/*
 
Copyright (c) 2017 Ahmed Kh. Zamil

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

*/

using System;
using System.IO;
using System.Collections;
using System.Security.Cryptography;
using System.Text;
using System.Reflection;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using Esiur.Core;

namespace Esiur.Data;

public class KeyList<KT, T> : IEnumerable<KeyValuePair<KT, T>>
{
    private readonly object syncRoot = new object();
    private Dictionary<KT, T> dic;

    public delegate void Modified(KT key, T oldValue, T newValue, KeyList<KT, T> sender);
    public delegate void Added(T value, KeyList<KT, T> sender);
    public delegate void Removed(KT key, T value, KeyList<KT, T> sender);
    public delegate void Cleared(KeyList<KT, T> sender);

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

    bool removableList;

    public object SyncRoot
    {
        get
        {
            return syncRoot;
        }
    }

    public T Take(KT key)
    {
        if (dic.ContainsKey(key))
        {
            var v = dic[key];
            Remove(key);
            return v;
        }
        else
            return default(T);
    }

    public void Sort(Func<KeyValuePair<KT, T>, object> keySelector)
    {
        dic = dic.OrderBy(keySelector).ToDictionary(x => x.Key, x => x.Value);
    }

    public T[] ToArray()
    {
        var a = new T[Count];
        dic.Values.CopyTo(a, 0);
        return a;
    }

    public void Add(KT key, T value)
    {
        lock (syncRoot)
        {
            if (removableList)
                if (value != null)
                    ((IDestructible)value).OnDestroy += ItemDestroyed;

            if (dic.ContainsKey(key))
            {
                var oldValue = dic[key];
                if (removableList)
                    if (oldValue != null)
                        ((IDestructible)oldValue).OnDestroy -= ItemDestroyed;
                dic[key] = value;
                if (OnModified != null)
                    OnModified(key, oldValue, value, this);
            }
            else
            {
                dic.Add(key, value);

                if (OnAdd != null)
                    OnAdd(value, this);
            }
        }
    }

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

    public void RemoveValue(T value)
    {
        var toRemove = new List<KT>();
        foreach (var kv in dic)
            if (kv.Value.Equals(value))
                toRemove.Add(kv.Key);

        foreach (var k in toRemove)
            Remove(k);
    }

    public T this[KT key]
    {
        get
        {
            if (dic.ContainsKey(key))
                return dic[key];
            else
                return default(T);
        }
        set
        {
            Add(key, value);
        }
    }


    public IEnumerator<KeyValuePair<KT, T>> GetEnumerator()
    {
        return dic.GetEnumerator();
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return dic.GetEnumerator();
    }


    public void Clear()
    {
        if (removableList)
            foreach (IDestructible v in dic.Values)
                if (v != null)
                    v.OnDestroy -= ItemDestroyed;

        lock (syncRoot)
            dic.Clear();

        if (OnCleared != null)
            OnCleared(this);
    }

    public Dictionary<KT, T>.KeyCollection Keys
    {
        get { return dic.Keys; }
    }

    public Dictionary<KT, T>.ValueCollection Values
    {
        get
        {
            return dic.Values;
        }
    }

    public void Remove(KT key)
    {
        if (!dic.ContainsKey(key))
            return;

        var value = dic[key];

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

        lock (syncRoot)
            dic.Remove(key);

        if (OnRemoved != null)
            OnRemoved(key, value, this);
    }

    public object Owner
    {
        get;
        set;
    }

    public int Count
    {
        get { return dic.Count; }
    }
    public bool Contains(KT Key)
    {
        return dic.ContainsKey(Key);
    }
    public bool ContainsKey(KT Key)
    {
        return dic.ContainsKey(Key);
    }
    public bool ContainsValue(T Value)
    {
        return dic.ContainsValue(Value);
    }


    public KeyList(object owner = null)
    {
#if NETSTANDARD
        removableList = (typeof(IDestructible).GetTypeInfo().IsAssignableFrom(typeof(T).GetTypeInfo()));
#else
        removableList = (typeof(IDestructible).IsAssignableFrom(typeof(T)));
#endif

        this.Owner = owner;

        if (typeof(KT) == typeof(string))
            dic = (Dictionary<KT, T>)(object)new Dictionary<string, T>(StringComparer.OrdinalIgnoreCase);
        else
            dic = new Dictionary<KT, T>();
    }
}