package ecumene.opengl;

import java.nio.FloatBuffer;

import org.lwjgl.BufferUtils;
import org.lwjgl.opengl.GL11;
import org.lwjgl.opengl.GL15;
import org.lwjgl.opengl.GL30;

/**
 * Links many vertices together and bind their attributes
 * into one vertex buffer object
 *
 * @author Ecumene
 */
public class Model {
	/*The model information*/
	private Vertex[] model;

	/**The model's per-vertex positions attribute*/
	private VertexAttrib positions;
	/**The model's per-vertex texture uv attribute*/
	private VertexAttrib textureUVs;
	/**The model's per-vertex normal attribute*/
	private VertexAttrib normals;
	/**The model's per-vertex color attribute*/
	private VertexAttrib colors;
	/**The model's drawing order*/
	private float[] indices;

	/**The vertex attribute array buffer*/
	private int va;

	/**The vertex indices id*/
	private int vi;

	/**
	 * Initializes the model with an array of vertices
	 *
	 * @param model The model information
	 */
	public Model(Vertex ... model){
		this.model = model;
	}

	/**
	 * Initializes the model with a size
	 *
	 * @param size The amount of vertices the model is intended
	 * to hold
	 */
	public Model(int size){
		model = new Vertex[size];
	}

	/**
	 * Adds a vertex to the current model
	 *
	 * @param index The index to add the vertex at
	 * @param vertices The vertex to add
	 */
	public void add(int index, Vertex vertex){
		model[index] = vertex;
	}

	/**
	 * Sets the drawing order of the mode's vertices
	 * (Sets indices)
	 * @param values The drawing order to set
	 */
	public void setDrawingOrder(float...values){
		indices = values;
	}

	/**
	 * Links the model's vertex data with the vertex attribute objects
	 *
	 * @param positions The vertex positions vertex attribute ID
	 * @param textures The vertex texture coordinate vertex attribute ID
	 * @param colors The vertex color vertex attribute ID
	 * @param normals The vertex normal vertex attribute ID
	 */
	public void link(int positions, int textures, int colors, int normals){
		float[] vertexPos = new float[model.length * 4];
		float[] textureUV = new float[model.length * 2];
		float[] color = new float[model.length * 4];
		float[] normal = new float[model.length * 3];

		for(int i = 0; i < model.length; i++){
			vertexPos[4*i+0] = model[i].position.x;
			vertexPos[4*i+1] = model[i].position.y;
			vertexPos[4*i+2] = model[i].position.z;
			vertexPos[4*i+3] = model[i].position.w;

			textureUV[2*i+0] = model[i].textureUV.x;
			textureUV[2*i+1] = model[i].textureUV.x;

			color[4*i+0] = model[i].color.getRed();
			color[4*i+1] = model[i].color.getGreen();
			color[4*i+2] = model[i].color.getBlue();
			color[4*i+3] = model[i].color.getAlpha();

			normal[3*i+0] = model[i].normal.x;
			normal[3*i+1] = model[i].normal.y;
			normal[3*i+2] = model[i].normal.z;
		}

		FloatBuffer indicesBuffer = BufferUtils.createFloatBuffer(indices.length);
		indicesBuffer.put(indices);
		indicesBuffer.flip();

		va = GL15.glGenBuffers();
		GL30.glBindVertexArray(va);
			this.positions = new VertexAttrib(positions, 4, vertexPos);
			this.textureUVs = new VertexAttrib(textures, 2, textureUV);
			this.colors = new VertexAttrib(colors, 4, color);
			this.normals = new VertexAttrib(normals, 3, normal);
		GL30.glBindVertexArray(0);

		vi = GL15.glGenBuffers();
		GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, vi);
		GL15.glBufferData(GL15.GL_ELEMENT_ARRAY_BUFFER, indicesBuffer, GL15.GL_STATIC_DRAW);
		GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, 0);
		System.out.println("linkeed");
	}

	/**
	 * Draws the vertex attribute object
	 * @param mode The mode to draw
	 */
	public void render(int mode){
		GL30.glBindVertexArray(va);
			positions.bind();
			textureUVs.bind();
			colors.bind();
			normals.bind();
				GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, vi);
				GL11.glDrawElements(mode, indices.length, GL11.GL_UNSIGNED_BYTE, 0);
				GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, 0);
				System.out.println("rendered");
			positions.unbind();
			textureUVs.unbind();
			colors.unbind();
			normals.unbind();
			System.out.println("\n");
		GL30.glBindVertexArray(0);
	}

	/**
	 * @return The model's vertices
	 */
	public Vertex[] getVertices(){
		return model;
	}
}