/**
 * GLCameraController
 * 
 * Default camera controller using mouse dragging 
 * 
 **/

using System;

using System.Drawing;
using OpenTK;
using System.Drawing.Drawing2D;

using org.budnhead.core;

namespace org.budnhead.graphics
{
	public class GLCameraController
	{
		private SceneWindow sceneWindow;
		private GLCamera camera;

		private Point mouseCapturePosition;
		private bool mouseCaptured;

		public Limits LimitUpDown { get; set; } = new Limits(-MathHelper.PiOver2,-MathHelper.Pi / 16);
		public Limits LimitLeftRight { get; set; } = new Limits(-Math.PI, Math.PI);


		public GLCameraController(GLCamera camera, SceneWindow sceneWindow){
			this.sceneWindow = sceneWindow;
			this.camera = camera;
		}
		public GLCameraController(GLCamera camera){
			this.sceneWindow = null;
			this.camera = camera;
		}

		public SceneWindow SceneWindow {
			get { return sceneWindow; }
			set { 
				releaseSceneWindow();
				sceneWindow = value;
				allocSceneWindow();
			}
		}

		public GLCamera Camera {
			get { return this.camera; }
			set { this.camera = value; }
		}


		private void releaseSceneWindow(){
			if (sceneWindow != null){
				sceneWindow.MouseWheel -= SceneWindow_MouseWheel;
				sceneWindow.MouseDown -= SceneWindow_MouseDown;
				sceneWindow.MouseUp -= SceneWindow_MouseUp;
				sceneWindow.MouseMove -= SceneWindow_MouseMove;
			}
		}
		private void allocSceneWindow(){
			if (sceneWindow != null){
				sceneWindow.MouseWheel += SceneWindow_MouseWheel;
				sceneWindow.MouseDown += SceneWindow_MouseDown;
				sceneWindow.MouseUp += SceneWindow_MouseUp;
				sceneWindow.MouseMove += SceneWindow_MouseMove;
			}
		}

		private void captureMouse()
		{
			mouseCapturePosition = new Point(sceneWindow.Mouse.X, sceneWindow.Mouse.Y);
			mouseCaptured = true;
			SceneWindow.CursorVisible = false;
		}

		private void releaseMouse()
		{
			mouseCaptured = false;
			SceneWindow.CursorVisible = true;
		}



		void SceneWindow_MouseWheel(object sender, OpenTK.Input.MouseWheelEventArgs e)
		{
			Vector3 p,  // Camera position
					v;  // Camera viewing direction

			p = camera.Position;
			v = camera.View;

			p += v * e.Delta;

			camera.Position = p;
		}

		void SceneWindow_MouseDown(object sender, OpenTK.Input.MouseButtonEventArgs e)
		{
			switch (e.Button)
			{
				case OpenTK.Input.MouseButton.Left:
					//markMouse(e.X,e.Y);
					break;
				case OpenTK.Input.MouseButton.Right:
					captureMouse();
					break;
			}
		}

		void SceneWindow_MouseUp(object sender, OpenTK.Input.MouseButtonEventArgs e)
		{
			releaseMouse();
		}

		void SceneWindow_MouseMove(object sender, OpenTK.Input.MouseMoveEventArgs e)
		{
			if (mouseCaptured)
			{
				Point delta = new Point(e.X - mouseCapturePosition.X, e.Y - mouseCapturePosition.Y);
				onMouseCapturedMove(delta);
				mouseCapturePosition = e.Position;
			}
			else {
			}
		}


		protected virtual void onMouseCapturedMove(Point delta)
		{
			rotateLeftRight(((float)delta.X) / -50.0f);
			rotateUpDown(((float)delta.Y) / -50.0f);
		}

		public void rotateUpDown(float arc)
		{
			Vector3 v,	// view direction
					t, 	// top direction
					r;  // rotation axis

			v = camera.View;
			t = camera.Top;
			r = Vector3.Cross(v, t);

			Matrix3 mrot = Matrix3.CreateFromAxisAngle(r, arc);

			v *= mrot;
			t *= mrot;

			camera.View = v;
			camera.Top = t;
		}
		public void rotateLeftRight(float arc)
		{
			Vector3 v,  // view direction
					t,  // top direction
					r;  // rotation axis

			v = camera.View;
			t = camera.Top;
			r = Vector3.UnitZ;

			Matrix3 mrot = Matrix3.CreateFromAxisAngle(r, arc);

			v *= mrot;
			t *= mrot;

			camera.View = v;
			camera.Top = t;
		}

		public void walk(float distance)
		{
		}

		public void strafe(float distance)
		{
		}
	}
}