using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections;
using Esiur.Engine;
using System.Reflection;

namespace Esiur.Data
{
    public class AutoList<T, ST> : IEnumerable
    {

        private readonly object syncRoot = new object();        
        private List<T> list = new List<T>();

        public delegate void Modified(ST sender, int index, T oldValue, T newValue);
        public delegate void Added(ST sender, T value);
        public delegate void Removed(ST sender, T value);
        public delegate void Cleared(ST sender);


        public event Modified OnModified;
        public event Removed OnRemoved;
        public event Cleared OnCleared;
        public event Added OnAdd;

        ST state;
        bool removableList;

        /*
        IOrderedEnumerable<T> OrderBy<T, TK>(Func<T, TK> keySelector)
        {
            return list.OrderBy<T,TK>(keySelector);
        }
        */

        public void Sort()
        {
            list.Sort();
        }

        public void Sort(IComparer<T> comparer)
        {
            list.Sort(comparer);
        }


        public IEnumerable<T> Where(Func<T, bool> predicate)
        {
            return list.Where(predicate);
        }

        /// <summary>
        /// Convert AutoList to array
        /// </summary>
        /// <returns>Array</returns>
        public T[] ToArray()
        {
        //    list.OrderBy()
            return list.ToArray();
        }

        /// <summary>
        /// Create a new instance of AutoList
        /// </summary>
        /// <param name="state">State object to be included when an event is raised.</param>
        public AutoList(ST state)
        {
            this.state = state;
#if NETSTANDARD1_5
            removableList = (typeof(IDestructible).GetTypeInfo().IsAssignableFrom(typeof(T).GetTypeInfo()));
#else
                        removableList = (typeof(IDestructible).IsAssignableFrom(typeof(T)));
#endif
        }

        /// <summary>
        /// Create a new instance of AutoList
        /// </summary>
        /// <param name="values">Populate the list with items</param>
        /// <returns></returns>
        public AutoList(T[] values)
        {

                #if NETSTANDARD1_5
                            removableList = (typeof(IDestructible).GetTypeInfo().IsAssignableFrom(typeof(T).GetTypeInfo()));
                #else
                                        removableList = (typeof(IDestructible).IsAssignableFrom(typeof(T)));
                #endif

             AddRange(values);
        }

        /// <summary>
        /// Synchronization lock of the list
        /// </summary>
        public object SyncRoot
        {
            get
            {
                return syncRoot;
            }
        }

        /// <summary>
        /// First item in the list
        /// </summary>
        public T First()
        {
            return list.First();
        }

        /// <summary>
        /// Get an item at a specified index
        /// </summary>
        public T this[int index]
        {
            get
            {
                return list[index];
            }
            set
            {
                var oldValue = list[index];

                if (removableList)
                {
                    if (oldValue != null)
                        ((IDestructible)oldValue).OnDestroy -= ItemDestroyed;
                    if (value != null)
                        ((IDestructible)value).OnDestroy += ItemDestroyed;
                }

                lock (syncRoot)
                    list[index] = value;

                OnModified?.Invoke(state, index, oldValue, value);
            }
        }

        /// <summary>
        /// Add item to the list
        /// </summary>
        public void Add(T value)
        {
            if (removableList)
                if (value != null)
                    ((IDestructible)value).OnDestroy += ItemDestroyed;

            lock (syncRoot)
                list.Add(value);

            OnAdd?.Invoke(state, value);
        }

        /// <summary>
        /// Add an array of items to the list
        /// </summary>
        public void AddRange(T[] values)
        {
            foreach (var v in values)
                Add(v);
        }

        private void ItemDestroyed(object sender)
        {
            Remove((T)sender);
        }

        public IEnumerator GetEnumerator()
        {
            return list.GetEnumerator();
        }

        /// <summary>
        /// Clear the list
        /// </summary>
        public void Clear()
        {
            if (removableList)
                foreach(IDestructible v in list)
                    if (v!=null)
                        v.OnDestroy -= ItemDestroyed;
            
            lock (syncRoot)
                list.Clear();

            OnCleared?.Invoke(state);
        }

        /// <summary>
        /// Remove an item from the list
        /// <param name="value">Item to remove</param>
        /// </summary>
        public void Remove(T value)
        {
            if (!list.Contains(value))
                return;

            if (removableList)
                if (value != null)
                    ((IDestructible)value).OnDestroy -= ItemDestroyed;

            lock (syncRoot)
                list.Remove(value);

            OnRemoved?.Invoke(state, value);
        }

        /// <summary>
        /// Number of items in the list
        /// </summary>
        public int Count
        {
            get { return list.Count; }
        }


        /// <summary>
        /// Check if an item exists in the list
        /// </summary>
        /// <param name="value">Item to check if exists</param>
        public bool Contains(T value)
        {
            return list.Contains(value);
        }

        /// <summary>
        /// Check if any item of the given array is in the list
        /// </summary>
        /// <param name="values">Array of items</param>
        public bool ContainsAny(T[] values)
        {
            foreach (var v in values)
                if (list.Contains(v))
                    return true;
            return false;
        }

        /// <summary>
        /// Check if any item of the given list is in the list
        /// </summary>
        /// <param name="values">List of items</param>
        public bool ContainsAny(AutoList<T, ST> values)
        {
            foreach (var v in values)
                if (list.Contains((T)v))
                    return true;
            return false;
        }
    }
}