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

static struct wl_compositor *compositor;
static struct xdg_wm_base *xdg_wm_base;
static struct wl_seat *seat;
static struct wl_keyboard *keyboard;

/* xkbcommon helpers */
static struct xkb_context *xkb_ctx = NULL;
static struct xkb_keymap *xkb_keymap = NULL;
static struct xkb_state *xkb_state = NULL;

// Всё ниже - для одного окна
static struct xdg_surface *xdg_surface;
static struct xdg_toplevel *xdg_toplevel;
static struct wl_surface *wl_surface;
static struct wl_buffer *buffer;
static struct wl_shm *shm;
static int16_t width = 200;
static int16_t height = 100;
static int8_t *data;
static int8_t need_close = 0;

int32_t alloc_shm(size_t size)
{
    char name[32];
    sprintf(name, "/wayland-shm-%d", getpid());

    int32_t fd = shm_open(name, O_RDWR | O_CREAT, 0600);
    if (fd == -1)
        return fd;
    shm_unlink(name);
    ftruncate(fd, size);
    return fd;
}

void resize_canvas()
{
    size_t stride = width * 4;
    size_t size = stride * height;
    int32_t fd = alloc_shm(size);

    data = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
    struct wl_shm_pool *pool = wl_shm_create_pool(shm, fd, size);
    buffer = wl_shm_pool_create_buffer(pool, 0, width, height, stride, WL_SHM_FORMAT_ARGB8888);
    wl_shm_pool_destroy(pool);
    close(fd);
}

void resize_new(int16_t w, int16_t h)
{
    if (!w || !h)
        return;
    if (width != w || height != h)
    {
        if(data)
            munmap(data, width*height*4);
        width = w;
        height = h;
        resize_canvas();
    }
}

/* ---------------- Keyboard handling ----------------- */

void keyboard_keymap(void *data, struct wl_keyboard *keyboard, uint32_t format, int fd, uint32_t size)
{
    printf("keyboard: keymap format=%u size=%u\n", format, size);
    if (fd < 0)
        return;

    /* Only support xkb v1 */
    if (format != WL_KEYBOARD_KEYMAP_FORMAT_XKB_V1)
    {
        /* nothing we can do */
        close(fd);
        return;
    }

    /* Map keymap to memory */
    char *map = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0);
    if (map == MAP_FAILED)
    {
        perror("mmap");
        close(fd);
        return;
    }

    if (!xkb_ctx)
        xkb_ctx = xkb_context_new(XKB_CONTEXT_NO_FLAGS);

    /* Free previous keymap/state */
    if (xkb_state)
    {
        xkb_state_unref(xkb_state);
        xkb_state = NULL;
    }
    if (xkb_keymap)
    {
        xkb_keymap_unref(xkb_keymap);
        xkb_keymap = NULL;
    }

    xkb_keymap = xkb_keymap_new_from_string(xkb_ctx, map, XKB_KEYMAP_FORMAT_TEXT_V1, XKB_KEYMAP_COMPILE_NO_FLAGS);
    if (!xkb_keymap)
    {
        fprintf(stderr, "Unable to compile xkb keymap\n");
        munmap(map, size);
        close(fd);
        return;
    }

    xkb_state = xkb_state_new(xkb_keymap);

    munmap(map, size);
    close(fd);
}

void keyboard_enter(void *data, struct wl_keyboard *keyboard, uint32_t serial, struct wl_surface *surface, struct wl_array *keys)
{
    printf("keyboard: enter serial=%u surface=%p\n", serial, surface);
}

void keyboard_leave(void *data, struct wl_keyboard *keyboard, uint32_t serial, struct wl_surface *surface)
{
    printf("keyboard: leave serial=%u surface=%p\n", serial, surface);
}

void keyboard_key(void *data, struct wl_keyboard *keyboard, uint32_t serial, uint32_t time, uint32_t key, uint32_t state)
{
    const char *s = (state == WL_KEYBOARD_KEY_STATE_PRESSED) ? "PRESSED" : "RELEASED";
    printf("keyboard: key serial=%u time=%u key=%u state=%s\n", serial, time, key, s);

