import entities.config.GLConfigVariable;
import org.lwjgl.glfw.GLFWErrorCallback;
import org.lwjgl.opengl.GL;

import static org.lwjgl.glfw.Callbacks.glfwFreeCallbacks;
import static org.lwjgl.glfw.GLFW.*;
import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.system.MemoryUtil.NULL;

public class GLWindow {

    private long window;

    public long getWindow() {
        return this.window;
    }

    public void init() {
        initWindow();
        initRender();
    }

    public void swapWindow() {
        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    public void destroyWindow() {
        glfwFreeCallbacks(window);
        glfwDestroyWindow(window);
        glfwTerminate();
        glfwSetErrorCallback(null).free();
    }

    public boolean windowShouldClose() {
        return glfwWindowShouldClose(window);
    }

    private void initWindow() {
        GLFWErrorCallback.createPrint(System.err).set();

        if (!glfwInit()) throw new IllegalStateException("Unable to initialize GLFW");
        glfwWindowHint(GLFW_RESIZABLE, GLFW_FALSE);

        window = glfwCreateWindow(GLConfigVariable.WIDTH, GLConfigVariable.HEIGHT, GLConfigVariable.TITLE_NAME, GLConfigVariable.IS_FULL_SCREEN ? glfwGetPrimaryMonitor() : NULL, NULL);
        if (window == NULL) throw new RuntimeException("Failed to create the window.");

        glfwMakeContextCurrent(window);
        glfwSwapInterval(1);
        glfwShowWindow(window);
    }

    private void initRender() {
        GL.createCapabilities();
        glClearColor(1.0f, 1.0f, 1.0f, 1.0f);

        glEnable(GL_TEXTURE_2D);
        glEnable(GL_BLEND);
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    }
}