docs: Add class diagram for the database schema of the hbar limiter redesign

docs/design/hbar-limiter.md

@@ -55,36 +55,128 @@ The purpose of the HBar Limiter is to track and control the spending of HBars in
 The Hbar limiter will be implemented as a separate service, used by other services/classes that need it. It will have two main purposes - to capture the gas fees for different operation and to check if an operation needs to be paused, due to exceeded Hbar limit
 
 ### Class Diagram
+
+#### Service Layer
 ```mermaid
 classDiagram
-    class sdkClient
+    class SdkClient {
+        -hbarLimitService: IHBarLimitService
+        -metricService: MetricService
+        +executeTransaction(transaction: Transaction, callerName: string, interactingEntity: string, requestId?: string): Promise<TransactionId>
+        +executeQuery~T~(query: Query~T~, callerName: string, interactingEntity: string, requestId?: string): Promise<Query~T~>
+    }
 
     class MetricService {
+      -hbarLimitService: IHBarLimitService
       +captureTransactionFees(transaction: Transaction, callerName: string, interactingEntity: string, requestId?: string) void
       +captureQueryFees~T~(query: Query~T~, callerName: string, interactingEntity: string, requestId?: string) void
     }
 
-    MetricService <|-- sdkClient
-
-    class HbarLimitService {
-        -mirrorNodeClient: MirrorNodeClient
+    class HBarLimitService {
+        -hbarSpendingPlanRepository: HbarSpendingPlanRepository
+        -ethAddressHbarSpendingPlanRepository: EthAddressHbarSpendingPlanRepository
+        -ipAddressHbarSpendingPlanRepository: IpAddressHbarSpendingPlanRepository
         +shouldLimit(txFrom: string, ip?: string) boolean
-        -getTransactionRecord(transactionld: string) TransactionRecord
         +resetLimiter() void
-        -getOperatorBalance() number
-        -getAddressLimit(address: string) number
-        -getAddressSpent(address: string) number
-        -getIpSpent(ip: string) number
+        +addExpense(amount: number, txFrom: string, ip?: string) void
+        -getSpendingPlanOfEthAddress(address: string): HbarSpendingPlan
+        -getSpendingPlanOfIpAddress(ip: string): HbarSpendingPlan
         -checkTotalSpent() boolean
         -shouldReset() boolean
     }
 
-    class IHBarLimitService {
-      +shouldLimit() boolean
-      +resetLimiter() void
+    class IHBarLimitService
+    <<interface>> IHBarLimitService
+    IHBarLimitService : shouldLimit() boolean
+    IHBarLimitService : resetLimiter() void
+    IHBarLimitService : addExpense() void
+
+    SdkClient --> MetricService : uses
+    SdkClient --> IHBarLimitService : uses
+    MetricService --> IHBarLimitService : uses
+    IHBarLimitService <|-- HBarLimitService: implements
+```
+
+#### Database Layer:
+```mermaid
+classDiagram
+    class HbarSpendingPlan {
+        -id: string
+        -subscriptionType: SubscriptionType
+        -createdAt: Date
+        -active: boolean
+        -spendingHistory: HbarSpendingRecord[]
+        -spentToday: number
+    }
+
+    class HbarSpendingRecord {
+        -amount: number
+        -timestamp: Date
+    }
+
+    class EthAddressHbarSpendingPlan {
+        -ethAddress: string
+        -planId: string
+    }
+
+    class IpAddressHbarSpendingPlan {
+        -ipAddress: string
+        -planId: string
+    }
+
+    class CacheService {
+        -internalCache: ICacheClient
+        -sharedCache: ICacheClient
+        +getAsync<T>(key: string, callingMethod: string, requestIdPrefix?: string): Promise<T>
+        +set(key: string, value: any, callingMethod: string, ttl?: number, requestIdPrefix?: string): Promise<void>
+        +multiSet(entries: Record<string, any>, callingMethod: string, ttl?: number, requestIdPrefix?: string): Promise<void>
+        +delete(key: string, callingMethod: string, requestIdPrefix?: string): Promise<void>
+        +clear(requestIdPrefix?: string): Promise<void>
+        +incrBy(key: string, amount: number, callingMethod: string, requestIdPrefix?: string): Promise<number>
+        +rPush(key: string, value: any, callingMethod: string, requestIdPrefix?: string): Promise<number>
+        +lRange<T>(key: string, start: number, end: number, callingMethod: string, requestIdPrefix?: string): Promise<T[]>
+    }
+
+    class HbarSpendingPlanRepository {
+        -cache: CacheService
+        +findById(id: string): Promise<IHbarSpendingPlan>
+        +findByIdWithDetails(id: string): Promise<IDetailedHbarSpendingPlan>
+        +create(subscriptionType: SubscriptionType): Promise<IDetailedHbarSpendingPlan>
+        +checkExistsAndActive(id: string): Promise<void>
+        +getSpendingHistory(id: string): Promise<HbarSpendingRecord[]>
+        +addAmountToSpendingHistory(id: string, amount: number): Promise<number>
+        +getSpentToday(id: string): Promise<number>
+        +addAmountToSpentToday(id: string, amount: number): Promise<void>
+    }
+
+    class EthAddressHbarSpendingPlanRepository {
+        -cache: CacheService
+        +findByAddress(ethAddress: string): Promise<EthAddressHbarSpendingPlan>
+        +save(ethAddressPlan: EthAddressHbarSpendingPlan): Promise<void>
+        +delete(ethAddress: string): Promise<void>
+    }
+
+    class IpAddressHbarSpendingPlanRepository {
+        -cache: CacheService
+        +findByIp(ip: string): Promise<IpAddressHbarSpendingPlan>
+        +save(ipAddressPlan: IpAddressHbarSpendingPlan): Promise<void>
+        +delete(ip: string): Promise<void>
     }
-    IHBarLimitService <|-- sdkClient
-    IHBarLimitService <|-- HbarLimitService
+
+    class SubscriptionType
+    <<Enumeration>> SubscriptionType
+    SubscriptionType : BASIC
+    SubscriptionType : EXTENDED
+    SubscriptionType : PRIVILEGED
+
+    HbarSpendingPlan --> SubscriptionType : could be one of the types
+    HbarSpendingPlan --> HbarSpendingRecord : stores history of
+    EthAddressHbarSpendingPlan --> HbarSpendingPlan : links an ETH address to
+    IpAddressHbarSpendingPlan --> HbarSpendingPlan : links an IP address to
+
+    HbarSpendingPlanRepository --> CacheService : uses
+    EthAddressHbarSpendingPlanRepository --> CacheService : uses
+    IpAddressHbarSpendingPlanRepository --> CacheService : uses
 ```
 
 ## Additional Considerations