///
/// Copyright (c) 2013-2021 Sensus Slovensko a.s.
///
using System;
using System.Collections.Generic;
using log4net;
using Common;
using Config.Resources;

namespace Config.Entities
{
    public class User : Common.IUser
    {
        static readonly ILog log = LogManager.GetLogger(typeof(User));

        public virtual int Id { get; protected set; }
        public virtual string UserName { get; set; }	/// = name, alias, abbreviation
		public virtual string FullName { get; set; }	/// = description
        public virtual string Tag { get; set; }
        public virtual int Number { get; set; }
		public virtual string Password { get; set; }
        public virtual string Password2 { get; set; }
        public virtual string Password3 { get; set; }
        public virtual string Password4 { get; set; }
        public virtual DateTime LastPwChange { get; set; }
        public virtual IList<Group> Groups { get; set; }   //User can be a member of a list of groups

        private bool powerUser;		        /// true for built-in users, power users have full access even with empty Groups list
        public virtual bool IsPowerUser() { return powerUser; }

        private string legalizator;         /// Not mapped to a database !!!, 2nd user entered in a logging dialog
        public virtual void SetLegalizator(string value) { legalizator = value; }
        public virtual string GetLegalizator() { return legalizator; }

        public User()
        {
            Groups = new List<Group>();
        }

        public User(string userName, int number, bool powerUser)
        {
            UserName = userName;
            Number = number;
            this.powerUser = powerUser;
            Groups = new List<Group>();
            FullName = powerUser ? "Power User" : string.Empty;
        }

		/// <summary>
		/// Adds a group to the user.
		/// </summary>
		/// <param name="group">Group to be added</param>
		public virtual void AddGroup(Group group)
		{
			Groups.Add(group);
		}

        /// <summary>
        /// All members are copied except of ID (so that NHibernate works properly).
        /// List of groups is empty.
        /// </summary>
        /// <param name="user"></param>
        /// <returns></returns>
        public virtual object Clone()
        {
            User newUser = new User(UserName, Number, false);
            newUser.FullName = FullName;
            newUser.Number = Number;
            newUser.Tag = Tag;
            newUser.Password = Password;
            newUser.LastPwChange = LastPwChange;
            return newUser;
        }

        public override string ToString()
        {
            return (UserName != null) ? UserName : Number.ToString();
        }

        /// ------------- Additional stuff not mapped into the database -------------

        /// <summary>
        /// Check whether user is a member of a group.
        /// </summary>
        /// <param name="groupId">Group GID</param>
        /// <returns>true is user is a member of the specified group</returns>
        public virtual bool IsMemberOf(GID groupId)
        {
            if (powerUser)
            {
                return true;
            }
            else if ((groupId >= 0) && (groupId < GID.NrOfGroups))
            {
                foreach (var g in Groups)
                {
                    if (g.GID == groupId) return true;
                }
            }

            return false;
        }

        /// <summary>
        /// Check whether user is a member of any of specified groups.
        /// Returns true also when no groups are defined (groupIds = null).
        /// </summary>
        /// <param name="groupIds">An array of group GID-s or null (no membership required)</param>
        /// <returns>true if user is a member of any of specified groups</returns>
        public virtual bool IsMemberOf(GID[] groupIds)
        {
            if (groupIds == null || powerUser)
            {
                return true;
            }

            foreach (var gid in groupIds)
            {
                if ((gid >= 0) && (gid < GID.NrOfGroups))
                {
                    /// for all group elements in User.Groups
                    foreach (var grp in Groups)
                    {
                        /// element GID = parameter GroupId ?
                        if (grp.GID == gid) return true;
                    }
                }
            }

            return false;
        }

        /// <summary>
        /// Checks requirements on the password regardless of the password history
        /// </summary>
        /// <param name="password">Password</param>
        /// <returns>true when the password is OK</returns>
        public static bool IsPasswordMeetsRequirements(string password, out string explanation)
        {
            return Common.Utils.IsPasswordMeetsRequirements(password, out explanation);
        }

        /// <summary>
        /// Returns true when password was already used in the past
        /// </summary>
        /// <param name="passwordCandidate">Password</param>
        /// <returns>false when password is new, true when it was used in the past</returns>
        public virtual bool IsPasswordUsedInPast(string passwordCandidate)
        {
            string encryptedPW = EncryptedPassword(passwordCandidate);
            return (encryptedPW == Password) || (encryptedPW == Password2) || (encryptedPW == Password3);
        }

        /// <summary>
        /// Checks 'LastPwChange' and returns true when password expired
        /// </summary>
        /// <returns></ returns>
        public virtual bool IsPasswordExpired()
        {
            if (IsPowerUser() || IsMemberOf(GID.Administrators) || CurrentUser.PasswdExpirationPeriodDays == 0)
            {
                /// Password cannot expirate for this user or this feature is disabled in Backup and Security options
                return false;
            }

            /// Password expiration time is 3 months
            return (DateTime.Now - LastPwChange > new TimeSpan(CurrentUser.PasswdExpirationPeriodDays, 0, 0, 0));
        }

        /// <summary>
        /// Encrypts and saves users password.
        /// </summary>
        /// <param name="password">Password</param>
        public virtual void SetPassword(string password)
        {
            Password4 = Password3;
            Password3 = Password2;
            Password2 = Password;
            Password = EncryptedPassword(password);
            LastPwChange = DateTime.Now;
        }

        string EncryptedPassword(string password)
        {
            return Common.Utils.GetHash(password);
        }

        /// <summary>
        /// Verifies users password. Used by static bool Authorisation(...)
        /// </summary>
        /// <param name="password">Password</param>
        /// <returns>true if password is correct</returns>
        public virtual bool IsCorrectPassword(string password)
        {
            if (string.IsNullOrEmpty(password) && string.IsNullOrEmpty(Password))
            {
                /// Currently saved and verified passwords are both empty => return true
                return true;
            }

            return (Password == EncryptedPassword(password));
        }

        public virtual string ToEncodedStr()
        {
            return string.Format("{0}~{1}~{2}", UserName, FullName, legalizator);
        }
    }
}