using UnityEngine;

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

public static class ExtensionList
{
    public static T Last<T>(this List<T> list, int index)
    {
        return list[list.Count - 1 - index];
    }

    public static T Prev<T>(this List<T> list, int index)
    {
        return list[(index + list.Count - 1) % list.Count];
    }

    public static T Next<T>(this List<T> list, int index)
    {
        return list[(index + 1) % list.Count];
    }

    public static T Random<T>(this List<T> list, bool remove = false)
    {
        if (list.Count == 0)
        {
            Debug.Log("Count is 0");
        }

        int index = UnityEngine.Random.Range(0, list.Count);

        if (remove)
        {
            T result = list[index];

            list.RemoveAt(index);

            return result;
        }
        else
        {
            return list[index];
        }
    }

    public static bool Valid<T>(this List<T> list)
    {
        if (list == null || list.Count == 0)
        {
            return false;
        }
        else
        {
            return true;
        }
    }

    public static bool UniqueAdd<T>(this List<T> list, T obj)
    {
        if (list.Contains(obj) == false)
        {
            list.Add(obj);

            return true;
        }
        else
        {
            return false;
        }
    }

    public static void LastRemoveAt<T>(this List<T> list, int index)
    {
        list.RemoveAt(list.Count - 1 - index);
    }
}