package engine.graphics;

import engine.utils.BufferUtils;

import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.opengl.GL15.*;
import static org.lwjgl.opengl.GL30.*;

public class VertexArray {

    private int VAO ,VBO, EBO, CBO, TBO;
    private int count;

    public VertexArray(float[] vertices, byte[] indices, float[] color, float[] texture) {
        count = indices.length;
        // VERTEX ARRAY OBJECT
        VAO = glGenVertexArrays();
        glBindVertexArray(VAO);

        glEnableVertexAttribArray(0);

        // VERTEX BUFFER OBJECT
        createVertexBufferObject(vertices);
        // COLOR BUFFER OBJECT
        if (color != null) createColorBufferObject(color);
        // TEXTURE BUFFER OBJECT
        if (texture != null) createTextureBufferObject(texture);

        EBO = glGenBuffers();
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
        glBufferData(GL_ELEMENT_ARRAY_BUFFER, BufferUtils.createByteBuffer(indices), GL_STATIC_DRAW);
        glBindBuffer(GL_ARRAY_BUFFER, 0);
        glBindVertexArray(0);

    }

    private void createVertexBufferObject(float[] vertices){
        VBO = glGenBuffers();
        glBindBuffer(GL_ARRAY_BUFFER, VBO);
        glBufferData(GL_ARRAY_BUFFER, BufferUtils.createFloatBuffer(vertices), GL_STATIC_DRAW);
        glVertexAttribPointer(0, 3, GL_FLOAT, false, 0, 0);
        glEnableVertexAttribArray(0);
    }

    private void createColorBufferObject(float[] color){
        CBO = glGenBuffers();
        glBindBuffer(GL_ARRAY_BUFFER, CBO);
        glBufferData(GL_ARRAY_BUFFER, BufferUtils.createFloatBuffer(color), GL_STATIC_DRAW);
        glVertexAttribPointer(1, 3, GL_FLOAT, false, 0, 0);
        glEnableVertexAttribArray(1);
    }

    private void createTextureBufferObject(float[] texture){
        TBO = glGenBuffers();
        glBindBuffer(GL_ARRAY_BUFFER, TBO);
        glBufferData(GL_ARRAY_BUFFER, BufferUtils.createFloatBuffer(texture), GL_STATIC_DRAW);
        glVertexAttribPointer(2, 2, GL_FLOAT, false, 0, 0);
        glEnableVertexAttribArray(2);
    }

    public void swapVertexBufferObject(float[] vertices){
        glBindBuffer(GL_ARRAY_BUFFER, VBO);
        glBufferData(GL_ARRAY_BUFFER, BufferUtils.createFloatBuffer(vertices), GL_STATIC_DRAW);
    }

    public void swapTextureBufferObject(float [] texture){
        glBindBuffer(GL_ARRAY_BUFFER, TBO);
        glBufferData(GL_ARRAY_BUFFER, BufferUtils.createFloatBuffer(texture), GL_STATIC_DRAW);
    }

    public void bind(){
        glBindVertexArray(this.VAO);
    }

    public void unbind(){
        glBindVertexArray(0);
    }

    public void draw(){
        glDrawElements(GL_TRIANGLES, count, GL_UNSIGNED_BYTE, 0);
    }

    public void render(){
        bind();
        draw();
        unbind();
    }

}