path: root/src/DevHive.Services/Services/UserService.cs

using AutoMapper;
using DevHive.Services.Options;
using DevHive.Services.Models.Identity.User;
using System.Threading.Tasks;
using DevHive.Data.Models;
using System;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using Microsoft.IdentityModel.Tokens;
using System.Text;
using System.Collections.Generic;
using DevHive.Common.Models.Identity;
using DevHive.Services.Interfaces;
using DevHive.Data.Interfaces.Repositories;
using System.Linq;
using DevHive.Common.Models.Misc;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Identity;

namespace DevHive.Services.Services
{
	public class UserService : IUserService
	{
		private readonly IUserRepository _userRepository;
		private readonly IRoleRepository _roleRepository;
		private readonly ILanguageRepository _languageRepository;
		private readonly ITechnologyRepository _technologyRepository;
		private readonly UserManager<User> _userManager;
		private readonly RoleManager<Role> _roleManager;
		private readonly IMapper _userMapper;
		private readonly JWTOptions _jwtOptions;
		private readonly ICloudService _cloudService;

		public UserService(IUserRepository userRepository,
			ILanguageRepository languageRepository,
			IRoleRepository roleRepository,
			ITechnologyRepository technologyRepository,
			UserManager<User> userManager,
			RoleManager<Role> roleManager,
			IMapper mapper,
			JWTOptions jwtOptions,
			ICloudService cloudService)
		{
			this._userRepository = userRepository;
			this._roleRepository = roleRepository;
			this._userMapper = mapper;
			this._jwtOptions = jwtOptions;
			this._languageRepository = languageRepository;
			this._technologyRepository = technologyRepository;
			this._userManager = userManager;
			this._roleManager = roleManager;
			this._cloudService = cloudService;
		}

		#region Authentication
		/// <summary>
        /// Adds a new user to the database with the values from the given model.
		/// Returns a JSON Web Token (that can be used for authorization)
        /// </summary>
		public async Task<TokenModel> LoginUser(LoginServiceModel loginModel)
		{
			if (!await this._userRepository.DoesUsernameExistAsync(loginModel.UserName))
				throw new ArgumentException("Invalid username!");

			User user = await this._userRepository.GetByUsernameAsync(loginModel.UserName);

			if (user.PasswordHash != PasswordModifications.GeneratePasswordHash(loginModel.Password))
				throw new ArgumentException("Incorrect password!");

			return new TokenModel(WriteJWTSecurityToken(user.Id, user.UserName, user.Roles));
		}

		/// <summary>
        /// Returns a new JSON Web Token (that can be used for authorization) for the given user
        /// </summary>
		public async Task<TokenModel> RegisterUser(RegisterServiceModel registerModel)
		{
			if (await this._userRepository.DoesUsernameExistAsync(registerModel.UserName))
				throw new ArgumentException("Username already exists!");

			if (await this._userRepository.DoesEmailExistAsync(registerModel.Email))
				throw new ArgumentException("Email already exists!");

			User user = this._userMapper.Map<User>(registerModel);
			user.PasswordHash = PasswordModifications.GeneratePasswordHash(registerModel.Password);
			user.ProfilePicture = new ProfilePicture() { PictureURL = "/assets/images/feed/profile-pic.png":w
		   	};

			// Make sure the default role exists
			//TODO: Move when project starts
			if (!await this._roleRepository.DoesNameExist(Role.DefaultRole))
				await this._roleRepository.AddAsync(new Role { Name = Role.DefaultRole });

			user.Roles.Add(await this._roleRepository.GetByNameAsync(Role.DefaultRole));

			IdentityResult userResult = await this._userManager.CreateAsync(user);
			User createdUser = await this._userRepository.GetByUsernameAsync(registerModel.UserName);

			if (!userResult.Succeeded)
				throw new ArgumentException("Unable to create a user");

			return new TokenModel(WriteJWTSecurityToken(createdUser.Id, createdUser.UserName, createdUser.Roles));
		}
		#endregion

		#region Read
		public async Task<UserServiceModel> GetUserById(Guid id)
		{
			User user = await this._userRepository.GetByIdAsync(id) ??
				throw new ArgumentException("User does not exist!");

			return this._userMapper.Map<UserServiceModel>(user);
		}

		public async Task<UserServiceModel> GetUserByUsername(string username)
		{
			User user = await this._userRepository.GetByUsernameAsync(username) ??
				throw new ArgumentException("User does not exist!");

			return this._userMapper.Map<UserServiceModel>(user);
		}
		#endregion

		#region Update
		public async Task<UserServiceModel> UpdateUser(UpdateUserServiceModel updateUserServiceModel)
		{
			await this.ValidateUserOnUpdate(updateUserServiceModel);

