0g-chain/x/kavadist/keeper/mint.go
2020-05-07 13:45:16 -04:00

89 lines
3.3 KiB
Go

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, sdk.NewCoin(denom, amountToMint).String()),
),
)
return nil
}