#include <wayland-client.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <stdio.h>
#include "xdg-shell-client-protocol.h"

static struct wl_display *display;
static struct wl_registry *registry;
static struct wl_compositor *compositor;
static struct wl_shm *shm;
static struct xdg_wm_base *xdg_wm_base;
static struct wl_surface *surface;
static struct xdg_surface *xdg_surface;
static struct xdg_toplevel *xdg_toplevel;
static volatile int running = 1;
static int width = 800, height = 600;

static void registry_global(void *data, struct wl_registry *registry, uint32_t name, const char *interface, uint32_t version) {
    if (strcmp(interface, "wl_compositor") == 0) {
        compositor = wl_registry_bind(registry, name, &wl_compositor_interface, 1);
    } else if (strcmp(interface, "wl_shm") == 0) {
        shm = wl_registry_bind(registry, name, &wl_shm_interface, 1);
    } else if (strcmp(interface, "xdg_wm_base") == 0) {
        xdg_wm_base = wl_registry_bind(registry, name, &xdg_wm_base_interface, 1);
    }
}

static void registry_global_remove(void *data, struct wl_registry *registry, uint32_t name) {}

static const struct wl_registry_listener registry_listener = {
    .global = registry_global,
    .global_remove = registry_global_remove,
};

static void create_buffer();

static void xdg_surface_configure(void *data, struct xdg_surface *xdg_surface, uint32_t serial) {
    xdg_surface_ack_configure(xdg_surface, serial);
    create_buffer();
}

static const struct xdg_surface_listener xdg_surface_listener = {
    .configure = xdg_surface_configure,
};

static void xdg_toplevel_configure(void *data, struct xdg_toplevel *xdg_toplevel, int32_t w, int32_t h, struct wl_array *states) {
    if (w > 0) width = w;
    if (h > 0) height = h;
}

static void xdg_toplevel_close(void *data, struct xdg_toplevel *xdg_toplevel) {
    running = 0;
}

static const struct xdg_toplevel_listener xdg_toplevel_listener = {
    .configure = xdg_toplevel_configure,
    .close = xdg_toplevel_close,
};

static void create_buffer() {
    char name[32];
    sprintf(name, "/wayland-shm-%d", getpid());
    int stride = width * 4;
    int size = stride * height;
    int fd = shm_open(name, O_RDWR | O_CREAT, 0600);
    if (fd == -1) return;
    ftruncate(fd, size);
    void *data = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
    memset(data, 0xFF, size); // white
    struct wl_shm_pool *pool = wl_shm_create_pool(shm, fd, size);
    struct wl_buffer *buffer = wl_shm_pool_create_buffer(pool, 0, width, height, stride, WL_SHM_FORMAT_ARGB8888);
    wl_surface_attach(surface, buffer, 0, 0);
    wl_surface_damage(surface, 0, 0, width, height);
    wl_surface_commit(surface);
    wl_buffer_destroy(buffer);
    wl_shm_pool_destroy(pool);
    close(fd);
    shm_unlink(name);
    munmap(data, size);
}

void run_wayland() {
    display = wl_display_connect(NULL);
    if (!display) return;
    registry = wl_display_get_registry(display);
    wl_registry_add_listener(registry, &registry_listener, NULL);
    wl_display_dispatch(display);
    wl_display_roundtrip(display);
    if (!compositor || !shm || !xdg_wm_base) return;
    surface = wl_compositor_create_surface(compositor);
    xdg_surface = xdg_wm_base_get_xdg_surface(xdg_wm_base, surface);
    xdg_surface_add_listener(xdg_surface, &xdg_surface_listener, NULL);
    xdg_toplevel = xdg_surface_get_toplevel(xdg_surface);
    xdg_toplevel_add_listener(xdg_toplevel, &xdg_toplevel_listener, NULL);
    wl_surface_commit(surface);
    while (running && wl_display_dispatch(display) != -1) {}
    wl_display_disconnect(display);
}