#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <math.h>
#include <assert.h>
#include <signal.h>

#include <linux/input.h>

#include <GLES2/gl2.h>
#include <EGL/egl.h>

#include "wayland_egl.h"

static int running = 1;

void(*fptr) (void*, wl_callback*, unsigned int);

typedef void (*wayland_egl_t)(void *, struct wl_callback*, unsigned int);

static void
init_egl(struct display *display, int opaque)
{
    static const EGLint context_attribs[] = {
        EGL_CONTEXT_CLIENT_VERSION, 2,
        EGL_NONE
    };

    EGLint config_attribs[] = {
        EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
        EGL_RED_SIZE, 8,
        EGL_GREEN_SIZE, 8,
        EGL_BLUE_SIZE, 8,
        EGL_ALPHA_SIZE, 8,
        EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
        EGL_DEPTH_SIZE, 24,
        EGL_NONE
    };

    EGLint major, minor, n;
    EGLBoolean ret;

    if (opaque)
        config_attribs[9] = 0;

    display->egl.dpy = eglGetDisplay(display->display);
    assert(display->egl.dpy);

    ret = eglInitialize(display->egl.dpy, &major, &minor);
    assert(ret == EGL_TRUE);
    ret = eglBindAPI(EGL_OPENGL_ES_API);
    assert(ret == EGL_TRUE);

    ret = eglChooseConfig(display->egl.dpy, config_attribs,
                  &display->egl.conf, 1, &n);
    assert(ret && n == 1);

    display->egl.ctx = eglCreateContext(display->egl.dpy,
                        display->egl.conf,
                        EGL_NO_CONTEXT, context_attribs);
    assert(display->egl.ctx);
}

static void
fini_egl(struct display *display)
{
    eglTerminate(display->egl.dpy);
    eglReleaseThread();
}

static void
handle_ping(void *data, struct wl_shell_surface *shell_surface,
        uint32_t serial)
{
    (void)data;
    wl_shell_surface_pong(shell_surface, serial);
}

static void
handle_configure(void *data, struct wl_shell_surface *shell_surface,
         uint32_t edges, int32_t width, int32_t height)
{
    struct window *window = (struct window*)data;
    (void)shell_surface;
    (void)edges;

    if (window->native)
        wl_egl_window_resize(window->native, width, height, 0, 0);

    window->geometry.width = width;
    window->geometry.height = height;

    if (!window->fullscreen)
        window->window_size = window->geometry;
}

static void
handle_popup_done(void *data, struct wl_shell_surface *shell_surface)
{
    (void)data;
    (void)shell_surface;
}

static const struct wl_shell_surface_listener shell_surface_listener = {
    handle_ping,
    handle_configure,
    handle_popup_done
};

static void
configure_callback(void *data, struct wl_callback *callback, uint32_t time)
{
    struct window *window = (struct window*)data;

    wl_callback_destroy(callback);

    window->configured = 1;

    if (window->callback == NULL)
        fptr(data, NULL, time);
}

static struct wl_callback_listener configure_callback_listener = {
    configure_callback,
};

static void
toggle_fullscreen(struct window *window, int fullscreen)
{
    struct wl_callback *callback;

    window->fullscreen = fullscreen;
    window->configured = 0;

    if (fullscreen) {
        wl_shell_surface_set_fullscreen(window->shell_surface,
                        WL_SHELL_SURFACE_FULLSCREEN_METHOD_DEFAULT,
                        0, NULL);
    } else {
        wl_shell_surface_set_toplevel(window->shell_surface);
        handle_configure(window, window->shell_surface, 0,
                 window->window_size.width,
                 window->window_size.height);
    }

    callback = wl_display_sync(window->display->display);
    wl_callback_add_listener(callback, &configure_callback_listener,
                 window);
}

static void
create_surface(struct window *window)
{
    struct display *display = window->display;
    EGLBoolean ret;

    window->surface = wl_compositor_create_surface(display->compositor);
    window->shell_surface = wl_shell_get_shell_surface(display->shell,
                               window->surface);

    wl_shell_surface_add_listener(window->shell_surface,
                      &shell_surface_listener, window);

    window->native =
        wl_egl_window_create(window->surface,
                     window->window_size.width,
                     window->window_size.height);
    window->egl_surface =
        eglCreateWindowSurface(display->egl.dpy,
                       display->egl.conf,
                       (EGLNativeWindowType)window->native, NULL);

    wl_shell_surface_set_title(window->shell_surface, "simple-egl");

    ret = eglMakeCurrent(window->display->egl.dpy, window->egl_surface,
                 window->egl_surface, window->display->egl.ctx);
    assert(ret == EGL_TRUE);

    toggle_fullscreen(window, window->fullscreen);
}

static void
destroy_surface(struct window *window)
{
    /* Required, otherwise segfault in egl_dri2.c: dri2_make_current()
     * on eglReleaseThread(). */
    eglMakeCurrent(window->display->egl.dpy, EGL_NO_SURFACE, EGL_NO_SURFACE,
               EGL_NO_CONTEXT);

