Program.cs

using AuthPracticeAPI.Data;
using AuthPracticeAPI.Models;
using AuthPracticeAPI.Services;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.AspNetCore.Identity;
using Microsoft.EntityFrameworkCore;
using Microsoft.IdentityModel.Tokens;
using Scalar.AspNetCore;
using System.Text;

var builder = WebApplication.CreateBuilder(args);

// -----------------------------
// Configure JWT
// -----------------------------
var jwtSettings = builder.Configuration.GetSection("Jwt");

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 = jwtSettings["Issuer"],
        ValidAudience = jwtSettings["Audience"],
        IssuerSigningKey = new SymmetricSecurityKey(
            Encoding.UTF8.GetBytes(jwtSettings["Key"] ?? string.Empty))
    };
});

// -----------------------------
// Configure EF Core with SQL Server
// -----------------------------
builder.Services.AddDbContext<AppDbContext>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection")));

// -----------------------------
// Configure Identity
// -----------------------------
builder.Services.AddIdentity<ApplicationUser, IdentityRole>(options =>
{
    options.Password.RequireDigit = true;
    options.Password.RequireLowercase = true;
    options.Password.RequireUppercase = true;
    options.Password.RequireNonAlphanumeric = false;
    options.Password.RequiredLength = 6;
})
.AddEntityFrameworkStores<AppDbContext>()
.AddDefaultTokenProviders();

// -----------------------------
// Configure External Authentication
// -----------------------------
builder.Services.AddAuthentication()
    .AddGoogle(options =>
    {
        options.ClientId = builder.Configuration["Authentication:Google:ClientId"]!;
        options.ClientSecret = builder.Configuration["Authentication:Google:ClientSecret"]!;
    })
    .AddFacebook(options =>
    {
        options.AppId = builder.Configuration["Authentication:Facebook:AppId"]!;
        options.AppSecret = builder.Configuration["Authentication:Facebook:AppSecret"]!;
    })
    .AddGitHub(options =>
    {
        options.ClientId = builder.Configuration["Authentication:GitHub:ClientId"]!;
        options.ClientSecret = builder.Configuration["Authentication:GitHub:ClientSecret"]!;
    });

// -----------------------------
// Add Services & Controllers
// -----------------------------
builder.Services.AddScoped<IAuthService, AuthService>(); // your AuthService
builder.Services.AddControllers();
builder.Services.AddEndpointsApiExplorer();

// -----------------------------
// Build App
// -----------------------------
var app = builder.Build();

// -----------------------------
// Middleware Pipeline
// -----------------------------
if (app.Environment.IsDevelopment())
{
    app.MapScalarApiReference();
}

app.UseHttpsRedirection();

app.UseAuthentication(); // Must come BEFORE Authorization
app.UseAuthorization();

app.MapControllers();

app.Run();