88 lines
2.5 KiB
Go
88 lines
2.5 KiB
Go
package mint
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import (
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"fmt"
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sdk "github.com/cosmos/cosmos-sdk/types"
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)
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// Minter represents the minting state
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type Minter struct {
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Inflation sdk.Dec `json:"inflation"` // current annual inflation rate
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AnnualProvisions sdk.Dec `json:"annual_provisions"` // current annual expected provisions
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}
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// Create a new minter object
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func NewMinter(inflation, annualProvisions sdk.Dec) Minter {
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return Minter{
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Inflation: inflation,
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AnnualProvisions: annualProvisions,
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}
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}
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// minter object for a new chain
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func InitialMinter(inflation sdk.Dec) Minter {
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return NewMinter(
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inflation,
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sdk.NewDec(0),
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)
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}
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// default initial minter object for a new chain
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// which uses an inflation rate of 13%
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func DefaultInitialMinter() Minter {
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return InitialMinter(
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sdk.NewDecWithPrec(13, 2),
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)
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}
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func validateMinter(minter Minter) error {
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if minter.Inflation.LT(sdk.ZeroDec()) {
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return fmt.Errorf("mint parameter Inflation should be positive, is %s",
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minter.Inflation.String())
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}
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return nil
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}
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// get the new inflation rate for the next hour
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func (m Minter) NextInflationRate(params Params, bondedRatio sdk.Dec) (
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inflation sdk.Dec) {
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// The target annual inflation rate is recalculated for each previsions cycle. The
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// inflation is also subject to a rate change (positive or negative) depending on
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// the distance from the desired ratio (67%). The maximum rate change possible is
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// defined to be 13% per year, however the annual inflation is capped as between
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// 7% and 20%.
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// (1 - bondedRatio/GoalBonded) * InflationRateChange
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inflationRateChangePerYear := sdk.OneDec().
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Sub(bondedRatio.Quo(params.GoalBonded)).
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Mul(params.InflationRateChange)
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inflationRateChange := inflationRateChangePerYear.Quo(sdk.NewDec(int64(params.BlocksPerYear)))
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// increase the new annual inflation for this next cycle
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inflation = m.Inflation.Add(inflationRateChange)
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if inflation.GT(params.InflationMax) {
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inflation = params.InflationMax
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}
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if inflation.LT(params.InflationMin) {
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inflation = params.InflationMin
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}
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return inflation
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}
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// calculate the annual provisions based on current total supply and inflation rate
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func (m Minter) NextAnnualProvisions(params Params, totalSupply sdk.Int) (
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provisions sdk.Dec) {
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return m.Inflation.MulInt(totalSupply)
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}
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// get the provisions for a block based on the annual provisions rate
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func (m Minter) BlockProvision(params Params) sdk.Coin {
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provisionAmt := m.AnnualProvisions.QuoInt(sdk.NewInt(int64(params.BlocksPerYear)))
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return sdk.NewCoin(params.MintDenom, provisionAmt.TruncateInt())
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}
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