/*******************************************************************************
 * Copyright (c) 2012, 2013 Association for Decentralized Information Management in
 * Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.g3d.shape;

import java.util.ArrayList;
import java.util.List;

import javax.vecmath.AxisAngle4d;
import javax.vecmath.Vector3d;

import org.simantics.g3d.math.MathTools;


public class Tube {
	List<Vector3d> vertices;
	List<Color4d> colors;
	List<Double> radiis;
	Double radius = 1.0;
	int resolution = 8;
	
	
	public void setResolution(int resolution) {
		if (resolution > 2)
			this.resolution = resolution;
	}
	
	public void setVertices(List<Vector3d> vertices) {
		this.vertices = vertices;
	}

	public void setColors(List<Color4d> colors) {
		this.colors = colors;
	}
	
	public void setRadiis(List<Double> radiis) {
		this.radiis = radiis;
	}
	
	public void setRadius(Double radius) {
		this.radius = radius;
	}
	
	
	
	public Mesh create() {
		if (vertices.size() < 2 )
			throw new IllegalArgumentException("Tube must have at least two vertices");
		
		Vector3d t = new Vector3d();
		
		for (int i = 0; i < vertices.size() - 1; i++) {
			t.set(vertices.get(i+1));
			t.sub(vertices.get(i));
			if (t.lengthSquared() < 0.0001)
				throw new IllegalArgumentException("vertices at index " + i + " are too close to each other");
		}
		
		List<Vector3d> points = new ArrayList<Vector3d>(vertices.size()*resolution);
		List<Vector3d> normals = new ArrayList<Vector3d>(vertices.size()*resolution);
		
		for (int i = 0; i < vertices.size(); i++) {
			createCircle(i,points,normals);
		}
		
		int index[] = new int[(vertices.size()-1)*resolution*6];
		
		createIndices(index);
		List<Integer> indices = new ArrayList<Integer>();
		for (int i = 0; i < index.length; i++) {
			indices.add(index[i]);
		}
		
		
		
		vertices.clear();
		if (colors != null)
			colors.clear();
		if (radiis != null)
			radiis.clear();
		
		return new Mesh(points, normals, indices);
		
	}
	
	private void createCircle(int i, List<Vector3d> points, List<Vector3d> normals) {
		final Vector3d up = new Vector3d(0,1,0);
		final Vector3d up2 = new Vector3d(0,0,1);
		Vector3d p = vertices.get(i);
		Vector3d t = getTangent(i);
		Vector3d n = new Vector3d();
		if (up.dot(t) < 0.99) {
			n.cross(up, t);
		} else {
			n.cross(up2, t);
		}
		n.normalize();
		if (radiis != null) {
			n.scale(radiis.get(i));
		} else {
			n.scale(radius);
		}
		
		for (int index = 0; index < resolution; index ++) {
			Vector3d v;
			if (index == 0) {
				v = new Vector3d(n);
				
			} else {
				AxisAngle4d aa = new AxisAngle4d(t, (Math.PI * 2 * (double)index)/(double)resolution);
				v = new Vector3d();
				MathTools.rotate(MathTools.getQuat(aa), n, v);
			}
			//int vIndex = (i*resolution + index)*3;
			Vector3d pt = new Vector3d(p);
			pt.add(v);
			//points.set(vIndex, pt);
			points.add(pt);
			v.normalize();
			//normals.set(vIndex, v);
			normals.add(v);
		}
	}
	
	private Vector3d getTangent(int i) {
		Vector3d p,n;
		if (i == 0) {
			p = vertices.get(0);
			n = vertices.get(1);
		} else if (i == vertices.size() - 1) {
			p = vertices.get(i-1);
			n = vertices.get(i);
		} else {
			p = vertices.get(i-1);
			n = vertices.get(i+1);
		}
		n = new Vector3d(n);
		n.sub(p);
		n.normalize();
		return n;
	}
	
	private void createIndices(int index[]) {
		for (int c = 0; c < vertices.size() - 1; c++) {
			for (int s = 0; s < resolution; s++) {
				int ii = (c * resolution + s) * 6;
				int iv = c*resolution + s;
				
				/*
			     iv+1 ---- iv + resolution + 1
				      | /|
				      |/ |
				   iv ---- iv + resolution 
				*/
				if (s < resolution - 1) {
					index[ii+2] = iv;
					index[ii+1] = iv+resolution;
					index[ii+0] = iv+resolution+1;
					
					index[ii+5] = iv;
					index[ii+4] = iv+resolution+1;
					index[ii+3] = iv+1;
				} else {
					index[ii+2] = iv;
					index[ii+1] = iv+resolution;
					index[ii+0] = iv+1;
					
					index[ii+5] = iv;
					index[ii+4] = iv+1;
					index[ii+3] = iv+1-resolution;
				}
			}
		}
	}

}