using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Shared
{
    public interface IUserService<TUser>
    {
        // Retrieves a user by their unique identifier (id).
        // 'id' is the unique identifier of the user.
        Task<TUser> GetUserById(int id);

        // Retrieves a user by their username.
        // 'username' is the username of the user to be retrieved.
        Task<TUser> GetUserByUsername(string username);

        // Retrieves a user by their email address.
        // 'email' is the email address of the user to be retrieved.
        Task<TUser> GetUserByEmail(string email);

        // Retrieves all users.
        // This returns a list of users with pagination information (e.g., total count, page size).
        Task<PaginationResult<TUser>> GetAllUser();

        // Retrieves a subset of users based on the provided index and page size.
        // 'index' is the starting point for pagination (page number).
        // 'pageSize' is the number of users per page.
        Task<PaginationResult<TUser>> GetSomeUser(int index, int pageSize);

        // Adds a new user to the system.
        // 'user' is the user object that will be added to the system.
        Task AddUser(TUser user);

        // Updates the details of an existing user identified by 'userId'.
        // 'userId' is the ID of the user to be updated, and 'user' contains the new user data.
        Task<TUser> UpdateUser(int userId, TUser user);

        // Removes a user from the system based on their unique identifier ('userId').
        // 'userId' is the unique identifier of the user to be removed.
        Task RemoveUser(int id);

        // Retrieves the hashed password for a given username.
        // 'username' is the username for which the password hash is to be retrieved.
        Task<string> GetHashPassword(string username);


        // Checks if a username already exists.
        // 'username' is the username to check for existence.
        Task<bool> ExistUsername(string username);

        // Checks if an email address already exists.
        // 'email' is the email address to check for existence.
        Task<bool> ExistEmail(string email);

        // Sets the admin role for a user.
        // 'isAdmin' is a boolean indicating whether the user should have admin privileges.
        Task SetAdminRole(bool isAdmin);

        // Retrieves the total count of users.
        Task<int> CountUser();

        // Retrieves the last user ID.
        Task<int> GetLastUserId();
    }
}