cosmos-sdk/x/stake/fee_distribution.go

package stake

import (
	sdk "github.com/cosmos/cosmos-sdk/types"
)

// Handle fee distribution to the validators and delegators
func (k Keeper) FeeHandler(ctx sdk.Context, collectedFees sdk.Coins) {
	pool := k.GetPool(ctx)
	params := k.GetParams(ctx)

	// XXX determine
	candidate := NewCandidate(addrs[0], pks[0], Description{})

	// calculate the proposer reward
	precommitPower := k.GetTotalPrecommitVotingPower(ctx)
	toProposer := coinsMulRat(collectedFees, (sdk.NewRat(1, 100).Add(sdk.NewRat(4, 100).Mul(precommitPower).Quo(pool.BondedShares))))
	candidate.ProposerRewardPool = candidate.ProposerRewardPool.Plus(toProposer)

	toReservePool := coinsMulRat(collectedFees, params.ReservePoolFee)
	pool.FeeReservePool = pool.FeeReservePool.Plus(toReservePool)

	distributedReward := (collectedFees.Minus(toProposer)).Minus(toReservePool)
	pool.FeePool = pool.FeePool.Plus(distributedReward)
	pool.FeeSumReceived = pool.FeeSumReceived.Plus(distributedReward)
	pool.FeeRecent = distributedReward

	// lastly update the FeeRecent term
	pool.FeeRecent = collectedFees

	k.setPool(ctx, pool)
}

func coinsMulRat(coins sdk.Coins, rat sdk.Rat) sdk.Coins {
	var res sdk.Coins
	for _, coin := range coins {
		coinMulAmt := rat.Mul(sdk.NewRat(coin.Amount)).Evaluate()
		coinMul := sdk.Coins{{coin.Denom, coinMulAmt}}
		res = res.Plus(coinMul)
	}
	return res
}

//____________________________________________________________________________-

// calculate adjustment changes for a candidate at a height
func CalculateAdjustmentChange(candidate Candidate, pool Pool, denoms []string, height int64) (Candidate, Pool) {

	heightRat := sdk.NewRat(height)
	lastHeightRat := sdk.NewRat(height - 1)
	candidateFeeCount := candidate.BondedShares.Mul(heightRat)
	poolFeeCount := pool.BondedShares.Mul(heightRat)

	for i, denom := range denoms {
		poolFeeSumReceived := sdk.NewRat(pool.FeeSumReceived.AmountOf(denom))
		poolFeeRecent := sdk.NewRat(pool.FeeRecent.AmountOf(denom))
		// calculate simple and projected pools
		simplePool := candidateFeeCount.Quo(poolFeeCount).Mul(poolFeeSumReceived)
		calc1 := candidate.PrevBondedShares.Mul(lastHeightRat).Quo(pool.PrevBondedShares.Mul(lastHeightRat)).Mul(poolFeeRecent)
		calc2 := candidate.BondedShares.Quo(pool.BondedShares).Mul(poolFeeRecent)
		projectedPool := calc1.Add(calc2)

		AdjustmentChange := simplePool.Sub(projectedPool)
		candidate.FeeAdjustments[i] = candidate.FeeAdjustments[i].Add(AdjustmentChange)
		pool.FeeAdjustments[i] = pool.FeeAdjustments[i].Add(AdjustmentChange)
	}

	return candidate, pool
}