# 📖 Nexus Reader

Nexus Reader is a state-of-the-art, cross-platform Blazor .NET 10 immersive e-book reader, powered by **Native AOT**, **Clean Architecture**, **CQRS**, and interactive **D3.js Relationship Graphs** built on vector-based AI semantics.

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## ✨ Features & Architecture Highlights

### 📁 Ingestion & Description persistence
- Extracted and persistent **book descriptions** from EPUB package metadata during book ingestion.
- The `Description` field propagates cleanly from the `Ebook` entity through Mapster to `LastReadBookDto` and `UserProfileDto`.

### 🔗 Deep-Link Routing
- Implemented deep-link route activation: `/reader/{bookId}?chapter=N`.
- Allows instant resume of reading session coordinates and loads the specific chapter chapter directly via URL query parameters.

### 🛡️ Downstream AI Resilience
- Standard resilience engine in `DependencyInjection.cs` utilizing the **Polly** package (`ai-retry`).
- Automatically intercepts, handles, and retries on both rate-limits (`429 Too Many Requests`) and downstream capacity overloads (`503 ServiceUnavailable` / `high demand`).

### ⚙️ Concurrent Request Deduplication
- Multi-client InteractiveAuto Blazor circuit synchronization is backed by a thread-safe active task registry in `KnowledgeService` which ensures that identical concurrent requests await a single shared task instance, eliminating redundant LLM queries.

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## 🛠️ Build & Verification Gate

Ensure the dotnet workload matches the active SDK, and compile the full solution utilizing:

```bash
dotnet build NexusReader.slnx --no-restore
```

Run test suite:

```bash
dotnet test --no-restore
```

## 🗄️ Database Migrations

Automatic database migrations at startup (`MigrateAsync()`) have been disabled to ensure compatibility with Native AOT compilation and prevent locking issues in multi-instance environments.

To apply database migrations locally, run the EF Core migration command from the solution root:

```bash
dotnet ef database update --project src/NexusReader.Infrastructure --startup-project src/NexusReader.Web
```
