using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Tango.BL.Enumerations;
using SimpleValidator.Extensions;
using Newtonsoft.Json;
using System.Xml.Serialization;
using Tango.Core.Cryptography;

namespace Tango.BL.Entities
{
    public partial class User : UserBase
    {
        private static IHashGenerator _hashGenerator;

        private bool _passwordGatewayModified = false;

        /// <summary>
        /// Determines whether the user has the specified permission.
        /// </summary>
        /// <param name="permission">The permission.</param>
        /// <returns>
        ///   <c>true</c> if the user has permission; otherwise, <c>false</c>.
        /// </returns>
        public bool HasPermission(Permissions permission)
        {
            return UsersRoles.Select(x => x.Role).ToList().SelectMany(x => x.RolesPermissions).ToList().Exists(x => x.Permission.Code == permission.ToInt32());
        }

        /// <summary>
        /// Determines whether the user has role.
        /// </summary>
        /// <param name="role">The role.</param>
        public bool HasRole(Roles role)
        {
            return UsersRoles.ToList().Exists(x => x.Role.Code == role.ToInt32());
        }

        /// <summary>
        /// Gets the aggregated user roles as enumerations.
        /// </summary>
        [NotMapped]
        public List<Role> Roles
        {
            get { return UsersRoles.Select(x => x.Role).ToList(); }
        }

        /// <summary>
        /// Gets the aggregated user permissions as enumerations.
        /// </summary>
        [NotMapped]
        public List<Permission> Permissions
        {
            get
            {
                return UsersRoles.Select(x => x.Role).ToList().SelectMany(x => x.RolesPermissions).Select(x => x.Permission).ToList();
            }
        }


        private String _passwordGateway;
        /// <summary>
        /// Gets or sets the password gate way.
        /// </summary>
        [NotMapped]
        [JsonIgnore]
        [XmlIgnore]
        public String PasswordGateWay
        {
            get
            {
                return _passwordGateway;
            }
            set
            {
                _passwordGateway = value;
                Password = GetHashGenerator().Encrypt(_passwordGateway);
                RaisePropertyChangedAuto();

                _passwordGatewayModified = true;
            }
        }

        protected override void RaisePropertyChanged(string propName)
        {
            base.RaisePropertyChanged(propName);

            if (propName == nameof(Password))
            {
                RaisePropertyChanged(nameof(PasswordGateWay));
            }
        }

        public override bool Validate(ObservablesContext context)
        {
            return base.Validate(context) && Contact.Validate(context) && Address.Validate(context);
        }

        protected override void OnValidating(ObservablesContext context)
        {
            base.OnValidating(context);

            var users = context.Users.ToList();

            if (users.Exists(x => x.Guid != Guid && x.Email.ToLower() == Email.ToLower()))
            {
                InsertError(nameof(Email), "The specified email is already taken by another account.");
            }

            if (!Email.IsEmail())
            {
                InsertError(nameof(Email), "The specified email address is invalid.");
            }

            if (_passwordGatewayModified)
            {
                if (!PasswordGateWay.IsBetweenLength(4, 30))
                {
                    InsertError(nameof(PasswordGateWay), "A user password must be at least 4 characters long and maximum 30.");
                }
            }
        }

        /// <summary>
        /// Gets the specified password hash.
        /// </summary>
        /// <param name="password">The password.</param>
        /// <returns></returns>
        public static String GetPasswordHash(String password)
        {
            return GetHashGenerator().Encrypt(password);
        }

        private static IHashGenerator GetHashGenerator()
        {
            if (_hashGenerator == null)
            {
                _hashGenerator = new BasicHashGenerator();
            }

            return _hashGenerator;
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="User" /> class.
        /// </summary>
        public User() : base()
        {

        }
    }
}