Architecture Modernization: Event System, CQRS, Repository Pattern + Production Integration

[Copilot]

Delivers Phase 2 architecture modernization infrastructure (Issues #202–#205) and integrates the new patterns into production code across the key leverage points.

Infrastructure Delivered

Event System (ACATCore/EventManagement/)

• IEventBus / EventBus — thread-safe pub/sub with weak-reference delegates; dead subscriptions pruned lazily on publish
• Domain event types: PanelShowEvent, PanelHideEvent, PanelActivateEvent, ActuatorSwitchActivatedEvent, ConfigurationReloadEvent, ConfigurationChangedEvent, ConfigurationReloadFailedEvent, AgentContextChangedEvent
• IEventBus registered as singleton in ServiceConfiguration.AddACATServices()

CQRS (ACATCore/Patterns/CQRS/)

• ICommand, IQuery<TResult>, ICommandHandler<T>, IQueryHandler<T,TResult> marker interfaces
• PanelCommands.cs — ShowPanelCommand, HidePanelCommand, GetActivePanelQuery
• Four reference handler implementations wired to IPanelManager, IActuatorManager, IAgentManager, EnvironmentConfiguration
• All four handlers registered in DI via ServiceConfiguration.AddACATServices()

Repository Pattern (ACATCore/DataAccess/)

• IRepository<T> with Load(key) / Save(entity, key) / GetDefault()
• PreferencesRepository<T> (XML via XmlUtils), ConfigurationRepository<T> (JSON via System.Text.Json), ThemeRepository
• IRepository<Theme> registered in DI

Interface Extraction Guide

docs/INTERFACE_EXTRACTION_GUIDE.md — naming conventions, directory layout, migration checklist, component priority tiers.

Production Integration

EventBus — Live in Production

Four managers now publish domain events via IEventBus:

• PanelManager → PanelShowEvent / PanelHideEvent
• ActuatorManager → ActuatorSwitchActivatedEvent
• AgentManager → AgentContextChangedEvent
• ConfigurationReloadService → ConfigurationReloadEvent / ConfigurationReloadFailedEvent

PanelActivityMonitor (ACATCore/Diagnostics/) is a real production subscriber active in both ACATApp and ACATTalk, demonstrating the event-driven pattern end-to-end with real-time panel lifecycle and switch activation logging.

CQRS — Live in Production

• ACATApp and ACATTalk resolve ICommandHandler<CreatePanelCommand> from DI for all entry-point panel creation, replacing direct PanelManager.Instance.CreatePanel() calls.

Repository — Live in Production

• PreferencesBase.Load<T> and Save now delegate to PreferencesRepository<T>, automatically migrating 20+ call sites throughout ActuatorManagement, TTSManagement, CommandManagement, and more.
• GlobalPreferences fully migrated to PreferencesRepository<T>.
• ThemeManager uses IRepository<Theme> via constructor injection from DI.

Tests

ACATCore.Tests.Architecture MSTest project (30 tests) covering EventBus, CQRS contracts, and repository CRUD. Added to CI workflow.

Implementation Status Report

docs/ARCHITECTURE_IMPLEMENTATION_STATUS.md provides a full audit of the migration state, documents all remaining call sites (incremental follow-on work), and serves as a guide for future contributors to continue the migration.

Pattern	Status
IEventBus.Publish()	✅ Active in 4 managers; PanelActivityMonitor subscribed in both apps
CQRS handlers	✅ Registered in DI; used in ACATApp + ACATTalk entry points
Repository	✅ PreferencesBase + GlobalPreferences + ThemeManager migrated (covers 20+ call sites)

Original prompt

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This section details on the original issue you should resolve

<issue_title>Architecture Modernization</issue_title>
<issue_description>Refactor architecture patterns to modern best practices, reduce coupling, improve maintainability.

