package org.example;

import org.joml.*;
import org.lwjgl.*;
import org.lwjgl.Version;
import org.lwjgl.glfw.*;
import org.lwjgl.opengl.*;
import org.lwjgl.system.*;

import java.lang.Math;
import java.nio.*;
import java.io.*;
import java.text.MessageFormat;

import static org.lwjgl.glfw.Callbacks.*;
import static org.lwjgl.glfw.GLFW.*;
import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.opengl.GL15.*;
import static org.lwjgl.opengl.GL20.*;
import static org.lwjgl.opengl.GL30.*;
import static org.lwjgl.system.MemoryStack.*;
import static org.lwjgl.system.MemoryUtil.*;

import com.mokiat.data.front.parser.*;
import org.lwjgl.system.MemoryStack;

public class Game
{
    public static final float Z_FAR = 1000.0f;
    public static final float Z_NEAR = 0.1f;
    public static final float FOV = (float) Math.toRadians(90.0f);
    private long window;
    private Matrix4f projection_matrix;

    public void run()
    {
        System.out.println("Running LWJGL Version " + Version.getVersion() + ".");

        init();
        loop();

        // Free the window callbacks and destroy the window
        glfwFreeCallbacks(window);
        glfwDestroyWindow(window);

        // Terminate GLFW and free the error callback
        glfwTerminate();
        glfwSetErrorCallback(null).free();
    }

    public void init()
    {
        GLFWErrorCallback.createPrint(System.err).set();

        if (!glfwInit())
            throw new IllegalStateException("Unable to Initialize GLFW");

        // Configure GLFW
        glfwDefaultWindowHints(); // optional, the current window hints are already the default
        glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE); // the window will stay hidden after creation
        glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE); // the window will be resizable

        // Create the window
        window = glfwCreateWindow(300, 300, "Hello World!", NULL, NULL);
        if ( window == NULL )
            throw new RuntimeException("Failed to create the GLFW window");

        // Setup a key callback. It will be called every time a key is pressed, repeated or released.
        glfwSetKeyCallback(window, (window, key, scancode, action, mods) -> {
            if ( key == GLFW_KEY_ESCAPE && action == GLFW_RELEASE )
                glfwSetWindowShouldClose(window, true); // We will detect this in the rendering loop
        });

        // Get the thread stack and push a new frame
        try ( MemoryStack stack = stackPush() ) {
            IntBuffer pWidth = stack.mallocInt(1); // int*
            IntBuffer pHeight = stack.mallocInt(1); // int*

            // Get the window size passed to glfwCreateWindow
            glfwGetWindowSize(window, pWidth, pHeight);

            // Get the resolution of the primary monitor
            GLFWVidMode vidmode = glfwGetVideoMode(glfwGetPrimaryMonitor());

            // Center the window
            glfwSetWindowPos(
                    window,
                    (vidmode.width() - pWidth.get(0)) / 2,
                    (vidmode.height() - pHeight.get(0)) / 2
            );
        } // the stack frame is popped automatically

        // Make the OpenGL context current
        glfwMakeContextCurrent(window);
        // Enable v-sync
        glfwSwapInterval(1);

        // Make the window visible
        glfwShowWindow(window);
    }

    private void loop()
    {
        // Setup world
        World world = new World();

        // Do open gl stuff
        GL.createCapabilities();
        glClearColor(0.0f, 0.0f, 0.0f, 0.0f);

        // Add stuff to world
        world.addEntity(new Entity("/objs/cube.obj", "/shaders/shader.frag", "/shaders/shader.vert"));

        // Calculate Perspective Matrix
        int w, h;
        glfwGetWindowSize(window, w, h);
        float aspect_ratio = (float) ;
        this.projection_matrix = new Matrix4f().perspective(FOV, )

        // Main loop or something
        while ( !glfwWindowShouldClose(window) )
        {
            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

            glfwSwapBuffers(window);

            for (Entity entity : world.entities)
                render(entity);

            glfwPollEvents();
        }
    }

    public void render(Entity entity) {
        entity.shader.bind();

        glBindVertexArray(entity.mesh.vao_id);
        glEnableVertexAttribArray(0);
        glEnableVertexAttribArray(1);
        glDrawElements(GL_TRIANGLES, entity.mesh.vertex_count, GL_UNSIGNED_INT, 0);
    }

    public static void main(String[] args)
    {
        new Game().run();
    }


}