/* 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.Diagnostics;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.Graphics;


namespace Pina3D.Particles
{
    public class Particle : Emission
    {
        protected ParticleSprite mParticleSprite;
        protected float mWidth;
        protected float mHeight;
        protected float mScale;
        protected Color mColor;         // RGBA
        protected float mRotation;

        public ParticleSprite ParticleSprite { set { mParticleSprite = value; } get { return mParticleSprite; } }
        public float Width { set { mWidth = value; } get { return mWidth; } }
        public float Height { set { mHeight = value; } get { return mHeight; } }
        public float Rotation { set { mRotation = value; } get { return mRotation; } }
        public override int ParticleCount { get { return 1; } }
        public override int EmitterCount { get { return 0; } }


        /// <summary>
        /// Creates a new particle
        /// </summary>
        /// <param name="position">Initial absolute position</param>
        /// <param name="lifeSpan">Time in seconds before the particle dies</param>
        /// <param name="imageName">The name of the image to use from the Particle Sprite sheet</param>
        /// <param name="width">Width of the sprite in pixels</param>
        /// <param name="height">Width of the sprite in pixels</param>
        /// <param name="initialRotation">In radians</param>
        /// <param name="name">Used for book</param>
        public Particle(Vector3 position, float lifeSpan, string imageName, float width, float height, float initialRotation) :
            base(imageName, position, false, lifeSpan)
        {
            if (imageName == null)
                mParticleSprite = new ParticleSprite();
            else
                mParticleSprite = new ParticleSprite(imageName);
            mWidth = width;
            mHeight = height;
            mRotation = initialRotation;
            mVelocity = new Vector3(0, 0, 0);
        }


        private Particle()  // TODO: Remove this?
        {
        }


        /// <summary>
        /// Returns a new instance exactly like this one
        /// </summary>
        /// <returns></returns>
        public override Object Clone()
        {
            Particle retPa = new Particle();
            retPa.mName = mName + "_clone";
            retPa.mPosition = new Vector3(mPosition.X, mPosition.Y, mPosition.Z);
            retPa.mAge = mAge;
            retPa.mLifeExpectancy = mLifeExpectancy;
            retPa.mVelocity = new Vector3(mVelocity.X, mVelocity.Y, mVelocity.Z);
            retPa.mMyModifiers = mMyModifiers;
            if (mMyForces != null)
            {
                retPa.mMyForces = new List<Force>();
                for (int i = 0; i < mMyForces.Count; i++)
                    retPa.mMyForces.Add((Force)mMyForces[i].Clone());
            }
            retPa.mAlive = mAlive;
            retPa.mImmortal = mImmortal;
            retPa.mParticleSprite = mParticleSprite;
            retPa.mWidth = mWidth;
            retPa.mHeight = mHeight;
            retPa.mRotation = mRotation;
            retPa.mTransform = mTransform;
            retPa.mRenderScale = mRenderScale;
            retPa.mRenderRotation = mRenderRotation;
            return retPa;
        }


        /// <summary>
        /// Jiggles the layer depth slightly to help fix z-fighting 
        /// </summary>
        public void DepthJiggle()       // TODO: remove all the auto-jiggly stuff
        {
        }


        /// <summary>
        /// Updates this particle's properites
        /// </summary>
        /// <param name="gameTime"></param>
        public override void Update()
        {
            base.Update();

            float dT = Pina.ElapsedSeconds;

            // Modifiers
            float[] combinedColor = { 1f, 1f, 1f, 1f };
            Modifier modifier;
            mScale = 1.0f;
            for (int i = 0; i < mMyModifiers.Count; i++)
            {
                modifier = mMyModifiers[i];

                // TODO: convert from [0,255] to [0,1] in the Modifier constructor and cut out all the /255 BS
                Color modColor = modifier.Color(mAge);
                combinedColor[0] *= (float)modColor.R / 255f;
                combinedColor[1] *= (float)modColor.G / 255f;
                combinedColor[2] *= (float)modColor.B / 255f;
                combinedColor[3] *= (float)modColor.A / 255f;

                mScale *= modifier.Scale(mAge);

                mRotation += modifier.AngularVelocity(mAge) * dT;
            }
            mColor = new Color(
                (byte)(combinedColor[0] * 255),
                (byte)(combinedColor[1] * 255),
                (byte)(combinedColor[2] * 255),
                (byte)(combinedColor[3] * 255));
            mRotation %= MathHelper.Pi * 2f;

            if (!mAlive)
                Pina.RemoveRenderable(this);
        }


        /// <summary>
        /// Draws the particle to the backbuffer
        /// </summary>
        /// <param name="spriteBatch"></param>
        public void Render()
        {          
            // Find screen translation
            float XTranslate = Sparx.ScreenTranslate.X;
            float YTranslate = Sparx.ScreenTranslate.Y;

            // Find the render transformation
            Vector3 transformedPosition;
            Vector3.Transform(ref mPosition, ref mTransform, out transformedPosition);

            transformedPosition.X += XTranslate;
            transformedPosition.Y += YTranslate;

            QuadRenderer.RenderOnNextFrame(ref ParticleSprite.SpriteSheet, mParticleSprite.UVUpperLeft, mParticleSprite.UVLowerRight, transformedPosition, mWidth * mScale * mRenderScale, mHeight * mScale * mRenderScale, mRotation + mRenderRotation, mColor);
        }
    }
}