namespace Diligent.WebAPI.Business.Services
{

    public class UserService : IUserService
    {
        private readonly FrontEndSettings _frontEndSettings;
        private readonly UserManager<User> _userManager;
        private readonly IMapper _mapper;
        private readonly DatabaseContext _databaseContext;
        private readonly IEmailer _emailer;
        private readonly ILogger<UserService> _logger;

        public UserService(IOptions<FrontEndSettings> frontEndSettings, UserManager<User> userManager, IMapper mapper, DatabaseContext databaseContext, IEmailer emailer, ILogger<UserService> logger)
        {
            _frontEndSettings = frontEndSettings.Value;
            _userManager = userManager;
            _mapper = mapper;
            _databaseContext = databaseContext;
            _emailer = emailer;
            _logger = logger;
        }

        public async Task<IEnumerable<User?>> GetAll()
        {
            _logger.LogInformation("Start getting all users");
            _logger.LogInformation("Getting data from DB");
            var fromDb = await _userManager.GetUsersInRoleAsync("Admin");
            _logger.LogInformation($"Received {fromDb.Count} ads from db.");
            return fromDb;
        }
        public async Task<User> GetFirst()
        {
            var result = await _userManager.Users.FirstOrDefaultAsync();
            if (result == null)
                throw new EntityNotFoundException("No users in database");
            return result;
        }
        #region REFACTORING CODE HERE TO CHECK IF USER IS NULL
        public async Task<User> GetById(int id)
        {
            _logger.LogInformation($"Start searching user with id = {id}");
            var result = await _userManager.FindByIdAsync(id.ToString());

            if (result == null)
            {
                throw new EntityNotFoundException("User not found");
            }

            return result;
        }
        public async Task<User> GetByEmail(string email)
        {
            _logger.LogInformation($"Start searching user with mail = {email}");
            var result = await _userManager.FindByEmailAsync(email);

            if (result == null)
            {
                throw new EntityNotFoundException("User not found");
            }

            return result;
        }
        #endregion
        public async Task CreateUser(CreateUserRequestDto model)
        {
            _logger.LogInformation($"Start creating user");
            var user = _mapper.Map<User>(model);
            _logger.LogInformation($"User created successfully");

            _logger.LogInformation($"Saving user to db...");
            await _userManager.CreateAsync(user, model.Password);
            _logger.LogInformation($"User saved to DB");
        }
        public async Task RemoveUser(User user)
        {
            await _userManager.DeleteAsync(user);

            await _databaseContext.SaveChangesAsync();
        }

        public async Task<bool?> ToggleEnable(User user)
        {
            user.IsEnabled = !user.IsEnabled;

            await _databaseContext.SaveChangesAsync();

            return user.IsEnabled;
        }

        public async Task<ServiceResponseDTO<object>> SendRegistrationLink(InviteDTO invite)
        {
            // check if user exists
            var check = await _userManager.FindByEmailAsync(invite.Email);
            if (check != null)
                return new ServiceResponseDTO<object>()
                {
                    IsError = true,
                    ErrorMessage = "User already registered."
                };

            // create template user
            // this user is disabled to log in until confirming invitation
            var user = new User
            {
                UserName = invite.Email,
                Email = invite.Email,
                FirstName = invite.FirstName,
                LastName = invite.LastName,
                IsEnabled = false
            };

            await _userManager.CreateAsync(user, StringGenerator.GenerateRandomPassword());
            await _userManager.AddToRoleAsync(user, "Admin");

            // generate invitation token for user
            // encoded for URLs
            var token = await _userManager.GeneratePasswordResetTokenAsync(user);
            token = HttpUtility.UrlEncode(token);

            // send link
            await _emailer.SendEmailAndWriteToDbAsync(invite.Email, "Welcome", HTMLHelper.RenderRegisterPage($"{_frontEndSettings.BaseUrl}/register?token={token}&email={invite.Email}"), isHtml: true);

            await _databaseContext.SaveChangesAsync();

            return new ServiceResponseDTO<object>
            {
                Data = new { Message = "Link has been sent!" }
            };
        }

        public async Task GrantCategoryToUserAsync(GrantUserCategoryRequestDto request)
        {
            //for (int i = 0; i < request.CategoriesId.Count; i++)
            //{
            //    await _databaseContext.UserCategories.AddAsync(new UserCategories { UserId = request.UserId, CategoryId = request.CategoriesId[i] });
            //}

            //await _databaseContext.SaveChangesAsync();
            for (int i = 0; i < request.Categories.Count; i++)
            {
                if (request.Categories[i].IsChecked == false) 
                {
                    var category = await _databaseContext.UserCategories.Where(x => x.UserId == request.UserId && x.CategoryId == request.Categories[i].Id).FirstOrDefaultAsync();
                    _databaseContext.UserCategories.Remove(category);
                }
                else
                {
                    await _databaseContext.UserCategories.AddAsync(new UserCategories { UserId = request.UserId, CategoryId = request.Categories[i].Id });
                }
            }

            await _databaseContext.SaveChangesAsync();
        }
    }
}