Hard: Kava delegators earn HARD rewards via the Incentive module (#776)

* add staking keeper to incentive module

* update hard with delegator methods

* add delegator methods to incentive

* implement delegator hook scaffolds

* implement hard delegator reward accumulation

* update claim names to delegator

* stakingKeeper expected keeper methods

* accumulate delegator rewards

* initialize delegator reward

* synchronize delegator reward

* add TODO comments to rewards

* implement staking hooks interface

* initial revisions

* remove outdated TODO

* update methods for test compatibility

* update method names for test compatibility

* implement initial accumulate delegator reward test

* attempt validator set up in staking module

* initial synchronize delegator reward test

* delegator accumulation test passing

* synchronize delegator rewards test (not passing)

* synchronize delegator rewards passing

* revisions

app/app.go

@@ -382,6 +382,7 @@ func NewApp(logger log.Logger, db dbm.DB, traceStore io.Writer, appOpts AppOptio
 		&cdpKeeper,
 		&hardKeeper,
 		app.accountKeeper,
+		&stakingKeeper,
 	)
 	app.issuanceKeeper = issuance.NewKeeper(
 		app.cdc,
@@ -394,7 +395,7 @@ func NewApp(logger log.Logger, db dbm.DB, traceStore io.Writer, appOpts AppOptio
 	// register the staking hooks
 	// NOTE: stakingKeeper above is passed by reference, so that it will contain these hooks
 	app.stakingKeeper = *stakingKeeper.SetHooks(
-		staking.NewMultiStakingHooks(app.distrKeeper.Hooks(), app.slashingKeeper.Hooks()))
+		staking.NewMultiStakingHooks(app.distrKeeper.Hooks(), app.slashingKeeper.Hooks(), app.incentiveKeeper.Hooks()))
 
 	app.cdpKeeper = *cdpKeeper.SetHooks(cdp.NewMultiCDPHooks(app.incentiveKeeper.Hooks()))
 

x/hard/types/keys.go

@@ -44,6 +44,7 @@ var (
 	TotalReservesPrefix           = []byte{0x10} // denom -> sdk.Coin
 	BorrowInterestFactorPrefix    = []byte{0x11} // denom -> sdk.Dec
 	SupplyInterestFactorPrefix    = []byte{0x12} // denom -> sdk.Dec
+	DelegatorInterestFactorPrefix = []byte{0x12} // denom -> sdk.Dec
 	LtvIndexPrefix                = []byte{0x13}
 	sep                           = []byte(":")
 )

x/incentive/keeper/hooks.go

@@ -2,6 +2,8 @@ package keeper
 
 import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	stakingtypes "github.com/cosmos/cosmos-sdk/x/staking/types"
+
 	cdptypes "github.com/kava-labs/kava/x/cdp/types"
 	hardtypes "github.com/kava-labs/kava/x/hard/types"
 )
@@ -13,10 +15,13 @@ type Hooks struct {
 
 var _ cdptypes.CDPHooks = Hooks{}
 var _ hardtypes.HARDHooks = Hooks{}
+var _ stakingtypes.StakingHooks = Hooks{}
 
 // Hooks create new incentive hooks
 func (k Keeper) Hooks() Hooks { return Hooks{k} }
 
+// ------------------- Cdp Module Hooks -------------------
+
 // AfterCDPCreated function that runs after a cdp is created
 func (h Hooks) AfterCDPCreated(ctx sdk.Context, cdp cdptypes.CDP) {
 	h.k.InitializeUSDXMintingClaim(ctx, cdp)
@@ -29,6 +34,8 @@ func (h Hooks) BeforeCDPModified(ctx sdk.Context, cdp cdptypes.CDP) {
 	h.k.SynchronizeUSDXMintingReward(ctx, cdp)
 }
 
