/*
 * Util.FrameRateDisplayComponent.cs
 * Authors: Adam Nabinger
 * Copyright (c) 2007-2008 Cornell University

 This program is free software; you can redistribute it and/or
 modify it under the terms of the GNU General Public License
 as published by the Free Software Foundation; either version 2
 of the License, or (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/

using System.Globalization;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;

namespace Util
{
	/// <summary>
	/// A Component to display the current FPS on the screen.
	/// </summary>
	public sealed class FrameRateDisplayComponent : DrawableGameScreenComponent
	{
		#region Constants

		// String constant for default file name for menu font
		private const string defaultfontname = @"Fonts\menufont";

		#endregion

		#region Fields

		// Reference to the current gamescreen
		//private readonly GameScreen mScreen;
		
		// The sprite batch used for rendering textures
		private SpriteBatch mSB;

		// The sprite font used for rendering text
		private SpriteFont mFont;
		
		// Position on screen for the frame rate display component
		private Vector2 mPosition = Vector2.Zero;

		// The color of the frame rate display component 
		private Color mColor = Color.White;

		// Whether or not the frame rate display component has been loaded
		private bool loaded;

		// The path name of the sprite font to use
		private readonly string fontname;

		// The current count of frames per second
		private int framecount;

		// The total time from each update
		private double time;

		// The amount of seconds between each update
		private double mUpdateInterval = 1;

		// The text to display in the frame rate display component
		private string displaytext = string.Empty;

		#endregion

		#region Properties

		/// <summary>
		/// Gets/Sets the Upper Left corner of where the FPS will be drawn to the screen
		/// </summary>
		public Vector2 Position
		{
			get { return mPosition; }
			set { mPosition = value; }
		}

		/// <summary>
		/// Gets/Sets the Color the Text will be drawn in.
		/// </summary>
		public Color Color
		{
			get { return mColor; }
			set { mColor = value; }
		}

		/// <summary>
		/// Gets/Sets how often, in seconds, the count will be updated.
		/// </summary>
		public double UpdateInterval
		{
			get { return mUpdateInterval; }
			set { mUpdateInterval = value; }
		}

		#endregion

		#region Creation

		/// <summary>
		/// Constructor
		/// </summary>
		internal FrameRateDisplayComponent()
		{}

		/// <summary>
		/// Constructor
		/// </summary>
		/// <param name="font">Path name for the sprite font to use</param>
		internal FrameRateDisplayComponent(string font)
		{
			fontname = font;
		}

		#endregion

		#region Initialization

		/// <summary>
		/// Initialize this component.
		/// </summary>
		public override void Initialize()
		{
			DrawOrder = parent.DrawOrder + 5;
			UpdateOrder = parent.UpdateOrder + 5;
			base.Initialize();
		}

		#endregion

		#region Management

		/// <summary>
		/// Loads in all necessary information for content dependent objects
		/// </summary>
		protected override void LoadContent()
		{
			if (!loaded)
			{
				mSB = new SpriteBatch(GraphicsDevice);
				mFont = fontname == null ? Game.Content.Load<SpriteFont>(defaultfontname) : parent.Content.Load<SpriteFont>(fontname);
				loaded = true;
			}
			base.LoadContent();
		}

		/// <summary>
		/// Unload any content dependent information
		/// </summary>
		protected override void UnloadContent()
		{
			if (loaded)
			{
				loaded = false;
			}
			base.UnloadContent();
		}

		/// <summary>
		/// Disposes of all unmanaged objects
		/// </summary>
		/// <param name="disposing">Whether or not this is currently being disposed</param>
		protected override void Dispose(bool disposing)
		{
			if (loaded && disposing)
			{
				mSB.Dispose();
			}
			base.Dispose(disposing);
		}

		#endregion

		#region Update

		/// <summary>
		/// Update this component.
		/// </summary>
		/// <param name="gameTime">Time passed in game</param>
		public override void Update(GameTime gameTime)
		{
			time += gameTime.ElapsedGameTime.TotalSeconds;
			if (time > mUpdateInterval)
			{
				displaytext = (framecount / time).ToString("F0", CultureInfo.CurrentCulture);
				time = 0;
				framecount = 0;
			}
			base.Update(gameTime);
		}

		#endregion

		#region Render

		/// <summary>
		/// Draw this component.
		/// </summary>
		/// <param name="gameTime">Time passed in game</param>
		public override void Draw(GameTime gameTime)
		{
			mSB.Begin();
			mSB.DrawString(mFont, displaytext, mPosition, mColor);
			mSB.End();
			++framecount;
			base.Draw(gameTime);
		}

		#endregion
	}
}