package org.xfe.engine;

import org.joml.*;

import java.lang.Math;

public class Engine
{
    public static final int TARGET_UPS = 30;
    private final GameLogic gameLogic;
    private final Render render;
    private final Window window;
    private final World world;
    private int target_fps;
    private int target_ups;
    private boolean running;

    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);
    public static final boolean WIREFRAME_MODE = false;
    public Engine(String window_title, Window.WindowOptions opts, GameLogic gameLogic) {
        window = new Window(window_title, opts, () -> {
            resize();
            return null;
        });
        target_fps = opts.fps;
        target_ups = opts.ups;

        this.gameLogic = gameLogic;
        this.render = new Render(window);
        this.world = new World();

        gameLogic.init(window, world, render);

        this.running = true;
    }

    private void cleanup() {
        this.gameLogic.cleanup();
        this.render.cleanup();
        this.world.cleanup();
        this.window.cleanup();
    }

    private void resize() {

    }

    private void run() {
        long initialTime = System.currentTimeMillis();
        float timeU = 1000.0f / target_ups;
        float timeR = target_fps > 0 ? 1000.0f / target_fps : 0;
        float deltaUpdate = 0;
        float deltaFps = 0;

        long updateTime = initialTime;
        while (running && !window.windowShouldClose()) {
            window.pollEvents();

            long now = System.currentTimeMillis();
            deltaUpdate += (now - initialTime) / timeU;
            deltaFps += (now - initialTime) / timeR;

            if (target_fps <= 0 || deltaFps >= 1) {
                gameLogic.input(window, world, now - initialTime);
            }

            if (deltaUpdate >= 1) {
                long diffTimeMillis = now - updateTime;
                gameLogic.update(window, world, diffTimeMillis);
                updateTime = now;
                deltaUpdate--;
            }

            if (target_fps <= 0 || deltaFps >= 1) {
                render.render(window, world);
                deltaFps--;
                window.update();
            }
            initialTime = now;
        }

        cleanup();
    }

    public void start() {
        running = true;
        run();
    }

    public void stop() {
        running = false;
    }
}