using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;

namespace Pilz.UI
{
    public class PaintingObjectListLayering
    {
        public PaintingObjectList ObjectList { get; private set; }
        public Dictionary<int, Func<PaintingObject, bool>> Conditions { get; private set; } = new Dictionary<int, Func<PaintingObject, bool>>();

        /// <summary>
    /// Get the order function will checkout the conditions.
    /// </summary>
    /// <returns>Returns true, if conditions are aviable, otherwise false.</returns>
        public bool EnableConditions
        {
            get
            {
                return Conditions.Any();
            }
        }

        /// <summary>
    /// Create a new instance of object list layer managing.
    /// </summary>
    /// <param name="list"></param>
        public PaintingObjectListLayering(PaintingObjectList list)
        {
            ObjectList = list;
        }

        /// <summary>
    /// Order all objects using the conditions. If no conditions are setted, this method will do nothing.
    /// </summary>
        public void OrderAll()
        {
            if (EnableConditions)
            {
                OrderAllPrivate();
            }
        }

        private void OrderAllPrivate()
        {
            var list = ObjectList;
            var listOld = list.ToList();
            var toRemove = new List<PaintingObject>();

            // Disable raising events
            ObjectList.EnableRaisingEvents = false;

            // Clear list
            list.Clear();

            // Add ordered
            foreach (var kvp in Conditions.OrderBy(n => n.Key))
            {
                var func = kvp.Value;
                foreach (PaintingObject obj in listOld)
                {
                    if (func(obj))
                    {
                        // Add to list
                        list.Add(obj);

                        // Add to remove
                        toRemove.Add(obj);
                    }
                }

                // Remove remembered objects
                foreach (PaintingObject obj in toRemove)
                    listOld.Remove(obj);
                toRemove.Clear();
            }

            // Enable raising events
            ObjectList.EnableRaisingEvents = true;

            // Refresh
            ObjectList.MyParent?.Refresh();
        }
    }
}