/*
    src/nanogui_helloworld.cpp -- C++ version of an helloworld example application
*/

#include <nanogui/opengl.h>
#include <nanogui/screen.h>
#include <nanogui/window.h>
#include <nanogui/layout.h>
#include <nanogui/label.h>
#include <nanogui/button.h>

#include <iostream>

using namespace nanogui;

class HelloWorldApplication : public Screen {
public:
    HelloWorldApplication() : Screen(Vector2i(400, 300), "NanoGUI Hello World") {
        inc_ref();
        window = new Window(this, "Demo Window");
        window->set_layout(new BoxLayout(Orientation::Vertical, Alignment::Middle, 20, 20));
        resize_event(size());

        new Label(window, "NanoGUI Demo", "sans-bold");

        Button *b = new Button(window, "Say hello!");
        b->set_callback([] { std::cout << "Well, 'ello there!" << std::endl; });
        b->set_tooltip("Push me!");

        perform_layout();
    }

    virtual bool resize_event(const Vector2i &size) {
        window->set_fixed_size(size);
        window->set_size(size);
        window->center();
        window->perform_layout(nvg_context());
        return true;
    }

    virtual bool keyboard_event(int key, int scancode, int action, int modifiers) {
        if (Screen::keyboard_event(key, scancode, action, modifiers))
            return true;
        if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS) {
            set_visible(false);
            return true;
        }
        return false;
    }

    virtual void draw(NVGcontext *ctx) {
        /* Draw the user interface */
        Screen::draw(ctx);
    }

private:
    Window *window;
};

int main(int /* argc */, char ** /* argv */) {
    try {
        nanogui::init();

        /* scoped variables */ {
            ref<HelloWorldApplication> app = new HelloWorldApplication();
            app->dec_ref();
            app->draw_all();
            app->set_visible(true);
            nanogui::mainloop(1 / 60.f * 1000);
        }

        nanogui::shutdown();
    } catch (const std::exception &e) {
        std::string error_msg = std::string("Caught a fatal error: ") + std::string(e.what());
        #if defined(_WIN32)
            MessageBoxA(nullptr, error_msg.c_str(), NULL, MB_ICONERROR | MB_OK);
        #else
            std::cerr << error_msg << std::endl;
        #endif
        return -1;
    } catch (...) {
        std::cerr << "Caught an unknown error!" << std::endl;
    }

    return 0;
}