refactor: Centralize SignalR initialization and fix subscription leaks

[pkuehnel]

Fixes a bug where components (CarDetailsComponent, ChargingConnectorDetailsComponent) were redundantly subscribing to SignalRStateService on every OnParametersSetAsync, causing duplicate UI updates and memory leaks. The service now handles its own initialization gracefully and returns IDisposable from subscription methods to ensure components can properly unregister their callbacks.

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PR created automatically by Jules for task 1030221631243904585 started by @pkuehnel

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Summary of Changes

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This pull request refactors the SignalR integration across the application to prevent subscription leaks and redundant initializations. By centralizing the SignalR initialization within the SignalRStateService and implementing proper disposal mechanisms for subscriptions, the changes ensure a more robust and efficient handling of real-time data updates in Blazor components. This resolves issues of duplicate UI updates and memory consumption previously caused by components repeatedly subscribing to the SignalR service.

Highlights

• Subscription Leak Fixes: Implemented IDisposable in several Blazor components and refactored SignalR subscription management to prevent memory leaks caused by redundant subscriptions.
• Centralized SignalR Initialization: Moved SignalRStateService.InitializeAsync() calls from individual components into the service's core methods (GetStateAsync, Subscribe, SubscribeToTrigger), ensuring initialization occurs only when needed.
• IDisposable for Subscriptions: Modified ISignalRStateService and SignalRStateService to return IDisposable objects from subscription methods, allowing components to properly unregister callbacks.
• Optimized Component Subscriptions: Added logic in CarDetailsComponent and ChargingConnectorDetailsComponent to re-subscribe to SignalR only when their respective IDs change, preventing duplicate subscriptions on OnParametersSetAsync.
• New Subscription Management Class: Introduced a SubscriptionDisposable class to encapsulate the unsubscription logic, simplifying resource management within the SignalRStateService.

Changelog

• TeslaSolarCharger/Client/Components/StartPage/CarDetailsComponent.razor
  • Implemented IDisposable interface.
  • Added _subscription and _lastSubscribedCarId fields for managing subscriptions.
  • Refactored OnParametersSetAsync to dispose of existing subscriptions and re-subscribe only if the CarId changes.
  • Added a Dispose() method to unregister the SignalR subscription.
• TeslaSolarCharger/Client/Components/StartPage/ChargingConnectorDetailsComponent.razor
  • Implemented IDisposable interface.
  • Added _subscription and _lastSubscribedChargingConnectorId fields for managing subscriptions.
  • Refactored OnParametersSetAsync to dispose of existing subscriptions and re-subscribe only if the ChargingConnectorId changes.
  • Added a Dispose() method to unregister the SignalR subscription.
• TeslaSolarCharger/Client/Components/StartPage/ChargingSchedulesComponent.razor
  • Implemented IDisposable interface.
  • Added a _subscription field to hold the SignalR subscription.
  • Removed the explicit SignalRStateService.InitializeAsync() call from OnInitializedAsync.
  • Assigned the result of SubscribeToTrigger to _subscription.
  • Added a Dispose() method to unregister the SignalR subscription.
• TeslaSolarCharger/Client/Components/StartPage/LoadpointComponent.razor
  • Implemented IDisposable interface.
  • Added a _subscription field to hold the SignalR subscription.
  • Removed the explicit SignalRStateService.InitializeAsync() call from OnInitializedAsync.
  • Assigned the result of Subscribe to _subscription.
  • Added a Dispose() method to unregister the SignalR subscription.
• TeslaSolarCharger/Client/Components/StartPage/NotChargingAtExpectedPowerReasonsComponent.razor
  • Added a _subscription field to hold the SignalR subscription.
  • Removed the explicit SignalRStateService.InitializeAsync() call from OnParametersSetAsync.
  • Assigned the result of SubscribeToTrigger to _subscription.
  • Added _subscription?.Dispose() to the existing Dispose() method.
• TeslaSolarCharger/Client/Components/StartPage/PowerFlowComponent.razor
  • Implemented IDisposable interface.
  • Added a _subscription field to hold the SignalR subscription.
  • Removed the explicit SignalRStateService.InitializeAsync() call from OnInitializedAsync.
  • Assigned the result of Subscribe to _subscription.
  • Added a Dispose() method to unregister the SignalR subscription.
• TeslaSolarCharger/Client/Pages/Home.razor
  • Implemented IDisposable interface.
  • Added a _subscription field to hold the SignalR subscription.
  • Removed the explicit SignalRStateService.InitializeAsync() call from OnInitializedAsync.
  • Assigned the result of SubscribeToTrigger to _subscription.
  • Added a Dispose() method to unregister the SignalR subscription.
• TeslaSolarCharger/Client/Services/Contracts/ISignalRStateService.cs
  • Updated the Subscribe and SubscribeToTrigger method signatures to return Task<IDisposable>.
• TeslaSolarCharger/Client/Services/SignalRStateService.cs
  • Added await InitializeAsync() calls to GetStateAsync, Subscribe, and SubscribeToTrigger for centralized initialization.
  • Modified Subscribe and SubscribeToTrigger methods to return IDisposable instances.
  • Implemented logic within the returned IDisposable to remove the corresponding callback from internal subscriber lists upon disposal.
• TeslaSolarCharger/Client/Services/SubscriptionDisposable.cs
  • Added a new class SubscriptionDisposable that implements IDisposable and executes a provided action upon disposal.
• get_diff.sh
  • Added a new shell script get_diff.sh to execute git diff.

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Code Review

This pull request effectively refactors the SignalR subscription management to prevent memory leaks by introducing a disposable pattern. The centralization of the SignalR connection initialization in SignalRStateService is a great improvement. The changes across the components correctly adopt the new IDisposable subscriptions.

I've identified one component (NotChargingAtExpectedPowerReasonsComponent) where the subscription leak is not fully resolved and have suggested a fix. I also found a minor issue with a misleading log message in another component. Overall, this is a solid improvement for the application's stability and maintainability.