+// ------------------- Hard Module Hooks -------------------
+
 // AfterDepositCreated function that runs after a deposit is created
 func (h Hooks) AfterDepositCreated(ctx sdk.Context, deposit hardtypes.Deposit) {
 	h.k.InitializeHardSupplyReward(ctx, deposit)
@@ -58,3 +65,46 @@ func (h Hooks) BeforeBorrowModified(ctx sdk.Context, borrow hardtypes.Borrow) {
 func (h Hooks) AfterBorrowModified(ctx sdk.Context, borrow hardtypes.Borrow) {
 	h.k.UpdateHardBorrowIndexDenoms(ctx, borrow)
 }
+
+// ------------------- Staking Module Hooks -------------------
+
+// BeforeDelegationCreated runs before a delegation is created
+func (h Hooks) BeforeDelegationCreated(ctx sdk.Context, delAddr sdk.AccAddress, valAddr sdk.ValAddress) {
+	h.k.InitializeHardDelegatorReward(ctx, delAddr)
+}
+
+// BeforeDelegationSharesModified runs before an existing delegation is modified
+func (h Hooks) BeforeDelegationSharesModified(ctx sdk.Context, delAddr sdk.AccAddress, valAddr sdk.ValAddress) {
+	h.k.SynchronizeHardDelegatorRewards(ctx, delAddr)
+}
+
+// NOTE: following hooks are just implemented to ensure StakingHooks interface compliance
+
+// BeforeValidatorSlashed is called before a validator is slashed
+func (h Hooks) BeforeValidatorSlashed(ctx sdk.Context, valAddr sdk.ValAddress, fraction sdk.Dec) {}
+
+// AfterValidatorBeginUnbonding is called after a validator begins unbonding
+func (h Hooks) AfterValidatorBeginUnbonding(ctx sdk.Context, consAddr sdk.ConsAddress, valAddr sdk.ValAddress) {
+}
+
+// AfterValidatorBonded is called after a validator is bonded
+func (h Hooks) AfterValidatorBonded(ctx sdk.Context, consAddr sdk.ConsAddress, valAddr sdk.ValAddress) {
+}
+
+// AfterDelegationModified runs after a delegation is modified
+func (h Hooks) AfterDelegationModified(ctx sdk.Context, delAddr sdk.AccAddress, valAddr sdk.ValAddress) {
+}
+
+// BeforeDelegationRemoved runs directly before a delegation is deleted
+func (h Hooks) BeforeDelegationRemoved(ctx sdk.Context, delAddr sdk.AccAddress, valAddr sdk.ValAddress) {
+}
+
+// AfterValidatorCreated runs after a validator is created
+func (h Hooks) AfterValidatorCreated(ctx sdk.Context, valAddr sdk.ValAddress) {}
+
+// BeforeValidatorModified runs before a validator is modified
+func (h Hooks) BeforeValidatorModified(ctx sdk.Context, valAddr sdk.ValAddress) {}
+
+// AfterValidatorRemoved runs after a validator is removed
+func (h Hooks) AfterValidatorRemoved(ctx sdk.Context, consAddr sdk.ConsAddress, valAddr sdk.ValAddress) {
+}

x/incentive/keeper/keeper.go

@@ -20,12 +20,13 @@ type Keeper struct {
 	key           sdk.StoreKey
 	paramSubspace subspace.Subspace
 	supplyKeeper  types.SupplyKeeper
+	stakingKeeper types.StakingKeeper
 }
 
 // NewKeeper creates a new keeper
 func NewKeeper(
 	cdc *codec.Codec, key sdk.StoreKey, paramstore subspace.Subspace, sk types.SupplyKeeper,
-	cdpk types.CdpKeeper, hk types.HardKeeper, ak types.AccountKeeper,
+	cdpk types.CdpKeeper, hk types.HardKeeper, ak types.AccountKeeper, stk types.StakingKeeper,
 ) Keeper {
 
 	return Keeper{
@@ -36,6 +37,7 @@ func NewKeeper(
 		key:           key,
 		paramSubspace: paramstore.WithKeyTable(types.ParamKeyTable()),
 		supplyKeeper:  sk,
+		stakingKeeper: stk,
 	}
 }
 
@@ -276,3 +278,20 @@ func (k Keeper) SetPreviousHardBorrowRewardAccrualTime(ctx sdk.Context, denom st
 	store := prefix.NewStore(ctx.KVStore(k.key), types.PreviousHardBorrowRewardAccrualTimeKeyPrefix)
 	store.Set([]byte(denom), k.cdc.MustMarshalBinaryBare(blockTime))
 }
+
+// GetPreviousHardDelegatorRewardAccrualTime returns the last time a denom accrued Hard protocol delegator rewards
+func (k Keeper) GetPreviousHardDelegatorRewardAccrualTime(ctx sdk.Context, denom string) (blockTime time.Time, found bool) {
+	store := prefix.NewStore(ctx.KVStore(k.key), types.PreviousHardDelegatorRewardAccrualTimeKeyPrefix)
+	bz := store.Get([]byte(denom))
+	if bz == nil {
+		return time.Time{}, false
+	}
+	k.cdc.MustUnmarshalBinaryBare(bz, &blockTime)
+	return blockTime, true
+}
+
+// SetPreviousHardDelegatorRewardAccrualTime sets the last time a denom accrued Hard protocol delegator rewards
+func (k Keeper) SetPreviousHardDelegatorRewardAccrualTime(ctx sdk.Context, denom string, blockTime time.Time) {
+	store := prefix.NewStore(ctx.KVStore(k.key), types.PreviousHardDelegatorRewardAccrualTimeKeyPrefix)
+	store.Set([]byte(denom), k.cdc.MustMarshalBinaryBare(blockTime))
+}

x/incentive/keeper/keeper_test.go

@@ -9,6 +9,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/x/auth"
 	authexported "github.com/cosmos/cosmos-sdk/x/auth/exported"
 	"github.com/cosmos/cosmos-sdk/x/auth/vesting"
+	stakingkeeper "github.com/cosmos/cosmos-sdk/x/staking/keeper"
 	supplyexported "github.com/cosmos/cosmos-sdk/x/supply/exported"
 
 	abci "github.com/tendermint/tendermint/abci/types"
@@ -26,16 +27,20 @@ type KeeperTestSuite struct {
 
 	keeper         keeper.Keeper
 	hardKeeper     hardkeeper.Keeper
+	stakingKeeper  stakingkeeper.Keeper
 	app            app.TestApp
 	ctx            sdk.Context
 	addrs          []sdk.AccAddress
+	validatorAddrs []sdk.ValAddress
 }
 
