/*
 * Copyright 2012-2013 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 * 
 *  http://aws.amazon.com/apache2.0
 * 
 * or in the "license" file accompanying this file. This file is distributed
 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 * express or implied. See the License for the specific language governing
 * permissions and limitations under the License.
 */

using System;

using Amazon.Runtime;
using System.Threading;
using Amazon.Runtime.Internal;
using Amazon.Runtime.Internal.Util;

namespace Amazon.DynamoDBv2
{
    internal class DynamoDBAsyncExecutor
    {
        private static Logger Logger = Logger.GetLogger(typeof(DynamoDBAsyncExecutor));

        public static void ExecuteAsync<T>(Func<T> function, AsyncOptions options, AmazonDynamoDBCallback<T> callback)
        {
            ThreadPool.QueueUserWorkItem((state) =>
            {
                T result = default(T);
                Exception exception = null;
                try
                {
                    result = function();
                }
                catch (Exception ex)
                {
                    exception = ex;
                }

                if (callback != null)
                {
	                if (options.ExecuteCallbackOnMainThread)
	                {
	                    UnityRequestQueue.Instance.ExecuteOnMainThread(() =>
	                    {
	                        callback(new AmazonDynamoDBResult<T>(result, exception, options.State));
	                    });
	                }
	                else
	                {
	                    try
	                    {
	                        callback(new AmazonDynamoDBResult<T>(result, exception, options.State));
	                    }
	                    catch(Exception callbackException)
	                    {
	                        // Catch any unhandled exceptions from the user callback 
	                        // and log it. 
	                        Logger.Error(callbackException,
	                            "An unhandled exception was thrown from the callback method {0}.",
	                            callback.Method.Name);
	                    }
	                }
                 }
            });
        }

        public static void ExecuteAsync(Action action, AsyncOptions options, AmazonDynamoDBCallback callback)
        {
            ThreadPool.QueueUserWorkItem((state) =>
            {
                Exception exception = null;
                try
                {
                    action();
                }
                catch (Exception ex)
                {
                    exception = ex;
                }

                if (callback != null)
                {
	                if (options.ExecuteCallbackOnMainThread)
	                {
	                    Amazon.Runtime.Internal.UnityRequestQueue.Instance.ExecuteOnMainThread(() =>
	                    {
	                        callback(new AmazonDynamoDBResult(exception, options.State));
	                    });
	                }
	                else
	                {
	                    try
	                    {
	                        callback(new AmazonDynamoDBResult(exception, options.State));
	                    }
	                    catch (Exception callbackException)
	                    {
	                        // Catch any unhandled exceptions from the user callback 
	                        // and log it. 
	                        Logger.Error(callbackException,
	                            "An unhandled exception was thrown from the callback method {0}.",
	                            callback.Method.Name);
	                    }
	                }
                 } 
            });
        }
    }
}