using API.DTO.Base;
using API.DTO.Base.Update;
using API.DTO.Login;
using API.Hashing.Interfaces;
using API.Services.Interfaces;
using DAL.Models;

namespace API.Services
{
	public class UserManager : IUserManager
	{
		private readonly IHashingFactory _hashingFactory;
		private readonly ILogger<UserManager> _logger;
		private readonly HashingType _preferredHashingType;
		private readonly UserService _userService;

		public UserManager(UserService userService, IHashingFactory hashingFactory, ILogger<UserManager> logger, HashingType preferredHashingType)
		{
			_userService = userService;
			_hashingFactory = hashingFactory;
			_logger = logger;
			_preferredHashingType = preferredHashingType;
		}

		public UserDTO? authenticateUser(UserLoginDTO loginDTO)
		{
			User? user = _userService.getNoAuthentication(x => x.phoneNumber.Equals(loginDTO.phoneNumber)).FirstOrDefault();

			if (user == null)
				return null;

			IHashingAlgorithm? hashingAlgorithm = _hashingFactory.getAlgorithm(user.hashingType);
			if (hashingAlgorithm == null)
			{
				_logger.Log(LogLevel.Warning, "User id '{id}' has a hashing type '{hashingType}' that isn't recognized by factory '{factory}'. Not logging in.", user.id, user.hashingType, nameof(_hashingFactory));
				return null;
			}

			string hashedPassword = hashingAlgorithm.hash(loginDTO.password, user.salt);

			if (!hashedPassword.Equals(user.password))
			{
				_logger.Log(LogLevel.Information, "Failed login attempt for user id '{id}.", user.id);
				return null;
			}

			if (user.hashingType != _preferredHashingType)
			{
				// todo The user is logged in at this point. Their hashing type needs to be updated, we need to rehash & salt the password and save it now. 
			}

			UserDTO dto = new UserDTO();
			dto.adaptFromModel(user);

			return dto;
		}

		public UserDTO? registerUser(UserRegisterDTO registerDTO, User? user = null, ulong? permissionId = null)
		{
			if (_userService.getNoAuthentication(x =>
				    x.phoneNumber.Equals(registerDTO.phoneNumber) ||
				    x.firstName.Equals(registerDTO.firstName) && x.lastName.Equals(registerDTO.lastName))
			    .Any())
			{
				return null;
			}

			IHashingAlgorithm? hashingAlgorithm = _hashingFactory.getAlgorithm(_preferredHashingType);
			if (hashingAlgorithm == null)
			{
				_logger.Log(LogLevel.Error, "Preferred hashing type '{hashingType}' that isn't recognized by factory '{factory}'.", _preferredHashingType, nameof(_hashingFactory));
				return null;
			}

			byte[] salt;
			string hashedPassword = hashingAlgorithm.hash(registerDTO.password, out salt);

			User? createdUser = _userService.add(registerDTO, hashedPassword, salt, user, permissionId);

			if (createdUser == null)
				return null;

			UserDTO dto = new UserDTO();
			dto.adaptFromModel(createdUser);

			return dto;
		}

		public UserDTO? changePassword(UserPasswordUpdateDTO userPasswordUpdateDTO, User changingUser)
		{
			User? destUser = _userService.getNoAuthentication(x => x.phoneNumber.Equals(userPasswordUpdateDTO.phoneNumber)).FirstOrDefault();
			if (destUser == null)
				return null;

			IHashingAlgorithm? hashingAlgorithm = _hashingFactory.getAlgorithm(_preferredHashingType);
			if (hashingAlgorithm == null){
				_logger.Log(LogLevel.Error, "Preferred hashing type '{hashingType}' that isn't recognized by factory '{factory}'.", _preferredHashingType, nameof(_hashingFactory));
				return null;
			}

			byte[] newSalt;
			string hashedNewPassword = hashingAlgorithm.hash(userPasswordUpdateDTO.newPassword, out newSalt);

			bool oldPasswordMatchNew = false;
			if (userPasswordUpdateDTO.oldPassword != null)
			{
				IHashingAlgorithm? userHashingAlgorithm = _hashingFactory.getAlgorithm(destUser.hashingType);
				if (userHashingAlgorithm == null)
				{
					_logger.Log(LogLevel.Warning, "User id '{id}' has a hashing type '{hashingType}' that isn't recognized by factory '{factory}'. Not logging in.", destUser.id, destUser.hashingType, nameof(_hashingFactory));
					return null;
				}

				string hashedOldPassword = userHashingAlgorithm.hash(userPasswordUpdateDTO.oldPassword, destUser.salt);

				if (hashedOldPassword.Equals(destUser.password))
				{
					oldPasswordMatchNew = true;
				}
			}

			User? updatedUser = _userService.changePassword(destUser, changingUser, hashedNewPassword, newSalt, oldPasswordMatchNew);

			if (updatedUser == null)
				return null;

			UserDTO dto = new UserDTO();
			dto.adaptFromModel(updatedUser);

			return dto;
		}
	}
}