 // The default state used by each test
 func (suite *KeeperTestSuite) SetupTest() {
 	tApp := app.NewTestApp()
 	ctx := tApp.NewContext(true, abci.Header{Height: 1, Time: tmtime.Now()})
+
 	tApp.InitializeFromGenesisStates()
+
 	_, addrs := app.GeneratePrivKeyAddressPairs(5)
 	keeper := tApp.GetIncentiveKeeper()
 	suite.app = tApp

x/incentive/keeper/params.go

@@ -53,6 +53,17 @@ func (k Keeper) GetHardBorrowRewardPeriod(ctx sdk.Context, denom string) (types.
 	return types.RewardPeriod{}, false
 }
 
+// GetHardDelegatorRewardPeriod returns the reward period with the specified collateral type if it's found in the params
+func (k Keeper) GetHardDelegatorRewardPeriod(ctx sdk.Context, denom string) (types.RewardPeriod, bool) {
+	params := k.GetParams(ctx)
+	for _, rp := range params.HardDelegatorRewardPeriods {
+		if rp.CollateralType == denom {
+			return rp, true
+		}
+	}
+	return types.RewardPeriod{}, false
+}
+
 // GetMultiplier returns the multiplier with the specified name if it's found in the params
 func (k Keeper) GetMultiplier(ctx sdk.Context, name types.MultiplierName) (types.Multiplier, bool) {
 	params := k.GetParams(ctx)

x/incentive/keeper/payout_test.go

@@ -54,7 +54,7 @@ func (suite *KeeperTestSuite) TestPayoutClaim() {
 				multipliers:              types.Multipliers{types.NewMultiplier(types.MultiplierName("small"), 1, d("0.25")), types.NewMultiplier(types.MultiplierName("large"), 12, d("1.0"))},
 				multiplier:               types.MultiplierName("large"),
 				timeElapsed:              86400,
-				expectedBalance:          cs(c("usdx", 10000000000), c("ukava", 10571385600)),
+				expectedBalance:          cs(c("usdx", 10000000000), c("ukava", 10576385600)),
 				expectedPeriods:          vesting.Periods{vesting.Period{Length: 31536000, Amount: cs(c("ukava", 10571385600))}},
 				isPeriodicVestingAccount: true,
 			},

x/incentive/keeper/rewards.go

@@ -400,6 +400,124 @@ func (k Keeper) UpdateHardBorrowIndexDenoms(ctx sdk.Context, borrow hardtypes.Bo
 	k.SetHardLiquidityProviderClaim(ctx, claim)
 }
 
