using back.DataModels;
using back.persistance.blob;
using back.persistance.data.repositories.Abstracts;
using back.services.engine.Crypto;
using back.services.engine.mailing;
using System.Text;
using System.Text.Json;

namespace back.services.bussines.UserService;

public class UserService(
    IUserRepository userRepository, ICryptoService cryptoService,
    IEmailService emailService,
    IBlobStorageService blobStorageService,
    JsonSerializerOptions jsonSerializerOptions
    ) : IUserService
{
    private readonly IUserRepository _repository = userRepository ?? throw new ArgumentNullException(nameof(userRepository));
    private readonly ICryptoService _cryptoService = cryptoService;
    private readonly IEmailService _emailService = emailService;
    private readonly IBlobStorageService _blobStorageService = blobStorageService;

    public async Task<User?> Create(string clientId, User user)
    {
        ArgumentNullException.ThrowIfNull(user);

        if (user.Id != null && await _repository.Exists(user.Id))
        {
            return await _repository.GetById(user.Id);
        }
        if (string.IsNullOrEmpty(user.Email) || string.IsNullOrEmpty(user.Password))
        {
            return null;
        }
        if (await _repository.Exists(user.Email))
        {
            return await _repository.GetByEmail(user.Email);
        }

        if (string.IsNullOrEmpty(user.Salt))
        {
            user.Salt = _cryptoService.Salt();
        }
        user.Password = _cryptoService.Decrypt(clientId, user.Password) ?? string.Empty;
        user.Password = _cryptoService.HashPassword(user.Password, user.Salt) ?? string.Empty;

        user.CreatedAt = DateTimeOffset.UtcNow.ToString("dd-MM-yyyy HH:mm:ss zz");

        //user.Roles.Add(Role.UserRole);

        await _repository.Insert(user);
        await _repository.SaveChanges();
        return user;
    }

    public async Task<User?> Update(User user)
    {
        ArgumentNullException.ThrowIfNull(user);
        if (user.Id == null || !await _repository.Exists(user.Id))
        {
            return null;
        }
        var existingUser = await _repository.GetById(user.Id);
        if (existingUser == null) return null;
        existingUser.Email = user.Email;
        await _repository.Update(existingUser);
        await _repository.SaveChanges();
        return existingUser;
    }

    public async Task<User?> Login(string email, string decryptedPass) 
    {
        var salt = await _repository.GetUserSaltByEmail(email);
        var hashedPassword = _cryptoService.HashPassword(decryptedPass, salt);
        var user = await _repository.Login(email, hashedPassword ?? string.Empty);
        return user;
    }

    public async Task<User?> Login(string email, string password, string clientId)
    {
        if (string.IsNullOrEmpty(email) || string.IsNullOrEmpty(password)) return null;

        try
        {
            var decryptedPass = _cryptoService.Decrypt(clientId, password);
            var user = await Login(email, decryptedPass ?? string.Empty);
            return user;
        }
        catch
        {
            return null;
        }
    }

    public async Task SendResetPassword(string email)
    {
        var exists = await _repository.ExistsByEmail(email);
        if (!exists)
        {
            return;
        }
        await _emailService.SendEmailAsync(
            tos: email,
            from: "admin@mmorales.photo",
            subject: "Reset Password",
            body: "If you received this email, it means that you have requested a password reset. Please follow the instructions in the email to reset your password."
        );
    }

    public async Task<User?> ValidateSystemUser(string email, string password, string systemKey, string clientId)
    {
        var decryptedPassword = _cryptoService.Decrypt(clientId, password) ?? string.Empty;
        var decryptedsystemKey = _cryptoService.Decrypt(clientId, systemKey) ?? string.Empty;
        if (string.IsNullOrEmpty(email) || string.IsNullOrEmpty(decryptedPassword) || string.IsNullOrEmpty(decryptedsystemKey))
        {
            return null;
        }
        if (!email.Equals(User.SystemUser.Email, StringComparison.InvariantCultureIgnoreCase))
        {
            return null;
        }

        var systemKeyBytes = await _blobStorageService.GetBytes("systemkey.lock");
        var systemKeyString = Encoding.UTF8.GetString(systemKeyBytes ?? []);
        var systemKeyObject = JsonSerializer.Deserialize<SystemKey>(systemKeyString, jsonSerializerOptions);
        if (systemKeyObject == null || !systemKeyObject.IsValid(email, decryptedPassword, decryptedsystemKey))
        {
            return null;
        }
        if (!await _repository.ExistsByEmail(email))
        {
            return null;
        }
        var user = await _repository.GetByEmail(email);
        if (user == null)
        {
            return null;
        }
       return await Login(user.Email!, decryptedPassword);
    }
}