Program.cs

using JwtAuthApi.Data;
using Microsoft.AspNetCore.Identity;
using Microsoft.EntityFrameworkCore;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.IdentityModel.Tokens;
using System.Text;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

// 1. Configure the Database Context (Entity Framework Core)
builder.Services.AddDbContext<AppDbContext>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection")));

// 2. Configure ASP.NET Core Identity
builder.Services.AddIdentity<IdentityUser, IdentityRole>()
    .AddEntityFrameworkStores<AppDbContext>();

// 3. Configure JWT Authentication
builder.Services.AddAuthentication(options =>
{
    options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
    options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
})
.AddJwtBearer(options =>
{
    options.TokenValidationParameters = new TokenValidationParameters
    {
        ValidateIssuer = true,
        ValidateAudience = true,
        ValidateLifetime = true,
        ValidateIssuerSigningKey = true,
        ValidIssuer = builder.Configuration["Jwt:Issuer"],
        ValidAudience = builder.Configuration["Jwt:Audience"],
        IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(builder.Configuration["Jwt:Key"]))
    };
});

// 4. Add CORS Policy
builder.Services.AddCors(options =>
{
    options.AddPolicy("AllowReactApp", builder =>
        builder.WithOrigins("http://localhost:3000") // Allow requests from React frontend
               .AllowAnyMethod()
               .AllowAnyHeader()
    );
});

// 5. Add Controllers support (necessary for MVC actions like Login, Register)
builder.Services.AddControllers();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseDeveloperExceptionPage();
    app.UseSwagger();
    app.UseSwaggerUI(c => c.SwaggerEndpoint("/swagger/v1/swagger.json", "My API V1"));
}

//app.UseHttpsRedirection();

// 6. Enable CORS
app.UseCors("AllowReactApp");  // Enable the CORS policy

// 7. Enable Authentication and Authorization Middleware
app.UseRouting();
app.UseAuthentication(); // This ensures that authentication is checked for every request
app.UseAuthorization();  // This ensures that the app enforces authorization policies

app.MapControllers(); // This maps the controllers to handle requests like /api/auth/register

app.Run();