			User currentUser = await this._userRepository.GetByIdAsync(updateUserServiceModel.Id);
			await this.PopulateUserModel(currentUser, updateUserServiceModel);

			await this.CreateRelationToFriends(currentUser, updateUserServiceModel.Friends.ToList());

			IdentityResult result = await this._userManager.UpdateAsync(currentUser);

			if (!result.Succeeded)
				throw new InvalidOperationException("Unable to edit user!");

			User newUser = await this._userRepository.GetByIdAsync(currentUser.Id);
			return this._userMapper.Map<UserServiceModel>(newUser);
		}

		/// <summary>
        /// Uploads the given picture and assigns it's link to the user in the database
        /// </summary>
		public async Task<ProfilePictureServiceModel> UpdateProfilePicture(UpdateProfilePictureServiceModel updateProfilePictureServiceModel)
		{
			User user = await this._userRepository.GetByIdAsync(updateProfilePictureServiceModel.UserId);

			if (!string.IsNullOrEmpty(user.ProfilePicture.PictureURL))
			{
				bool success = await _cloudService.RemoveFilesFromCloud(new List<string> { user.ProfilePicture.PictureURL });
				if (!success)
					throw new InvalidCastException("Could not delete old profile picture!");
			}

			string fileUrl = (await this._cloudService.UploadFilesToCloud(new List<IFormFile> { updateProfilePictureServiceModel.Picture }))[0] ??
				throw new ArgumentNullException("Unable to upload profile picture to cloud");

			bool successful = await this._userRepository.UpdateProfilePicture(updateProfilePictureServiceModel.UserId, fileUrl);

			if (!successful)
				throw new InvalidOperationException("Unable to change profile picture!");

			return new ProfilePictureServiceModel() { ProfilePictureURL = fileUrl };
		}
		#endregion

		#region Delete
		public async Task<bool> DeleteUser(Guid id)
		{
			if (!await this._userRepository.DoesUserExistAsync(id))
				throw new ArgumentException("User does not exist!");

			User user = await this._userRepository.GetByIdAsync(id);
			IdentityResult result = await this._userManager.DeleteAsync(user);

			return result.Succeeded;
		}
		#endregion

		#region Validations
		/// <summary>
        /// Checks whether the given user, gotten by the "id" property,
		/// is the same user as the one in the token (uness the user in the token has the admin role)
		/// and the roles in the token are the same as those in the user, gotten by the id in the token
        /// </summary>
		public async Task<bool> ValidJWT(Guid id, string rawTokenData)
		{
			// There is authorization name in the beginning, i.e. "Bearer eyJh..."
			var jwt = new JwtSecurityTokenHandler().ReadJwtToken(rawTokenData.Remove(0, 7));

			Guid jwtUserID = new Guid(this.GetClaimTypeValues("ID", jwt.Claims).First());
			List<string> jwtRoleNames = this.GetClaimTypeValues("role", jwt.Claims);

			User user = await this._userRepository.GetByIdAsync(jwtUserID)
				?? throw new ArgumentException("User does not exist!");

			/* Check if user is trying to do something to himself, unless he's an admin */

			/* Check roles */
			if (!jwtRoleNames.Contains(Role.AdminRole))
				if (user.Id != id)
					return false;

			// Check if jwt contains all user roles (if it doesn't, jwt is either old or tampered with)
			foreach (var role in user.Roles)
			{
				if (!jwtRoleNames.Contains(role.Name))
					return false;
			}

			// Check if jwt contains only roles of user
			if (jwtRoleNames.Count != user.Roles.Count)
				return false;

			return true;
		}

		/// <summary>
        /// Returns all values from a given claim type
        /// </summary>
		private List<string> GetClaimTypeValues(string type, IEnumerable<Claim> claims)
		{
			List<string> toReturn = new();

			foreach (var claim in claims)
				if (claim.Type == type)
					toReturn.Add(claim.Value);

			return toReturn;
		}

		/// <summary>
        /// Checks whether the user in the model exists
		/// and whether the username in the model is already taken.
		/// If the check fails (is false), it throws an exception, otherwise nothing happens
        /// </summary>
		private async Task ValidateUserOnUpdate(UpdateUserServiceModel updateUserServiceModel)
		{
			if (!await this._userRepository.DoesUserExistAsync(updateUserServiceModel.Id))
				throw new ArgumentException("User does not exist!");

			if (updateUserServiceModel.Friends.Any(x => x.UserName == updateUserServiceModel.UserName))
				throw new ArgumentException("You cant add yourself as a friend(sry, bro)!");

			if (!this._userRepository.DoesUserHaveThisUsername(updateUserServiceModel.Id, updateUserServiceModel.UserName)
					&& await this._userRepository.DoesUsernameExistAsync(updateUserServiceModel.UserName))
				throw new ArgumentException("Username already exists!");