+// SynchronizeHardDelegatorRewards updates the claim object by adding any accumulated rewards
+func (k Keeper) SynchronizeHardDelegatorRewards(ctx sdk.Context, delegator sdk.AccAddress) {
+	claim, found := k.GetHardLiquidityProviderClaim(ctx, delegator)
+	if !found {
+		return
+	}
+
+	delagatorFactor, found := k.GetHardDelegatorRewardFactor(ctx, types.BondDenom)
+	if !found {
+		return
+	}
+
+	delegatorIndex, hasDelegatorRewardIndex := claim.HasDelegatorRewardIndex(types.BondDenom)
+	if !hasDelegatorRewardIndex {
+		return
+	}
+
+	userRewardFactor := claim.DelegatorRewardIndexes[delegatorIndex].RewardFactor
+	rewardsAccumulatedFactor := delagatorFactor.Sub(userRewardFactor)
+	if rewardsAccumulatedFactor.IsZero() {
+		return
+	}
+	claim.DelegatorRewardIndexes[delegatorIndex].RewardFactor = delagatorFactor
+
+	totalDelegated := sdk.ZeroDec()
+
+	// TODO: set reasonable max limit on delegation iteration
+	maxUInt := ^uint16(0)
+	delegations := k.stakingKeeper.GetDelegatorDelegations(ctx, delegator, maxUInt)
+	for _, delegation := range delegations {
+		validator, found := k.stakingKeeper.GetValidator(ctx, delegation.GetValidatorAddr())
+		if !found {
+			continue
+		}
+
+		// Delegators don't accumulate rewards if their validator is unbonded/slashed
+		if validator.GetStatus() != sdk.Bonded {
+			continue
+		}
+
+		if validator.GetTokens().IsZero() {
+			continue
+		}
+
+		delegatedTokens := validator.TokensFromShares(delegation.GetShares())
+		if delegatedTokens.IsZero() || delegatedTokens.IsNegative() {
+			continue
+		}
+		totalDelegated = totalDelegated.Add(delegatedTokens)
+	}
+
+	rewardsEarned := rewardsAccumulatedFactor.Mul(totalDelegated).RoundInt()
+	if rewardsEarned.IsZero() || rewardsEarned.IsNegative() {
+		return
+	}
+
+	// Add rewards to delegator's hard claim
+	newRewardsCoin := sdk.NewCoin(types.HardLiquidityRewardDenom, rewardsEarned)
+	claim.Reward = claim.Reward.Add(newRewardsCoin)
+	k.SetHardLiquidityProviderClaim(ctx, claim)
+}
+
+// AccumulateHardDelegatorRewards updates the rewards accumulated for the input reward period
+func (k Keeper) AccumulateHardDelegatorRewards(ctx sdk.Context, rewardPeriod types.RewardPeriod) error {
+	previousAccrualTime, found := k.GetPreviousHardDelegatorRewardAccrualTime(ctx, rewardPeriod.CollateralType)
+	if !found {
+		k.SetPreviousHardDelegatorRewardAccrualTime(ctx, rewardPeriod.CollateralType, ctx.BlockTime())
+		return nil
+	}
+	timeElapsed := CalculateTimeElapsed(rewardPeriod, ctx.BlockTime(), previousAccrualTime)
+	if timeElapsed.IsZero() {
+		return nil
+	}
+	if rewardPeriod.RewardsPerSecond.Amount.IsZero() {
+		k.SetPreviousHardDelegatorRewardAccrualTime(ctx, rewardPeriod.CollateralType, ctx.BlockTime())
+		return nil
+	}
+
+	totalBonded := k.stakingKeeper.TotalBondedTokens(ctx).ToDec()
+	if totalBonded.IsZero() {
+		k.SetPreviousHardDelegatorRewardAccrualTime(ctx, rewardPeriod.CollateralType, ctx.BlockTime())
+		return nil
+	}
+
+	newRewards := timeElapsed.Mul(rewardPeriod.RewardsPerSecond.Amount)
+	rewardFactor := newRewards.ToDec().Quo(totalBonded)
+
+	previousRewardFactor, found := k.GetHardDelegatorRewardFactor(ctx, rewardPeriod.CollateralType)
+	if !found {
+		previousRewardFactor = sdk.ZeroDec()
+	}
+	newRewardFactor := previousRewardFactor.Add(rewardFactor)
+	k.SetHardDelegatorRewardFactor(ctx, rewardPeriod.CollateralType, newRewardFactor)
+	k.SetPreviousHardDelegatorRewardAccrualTime(ctx, rewardPeriod.CollateralType, ctx.BlockTime())
+	return nil
+}
+
+// InitializeHardDelegatorReward initializes the delegator reward index of a hard claim
+func (k Keeper) InitializeHardDelegatorReward(ctx sdk.Context, delegator sdk.AccAddress) {
+	delegatorFactor, foundDelegatorFactor := k.GetHardDelegatorRewardFactor(ctx, types.BondDenom)
+	if !foundDelegatorFactor { // Should always be found...
+		delegatorFactor = sdk.ZeroDec()
+	}
+
+	delegatorRewardIndexes := types.NewRewardIndex(types.BondDenom, delegatorFactor)
+
+	claim, found := k.GetHardLiquidityProviderClaim(ctx, delegator)
+	if !found {
+		// Instantiate claim object
+		claim = types.NewHardLiquidityProviderClaim(delegator,
+			sdk.NewCoin(types.HardLiquidityRewardDenom, sdk.ZeroInt()),
+			nil, nil, nil)
+	}
+
+	claim.DelegatorRewardIndexes = types.RewardIndexes{delegatorRewardIndexes}
+	k.SetHardLiquidityProviderClaim(ctx, claim)
+}
+
 // ZeroClaim zeroes out the claim object's rewards and returns the updated claim object
 func (k Keeper) ZeroClaim(ctx sdk.Context, claim types.USDXMintingClaim) types.USDXMintingClaim {
 	claim.Reward = sdk.NewCoin(claim.Reward.Denom, sdk.ZeroInt())

x/incentive/keeper/rewards_test.go

@@ -4,8 +4,9 @@ import (
 	"time"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
-
+	"github.com/cosmos/cosmos-sdk/x/staking"
 	abci "github.com/tendermint/tendermint/abci/types"
+	"github.com/tendermint/tendermint/crypto/ed25519"
 	tmtime "github.com/tendermint/tendermint/types/time"
 
 	"github.com/kava-labs/kava/app"
@@ -866,36 +867,292 @@ func (suite *KeeperTestSuite) TestUpdateHardBorrowIndexDenoms() {
 	}
 }
 
