Nexus.Reader/src/NexusReader.Web.Client/Program.cs

using Microsoft.AspNetCore.Components.WebAssembly.Hosting;
using Microsoft.AspNetCore.Components.Authorization;
using NexusReader.Application.Abstractions.Services;
using NexusReader.Web.Client.Services;
using NexusReader.UI.Shared.Services;
using NexusReader.Application;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.AI;
using NexusReader.Data.Persistence;
using NexusReader.Application.Abstractions.Persistence;
using NexusReader.Application.Abstractions.Messaging;
using NexusReader.Domain.Entities;


var builder = WebAssemblyHostBuilder.CreateDefault(args);

// Platform & UI Services
builder.Services.AddScoped<IPlatformService, WebPlatformService>();
builder.Services.AddScoped<INativeStorageService, WebStorageService>();
builder.Services.AddScoped<IThemeService, ThemeService>();
builder.Services.AddScoped<IQuizStateService, QuizStateService>();
builder.Services.AddScoped<IFocusModeService, FocusModeService>();
builder.Services.AddScoped<IReaderNavigationService, ReaderNavigationService>();
builder.Services.AddScoped<IKnowledgeGraphService, KnowledgeGraphService>();
builder.Services.AddScoped<IReaderInteractionService, ReaderInteractionService>();
builder.Services.AddScoped<KnowledgeCoordinator>();
builder.Services.AddScoped<ISyncService, SyncService>();

// Identity & Auth Services
builder.Services.AddOptions();
builder.Services.AddAuthorizationCore();
builder.Services.AddScoped<IIdentityService, IdentityService>();
builder.Services.AddScoped<NexusAuthenticationStateProvider>();
builder.Services.AddScoped<AuthenticationStateProvider>(sp => sp.GetRequiredService<NexusAuthenticationStateProvider>());
builder.Services.AddCascadingAuthenticationState();

// AI & Content Services
builder.Services.AddScoped<IKnowledgeService, WasmKnowledgeService>();

builder.Services.AddTransient<NexusReader.Web.Client.Handlers.AuthenticationHeaderHandler>();
builder.Services.AddHttpClient("NexusAPI", client => 
{
    client.BaseAddress = new Uri(builder.HostEnvironment.BaseAddress);
}).AddHttpMessageHandler<NexusReader.Web.Client.Handlers.AuthenticationHeaderHandler>();

builder.Services.AddScoped(sp => sp.GetRequiredService<IHttpClientFactory>().CreateClient("NexusAPI"));

// Dummy registrations for server-only handlers to satisfy DI validation in WASM
builder.Services.AddSingleton<IDbContextFactory<AppDbContext>>(new ThrowingDbContextFactory());
builder.Services.AddSingleton<IEmbeddingGenerator<string, Embedding<float>>>(new ThrowingEmbeddingGenerator());
builder.Services.AddSingleton<IBookStorageService>(new ThrowingBookStorageService());
builder.Services.AddSingleton<IEbookRepository>(new ThrowingEbookRepository());
builder.Services.AddSingleton<ISyncBroadcaster>(new ThrowingSyncBroadcaster());

builder.Services.AddApplication();
builder.Services.AddScoped<IEpubReader, WasmEpubReader>();
builder.Services.AddScoped<IEpubMetadataExtractor, WasmEpubMetadataExtractor>();

await builder.Build().RunAsync();

public class ThrowingDbContextFactory : IDbContextFactory<AppDbContext>
{
    public AppDbContext CreateDbContext() => throw new NotSupportedException("DbContext cannot be used in WASM client.");
}

public class ThrowingEmbeddingGenerator : IEmbeddingGenerator<string, Embedding<float>>
{
    public void Dispose() { }
    public Task<GeneratedEmbeddings<Embedding<float>>> GenerateAsync(IEnumerable<string> values, EmbeddingGenerationOptions? options = null, CancellationToken cancellationToken = default) 
        => throw new NotSupportedException("Embedding generation cannot be used in WASM client.");
    public object? GetService(Type serviceType, object? serviceKey = null) => null;
}

public class ThrowingBookStorageService : IBookStorageService
{
    private const string ErrorMessage = "File storage operations are not supported in the WASM client. Use the API endpoint for ingestion.";

    public Task<string> SaveEbookAsync(byte[] data, string fileName) => throw new NotSupportedException(ErrorMessage);
    public Task<string> SaveEbookAsync(Stream data, string fileName) => throw new NotSupportedException(ErrorMessage);
    public Task<string?> SaveCoverAsync(byte[] data, string fileName) => throw new NotSupportedException(ErrorMessage);
    public Task<string?> SaveCoverAsync(Stream data, string fileName) => throw new NotSupportedException(ErrorMessage);
}

public class ThrowingEbookRepository : IEbookRepository
{
    private const string ErrorMessage = "Ebook repository operations are not supported in the WASM client. Use the API endpoint for data access.";

    public Task<Author?> FindAuthorByNameAsync(string name, CancellationToken cancellationToken = default) => throw new NotSupportedException(ErrorMessage);
    public void AddAuthor(Author author) => throw new NotSupportedException(ErrorMessage);
    public void AddEbook(Ebook ebook) => throw new NotSupportedException(ErrorMessage);
    public Task<int> SaveChangesAsync(CancellationToken cancellationToken = default) => throw new NotSupportedException(ErrorMessage);
}

public class ThrowingSyncBroadcaster : ISyncBroadcaster
{
    public Task BroadcastProgressAsync(string userId, string pageId, DateTime timestamp, string? excludedConnectionId, CancellationToken cancellationToken = default) 
        => throw new NotSupportedException("Real-time broadcasting can only be performed by the server.");

    public Task BroadcastIngestionProgressAsync(string userId, string message, double progress, CancellationToken cancellationToken = default)
        => throw new NotSupportedException("Real-time broadcasting can only be performed by the server.");
}