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


struct client_state {
    /* Globals */
    struct wl_display *wl_display;
    struct wl_registry *wl_registry;
    struct wl_compositor *wl_compositor;
    struct wl_shm *wl_shm;
    struct xdg_wm_base *xdg_wm_base;
    /* Objects */
    struct wl_buffer *wl_buffer;
    struct wl_surface *wl_surface;
    struct xdg_surface *xdg_surface;
    struct xdg_toplevel *xdg_toplevel;
};

int WIDTH = 480;
int HEIGHT = 360;

/*
 * Create a new, unique, anonymous file of the given size, and
 * return the file descriptor for it. The file descriptor is set
 * CLOEXEC. The file is immediately suitable for mmap()'ing
 * the given size at offset zero.

 * The file is suitable for buffer sharing between processes by
 * transmitting the file descriptor over Unix sockets using the
 * SCM_RIGHTS methods.
 */
int
os_create_anonymous_file(off_t size)
{
    int fd;
    fd = memfd_create("wayland-shm", MFD_CLOEXEC);

    if (fd < 0)
        return -1;

    if (ftruncate(fd, size) < 0) {
        close(fd);
        return -1;
    }

    return fd;
}

static struct wl_buffer *
create_buffer(struct client_state *state) {
    struct wl_shm_pool *pool;
    int stride = WIDTH * 4; // 4 bytes per pixel
    int size = stride * HEIGHT;
    int fd;
    struct wl_buffer *buff;

    fd = os_create_anonymous_file(size);
    if (fd < 0) {
        fprintf(stderr, "creating a buffer file for %d B failed: %m\n",
                size);
        exit(1);
    }

    void *shm_data = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
    if (shm_data == MAP_FAILED) {
        fprintf(stderr, "mmap failed: %m\n");
        close(fd);
        exit(1);
    }

    uint32_t *pixel = shm_data;

    fprintf(stderr, "Painting pixels\n");
//    for (int n =0; n < WIDTH*HEIGHT; n++) {
//        *pixel++ = 0xffff;
//    }
    /* Draw checkerboxed background */
    for (int y = 0; y < HEIGHT; ++y) {
        for (int x = 0; x < WIDTH; ++x) {
            if ((x + y / 8 * 8) % 16 < 8)
                pixel[y * WIDTH + x] = 0xFF666666;
            else
                pixel[y * WIDTH + x] = 0xFFEEEEEE;
        }
    }


    pool = wl_shm_create_pool(state->wl_shm, fd, size);
    buff = wl_shm_pool_create_buffer(pool, 0,
                                     WIDTH, HEIGHT,
                                     stride,
                                     WL_SHM_FORMAT_XRGB8888);
    //wl_buffer_add_listener(buffer, &buffer_listener, buffer);
    wl_shm_pool_destroy(pool);
    return buff;
}

static void
handle_configure(void *data, struct xdg_surface *xdg_surface, uint32_t serial)
{
    struct client_state *state = data;
    xdg_surface_ack_configure(xdg_surface, serial);
    fprintf(stderr, "xdg_surface configured\n");

    state->wl_buffer = create_buffer(state);

    wl_surface_attach(state->wl_surface, state->wl_buffer, 0, 0);
    //wl_surface_damage(surface, 0, 0, WIDTH, HEIGHT);
    wl_surface_commit(state->wl_surface);
}

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

static void
shm_format(void *data, struct wl_shm *wl_shm, uint32_t format)
{
    //struct display *d = data;

    //        d->formats |= (1 << format);
    fprintf(stderr, "Format %d\n", format);
}

struct wl_shm_listener shm_listener = {
        shm_format
};

static void
xdg_wm_base_ping(void *data, struct xdg_wm_base *xdg_wm_base, uint32_t serial)
{
    xdg_wm_base_pong(xdg_wm_base, serial);
}

static const struct xdg_wm_base_listener xdg_wm_base_listener = {
        .ping = xdg_wm_base_ping,
};

static void
global_registry_handler(void *data, struct wl_registry *registry, uint32_t id,
               const char *interface, uint32_t version)
{
    struct client_state *state = data;

    if (strcmp(interface, wl_compositor_interface.name) == 0) {
        state->wl_compositor = wl_registry_bind(registry, id,
                                                &wl_compositor_interface, 4);

    } else if (strcmp(interface, wl_shm_interface.name) == 0) {
        state->wl_shm = wl_registry_bind(registry, id, &wl_shm_interface, 1);
        wl_shm_add_listener(state->wl_shm, &shm_listener, state);

    } else if (strcmp(interface, xdg_wm_base_interface.name) == 0) {
        state->xdg_wm_base = wl_registry_bind(registry, id,
                                              &xdg_wm_base_interface, 1);
        xdg_wm_base_add_listener(state->xdg_wm_base, &xdg_wm_base_listener, state);
    }
}

static void
global_registry_remover(void *data, struct wl_registry *registry, uint32_t id)
{
    printf("Got a registry losing event for %d\n", id);
}

static const struct wl_registry_listener registry_listener = {
    global_registry_handler,
    global_registry_remover
};


int main(int argc, char **argv) {

    struct client_state state = { 0 };

    state.wl_display = wl_display_connect(NULL);
    if (state.wl_display == NULL) {
        fprintf(stderr, "Can't connect to display\n");
        exit(1);
    }
    printf("connected to display\n");

    state.wl_registry = wl_display_get_registry(state.wl_display);
    wl_registry_add_listener(state.wl_registry, &registry_listener, &state);

    wl_display_dispatch(state.wl_display);
    wl_display_roundtrip(state.wl_display);

    /* By now we should have wl_compositor, wl_shm and xdg_wm_base from global_registry */

    if (state.wl_compositor == NULL) {
        fprintf(stderr, "Can't find compositor\n");
        exit(1);
    } else {
        fprintf(stderr, "Found compositor\n");
    }

    state.wl_surface = wl_compositor_create_surface(state.wl_compositor);
    if (state.wl_surface == NULL) {
        fprintf(stderr, "Can't create surface\n");
        exit(1);
    } else {
        fprintf(stderr, "Created surface\n");
    }

    if (state.xdg_wm_base == NULL) {
        fprintf(stderr, "no wm_base\n");
        exit(1);
    }
    state.xdg_surface = xdg_wm_base_get_xdg_surface(state.xdg_wm_base, state.wl_surface);
    if (state.xdg_surface == NULL) {
        fprintf(stderr, "no xdg_surface\n");
        exit(1);
    } else {
        fprintf(stderr, "Got xdg_surface\n");
    }
    xdg_surface_add_listener(state.xdg_surface, &xdg_surface_listener, &state);

    state.xdg_toplevel = xdg_surface_get_toplevel(state.xdg_surface);
    if (state.xdg_toplevel == NULL) {
        fprintf(stderr, "no xdg_toplevel\n");
        exit(1);
    } else {
        fprintf(stderr, "got xdg_toplevel\n");
    }
    xdg_toplevel_set_title(state.xdg_toplevel, "A surface");
    wl_surface_commit(state.wl_surface);


    while (wl_display_dispatch(state.wl_display)) {
        ;
    }

    wl_display_disconnect(state.wl_display);
    printf("disconnected from display\n");

    exit(0);
}