    /* Convert keycode to keysym using xkb */
    if (xkb_state)
    {
        /* xkb uses keycodes offset by 8 */
        xkb_keycode_t kc = (xkb_keycode_t)key + 8;
        xkb_keysym_t ks = xkb_state_key_get_one_sym(xkb_state, kc);
        if (ks != XKB_KEY_NoSymbol)
        {
            char buf[64];
            int n = xkb_keysym_to_utf8(ks, buf, sizeof(buf));
            if (n > 0)
                printf("keyboard: symbol '%s' (keysym 0x%x)\n", buf, ks);
            else
                printf("keyboard: keysym 0x%x (no UTF-8 representation)\n", ks);
        }
    }
}

void keyboard_modifiers(void *data, struct wl_keyboard *keyboard, uint32_t serial, uint32_t mods_depressed, uint32_t mods_latched, uint32_t mods_locked, uint32_t group)
{
    printf("keyboard: modifiers serial=%u depressed=%u latched=%u locked=%u group=%u\n", serial, mods_depressed, mods_latched, mods_locked, group);
    if (xkb_state)
    {
        /* newer libxkbcommon uses three layout args; use group for depressed */
        xkb_state_update_mask(xkb_state, mods_depressed, mods_latched, mods_locked, group, 0, 0);
    }
}

void keyboard_repeat_info(void *data, struct wl_keyboard *keyboard, int32_t rate, int32_t delay)
{
    printf("keyboard: repeat rate=%d delay=%d\n", rate, delay);
}

struct wl_keyboard_listener keyboard_listener = {
    .keymap = keyboard_keymap,
    .enter = keyboard_enter,
    .leave = keyboard_leave,
    .key = keyboard_key,
    .modifiers = keyboard_modifiers,
    .repeat_info = keyboard_repeat_info
};

void seat_capabilities(void *data, struct wl_seat *seat, uint32_t caps)
{
    if ((caps & WL_SEAT_CAPABILITY_KEYBOARD) && !keyboard)
    {
        keyboard = wl_seat_get_keyboard(seat);
        wl_keyboard_add_listener(keyboard, &keyboard_listener, 0);
        printf("Seat reports keyboard capability - keyboard bound\n");
    }
    else if (!(caps & WL_SEAT_CAPABILITY_KEYBOARD) && keyboard)
    {
        wl_keyboard_destroy(keyboard);
        keyboard = NULL;
        if (xkb_state)
        {
            xkb_state_unref(xkb_state);
            xkb_state = NULL;
        }
        if (xkb_keymap)
        {
            xkb_keymap_unref(xkb_keymap);
            xkb_keymap = NULL;
        }
    }
}

void seat_name(void *data, struct wl_seat *seat, const char *name)
{
    printf("Seat name: %s\n", name);
}

struct wl_seat_listener seat_listener = {
    .capabilities = seat_capabilities,
    .name = seat_name
};

int8_t c;
void draw()
{
    size_t stride = width * 4;
    size_t size = stride * height;

    memset(data, c++, size);

    wl_surface_attach(wl_surface, buffer, 0, 0);
    wl_surface_damage_buffer(wl_surface, 0, 0, width, height);
    wl_surface_commit(wl_surface);
}

void xdg_surface_conf(void *data, struct xdg_surface *xdg_surface, uint32_t serial)
{
    xdg_surface_ack_configure(xdg_surface, serial);
    if (!data)
        resize_canvas();

    draw();
}

void xdg_toplevel_conf(void *data, struct xdg_toplevel *xdg_top, int32_t w, int32_t h, struct wl_array *states)
{
    resize_new(w, h);
}

void xdg_toplevel_cls(void *data, struct xdg_toplevel *xdg_top)
{
    need_close = 1;
}

