using System;

using OpenTK.Graphics.OpenGL;
using OpenTK.Graphics;
using OpenTK;
using org.budnhead.audio;

namespace org.budnhead.graphics
{
	public class GLCamera : GLSceneOrientation
	{
		float fov;
		float width, height;
		float aspect;

		Vector3 vPosition,
			vView,
			vTop;

		GLCameraController controller;

		public GLCamera()
		{
			controller = new GLCameraController(this);

			fov = MathHelper.PiOver2;
			width = 100;
			height = 100;
			aspect = 1;

			vPosition = new Vector3(0,0,1000);
			vView = new Vector3(0,0,-1);
			vTop = new Vector3(0,1,0);

			buildProjection();
			buildMatrices();
		}

		override public void setViewport(int width, int height)
		{
			this.width = (float)width;
			this.height = (float)height;

			buildProjection();
		}
		public void setFoV(float fov){
			this.fov = fov;
			buildProjection();
		}

		private void buildProjection(){
			aspect = width / height;

			_mProjection = Matrix4.CreatePerspectiveFieldOfView(
				fov,
				aspect,
				1.0f,
				50000.0f
			);
		}

		public GLCameraController CameraController {
			get { return this.controller; }
			set { this.controller = value; }
		}

		public Vector3 Position
		{
			get { return new Vector3(vPosition); }
			set { this.vPosition = new Vector3(value); buildMatrices(); nhListener.setPosition(this.vPosition);}
		}
		public Vector3 View
		{
			get { return new Vector3(vView); }
			set { this.vView = new Vector3(value).Normalized(); buildMatrices(); nhListener.setView(this.vView); }
		}

		public Vector3 Top
		{
			get { return new Vector3(vTop); }
			set { this.vTop = new Vector3(value).Normalized(); buildMatrices(); nhListener.setTop(this.vTop);}
		}

		private void buildMatrices(){
			
			Matrix4 mTranslation = Matrix4.CreateTranslation( -this.vPosition );
			Vector3 x,y,z;
			
			z = -vView;
			x = Vector3.Cross( vTop, z ).Normalized();
			y = Vector3.Cross( z, x );
			
			Matrix4 mRotation = new Matrix4(
										new Vector4(x,0),
										new Vector4(y,0),
										new Vector4(z,0),
										new Vector4(0,0,0,1)
										);
			mRotation.Transpose();
		
			_mCamera = mTranslation * mRotation;
		}

		public Vector3 pickRay(float x,float y){
			float y_arc,x_arc;

			x_arc = (( (2*x) ) - width) * aspect;
			y_arc = height - ( (2*y) );

			x_arc /= width;
			y_arc /= height;

			Vector4 ray = new Vector4(x_arc,y_arc,1,1);

			Console.WriteLine("Pick Ray:         {0}",ray);
			Matrix4 mpi = _mProjection.Inverted();
			mpi.Transpose();
			ray = mpi * ray;
			ray.Normalize();
			Console.WriteLine("Pick Ray (PROJ):  {0}",ray);

//			ray.Z = -1;
//			ray.W = 0;

			//Console.WriteLine("Pick Ray (CAM):   {0}",ray);
			Matrix4 mci = _mCamera.Inverted();
			mci.Transpose();
			ray =  mci * ray;

			Console.WriteLine("Pick Ray (CAM):   {0}",ray);

			//Console.WriteLine("Pick Ray Angles: x:{0} / y:{1}",x_arc,y_arc);
			//ray = Matrix4.CreateRotationY(-y_arc) * Matrix4.CreateRotationX( x_arc ) * ray;

			Vector3 pr = ray.Xyz.Normalized();
			if (pr.Z > 0){
				pr *= -1;
			}

			Console.WriteLine("Pick Ray (World): {0}",pr);
			Console.WriteLine("--------------------------------------------------");
			return pr;
		}


		/**
		 * Group of Methods: LookXXXX
		 * 
		 * Arrange Camera to point on/to/...
		 * 
		 **/

		public void lookAt(Vector3 position){
			Vector3 v = position - Position;
			v.Normalize();

			View = v;
		}




	}
}