+func (suite *KeeperTestSuite) TestAccumulateHardDelegatorRewards() {
+	type args struct {
+		delegation           sdk.Coin
+		rewardsPerSecond     sdk.Coin
+		initialTime          time.Time
+		timeElapsed          int
+		expectedRewardFactor sdk.Dec
+	}
+	type test struct {
+		name string
+		args args
+	}
+	testCases := []test{
+		{
+			"7 seconds",
+			args{
+				delegation:           c("ukava", 1_000_000),
+				rewardsPerSecond:     c("hard", 122354),
+				initialTime:          time.Date(2020, 12, 15, 14, 0, 0, 0, time.UTC),
+				timeElapsed:          7,
+				expectedRewardFactor: d("0.428239000000000000"),
+			},
+		},
+		{
+			"1 day",
+			args{
+				delegation:           c("ukava", 1_000_000),
+				rewardsPerSecond:     c("hard", 122354),
+				initialTime:          time.Date(2020, 12, 15, 14, 0, 0, 0, time.UTC),
+				timeElapsed:          86400,
+				expectedRewardFactor: d("5285.692800000000000000"),
+			},
+		},
+		{
+			"0 seconds",
+			args{
+				delegation:           c("ukava", 1_000_000),
+				rewardsPerSecond:     c("hard", 122354),
+				initialTime:          time.Date(2020, 12, 15, 14, 0, 0, 0, time.UTC),
+				timeElapsed:          0,
+				expectedRewardFactor: d("0.0"),
+			},
+		},
+	}
+	for _, tc := range testCases {
+		suite.Run(tc.name, func() {
+			suite.SetupWithGenState()
+			suite.ctx = suite.ctx.WithBlockTime(tc.args.initialTime)
+
+			// Mint coins to hard module account
+			supplyKeeper := suite.app.GetSupplyKeeper()
+			hardMaccCoins := sdk.NewCoins(sdk.NewCoin("usdx", sdk.NewInt(200000000)))
+			supplyKeeper.MintCoins(suite.ctx, hardtypes.ModuleAccountName, hardMaccCoins)
+
+			// Set up incentive state
+			params := types.NewParams(
+				types.RewardPeriods{types.NewRewardPeriod(true, tc.args.delegation.Denom, tc.args.initialTime, tc.args.initialTime.Add(time.Hour*24*365*4), tc.args.rewardsPerSecond)},
+				types.RewardPeriods{types.NewRewardPeriod(true, tc.args.delegation.Denom, tc.args.initialTime, tc.args.initialTime.Add(time.Hour*24*365*4), tc.args.rewardsPerSecond)},
+				types.RewardPeriods{types.NewRewardPeriod(true, tc.args.delegation.Denom, tc.args.initialTime, tc.args.initialTime.Add(time.Hour*24*365*4), tc.args.rewardsPerSecond)},
+				types.RewardPeriods{types.NewRewardPeriod(true, tc.args.delegation.Denom, tc.args.initialTime, tc.args.initialTime.Add(time.Hour*24*365*4), tc.args.rewardsPerSecond)},
+				types.Multipliers{types.NewMultiplier(types.MultiplierName("small"), 1, d("0.25")), types.NewMultiplier(types.MultiplierName("large"), 12, d("1.0"))},
+				tc.args.initialTime.Add(time.Hour*24*365*5),
+			)
+			suite.keeper.SetParams(suite.ctx, params)
+			suite.keeper.SetPreviousHardDelegatorRewardAccrualTime(suite.ctx, tc.args.delegation.Denom, tc.args.initialTime)
+			suite.keeper.SetHardDelegatorRewardFactor(suite.ctx, tc.args.delegation.Denom, sdk.ZeroDec())
+
+			// Set up hard state (interest factor for the relevant denom)
+			suite.hardKeeper.SetPreviousAccrualTime(suite.ctx, tc.args.delegation.Denom, tc.args.initialTime)
+
+			err := suite.deliverMsgCreateValidator(suite.ctx, suite.validatorAddrs[0], tc.args.delegation)
+			suite.Require().NoError(err)
+			suite.deliverMsgDelegate(suite.ctx, suite.addrs[0], suite.validatorAddrs[0], tc.args.delegation)
+			suite.Require().NoError(err)
+
+			staking.EndBlocker(suite.ctx, suite.stakingKeeper)
+
+			// Set up chain context at future time
+			runAtTime := suite.ctx.BlockTime().Add(time.Duration(int(time.Second) * tc.args.timeElapsed))
+			runCtx := suite.ctx.WithBlockTime(runAtTime)
+
+			// Run Hard begin blocker in order to update the denom's index factor
+			hard.BeginBlocker(runCtx, suite.hardKeeper)
+
+			rewardPeriod, found := suite.keeper.GetHardDelegatorRewardPeriod(runCtx, tc.args.delegation.Denom)
+			suite.Require().True(found)
+			err = suite.keeper.AccumulateHardDelegatorRewards(runCtx, rewardPeriod)
+			suite.Require().NoError(err)
+
+			rewardFactor, found := suite.keeper.GetHardDelegatorRewardFactor(runCtx, tc.args.delegation.Denom)
+			suite.Require().Equal(tc.args.expectedRewardFactor, rewardFactor)
+		})
+	}
+}
+
+func (suite *KeeperTestSuite) TestSynchronizeHardDelegatorReward() {
+	type args struct {
+		delegation           sdk.Coin
+		rewardsPerSecond     sdk.Coin
+		initialTime          time.Time
+		blockTimes           []int
+		expectedRewardFactor sdk.Dec
+		expectedRewards      sdk.Coin
+	}
+	type test struct {
+		name string
+		args args
+	}
+
+	testCases := []test{
+		{
+			"10 blocks",
+			args{
+				delegation:           c("ukava", 1_000_000),
+				rewardsPerSecond:     c("hard", 122354),
+				initialTime:          time.Date(2020, 12, 15, 14, 0, 0, 0, time.UTC),
+				blockTimes:           []int{10, 10, 10, 10, 10, 10, 10, 10, 10, 10},
+				expectedRewardFactor: d("6.117700000000000000"),
+				expectedRewards:      c("hard", 6117700),
+			},
+		},
+		{
+			"10 blocks - long block time",
+			args{
