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 class TestTile implements TileData {
  private List<IndexedTriangle> triangleData;
  private float[][] heightmap;
  private VertexBuffer vertexBuffer;
  private IntBuffer indexBuffer;
  
  
  public TestTile() {
    heightmap = new float[getSize()+1][getSize()+1];
    
    for(int i = 0; i <= getSize(); ++i) {
      for(int j = 0; j <= getSize(); ++j) {
        heightmap[i][j] = ((i-4)*(i-4)+(j-4)*(j-4))*0.05f;
      }
    }
    
    createTileData();
  }
  
  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 > getSize()) {
      return (getSize()+1)*(getSize()+1) + (y-getSize()-1)*getSize() + x;
    } else {
      return y*(getSize()+1) + x;
    }
  }
  
  private void createTileData() {
    triangleData = new Vector<IndexedTriangle>();
    
    vertexBuffer = new VertexBuffer((getSize()+1)*(getSize()+1) + getSize()*getSize());
    
    for(int x = 0; x < heightmap.length; ++x) {
      for(int y = 0; y < heightmap[x].length; ++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, y+getSize(), center);
        }
      }
    }
    
    for(int x = 0; x < heightmap.length-1; ++x) {
      for(int y = 0; y < heightmap[x].length-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, y+getSize()+1);
          int v3 = getVertexIndex(x + i_2/2, y + i_1/2);
          
          triangleData.add(new IndexedTriangle(vertexBuffer, v1, v2, v3));
        }
      }
    }
    
    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);
      }
    }
    
    for(int i = 0; i < vertexBuffer.getSize(); ++i) {
      Vector3f normal = vertexBuffer.getNormal(i);
      normal.normalize();
      vertexBuffer.setNormal(i, normal);
    }
    
    indexBuffer = IntBuffer.allocate(3 * triangleData.size());
    for(IndexedTriangle t : triangleData) {
      for(int i = 0; i < 3; ++i) {
        indexBuffer.put(t.getIndex(i));
      }
    }
  }
  
  @Override
  public int getSize() {
    return 8;
  }
  
  @Override
  public float[][] getHeightmap() {
    return heightmap;
  }

  @Override
  public TileType getType() {
    return new TileType();
  }

  @Override
  public List<IndexedTriangle> getTriangles() {
    return triangleData;
  }

  @Override
  public IntBuffer getIndexBuffer() {
    return indexBuffer;
  }
}