72 lines
2.3 KiB
Go
72 lines
2.3 KiB
Go
package mint
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import (
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"fmt"
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"time"
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sdk "github.com/cosmos/cosmos-sdk/types"
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)
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// current inflation state
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type Minter struct {
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InflationLastTime time.Time `json:"inflation_last_time"` // block time which the last inflation was processed
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Inflation sdk.Dec `json:"inflation"` // current annual inflation rate
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}
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// minter object for a new minter
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func InitialMinter() Minter {
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return Minter{
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InflationLastTime: time.Unix(0, 0),
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Inflation: 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 ", minter.Inflation.String())
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}
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if minter.Inflation.GT(sdk.OneDec()) {
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return fmt.Errorf("mint parameter Inflation must be <= 1, is %s", minter.Inflation.String())
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}
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return nil
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}
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var hrsPerYr = sdk.NewDec(8766) // as defined by a julian year of 365.25 days
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// process provisions for an hour period
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func (m Minter) ProcessProvisions(params Params, totalSupply, bondedRatio sdk.Dec) (
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minter Minter, provisions sdk.Coin) {
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m.Inflation = m.NextInflation(params, bondedRatio)
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provisionsDec := m.Inflation.Mul(totalSupply).Quo(hrsPerYr)
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provisions = sdk.NewCoin(params.MintDenom, provisionsDec.TruncateInt())
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return m, provisions
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}
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// get the next inflation rate for the hour
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func (m Minter) NextInflation(params Params, bondedRatio sdk.Dec) (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(hrsPerYr)
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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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