Program.cs

using Microsoft.EntityFrameworkCore;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.IdentityModel.Tokens;
using System.Text;
using ECommerceAPI.Models;
using ECommerceAPI.Services;

var builder = WebApplication.CreateBuilder(args);

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

// Database
builder.Services.AddDbContext<ECommerceDbContext>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection")));

// JWT Authentication
var jwtSettings = builder.Configuration.GetSection("JwtSettings");
var secretKey = jwtSettings["SecretKey"];

builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
    .AddJwtBearer(options =>
    {
        options.TokenValidationParameters = new TokenValidationParameters
        {
            ValidateIssuer = true,
            ValidateAudience = true,
            ValidateLifetime = true,
            ValidateIssuerSigningKey = true,
            ValidIssuer = jwtSettings["Issuer"],
            ValidAudience = jwtSettings["Audience"],
            IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(secretKey!))
        };
    });

// Services
builder.Services.AddScoped<IAuthService, AuthService>();

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

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseHttpsRedirection();
app.UseCors("AllowAll");
app.UseAuthentication();
app.UseAuthorization();

app.MapControllers();

// Ensure database is created
using (var scope = app.Services.CreateScope())
{
    var context = scope.ServiceProvider.GetRequiredService<ECommerceDbContext>();
    context.Database.EnsureCreated();
}

app.Run();