using System;
using System.Linq;

namespace EnVisage.Code
{
	/// <summary>
	/// Represents a permission display properties
	/// </summary>
	public class PermissionItemAttribute : DisplayValueAttribute
    {
		public Areas ParentItem;
		public short Level = 1;
		public bool DisplayBold = false; 

		public PermissionItemAttribute(string displayValue): base(displayValue)
        {
        }
	}

	public static class PermissionItemExtensions
	{
		private static PermissionItemAttribute getAttributeItem(Areas value)
		{
			PermissionItemAttribute result = null;

			if (value != null)
			{
				var members = value.GetType().GetMember(value.ToString());
				var attrItem =
					members.Length > 0 ?
					members.First().GetCustomAttributes(typeof(PermissionItemAttribute), true).Cast<PermissionItemAttribute>().FirstOrDefault() :
					null;

				result = attrItem;
			}

			return result;
		}

		/// <summary>
		/// Returns TRUE, if item must be displayed with bold font
		/// </summary>
		public static bool DisplayAsBold(this Areas value)
		{
			PermissionItemAttribute attrItem = getAttributeItem(value);
			bool result = (attrItem != null) && attrItem.DisplayBold;
			return result;
		}

		/// <summary>
		/// Returns parent permission or NULL
		/// </summary>
		public static Areas? GetParentItem(this Areas value)
		{
			PermissionItemAttribute attrItem = getAttributeItem(value);
			Areas? result = ((attrItem != null) && (attrItem.Level > 1)) ? attrItem.ParentItem : (Areas?)null;
			return result;
		}

		/// <summary>
		/// Returns TRUE, if item has parent permission
		/// </summary>
		public static bool HasParentItem(this Areas value)
		{
			PermissionItemAttribute attrItem = getAttributeItem(value);
			bool result = (attrItem != null) && (attrItem.Level > 1);
			return result;
		}

		/// <summary>
		/// Returns item indent level in the permission Tree. Root items has level 1
		/// </summary>
		public static int GetLevelInTree(this Areas value)
		{
			PermissionItemAttribute attrItem = getAttributeItem(value);
			int result = ((attrItem != null) && attrItem.Level >= 1) ? attrItem.Level : 1;
			return result;
		}
	}
}