/*
 * Message.cs
 * Authors: August Zinsser, 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;
using System.Collections.Generic;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Content;
using Util;

namespace MaritimeDefender
{
	/// <summary>
	/// Displays text and/or pictures in various manners on top of all other graphics.
	/// This is uesful for outputting text to a HUD or displaying popup text or graphics.
	/// </summary>
	public class Message
	{
		#region Constants

		/// <summary>
		/// Constant value for the duration of time for fading out
		/// </summary>
		public const int FADE_TIME = 1;

		#endregion

		#region Fields

		// The content manager used for loading content
		private ContentManager mContent;
		
		// The sprite batch used for rendering textures
		private SpriteBatch mSpriteBatch;
		
		// The texture to render
		private Texture2D mImage;
		
		// The sprite font used for rendering text
		private SpriteFont mFont;

		// The path name of the texture file to use
		private string mImagePath;

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

		// The text to be displayed in the message
		private string mText = string.Empty;

		// The position of the message via 2 dimensions
		private Vector2 mPosition;

		// The velocity of the message via 2 dimensions
		private Vector2 mVelocity;

		// The width of the message
		private int mWidth;
		
		// The height of the message
		private int mHeight;

		// Whether or not the message fades in
		private bool mFadesIn;

		// Whether or not the message fades out
		private bool mFadesOut;

		// The coloring tint of the message
		private Color mTint = Color.White;

		// The current opacity of the message
		private float mCurOpacity = 1f;

		// The opacity of the message at the end of fading out
		private float mFinOpacity = 1f;

		// The lifetime of the message
		private float mLifetime;

		// The scale size of the message
		private float mScale = 1f;

		#endregion

		#region Properties

		/// <summary>
		/// Sets the sprite batch object used for rendering textures
		/// </summary>
		public SpriteBatch SpriteBatch { set { mSpriteBatch = value; } }

		/// <summary>
		/// Gets whether or not the meesage fades out
		/// </summary>
		public bool FadesOut { get { return mFadesOut; } }

		/// <summary>
		/// Gets the lifetime of the message
		/// </summary>
		public float Lifetime { get { return mLifetime; } }

		/// <summary>
		/// Sets the scale size of the message
		/// </summary>
		public float Scale { set { mScale = value; } }

		#endregion

		#region Creation

		/// <summary>
		/// Displays a string and/or graphic on top of all other graphics
		/// </summary>
		/// <param name="content">The content manager used to load/unload graphics content with</param>
		/// <param name="text">The string to display</param>
		/// <param name="imagePath">The path of the image</param>
		/// <param name="fontPath">Which font to use</param>
		/// <param name="offsetFromCenter">Offset in pixels to draw the message, relative to the screen's center and the message's center</param>
		/// <param name="velocity">The speed and direction of the image and font</param>
		/// <param name="color">The color of the image and font</param>
		/// <param name="opacity">How transparent the image and font are</param>
		/// <param name="seconds">Duration to display the message</param>
		/// <param name="fade">Whether or not to fade in and fade out the message</param>
		/// <param name="velocity">Velocity (in pixels/second) to scroll the text</param>
		public Message(ContentManager content, string text, string imagePath, string fontPath, Vector2 offsetFromCenter, 
			Vector2 velocity, Color color, float opacity, float seconds, bool fade, Viewport Viewport)
			: base()
		{
			mContent = content;
			mText = text;
			mImagePath = imagePath;
			mFontPath = fontPath;
			mPosition = new Vector2((Viewport.Width >> 1) + offsetFromCenter.X, (Viewport.Height >> 1) + offsetFromCenter.Y);
			mVelocity = velocity;
			mTint = color;
			mLifetime = seconds;
			mFinOpacity = opacity;
			mFadesIn = fade;
			mFadesOut = fade;
			mCurOpacity = fade ? 0f : opacity;
			LoadContent();
		}

		#endregion

		#region Management

		/// <summary>
		/// Load in necessary graphics content
		/// </summary>
		public void LoadContent()
		{
			if (mImagePath != null)
			{
				mImage = mContent.Load<Texture2D>(mImagePath);
			}
			if (mText != null && mFontPath != null)
			{
				mFont = mContent.Load<SpriteFont>(mFontPath);
				// Find the string's dimensions
				mWidth = (int)mFont.MeasureString(mText).X;
				mHeight = (int)mFont.MeasureString(mText).Y;
			}
		}

		#endregion

		#region Update

		/// <summary>
		/// Call this during the main game's update cycle
		/// </summary>
		public void Update(GameTime gameTime)
		{
			float dT = (float)gameTime.ElapsedGameTime.TotalSeconds;
			// Update lifetime
			mLifetime -= dT;
			// Alter position
			mPosition += mVelocity * dT;
			// Alter opacity
			if (mFadesIn && mCurOpacity < mFinOpacity)
			{
				mCurOpacity += dT * FADE_TIME;
				if (mCurOpacity >= mFinOpacity)
				{
					mFadesIn = false;
					mCurOpacity = mFinOpacity;
				}
			}
			if (mFadesOut && mLifetime < 0)
			{
				mCurOpacity -= dT * FADE_TIME;
			}
			if (mCurOpacity < 0)
			{
				mCurOpacity = 0f;
			}
		}

		#endregion

		#region Render

		/// <summary>
		/// Draws all registered text on a new spritebatch
		/// </summary>
		public void Draw()
		{
			int paddingX = 0;
			if (mImage != null)
			{
				paddingX = (int)(mImage.Width * mScale) >> 1;
				mSpriteBatch.Draw(mImage, new Rectangle((int)(mPosition.X - (mImage.Width * mScale)), (int)mPosition.Y - (((int)(mImage.Height * mScale)) >> 1), ((int)(mImage.Width * mScale)), ((int)(mImage.Height * mScale))), new Color(mTint.R, mTint.G, mTint.B, (byte)(255 * mCurOpacity)));
			}
			mSpriteBatch.DrawString(mFont, mText, new Vector2((int)mPosition.X - (mWidth >> 1) + paddingX, (int)mPosition.Y), new Color(mTint.R, mTint.G, mTint.B, (byte)(255 * mCurOpacity)));
		}

		#endregion

		#region Predicates

		/// <summary>
		/// Check for and Remove expired messages
		/// </summary>
		public static readonly Predicate<Message> NotAlive = new Predicate<Message>(delegate(Message m)
		{ 
			return (m.Lifetime < 0 && !m.FadesOut) || (m.Lifetime + FADE_TIME < 0 && m.FadesOut);
		});

		#endregion
	}
}