+				delegation:           c("ukava", 1_000_000),
+				rewardsPerSecond:     c("hard", 122354),
+				initialTime:          time.Date(2020, 12, 15, 14, 0, 0, 0, time.UTC),
+				blockTimes:           []int{86400, 86400, 86400, 86400, 86400, 86400, 86400, 86400, 86400, 86400},
+				expectedRewardFactor: d("52856.928000000000000000"),
+				expectedRewards:      c("hard", 52856928000),
+			},
+		},
+	}
+	for _, tc := range testCases {
+		suite.Run(tc.name, func() {
+			suite.SetupWithGenState()
+			suite.ctx = suite.ctx.WithBlockTime(tc.args.initialTime)
+
+			// Mint coins to hard module account
+			supplyKeeper := suite.app.GetSupplyKeeper()
+			hardMaccCoins := sdk.NewCoins(sdk.NewCoin("usdx", sdk.NewInt(200000000)))
+			supplyKeeper.MintCoins(suite.ctx, hardtypes.ModuleAccountName, hardMaccCoins)
+
+			// setup incentive state
+			params := types.NewParams(
+				types.RewardPeriods{types.NewRewardPeriod(true, tc.args.delegation.Denom, tc.args.initialTime, tc.args.initialTime.Add(time.Hour*24*365*4), tc.args.rewardsPerSecond)},
+				types.RewardPeriods{types.NewRewardPeriod(true, tc.args.delegation.Denom, tc.args.initialTime, tc.args.initialTime.Add(time.Hour*24*365*4), tc.args.rewardsPerSecond)},
+				types.RewardPeriods{types.NewRewardPeriod(true, tc.args.delegation.Denom, tc.args.initialTime, tc.args.initialTime.Add(time.Hour*24*365*4), tc.args.rewardsPerSecond)},
+				types.RewardPeriods{types.NewRewardPeriod(true, tc.args.delegation.Denom, tc.args.initialTime, tc.args.initialTime.Add(time.Hour*24*365*4), tc.args.rewardsPerSecond)},
+				types.Multipliers{types.NewMultiplier(types.MultiplierName("small"), 1, d("0.25")), types.NewMultiplier(types.MultiplierName("large"), 12, d("1.0"))},
+				tc.args.initialTime.Add(time.Hour*24*365*5),
+			)
+			suite.keeper.SetParams(suite.ctx, params)
+			suite.keeper.SetPreviousHardDelegatorRewardAccrualTime(suite.ctx, tc.args.delegation.Denom, tc.args.initialTime)
+			suite.keeper.SetHardDelegatorRewardFactor(suite.ctx, tc.args.delegation.Denom, sdk.ZeroDec())
+
+			// Set up hard state (interest factor for the relevant denom)
+			suite.hardKeeper.SetPreviousAccrualTime(suite.ctx, tc.args.delegation.Denom, tc.args.initialTime)
+
+			// Delegator delegates
+			err := suite.deliverMsgCreateValidator(suite.ctx, suite.validatorAddrs[0], tc.args.delegation)
+			suite.Require().NoError(err)
+			suite.deliverMsgDelegate(suite.ctx, suite.addrs[0], suite.validatorAddrs[0], tc.args.delegation)
+			suite.Require().NoError(err)
+
+			staking.EndBlocker(suite.ctx, suite.stakingKeeper)
+
+			// Check that Staking hooks initialized a HardLiquidityProviderClaim
+			claim, found := suite.keeper.GetHardLiquidityProviderClaim(suite.ctx, suite.addrs[0])
+			suite.Require().True(found)
+			suite.Require().Equal(sdk.ZeroDec(), claim.DelegatorRewardIndexes[0].RewardFactor)
+
+			// Run accumulator at several intervals
+			var timeElapsed int
+			previousBlockTime := suite.ctx.BlockTime()
+			for _, t := range tc.args.blockTimes {
+				timeElapsed += t
+				updatedBlockTime := previousBlockTime.Add(time.Duration(int(time.Second) * t))
+				previousBlockTime = updatedBlockTime
+				blockCtx := suite.ctx.WithBlockTime(updatedBlockTime)
+
+				// Run Hard begin blocker for each block ctx to update denom's interest factor
+				hard.BeginBlocker(blockCtx, suite.hardKeeper)
+
+				rewardPeriod, found := suite.keeper.GetHardDelegatorRewardPeriod(blockCtx, tc.args.delegation.Denom)
+				suite.Require().True(found)
+
+				err := suite.keeper.AccumulateHardDelegatorRewards(blockCtx, rewardPeriod)
+				suite.Require().NoError(err)
+			}
+			updatedBlockTime := suite.ctx.BlockTime().Add(time.Duration(int(time.Second) * timeElapsed))
+			suite.ctx = suite.ctx.WithBlockTime(updatedBlockTime)
+
+			// After we've accumulated, run synchronize
+			suite.Require().NotPanics(func() {
+				suite.keeper.SynchronizeHardDelegatorRewards(suite.ctx, suite.addrs[0])
+			})
+
+			// Check that reward factor and claim have been updated as expected
+			rewardFactor, found := suite.keeper.GetHardDelegatorRewardFactor(suite.ctx, tc.args.delegation.Denom)
+			suite.Require().Equal(tc.args.expectedRewardFactor, rewardFactor)
+
+			claim, found = suite.keeper.GetHardLiquidityProviderClaim(suite.ctx, suite.addrs[0])
+			suite.Require().True(found)
+			suite.Require().Equal(tc.args.expectedRewardFactor, claim.DelegatorRewardIndexes[0].RewardFactor)
+			suite.Require().Equal(tc.args.expectedRewards, claim.Reward)
+		})
+	}
+}
+
 func (suite *KeeperTestSuite) SetupWithGenState() {
+	config := sdk.GetConfig()
+	app.SetBech32AddressPrefixes(config)
+
+	_, allAddrs := app.GeneratePrivKeyAddressPairs(10)
+	suite.addrs = allAddrs[:5]
+	for _, a := range allAddrs[5:] {
+		suite.validatorAddrs = append(suite.validatorAddrs, sdk.ValAddress(a))
+	}
+
 	tApp := app.NewTestApp()
 	ctx := tApp.NewContext(true, abci.Header{Height: 1, Time: tmtime.Now()})
 
