err } } // Case 4 - period hasn't started if period.Start.After(ctx.BlockTime()) || period.Start.Equal(ctx.BlockTime()) { continue } } k.SetPreviousBlockTime(ctx, ctx.BlockTime()) return nil } func (k Keeper) mintInflationaryCoins(ctx sdk.Context, inflationRate sdk.Dec, timePeriods sdk.Int, denom string) error { totalSupply := k.supplyKeeper.GetSupply(ctx).GetTotal().AmountOf(denom) // used to scale accumulator calculations by 10^18 scalar := sdk.NewInt(1000000000000000000) // convert inflation rate to integer inflationInt := inflationRate.Mul(sdk.NewDecFromInt(scalar)).TruncateInt() // calculate the multiplier (amount to multiply the total supply by to achieve the desired inflation) // multiply the result by 10^-18 because RelativePow returns the result scaled by 10^18 accumulator := sdk.NewDecFromInt(cdptypes.RelativePow(inflationInt, timePeriods, scalar)).Mul(sdk.SmallestDec()) // calculate the number of coins to mint amountToMint := (sdk.NewDecFromInt(totalSupply).Mul(accumulator)).Sub(sdk.NewDecFromInt(totalSupply)).TruncateInt() if amountToMint.IsZero() { return nil } err := k.supplyKeeper.MintCoins(ctx, types.KavaDistMacc, sdk.NewCoins(sdk.NewCoin(denom, amountToMint))) if err != nil { return err } ctx.EventManager().EmitEvent( sdk.NewEvent( types.EventTypeKavaDist, sdk.NewAttribute(types.AttributeKeyInflation, amountToMint.String()), ), ) return nil }