void xdg_toplevel_bounds(void *data, struct xdg_toplevel *xdg_top, int32_t w, int32_t h)
{
}

void xdg_toplevel_wm_caps(void *data, struct xdg_toplevel *xdg_top, struct wl_array *caps)
{
}

struct wl_callback_listener callback_listener;
void frame_new(void *date, struct wl_callback *cb, uint32_t _)
{
    wl_callback_destroy(cb);
    cb = wl_surface_frame(wl_surface);
    wl_callback_add_listener(cb, &callback_listener, 0);
    draw();
}

void wm_base_ping(void *data, struct xdg_wm_base *wm_base, uint32_t serial)
{
    xdg_wm_base_pong(wm_base, serial);
}

struct xdg_wm_base_listener wm_base_listener;
// Функция для прослушивания глобальных объектов
void registry_global(void *data, struct wl_registry *reg, uint32_t name, const char *intf, uint32_t version)
{
    printf("%u\t%s\tv:%u\n", name, intf, version);
    if (!strcmp(intf, wl_compositor_interface.name))
    {
        compositor = wl_registry_bind(reg, name, &wl_compositor_interface, version);
    }
    else if (!strcmp(intf, wl_shm_interface.name))
    {
        shm = wl_registry_bind(reg, name, &wl_shm_interface, version);
    }
    else if (!strcmp(intf, xdg_wm_base_interface.name))
    {
        xdg_wm_base = wl_registry_bind(reg, name, &xdg_wm_base_interface, version);
        xdg_wm_base_add_listener(xdg_wm_base, &wm_base_listener, 0);
    }
    else if (!strcmp(intf, wl_seat_interface.name))
    {
        seat = wl_registry_bind(reg, name, &wl_seat_interface, version);
        wl_seat_add_listener(seat, &seat_listener, 0);
    }
}

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

struct wl_callback_listener callback_listener = {
    .done = frame_new};

struct xdg_wm_base_listener wm_base_listener = {
    .ping = wm_base_ping};

struct xdg_toplevel_listener top_listener = {
    .configure = xdg_toplevel_conf,
    .close = xdg_toplevel_cls,
    .configure_bounds = xdg_toplevel_bounds,
    .wm_capabilities = xdg_toplevel_wm_caps};

struct xdg_surface_listener surface_listener = {
    .configure = xdg_surface_conf};

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

int32_t run_wayland()
{
    struct wl_display *display = wl_display_connect(0);
    if (!display)
        return -1;
    struct wl_registry *registry = wl_display_get_registry(display);
    wl_registry_add_listener(registry, &registry_listener, 0);
    wl_display_roundtrip(display);

    wl_surface = wl_compositor_create_surface(compositor);
    struct wl_callback *wl_callback = wl_surface_frame(wl_surface);
    wl_callback_add_listener(wl_callback, &callback_listener, 0);

    xdg_surface = xdg_wm_base_get_xdg_surface(xdg_wm_base, wl_surface);
    xdg_surface_add_listener(xdg_surface, &surface_listener, 0);
    xdg_toplevel = xdg_surface_get_toplevel(xdg_surface);
    xdg_toplevel_add_listener(xdg_toplevel, &top_listener, 0);
    xdg_toplevel_set_title(xdg_toplevel, "Custom client");
    wl_surface_commit(wl_surface);

    while (wl_display_dispatch(display))
    {
        if (need_close)
        {
            printf("Window closing\n");
            break;
        }
    }

    if (buffer)
        wl_buffer_destroy(buffer);
    xdg_toplevel_destroy(xdg_toplevel);
    xdg_surface_destroy(xdg_surface);
    wl_surface_destroy(wl_surface);
    if (keyboard)
        wl_keyboard_destroy(keyboard);
    if (seat)
        wl_seat_destroy(seat);
    wl_display_disconnect(display);
    return 0;
}