fix(staker): Introduce Tier type and simplify casting in reward logic

contract/r/gnoswap/v1/staker/api.gno

@@ -177,7 +177,7 @@ func ApiGetInternalIncentivesByPoolPath(targetPoolPath string) string {
 		return ""
 	}
 
-	internalIctv := newApiInternalIncentive(targetPoolPath, tier)
+	internalIctv := newApiInternalIncentive(targetPoolPath, tier.Uint64())
 	apiInternalIncentives = append(apiInternalIncentives, internalIctv)
 
 	rsps := make([]JsonResponse, len(apiInternalIncentives))

contract/r/gnoswap/v1/staker/getter.gno

@@ -210,26 +210,26 @@ func GetDepositWarmUp(lpTokenId uint64) []Warmup {
 
 // GetPoolTier returns the tier of a pool.
 func GetPoolTier(poolPath string) uint64 {
-	return poolTier.CurrentTier(poolPath)
+	return poolTier.CurrentTier(poolPath).Uint64()
 }
 
 // GetPoolTierRatio returns the current reward ratio for a pool's tier.
-func GetPoolTierRatio(poolPath string) uint64 {
+func GetPoolTierRatio(poolPath string) int64 {
 	tier := GetPoolTier(poolPath)
-	return poolTier.tierRatio.Get(tier)
+	return poolTier.tierRatio.Get(TierFromUint64(tier))
 }
 
 // GetPoolTierCount returns the number of pools in a tier.
-func GetPoolTierCount(tier uint64) uint64 {
+func GetPoolTierCount(tier uint64) int64 {
 	if tier == 0 {
 		return 0
 	}
-	return uint64(poolTier.CurrentCount(tier))
+	return poolTier.CurrentCount(TierFromUint64(tier))
 }
 
 // GetPoolReward returns the current reward amount for a tier.
 func GetPoolReward(tier uint64) int64 {
-	return poolTier.CurrentReward(tier)
+	return poolTier.CurrentReward(TierFromUint64(tier))
 }
 
 // GetExternalIncentiveByPoolPath returns all external incentives for a pool.

contract/r/gnoswap/v1/staker/manage_pool_tier_and_warmup.gno

@@ -14,10 +14,6 @@ import (
 	pl "gno.land/r/gnoswap/v1/pool"
 )
 
-const (
-	NOT_EMISSION_TARGET_TIER uint64 = 0
-)
-
 // SetPoolTier assigns a tier level to a pool for internal GNS emission rewards.
 // Only admin or governance can call this function.
 func SetPoolTier(cur realm, poolPath string, tier uint64) {
@@ -120,30 +116,28 @@ func setPoolTier(poolPath string, tier uint64, currentTime int64) {
 	en.MintAndDistributeGns(cross)
 
 	pools.GetOrCreate(poolPath)
-	poolTier.changeTier(runtime.ChainHeight(), currentTime, pools, poolPath, tier)
+	poolTier.changeTier(runtime.ChainHeight(), currentTime, pools, poolPath, TierFromUint64(tier))
 }
 
 // changePoolTier internally changes the pool tier and returns old and new tiers.
 func changePoolTier(poolPath string, tier uint64, currentTime int64) (uint64, uint64) {
 	en.MintAndDistributeGns(cross)
-	previousTier := poolTier.CurrentTier(poolPath)
 
-	poolTier.changeTier(runtime.ChainHeight(), currentTime, pools, poolPath, tier)
+	previousTier := poolTier.CurrentTier(poolPath)
+	poolTier.changeTier(runtime.ChainHeight(), currentTime, pools, poolPath, TierFromUint64(tier))
 
-	return previousTier, tier
+	return previousTier.Uint64(), tier
 }
 
 // removePoolTier internally removes the pool from tier system.
 func removePoolTier(poolPath string, currentTime int64) {
 	en.MintAndDistributeGns(cross)
-
-	poolTier.changeTier(runtime.ChainHeight(), currentTime, pools, poolPath, NOT_EMISSION_TARGET_TIER)
+	poolTier.changeTier(runtime.ChainHeight(), currentTime, pools, poolPath, TierNone)
 }
 
 // setWarmUp internally sets the warm-up parameters.
 func setWarmUp(pct, timeDuration int64) {
 	en.MintAndDistributeGns(cross)
-
 	modifyWarmup(pctToIndex(pct), timeDuration)
 }
 

contract/r/gnoswap/v1/staker/query.gno

@@ -47,7 +47,7 @@ func QueryPoolData(poolPath string) (*PoolData, error) {
 
 	return &PoolData{
 		PoolPath:         poolPath,
-		Tier:             tier,
+		Tier:             tier.Uint64(),
 		ActiveIncentives: ictvIds,
 		StakedLiquidity:  pool.CurrentStakedLiquidity(currentTimestamp),
 	}, nil

contract/r/gnoswap/v1/staker/reward_calculation_canonical_env_test.gno

@@ -30,11 +30,11 @@ func (self *canonicalPool) InternalReward(emission uint64, ratio TierRatio, coun
 	case 0:
 		return 0
 	case 1:
-		return int64(emission * ratio.Tier1 / count / 100)
+		return int64(emission) * ratio.Tier1 / int64(count) / 100
 	case 2:
-		return int64(emission * ratio.Tier2 / count / 100)
+		return int64(emission) * ratio.Tier2 / int64(count) / 100
 	case 3:
-		return int64(emission * ratio.Tier3 / count / 100)
+		return int64(emission) * ratio.Tier3 / int64(count) / 100
 	default:
 		panic("invalid tier")
 	}
@@ -515,7 +515,7 @@ func (self *canonicalRewardState) ChangePoolTier(poolPath string, tier uint64) {
 	if !self.global.pools.Has(poolPath) {
 		self.global.pools.set(poolPath, NewPool(poolPath, self.CurrentTime()))
 	}
-	self.global.poolTier.changeTier(runtime.ChainHeight(), self.CurrentTime(), self.global.pools, poolPath, tier)
+	self.global.poolTier.changeTier(runtime.ChainHeight(), self.CurrentTime(), self.global.pools, poolPath, TierFromUint64(tier))
 }
 
 func (self *canonicalRewardState) CreatePool(poolPath string, initialTier uint64, initialTick int32) {
@@ -527,7 +527,7 @@ func (self *canonicalRewardState) CreatePool(poolPath string, initialTier uint64
 		tickCrossHook: self.tickCrossHook,
 	}
 	self.global.pools.set(poolPath, NewPool(poolPath, self.CurrentTime()))
-	self.global.poolTier.changeTier(runtime.ChainHeight(), self.CurrentTime(), self.global.pools, poolPath, initialTier)
+	self.global.poolTier.changeTier(runtime.ChainHeight(), self.CurrentTime(), self.global.pools, poolPath, TierFromUint64(initialTier))
 }
 
 func (self *canonicalRewardState) MoveTick(poolPath string, tick int32) {