Key Deliverables:

• Interface extraction
• Event-driven patterns
• Command/Query separation
• Repository pattern

Benefits:

• Reduced coupling
• Better separation of concerns
• Easier testing
• Clearer responsibilities

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🔗 Dependencies

• Depends on Dependency Injection Infrastructure #190 (Dependency Injection Infrastructure)

Epic: Phase 2 - Core Infrastructure Modernization

Estimated Effort: 2-3 weeks

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📋 Tasks

• Interface Extraction Strategy #202 Interface Extraction Strategy
• Event System Implementation #203 Event System Implementation
• Command/Query Separation #204 Command/Query Separation
• Repository Pattern for Data Access #205 Repository Pattern for Data Access

</issue_description>

<agent_instructions>Use this as the final review that all sub-tasks have been completed and a final wrapup of this feature.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Architecture Modernization #194

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[michaelbeale-IL]

@copilot - I've merged all the changes from master and now have build failing and tests failing. can you reconcile things?

[Copilot]

@copilot - I've merged all the changes from master and now have build failing and tests failing. can you reconcile things?

Fixed in commit 2c688f7. The master merge introduced conflicts in three areas:

1. Ambiguous type references — HandleActuatorSwitchCommand and GetConfigurationValueQuery were defined in both PanelCommands.cs (our namespace) and Samples/ (master's namespace). Removed the duplicates from PanelCommands.cs so only the Samples versions remain.

2. EventBus API change — Master replaced the token-based subscribe/unsubscribe with a handler-reference API, and renamed event types (PanelShownEvent → PanelShowEvent, ActuatorSwitchEvent → ActuatorSwitchActivatedEvent, etc.). Updated EventBusTests.cs in ACATCore.Tests.Architecture to match the new API and event names.

3. Repository API change — Master replaced the CRUD-style repository with a Load(key)/Save(entity,key)/GetDefault() pattern and made ConfigurationRepository and PreferencesRepository generic. Updated RepositoryTests.cs to use the new API, and cleaned up duplicate Compile entries in ACAT.Core.csproj.

[michaelbeale-IL]

@copilot - Review all the changes in this PR and determine if we have met the spirit of the acceptance criteria of Feature #194.

[Copilot]

@copilot - Review all the changes in this PR and determine if we have met the spirit of the acceptance criteria of Feature #194.

Yes — the PR meets the spirit of the acceptance criteria for Feature #194. Here's the assessment against each deliverable:

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✅ Interface Extraction (#202)
All major manager interfaces (IPanelManager, IAgentManager, IActuatorManager, IThemeManager, etc.) exist and are registered in DI via ServiceConfiguration.AddACATServices(). docs/INTERFACE_EXTRACTION_GUIDE.md documents the conventions and migration checklist.

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✅ Event-Driven Patterns (#203)
IEventBus / EventBus infrastructure is complete and wired into real production code:

• PanelManager publishes PanelShowEvent / PanelHideEvent
• ActuatorManager publishes ActuatorSwitchActivatedEvent
• AgentManager publishes AgentContextChangedEvent
• ConfigurationReloadService publishes ConfigurationReloadEvent / ConfigurationReloadFailedEvent
• PanelActivityMonitor is a real subscriber active in both ACATApp and ACATTalk that logs panel lifecycle and switch activation in real time — demonstrating the pattern end-to-end.

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✅ Command/Query Separation (#204)
CQRS interfaces and sample handlers are complete and wired:

• All four handlers registered in DI (in ServiceConfiguration)
• ACATApp and ACATTalk both resolve ICommandHandler<CreatePanelCommand> via DI for all entry-point panel creation — replacing direct PanelManager.Instance.CreatePanel() calls

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✅ Repository Pattern (#205)
IRepository<T> / RepositoryBase<T> / three concrete implementations are complete and in use:

• PreferencesBase.Load<T> and Save now delegate to PreferencesRepository<T> — this is the highest-leverage change, covering 20+ call sites throughout ActuatorManagement, TTSManagement, CommandManagement, etc., automatically
• GlobalPreferences migrated to PreferencesRepository<T>
• ThemeManager uses IRepository<Theme> via constructor injection
• IRepository<Theme> registered in DI

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What's remaining (documented in docs/ARCHITECTURE_IMPLEMENTATION_STATUS.md):
The remaining work is incremental tactical migration — ~65 actuator pause/resume call sites, remaining CreatePanel sites in extensions, legacy += event subscriptions — but these are follow-on work items. The architectural patterns are in place, the key leverage points have been migrated, CI is green, and the codebase now supports loose coupling, testability, and future incremental adoption.