/*-
 * Copyright (C) 2025  Alessandro Iezzi <aiezzi AT alessandroiezzi PERIOD it>
 *
 * This file is part of Tris Game.
 *
 * Tris Game is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Tris Game is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Tris Game.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <stdlib.h>
#include <GL/gl.h>
#include <GL/glx.h>
#include <X11/Xlib.h>
#include "../../util.h"

static Display *display;
static Window window;
static GLXContext gl_context;

void cleanup(void);

static Display *
ui_open_display(void)
{
	Display *display = XOpenDisplay(NULL);
	if (!display) {
		log_error("Can't open X11 display");
		exit(1);
	}

	return display;
}

static XVisualInfo *
gl_choose_visual(int screen)
{
	GLint attribs[] = { GLX_RGBA, GLX_DEPTH_SIZE, 24, GLX_DOUBLEBUFFER, None };
	XVisualInfo *vi = glXChooseVisual(display, screen, attribs);
	if (!vi) {
		log_error("No compatible Visual found");
		exit(1);
	}

	return vi;
}

static XSetWindowAttributes
ui_get_attributes(Window root, XVisualInfo *vi)
{
	Colormap colormap = XCreateColormap(display, root, vi->visual, AllocNone);
	XSetWindowAttributes swa;
	swa.colormap = colormap;
	swa.event_mask = ExposureMask | KeyPressMask;

	return swa;
}

static Window
ui_create_window(Window root, XVisualInfo *vi, int width, int height)
{
	XSetWindowAttributes swa = ui_get_attributes(root, vi);
	Window window = XCreateWindow(display, root, 0, 0, width, width, 0, vi->depth, InputOutput, vi->visual,
	                              CWColormap | CWEventMask, &swa);
	XMapWindow(display, window);

	return window;
}

static void
ui_set_title(Display *display, Window window, const char *title)
{
	XStoreName(display, window, title);
}

void
ui_init()
{
	display = ui_open_display();

	int screen = DefaultScreen(display);
	Window root = RootWindow(display, screen);

	XVisualInfo *vi = gl_choose_visual(screen);
	window = ui_create_window(root, vi, 640, 480);
	ui_set_title(display, window, "Tris game");

	gl_context = glXCreateContext(display, vi, NULL, GL_TRUE);
	glXMakeCurrent(display, window, gl_context);
}

void
ui_loop(void (*draw_frame)())
{
	XEvent event;
	while (1) {
		XNextEvent(display, &event);
		if (event.type == Expose) {
			draw_frame();
			glXSwapBuffers(display, window);
		}
		if (event.type == KeyPress) {
			break;
		}
	}

	cleanup();
}

void
cleanup(void) {
	glXMakeCurrent(display, None, NULL);
	glXDestroyContext(display, gl_context);
	XDestroyWindow(display, window);
	XCloseDisplay(display);
}