using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using SlatedGameToolkit.Framework.Exceptions;

namespace SlatedGameToolkit.Framework.Utilities.Collections.Pooling
{
    public class ObjectPool <Poolable> where Poolable : IPoolable
    {
        public int Size { get; private set; }
        public int Count {
            get {
                return pool.Count;
            }
        }
        private Func<Poolable> creator;
        private ConcurrentBag<Poolable> pool;

        public ObjectPool(Func<Poolable> creator, int size = 0, int initialCount = 0) {
            this.creator = creator ?? throw new ArgumentNullException("creator");
            this.pool = new ConcurrentBag<Poolable>();
            this.Size = size;
            CreateAmount(initialCount);
        }

        public void CreateAmount(int amount) {
            if (Size >= 0 && Count + amount >= Size) throw new FrameworkUsageException(string.Format("Object pool surpassed set size of {0}", Size));
            for (int i = 0; i < amount; i++) {
                pool.Add(creator());
            }
        }

        public Poolable Retrieve() {
            if (pool.Count == 0) {
                CreateAmount(1);
            }
            Poolable result;
            pool.TryTake(out result);
            return result;
        }

        public void Release(Poolable poolable) {
            if (Size >= 0 && Count + 1 >= Size) throw new FrameworkUsageException(string.Format("Object pool surpassed set size of {0}", Size));
            poolable.Reset();
            pool.Add(poolable);
        }
    }
}