package de.gamezock.metacraft.data;

import java.nio.IntBuffer;
import java.util.List;
import java.util.Vector;

import javax.vecmath.Point3f;
import javax.vecmath.Vector3f;


public abstract class Map {
  private float[][] heightmap;
  
  private VertexBuffer vertexBuffer;
  private IntBuffer indexBuffer;
  
	
	private void setVertex(int x, int y, Point3f vertex) {
    vertexBuffer.setVertex(getVertexIndex(x, y), vertex);
  }
  
  private Point3f getVertex(int x, int y) {
    return vertexBuffer.getVertex(getVertexIndex(x, y));
  }
  
  private int getVertexIndex(int x, int y) {
    if(y >= getHeight()) {
      return getWidth()*getHeight() + (y-getHeight())*(getWidth()-1) + x;
    } else {
      return y*getWidth() + x;
    }
  }
  
  public VertexBuffer getVertexBuffer() {
    return vertexBuffer;
  }
  
  public IntBuffer getIndexBuffer() {
    return indexBuffer;
  }
	
	protected void createMapData(float[][] heightmap) {
	  this.heightmap = heightmap;
	  
	  List<IndexedTriangle> triangleData = new Vector<IndexedTriangle>();
	  
	  vertexBuffer = new VertexBuffer(getWidth()*getHeight() + (getWidth()-1)*(getHeight()-1));
	  
	  for(int x = 0; x < getWidth(); ++x) {
	    for(int y = 0; y < getHeight(); ++y) {
	      setVertex(x, y, new Point3f(x, y, heightmap[x][y]));

	      if(x > 0 && y > 0) {
	        Point3f center = new Point3f();

	        center.add(getVertex(x-1, y-1));
	        center.add(getVertex(x, y-1));
	        center.add(getVertex(x-1, y));
	        center.add(getVertex(x, y));

	        center.scale(0.25f);

	        setVertex(x-1, getHeight()+y-1, center);
	      }
	    }
	  }
	  
	  for(int x = 0; x < getWidth()-1; ++x) {
	    for(int y = 0; y < getHeight()-1; ++y) {
	      for(int i = 0; i < 4; ++i) {
	        int i_1 = (i+1)%4;
	        int i_2 = (i+2)%4;

	        int v1 = getVertexIndex(x + i_1/2, y + i/2);
	        int v2 = getVertexIndex(x, getHeight()+y);
	        int v3 = getVertexIndex(x + i_2/2, y + i_1/2);

	        triangleData.add(new IndexedTriangle(vertexBuffer, v1, v2, v3));
	      }
	    }
	  }
	  
	  indexBuffer = IntBuffer.allocate(3 * triangleData.size());
	  for(IndexedTriangle t : triangleData) {
	    Vector3f normal = t.getNormal();
      
      for(int i = 0; i < 3; ++i) {
        int index = t.getIndex(i);
        
        Vector3f vNormal = vertexBuffer.getNormal(index);
        vNormal.add(normal);
        vertexBuffer.setNormal(index, vNormal);
        
        indexBuffer.put(index);
      }
	  }
	  
	  for(int i = 0; i < vertexBuffer.getSize(); ++i) {
      Vector3f normal = vertexBuffer.getNormal(i);
      normal.normalize();
      vertexBuffer.setNormal(i, normal);
    }
	}
	
	public int getWidth() {
	  return heightmap.length;
	}
	
	public int getHeight() {
	  return heightmap[0].length;
	}
}