jsedlak

#region License
// 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.
//
// (C) 2008 John Sedlak
//
// Authors:
//   John Sedlak (kriscsc@msn.com)
//
#endregion

using System;
using System.Threading;
using System.Collections.Generic;
using Microsoft.Xna.Framework.Content;

using FocusedGames.Thrust;

namespace FocusedGames.Thrust.Content
{
    /// <summary>
    /// Manages content both synchronously and asynchronously and allows for the piece-wise unloading of assets.
    /// </summary>
    public class AssetManager : ContentManager
    {
        #region Private Members
        private List<ILoadable> content = new List<ILoadable>();
        private Queue<ILoadable> asyncLoadables = new Queue<ILoadable>();

        private int current;
        private int total;
        private bool isLoading = false;

        private bool simulateLargeContent = false;
        #endregion

        #region Events
        private event EventHandler InternalBeginLoad;

        /// <summary>
        /// Fired when the asset manager has finished loading a group of assets.
        /// </summary>
        public event EventHandler FinishedLoad;
        #endregion

        #region Constructors
        /// <summary>
        /// Default constructor.
        /// </summary>
        /// <param name="serviceProvider">The Game's service container.</param>
        public AssetManager(IServiceProvider serviceProvider)
            : this(serviceProvider, String.Empty)
        {
        }

        /// <summary>
        /// Secondary constructor.
        /// </summary>
        /// <param name="serviceProvider">The Game's service container.</param>
        /// <param name="rootDirectory">The base directory where all assets are stored.</param>
        public AssetManager(IServiceProvider serviceProvider, string rootDirectory)
            : base(serviceProvider, rootDirectory)
        {
            InternalBeginLoad += OnBeginLoad;
        }
        #endregion

        #region Unloading
        /// <summary>
        /// DO NOT USE THIS. IT DOES NOTHING.
        /// </summary>
        /// <see cref="Unload(ILoadable)"/>
        public new void Unload()
        {
        }

        /// <summary>
        /// Unloads a single asset.
        /// </summary>
        /// <param name="asset">The asset to unload.</param>
        public void Unload(ILoadable asset)
        {
            if (content.Contains(asset))
                content.Remove(asset);

            asset.Unload();

            asset = null;
        }
        #endregion

        #region Loading
        /// <summary>
        /// Loads a custom asset.
        /// </summary>
        /// <typeparam name="K">The type of asset to load.</typeparam>
        /// <param name="source">The source file of the asset.</param>
        /// <param name="asyncLoad">Whether to load it now or asynchronously and later on.</param>
        /// <returns>A custom asset object.</returns>
        public K LoadCustom<K>(string source, bool asyncLoad) where K : IAsset, new()
        {
            K newAsset = new K();
            newAsset.Source = source;
            newAsset.AssetManager = this;

            if (!asyncLoad)
            {
                newAsset.Load();

                content.Add(newAsset);
            }
            else
            {
                asyncLoadables.Enqueue(newAsset);
            }

            return newAsset;
        }

        /// <summary>
        /// Loads an asset.
        /// </summary>
        /// <typeparam name="T">The type of content item to load.</typeparam>
        /// <param name="source">The source file of the asset.</param>
        /// <param name="asyncLoad">Whether to load it now or asynchronously and later on.</param>
        /// <returns>An Asset object.</returns>
        /// <seealso cref="Asset{T}"/>
        public Asset<T> Load<T>(string source, bool asyncLoad) where T : class
        {
            Asset<T> newAsset = new Asset<T>();
            newAsset.Source = source;
            newAsset.AssetManager = this;

            if (!asyncLoad)
            {
                newAsset.Load();

                content.Add(newAsset);
            }
            else
            {
                asyncLoadables.Enqueue(newAsset);
            }

            return newAsset;
        }
        #endregion

        #region Internal Loading (Async)
        /// <summary>
        /// Begins the asynchronous process of loading.
        /// </summary>
        public void BeginLoad()
        {
            isLoading = true;

#if ZUNE
            InternalBeginLoad.Invoke(this, EventArgs.Empty);

            OnFinishLoad(null);
#else
            InternalBeginLoad.BeginInvoke(this, EventArgs.Empty, OnFinishLoad, null);
#endif
        }

        private void OnBeginLoad(object sender, EventArgs e)
        {
            total = asyncLoadables.Count;
            current = 0;

            while (asyncLoadables.Count > 0)
            {
                ILoadable asset = asyncLoadables.Dequeue();

                if (asset.IsLoaded || content.Contains(asset))
                    continue;

                asset.Load();

                current++;

                content.Add(asset);

                if (SimulateLargeContent)
                    Thread.Sleep(250);
            }
        }

        private void OnFinishLoad(IAsyncResult result)
        {
#if !ZUNE
            InternalBeginLoad.EndInvoke(result);
#endif

            isLoading = false;

            if (FinishedLoad != null)
                FinishedLoad.Invoke(this, EventArgs.Empty);
        }
        #endregion

        #region Properties
        /// <summary>
        /// Gets or Sets whether or not to simulate large content.
        /// </summary>
        public bool SimulateLargeContent
        {
            get { return simulateLargeContent; }
            set { simulateLargeContent = value; }
        }

        /// <summary>
        /// Gets the current number of assets loaded.
        /// </summary>
        public int Current { get { return current; } }

        /// <summary>
        /// Gets the total number of assets that need to be loaded.
        /// </summary>
        public int Total { get { return total; } }

        /// <summary>
        /// Gets whether or not the object is loading assets.
        /// </summary>
        public bool IsLoading { get { return isLoading; } }
        #endregion
    }
}