-	_, addrs := app.GeneratePrivKeyAddressPairs(5)
-
-	authGS := app.NewAuthGenState(
-		[]sdk.AccAddress{addrs[3]},
-		[]sdk.Coins{
-			sdk.NewCoins(
-				sdk.NewCoin("bnb", sdk.NewInt(1000000000000000)),
-				sdk.NewCoin("ukava", sdk.NewInt(1000000000000000)),
-				sdk.NewCoin("btcb", sdk.NewInt(1000000000000000)),
-				sdk.NewCoin("xrp", sdk.NewInt(1000000000000000)),
-			),
-		},
-	)
-
 	tApp.InitializeFromGenesisStates(
-		authGS,
+		coinsAuthGenState(allAddrs, cs(c("ukava", 5_000_000))),
+		stakingGenesisState(),
 		NewPricefeedGenStateMulti(),
 		NewCDPGenStateMulti(),
 		NewHardGenStateMulti(),
 	)
 
-	keeper := tApp.GetIncentiveKeeper()
-	hardKeeper := tApp.GetHardKeeper()
 	suite.app = tApp
 	suite.ctx = ctx
-	suite.keeper = keeper
-	suite.hardKeeper = hardKeeper
-	suite.addrs = addrs
+	suite.keeper = tApp.GetIncentiveKeeper()
+	suite.hardKeeper = tApp.GetHardKeeper()
+	suite.stakingKeeper = tApp.GetStakingKeeper()
+}
+
+func coinsAuthGenState(addresses []sdk.AccAddress, coins sdk.Coins) app.GenesisState {
+	coinsList := []sdk.Coins{}
+	for range addresses {
+		coinsList = append(coinsList, coins)
+	}
+
+	// Load up our primary user address
+	if len(addresses) >= 4 {
+		coinsList[3] = sdk.NewCoins(
+			sdk.NewCoin("bnb", sdk.NewInt(1000000000000000)),
+			sdk.NewCoin("ukava", sdk.NewInt(1000000000000000)),
+			sdk.NewCoin("btcb", sdk.NewInt(1000000000000000)),
+			sdk.NewCoin("xrp", sdk.NewInt(1000000000000000)),
+		)
+	}
+
+	return app.NewAuthGenState(addresses, coinsList)
+}
+
+func stakingGenesisState() app.GenesisState {
+	genState := staking.DefaultGenesisState()
+	genState.Params.BondDenom = "ukava"
+	return app.GenesisState{
+		staking.ModuleName: staking.ModuleCdc.MustMarshalJSON(genState),
+	}
+}
+
+func (suite *KeeperTestSuite) deliverMsgCreateValidator(ctx sdk.Context, address sdk.ValAddress, selfDelegation sdk.Coin) error {
+	msg := staking.NewMsgCreateValidator(
+		address,
+		ed25519.GenPrivKey().PubKey(),
+		selfDelegation,
+		staking.Description{},
+		staking.NewCommissionRates(sdk.ZeroDec(), sdk.ZeroDec(), sdk.ZeroDec()),
+		sdk.NewInt(1_000_000),
+	)
+	handleStakingMsg := staking.NewHandler(suite.stakingKeeper)
+	_, err := handleStakingMsg(ctx, msg)
+	return err
+}
+
+func (suite *KeeperTestSuite) deliverMsgDelegate(ctx sdk.Context, delegator sdk.AccAddress, validator sdk.ValAddress, amount sdk.Coin) error {
+	msg := staking.NewMsgDelegate(
+		delegator,
+		validator,
+		amount,
+	)
+	handleStakingMsg := staking.NewHandler(suite.stakingKeeper)
+	_, err := handleStakingMsg(ctx, msg)
+	return err
 }

x/incentive/types/claims.go

@@ -11,6 +11,7 @@ import (
 const (
 	USDXMintingClaimType           = "usdx_minting"
 	HardLiquidityProviderClaimType = "hard_liquidity_provider"
+	BondDenom                      = "ukava"
 )
 
