/* Sparx
 * Copyright August Zinsser 2007
 * This program is distributed under the terms of the GNU General Public License
 */


using System;
using System.Collections.Generic;
using System.Text;
using System.Reflection;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;


namespace Pina3D.Particles
{
    /// <summary>
    /// Manages the images used for particles.
    /// </summary>
    public class ParticleSprite
    {
        /// <summary>
        /// The standard particle sprite sheet, made public so it can be passed by reference
        /// </summary>
        public static Texture2D SpriteSheet;
        
        private static Dictionary<string, Vector4> mImageCoords;    // Refers to each individual image in the sprite sheet

        private Vector2 mUVUpperLeft;                   // Pick a slice out of the sprite sheet 
        private Vector2 mUVLowerRight;                  // ''

        public static Dictionary<string, Vector4> ImageCoords { get { return mImageCoords; } }
        public Vector2 UVUpperLeft { set { mUVUpperLeft = value; } get { return mUVUpperLeft; } }
        public Vector2 UVLowerRight { set { mUVLowerRight = value; } get { return mUVLowerRight; } }

        /// <summary>
        /// Create a new sprite using the entire spritesheet as the texture
        /// </summary>
        public ParticleSprite()
            : this ("CrispDot")
        {
        }


        /// <summary>
        /// Create a new sprite using a region of the spritesheet as the texture
        /// </summary>
        /// <param name="imageName">The name of the image within the sprite sheet to use</param>
        public ParticleSprite(string imageName)
        {
            PopulateImages();

            // Lookup the appropriate image (allow an exception to be thrown if an image isn't found)
            mUVUpperLeft = new Vector2(mImageCoords[imageName].X, mImageCoords[imageName].Y);
            mUVLowerRight = new Vector2(mImageCoords[imageName].Z, mImageCoords[imageName].W);
        }


        /// <summary>
        /// Create a new sprite using a region of the spritesheet as the texture
        /// </summary>
        /// <param name="uvUpperLeft">UV Coords of the upper left corner</param>
        /// <param name="uvUpperRight">UV Coords of the lower right corner</param>
        public ParticleSprite(Vector2 uvUpperLeft, Vector2 uvLowerRight)
        {
            PopulateImages();

            mUVUpperLeft = uvUpperLeft;
            mUVLowerRight = uvLowerRight;
        }


        /// <summary>
        /// Load in the sprite sheet and image coordinates
        /// </summary>
        private static void PopulateImages()
        {
            // Load the sprite sheet from the assembly's meta data
            if (SpriteSheet == null)
            {
                Assembly assembly = Assembly.GetExecutingAssembly();
                string[] resourceNames = assembly.GetManifestResourceNames();
                foreach (string resourceName in resourceNames)
                {
                    if (resourceName == "Pina3D.Resources.resources")
                    {
                        SpriteSheet = Pina.ResourceContent.Load<Texture2D>(@"ParticleSpritesSTD");
                    }
                }
            }

            // Fill the image lookup info
            if (mImageCoords == null)
            {
                // Vector4 format: (left U, top V, right U, bottom V) == (upperLeft(u,v), lowerRight(u,v))
                mImageCoords = new Dictionary<string, Vector4>();
                mImageCoords.Add("CrispDot", new Vector4(0f, 0f, .1f, .1f));
                mImageCoords.Add("FuzzyGreyDot", new Vector4(.1f, .05f, .15f, .10f));
                mImageCoords.Add("Blast1", new Vector4(.20f, .10f, .30f, .20f));
                mImageCoords.Add("FuzzyBlast", new Vector4(.1f, 0f, .15f, .05f));
                mImageCoords.Add("Spark", new Vector4(.1f, .1f, .2f, .2f));
                mImageCoords.Add("Squiggle", new Vector4(.15f, 0f, .20f, .10f));
                mImageCoords.Add("Star", new Vector4(0f, .10f, .10f, .20f));
                mImageCoords.Add("Puff", new Vector4(.20f, 0f, .30f, .10f));
                mImageCoords.Add("Meteorite", new Vector4(0f, .20f, .20f, .40f));
            }
        }
    }
}