			List<string> usernames = new();
			foreach (var friend in updateUserServiceModel.Friends)
				usernames.Add(friend.UserName);

			if (!await this._userRepository.ValidateFriendsCollectionAsync(usernames))
				throw new ArgumentException("One or more friends do not exist!");
		}

		/// <summary>
        /// Return a new JSON Web Token, containing the user id, username and roles.
		/// Tokens have an expiration time of 7 days.
        /// </summary>
		private string WriteJWTSecurityToken(Guid userId, string username, HashSet<Role> roles)
		{
			byte[] signingKey = Encoding.ASCII.GetBytes(_jwtOptions.Secret);
			HashSet<Claim> claims = new()
			{
				new Claim("ID", $"{userId}"),
				new Claim("Username", username),
			};

			foreach (var role in roles)
			{
				claims.Add(new Claim(ClaimTypes.Role, role.Name));
			}

			SecurityTokenDescriptor tokenDescriptor = new()
			{
				Subject = new ClaimsIdentity(claims),
				Expires = DateTime.Today.AddDays(7),
				SigningCredentials = new SigningCredentials(
					new SymmetricSecurityKey(signingKey),
					SecurityAlgorithms.HmacSha512Signature)
			};

			JwtSecurityTokenHandler tokenHandler = new();
			SecurityToken token = tokenHandler.CreateToken(tokenDescriptor);
			return tokenHandler.WriteToken(token);
		}
		#endregion

		#region Misc
		public async Task<TokenModel> SuperSecretPromotionToAdmin(Guid userId)
		{
			User user = await this._userRepository.GetByIdAsync(userId) ??
				throw new ArgumentException("User does not exist! Can't promote shit in this country...");

			if (!await this._roleRepository.DoesNameExist(Role.AdminRole))
			{
				Role adminRole = new()
				{
					Name = Role.AdminRole
				};
				adminRole.Users.Add(user);

				await this._roleRepository.AddAsync(adminRole);
			}

			Role admin = await this._roleManager.FindByNameAsync(Role.AdminRole);

			user.Roles.Add(admin);
			await this._userManager.UpdateAsync(user);

			User newUser = await this._userRepository.GetByIdAsync(userId);

			return new TokenModel(WriteJWTSecurityToken(newUser.Id, newUser.UserName, newUser.Roles));
		}

		private async Task PopulateUserModel(User user, UpdateUserServiceModel updateUserServiceModel)
		{
			//Do NOT allow a user to change his roles, unless he is an Admin
			bool isAdmin = await this._userManager.IsInRoleAsync(user, Role.AdminRole);

			if (isAdmin)
			{
				HashSet<Role> roles = new();
				foreach (var role in updateUserServiceModel.Roles)
				{
					Role returnedRole = await this._roleRepository.GetByNameAsync(role.Name) ??
						throw new ArgumentException($"Role {role.Name} does not exist!");

					roles.Add(returnedRole);
				}
				user.Roles = roles;
			}

			HashSet<Language> languages = new();
			int languagesCount = updateUserServiceModel.Languages.Count;
			for (int i = 0; i < languagesCount; i++)
			{
				Language language = await this._languageRepository.GetByNameAsync(updateUserServiceModel.Languages.ElementAt(i).Name) ??
					throw new ArgumentException("Invalid language name!");

				languages.Add(language);
			}
			user.Languages = languages;

			/* Fetch Technologies and replace model's*/
			HashSet<Technology> technologies = new();
			int technologiesCount = updateUserServiceModel.Technologies.Count;
			for (int i = 0; i < technologiesCount; i++)
			{
				Technology technology = await this._technologyRepository.GetByNameAsync(updateUserServiceModel.Technologies.ElementAt(i).Name) ??
					throw new ArgumentException("Invalid technology name!");

				technologies.Add(technology);
			}
			user.Technologies = technologies;
		}

		private async Task CreateRelationToFriends(User user, List<UpdateFriendServiceModel> friends)
		{
			foreach (var friend in friends)
			{
				User amigo = await this._userRepository.GetByUsernameAsync(friend.UserName);

				user.Friends.Add(amigo);
				amigo.Friends.Add(user);

				await this._userManager.UpdateAsync(amigo);
			}
		}
		#endregion
	}
}