Program.cs

using Microsoft.EntityFrameworkCore;
using Server.Data;
using Microsoft.AspNetCore.RateLimiting;
using System.Threading.RateLimiting;

var builder = WebApplication.CreateBuilder(args);

// Add services
builder.Services.AddControllers()
    .AddJsonOptions(options =>
    {
        options.JsonSerializerOptions.ReferenceHandler = System.Text.Json.Serialization.ReferenceHandler.IgnoreCycles;
        options.JsonSerializerOptions.WriteIndented = true;
    });

builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

// ✅ Configure built-in rate limiter
builder.Services.AddRateLimiter(options =>
{
    options.RejectionStatusCode = 429;

    options.AddPolicy("fixed", httpContext =>
        RateLimitPartition.GetFixedWindowLimiter(
            partitionKey: httpContext.User.Identity?.Name ?? "anonymous",
            factory: _ => new FixedWindowRateLimiterOptions
            {
                PermitLimit = 10,
                Window = TimeSpan.FromSeconds(10),
                
            }
        )
    );
});

// Database
builder.Services.AddDbContext<AppDbContext>(options =>
    options.UseMySql(
        builder.Configuration.GetConnectionString("DefaultConnection") 
        ?? "Server=localhost;Port=3306;Database=ExamChecker;Uid=root;Pwd=12345678;",
        new MySqlServerVersion(new Version(8, 0, 21))
    )
);

// CORS
const string AllowAll = "AllowAll";
builder.Services.AddCors(options =>
{
    options.AddPolicy(AllowAll, policy =>
        policy.AllowAnyOrigin().AllowAnyHeader().AllowAnyMethod());
});

var app = builder.Build();

// Ensure DB is created
using (var scope = app.Services.CreateScope())
{
    var db = scope.ServiceProvider.GetRequiredService<AppDbContext>();
    db.Database.EnsureCreated();
}

// Middleware
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseCors(AllowAll);
app.UseRateLimiter();  // ✅ 
app.UseAuthorization();
app.MapControllers();

// Seed data
using (var scope = app.Services.CreateScope())
{
    var context = scope.ServiceProvider.GetRequiredService<AppDbContext>();
    await context.Database.EnsureCreatedAsync();
    await SeedData.SeedAsync(context);
}

app.Run();