using System;
using System.Collections.Generic;
using System.Text;

using TBF.Entities;
using NHibernate;
using FluentNHibernate;

namespace TBF
{
    /// <summary>
    /// Enum Grp.GID specifies GID-s of user groups.
    /// An instance of this class represenst a group, which contains a list of its members (users).
    /// Static private array 'groups' of this class, accesible through indexer, contains all groups.
    /// </summary>
    public class Grp
    {
        /// <summary>
        /// GID-s of user groups, each user is member of one or more groups.
        /// </summary>
        public enum GID
        {
            // The first NrOfGroups items are GroupID-s (0..NrOfGroups-1)
            Testers = 0,                 
            TestingSpecialists,
            HeadOfLab,
            MaintenanceSpecialists,
            Metrologists,
            CalibrationSpecialists,
            Administrators,             // application / network / database administrator
            Custom1,
            Custom2,
            Custom3,
            NrOfGroups,                 // Number of groups (this is not a GroupID)
            None,                       // Not a GroupID, can be used to indicate no group membership is required
            Invalid = -1,               // Not a GroupID, indicates a variable has not been properly set so far
        }

        /// <summary>
        /// Number of groups.
        /// </summary>
        public const int Count = (int)GID.NrOfGroups;

        // Static array of all groups.
        static Grp[] groups;

        /// <summary>
        /// Static constructor, creates all groups with no members.
        /// </summary>
        static Grp()
        {
            groups = new Grp[Count];
            for (int i = 0; i < Count; i++)
            {
                groups[i] = new Grp((GID)i);
            }
        }

        /// <summary>
        /// Returns a Group from Id.
        /// </summary>
        /// <param name="id">Group Gid</param>
        /// <returns>Entities.Group object reference</returns>
        public static Entities.Group FromId(GID gid)
        {
            int i = (int)gid;

            if (i >= 0 && i < Count)
            {
                return groups[i].group;
            }
            else
            {
                return null;
            }
        }

        ///////////////////// ^ static ^ ///////////////////// v instance v /////////////////////

        /// Public properties
        public GID Gid { get { return (GID)group.Gid; } }
        public string Name { get { return group.Name; } set { group.Name = value; } }

        /// Private fields
        Entities.Group group;

        /// <summary>
        /// Instance constructor.
        /// </summary>
        /// <param name="id"></param>
        public Grp(GID gid)
        {
            group = new Entities.Group();
            this.group.Gid = (int)gid;
            this.group.Name = gid.ToString();
        }
    }
}