using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;

public class InterthreadMessageQueue<T>
{
    private DateTime lastReadTime = DateTime.Now;

    public DateTime LastReadTime
    {
        get { return lastReadTime; }
        private set { lastReadTime = value; }
    }

    Queue<T> _queue = new  Queue<T>();

    /// <summary>
    /// Post a message to the queue.
    /// </summary>
    public void PostItem(T item)
    {

        lock (_queue)
        {
            _queue.Enqueue(item);
            if (_queue.Count == 1)
                Monitor.Pulse(_queue);
        }
    }

    /// <summary>
    /// Post a message to the queue.
    /// </summary>
    public void PostItems(List<T> items)
    {

        lock (_queue)
        {
            foreach (T item in items)
                _queue.Enqueue(item);

            if (_queue.Count == 1)
                Monitor.Pulse(_queue);
        }
    }


    /// <summary>
    /// Retrieve a message from the queue.
    /// </summary>
    /// <param name="maxWait">Number of milliseconds to block ifnothing is available. -1 means "block indefinitely"</param>
    /// <returns>The next item in the queue, or default(T) if queue is empty</returns>
    public T GetItem(int maxWait)
    {
        lock (_queue)
        {
            LastReadTime = DateTime.Now;
            if (_queue.Count == 0)
            {
                if (maxWait == 0)
                    return default(T);
                Monitor.Wait(_queue, maxWait);
                if (_queue.Count == 0)
                    return default(T);
            }
            return _queue.Dequeue();
        }
    }

    public T Peek(int maxWait)
    {
        lock (_queue)
        {
            if (_queue.Count == 0)
            {
                if (maxWait == 0)
                    return default(T);
                Monitor.Wait(_queue, maxWait);
                if (_queue.Count == 0)
                    return default(T);
            }
            return _queue.Peek();
        }
    }

    public void Remove(T item)
    {
        lock (_queue)
        {
            if (_queue.Count != 0)
            {
                T itemPeek = _queue.Peek();
                if (itemPeek.Equals(item))
                {
                    _queue.Dequeue();
                }
            }
        }
    }

    public void Clear()
    {
        lock (_queue)
        {
            if (_queue.Count != 0)
            {
                _queue.Clear();
            }
        }
    }

    public List<T> ToList()
    {
        lock (_queue)
        {
            return _queue.ToList();
        }
    }

    public int Count
    {
        get
        {
            lock (_queue)
            {
                return _queue.Count;
            }
        }
    }
}