using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Objects;
using System.Data.Linq;
using System.Linq;
using System.Security.Cryptography;
using System.Text;

namespace ScorBotRobotics.Repository
{
    public interface IUserRepository : IRepository<User>
    {
        /// <summary>
        /// Retrieves a User by his username and matching password.
        /// </summary>
        /// <param name="username">The User's username.</param>
        /// <param name="password">The User's password.</param>
        /// <returns>Returns the first matching user, or a default value if no user is found.</returns>
        User GetUserByNameAndPassword(string username, string password);
    }

    public class UserRepository : IUserRepository
    {
        private ScorBotDataContext context;

        public UserRepository()
            : this(new ScorBotDataContext())
        {
        }

        public UserRepository(ScorBotDataContext context)
        {
            this.context = context;
        }

        public Binary ComputeHash(string password)
        {
            using (var sha1 = SHA1Managed.Create())
            {
                return sha1.ComputeHash(Encoding.Default.GetBytes(password));
            }
        }

        #region IUserRepository Members

        /// <summary>
        /// Retrieves a User by his username and matching password.
        /// </summary>
        /// <param name="username">The User's username.</param>
        /// <param name="password">The User's password.</param>
        /// <returns>Returns the first matching user, or a default value if no user is found.</returns>
        public User GetUserByNameAndPassword(string username, string password)
        {
            var result =
                from user in context.Users
                where user.Username == username
                where user.Password == ComputeHash(password)
                select user;

            return result.FirstOrDefault();
        }

        #endregion

        #region IRepository<User> Members

        public User GetById(int id)
        {
            return context.Users.FirstOrDefault(u => u.UserId == id);
        }

        public IQueryable<User> GetAll()
        {
            return context.Users;
        }

        public void InsertOnSubmit(User entity)
        {
            context.Users.InsertOnSubmit(entity);
        }

        public void DeleteOnSubmit(User entity)
        {
            context.Users.DeleteOnSubmit(entity);
        }

        public void SubmitChanges()
        {
            context.SubmitChanges();
        }

        #endregion
    }
}