 // Claim is an interface for handling common claim actions
@@ -125,12 +126,12 @@ type HardLiquidityProviderClaim struct {
 	BaseClaim              `json:"base_claim" yaml:"base_claim"`
 	SupplyRewardIndexes    RewardIndexes `json:"supply_reward_indexes" yaml:"supply_reward_indexes"`
 	BorrowRewardIndexes    RewardIndexes `json:"borrow_reward_indexes" yaml:"borrow_reward_indexes"`
-	DelegationRewardIndexes RewardIndexes `json:"delegation_reward_indexes" yaml:"delegation_reward_indexes"`
+	DelegatorRewardIndexes RewardIndexes `json:"delegator_reward_indexes" yaml:"delegator_reward_indexes"`
 }
 
 // NewHardLiquidityProviderClaim returns a new HardLiquidityProviderClaim
 func NewHardLiquidityProviderClaim(owner sdk.AccAddress, reward sdk.Coin, supplyRewardIndexes,
-	borrowRewardIndexes, delegationRewardIndexes RewardIndexes) HardLiquidityProviderClaim {
+	borrowRewardIndexes, delegatorRewardIndexes RewardIndexes) HardLiquidityProviderClaim {
 	return HardLiquidityProviderClaim{
 		BaseClaim: BaseClaim{
 			Owner:  owner,
@@ -138,7 +139,7 @@ func NewHardLiquidityProviderClaim(owner sdk.AccAddress, reward sdk.Coin, supply
 		},
 		SupplyRewardIndexes:    supplyRewardIndexes,
 		BorrowRewardIndexes:    borrowRewardIndexes,
-		DelegationRewardIndexes: delegationRewardIndexes,
+		DelegatorRewardIndexes: delegatorRewardIndexes,
 	}
 }
 
@@ -155,7 +156,7 @@ func (c HardLiquidityProviderClaim) Validate() error {
 		return err
 	}
 
-	if err := c.DelegationRewardIndexes.Validate(); err != nil {
+	if err := c.DelegatorRewardIndexes.Validate(); err != nil {
 		return err
 	}
 
@@ -167,8 +168,8 @@ func (c HardLiquidityProviderClaim) String() string {
 	return fmt.Sprintf(`%s
 	Supply Reward Indexes: %s,
 	Borrow Reward Indexes: %s,
-	Delegation Reward Indexes: %s,
-	`, c.BaseClaim, c.SupplyRewardIndexes, c.BorrowRewardIndexes, c.DelegationRewardIndexes)
+	Delegator Reward Indexes: %s,
+	`, c.BaseClaim, c.SupplyRewardIndexes, c.BorrowRewardIndexes, c.DelegatorRewardIndexes)
 }
 
 // HasSupplyRewardIndex check if a claim has a supply reward index for the input collateral type
@@ -191,9 +192,9 @@ func (c HardLiquidityProviderClaim) HasBorrowRewardIndex(denom string) (int64, b
 	return 0, false
 }
 
-// HasDelegationRewardIndex check if a claim has a delegation reward index for the input collateral type
-func (c HardLiquidityProviderClaim) HasDelegationRewardIndex(collateralType string) (int64, bool) {
-	for index, ri := range c.SupplyRewardIndexes {
+// HasDelegatorRewardIndex check if a claim has a delegator reward index for the input collateral type
+func (c HardLiquidityProviderClaim) HasDelegatorRewardIndex(collateralType string) (int64, bool) {
+	for index, ri := range c.DelegatorRewardIndexes {
 		if ri.CollateralType == collateralType {
 			return int64(index), true
 		}

x/incentive/types/expected_keepers.go

@@ -3,6 +3,7 @@ package types
 import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	authexported "github.com/cosmos/cosmos-sdk/x/auth/exported"
+	stakingtypes "github.com/cosmos/cosmos-sdk/x/staking/types"
 	supplyexported "github.com/cosmos/cosmos-sdk/x/supply/exported"
 
 	cdptypes "github.com/kava-labs/kava/x/cdp/types"
@@ -15,6 +16,13 @@ type SupplyKeeper interface {
 	SendCoinsFromModuleToAccount(ctx sdk.Context, senderModule string, recipientAddr sdk.AccAddress, amt sdk.Coins) error
 }
 
+// StakingKeeper defines the expected staking keeper for module accounts
+type StakingKeeper interface {
+	GetDelegatorDelegations(ctx sdk.Context, delegator sdk.AccAddress, maxRetrieve uint16) (delegations []stakingtypes.Delegation)
+	GetValidator(ctx sdk.Context, addr sdk.ValAddress) (validator stakingtypes.Validator, found bool)
+	TotalBondedTokens(ctx sdk.Context) sdk.Int
+}
+
 // CdpKeeper defines the expected cdp keeper for interacting with cdps
 type CdpKeeper interface {
 	GetInterestFactor(ctx sdk.Context, collateralType string) (sdk.Dec, bool)