Program.cs

using FluentValidation;
using FluentValidation.AspNetCore;
using KanS;
using KanS.Entities;
using KanS.Interfaces;
using KanS.Middleware;
using KanS.Models;
using KanS.Models.Validators;
using KanS.Services;
using Microsoft.AspNetCore.Identity;
using Microsoft.EntityFrameworkCore;
using Microsoft.IdentityModel.Tokens;
using Microsoft.OpenApi.Models;
using System.Text;

var builder = WebApplication.CreateBuilder(args);

var authenticationSettings = new AuthenticationSettings();
builder.Configuration.GetSection("Authentication").Bind(authenticationSettings);

// Add services to the container.

builder.Services.AddSingleton(authenticationSettings);

builder.Services.AddAuthentication(option => {
    option.DefaultAuthenticateScheme = "Bearer";
    option.DefaultScheme = "Bearer";
    option.DefaultChallengeScheme = "Bearer";
}).AddJwtBearer(cfg => {
    cfg.RequireHttpsMetadata = false;
    cfg.SaveToken = true;
    cfg.TokenValidationParameters = new TokenValidationParameters {
        ValidIssuer = authenticationSettings.JwtIssuer,
        ValidAudience = authenticationSettings.JwtIssuer,
        IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(authenticationSettings.JwtKey)),
    };
});

builder.Services.AddCors(options => {
    options.AddDefaultPolicy(
        policy => {
            policy.WithOrigins("http://localhost:3000")
            .AllowAnyHeader()
            .AllowAnyMethod()
            .AllowCredentials();
        });
});

builder.Services.AddControllers();

builder.Services.AddSwaggerGen(c => {
    c.AddSecurityDefinition("Bearer", new OpenApiSecurityScheme {
        In = ParameterLocation.Header,
        Description = "Please insert JWT with Bearer into field",
        Name = "Authorization",
        Type = SecuritySchemeType.ApiKey
    });
    c.AddSecurityRequirement(new OpenApiSecurityRequirement {
   {
     new OpenApiSecurityScheme
     {
       Reference = new OpenApiReference
       {
         Type = ReferenceType.SecurityScheme,
         Id = "Bearer"
       }
      },
      new string[] { }
    }
  });
});

builder.Services.AddFluentValidationAutoValidation();
builder.Services.AddFluentValidationClientsideAdapters();

builder.Services.AddDbContext<KansDbContext>(
    o => o.UseNpgsql(builder.Configuration.GetConnectionString("DefaultConnection"))
);

builder.Services.AddHostedService<DataCoherenceBackgroundService>();

builder.Services.AddAutoMapper(AppDomain.CurrentDomain.GetAssemblies());

builder.Services.AddScoped<ErrorHandlingMiddleware>();

builder.Services.AddScoped<IAccountService, AccountService>();
builder.Services.AddScoped<IBoardService, BoardService>();
builder.Services.AddScoped<ISectionService, SectionService>();
builder.Services.AddScoped<ITaskService, TaskService>();
builder.Services.AddScoped<IPasswordHasher<User>, PasswordHasher<User>>();
builder.Services.AddScoped<IValidator<UserRegisterDto>, UserRegisterDtoValidator>();
builder.Services.AddScoped<IUserContextService, UserContextService>();
builder.Services.AddHttpContextAccessor();

var app = builder.Build();

// Configure the HTTP request pipeline.

app.UseMiddleware<ErrorHandlingMiddleware>();

app.UseAuthentication();

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

app.UseHttpsRedirection();

app.UseCors();

app.UseAuthorization();

app.MapControllers();

app.Run();