# Code Structure

## Build System
- **Type**: .NET SDK (MSBuild / dotnet CLI)
- **Configuration**: `SlpModularCms.sln` — solution file referencing all projects
- **Target Framework**: `net10.0`

## Project Structure

```
SlpModularCms/
+-- src/
|   +-- SlpModularCms.Api/                     # API host
|   |   +-- Extensions/
|   |   |   +-- ServiceCollectionExtensions.cs # DI setup (JWT, Identity, EF, Auth)
|   |   +-- Infrastructure/                    # Global exception handler
|   |   +-- Properties/launchSettings.json
|   |   +-- Program.cs                         # App startup and module loading
|   |   +-- appsettings.json
|   |   +-- appsettings.local.json             # Local dev overrides
|   |
|   +-- SlpModularCms.Core/                    # Shared core
|   |   +-- Availability/
|   |   |   +-- AvailabilityOptions.cs         # Circuit breaker config
|   |   |   +-- AvailabilityStatus.cs          # Enum: Available, Maintenance, Unavailable
|   |   +-- Data/
|   |   |   +-- ApplicationDbContext.cs        # EF Core DbContext
|   |   +-- Exceptions/                        # Custom exception types
|   |   +-- Identity/
|   |   |   +-- Authorization/                 # Policy handlers
|   |   |   +-- Entities/
|   |   |   |   +-- ApplicationUser.cs         # IdentityUser<Guid> + IsActive + CreatedAt
|   |   |   |   +-- ApplicationRole.cs         # IdentityRole<Guid>
|   |   |   |   +-- RefreshToken.cs            # Refresh token entity
|   |   |   |   +-- Invitation.cs              # Invite entity with expiry
|   |   |   |   +-- GlobalAvailabilityState.cs # Persisted system status
|   |   |   +-- Models/                        # DTOs/request-response models
|   |   |   +-- Services/
|   |   |       +-- AuthService.cs             # JWT generation + token validation
|   |   |       +-- InvitationService.cs       # Invite creation + completion
|   |   |       +-- SetupService.cs            # Initial owner creation
|   |   +-- Migrations/                        # EF Core migrations
|   |   +-- Modules/
|   |       +-- IModule.cs                     # Module interface (Name, Version, RegisterServices, UseModule)
|   |       +-- ModuleInfo.cs                  # Module metadata record
|   |
|   +-- SlpModularCms.Modules.Identity/        # Identity feature module
|   |   +-- Controllers/
|   |       +-- AuthController.cs              # /auth/* endpoints
|   |       +-- SetupController.cs             # /setup/* endpoints
|   |       +-- UsersController.cs             # /users/* endpoints
|   |
|   +-- SlpModularCms.Modules.Availability/    # Availability feature module
|   |   +-- Controllers/
|   |   |   +-- AvailabilityController.cs      # /availability/* endpoints
|   |   +-- Middleware/                        # Availability check middleware
|   |   +-- Services/
|   |       +-- PersistentAvailabilityService.cs  # Reads/writes status to DB + cache
|   |
|   +-- SlpModularCms.Core.Tests/              # Core unit tests
|   +-- SlpModularCms.Modules.Availability.Tests/  # Availability unit tests
|
+-- aidlc-docs/                               # AI-DLC workflow documentation
```

## Key Classes/Modules

### Core Domain Entities
- `ApplicationUser` — extends `IdentityUser<Guid>` with `IsActive`, `CreatedAt`, `Naam`
- `ApplicationRole` — extends `IdentityRole<Guid>`
- `RefreshToken` — linked to user; has `Token`, `ExpiryDate`, `IsRevoked`, `IsActive`
- `Invitation` — linked to user (invitee); has `Token`, `ExpiryDate`, `IsUsed`, `Role`
- `GlobalAvailabilityState` — singleton-ish entity storing `Status`, `Message`, `LastUpdatedAt`, `UpdatedBy`

### Core Services
- `IAuthService` / `AuthService` — `AuthenticateAsync`, `RefreshTokenAsync`, `RevokeTokenAsync`
- `IInvitationService` / `InvitationService` — `CreateInvitationAsync`, `CompleteInvitationAsync`, `ValidateInvitationAsync`
- `ISetupService` / `SetupService` — `IsSystemInitializedAsync`, `CreateInitialOwnerAsync`
- `IAvailabilityService` / `PersistentAvailabilityService` — `IsAvailableAsync`, `UpdateStatusAsync`

### Module System
- `IModule` — interface: `RegisterServices(IServiceCollection)`, `UseModule(IApplicationBuilder)`
- Modules discovered at startup and invoked in sequence

## Design Patterns
### Module Pattern
- **Location**: `SlpModularCms.Core/Modules/`, `SlpModularCms.Api/Program.cs`
- **Purpose**: Allows features to be developed, tested, and deployed independently
- **Implementation**: Each module class implements `IModule` and is registered in the API host

### Repository Pattern via EF Core
- **Location**: `ApplicationDbContext` used directly in services
- **Purpose**: Centralized persistence with Entity Framework

### JWT with Refresh Token Rotation
- **Location**: `AuthService.cs`, `AuthController.cs`
- **Purpose**: Stateless auth with token refresh capability

## Critical Dependencies
### ASP.NET Core Identity
- **Version**: .NET 10 built-in
- **Usage**: User/Role management, password hashing
- **Purpose**: Provides authentication primitives

### Entity Framework Core
- **Version**: .NET 10 built-in
- **Usage**: Data persistence with SQL Server provider
- **Purpose**: ORM for all domain entities