    eglDestroySurface(window->display->egl.dpy, window->egl_surface);
    wl_egl_window_destroy(window->native);

    wl_shell_surface_destroy(window->shell_surface);
    wl_surface_destroy(window->surface);

    if (window->callback)
        wl_callback_destroy(window->callback);
}

static void
pointer_handle_enter(void *data, struct wl_pointer *pointer,
             uint32_t serial, struct wl_surface *surface,
             wl_fixed_t sx, wl_fixed_t sy)
{
    struct display *display = (struct display*)data;
    struct wl_buffer *buffer;
    struct wl_cursor *cursor = display->default_cursor;
    struct wl_cursor_image *image;
    (void)surface;
    (void)sx;
    (void)sy;

    if (display->window->fullscreen)
        wl_pointer_set_cursor(pointer, serial, NULL, 0, 0);
    else if (cursor) {
        image = display->default_cursor->images[0];
        buffer = wl_cursor_image_get_buffer(image);
        wl_pointer_set_cursor(pointer, serial,
                      display->cursor_surface,
                      image->hotspot_x,
                      image->hotspot_y);
        wl_surface_attach(display->cursor_surface, buffer, 0, 0);
        wl_surface_damage(display->cursor_surface, 0, 0,
                  image->width, image->height);
        wl_surface_commit(display->cursor_surface);
    }
}

static void
pointer_handle_leave(void *data, struct wl_pointer *pointer,
             uint32_t serial, struct wl_surface *surface)
{
    (void)data;
    (void)pointer;
    (void)serial;
    (void)surface;
}

static void
pointer_handle_motion(void *data, struct wl_pointer *pointer,
              uint32_t time, wl_fixed_t sx, wl_fixed_t sy)
{
    (void)data;
    (void)pointer;
    (void)time;
    (void)sx;
    (void)sy;
}

static void
pointer_handle_button(void *data, struct wl_pointer *wl_pointer,
              uint32_t serial, uint32_t time, uint32_t button,
              uint32_t state)
{
    struct display *display = (struct display*)data;
    (void)wl_pointer;
    (void)serial;
    (void)time;

    if (button == BTN_LEFT && state == WL_POINTER_BUTTON_STATE_PRESSED)
        wl_shell_surface_move(display->window->shell_surface,
                      display->seat, serial);
}

static void
pointer_handle_axis(void *data, struct wl_pointer *wl_pointer,
            uint32_t time, uint32_t axis, wl_fixed_t value)
{
    (void)data;
    (void)wl_pointer;
    (void)time;
    (void)axis;
    (void)value;
}

static const struct wl_pointer_listener pointer_listener = {
    pointer_handle_enter,
    pointer_handle_leave,
    pointer_handle_motion,
    pointer_handle_button,
    pointer_handle_axis,
    NULL,
    NULL,
    NULL,
    NULL
};

static void
keyboard_handle_keymap(void *data, struct wl_keyboard *keyboard,
               uint32_t format, int fd, uint32_t size)
{
    (void)data;
    (void)keyboard;
    (void)format;
    (void)fd;
    (void)size;
}

static void
keyboard_handle_enter(void *data, struct wl_keyboard *keyboard,
              uint32_t serial, struct wl_surface *surface,
              struct wl_array *keys)
{
    (void)data;
    (void)keyboard;
    (void)serial;
    (void)surface;
    (void)keys;
}

static void
keyboard_handle_leave(void *data, struct wl_keyboard *keyboard,
              uint32_t serial, struct wl_surface *surface)
{
    (void)data;
    (void)keyboard;
    (void)serial;
    (void)surface;
}

static void
keyboard_handle_key(void *data, struct wl_keyboard *keyboard,
            uint32_t serial, uint32_t time, uint32_t key,
            uint32_t state)
{
    struct display *d = (struct display*)data;
    (void)keyboard;
    (void)serial;
    (void)time;

    if (key == KEY_F11 && state)
        toggle_fullscreen(d->window, d->window->fullscreen ^ 1);
    else if (key == KEY_ESC && state)
        running = 0;
}

static void
keyboard_handle_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)
{
    (void)data;
    (void)keyboard;
    (void)serial;
    (void)mods_depressed;
    (void)mods_latched;
    (void)mods_locked;
    (void)group;
}

static const struct wl_keyboard_listener keyboard_listener = {
    keyboard_handle_keymap,
    keyboard_handle_enter,
    keyboard_handle_leave,
    keyboard_handle_key,
    keyboard_handle_modifiers,
    NULL
};

static void
seat_handle_capabilities(void *data, struct wl_seat *seat,
             enum wl_seat_capability caps)
{
    struct display *d = (struct display*)data;

    if ((caps & WL_SEAT_CAPABILITY_POINTER) && !d->pointer) {
        d->pointer = wl_seat_get_pointer(seat);
        wl_pointer_add_listener(d->pointer, &pointer_listener, d);
    } else if (!(caps & WL_SEAT_CAPABILITY_POINTER) && d->pointer) {
        wl_pointer_destroy(d->pointer);
        d->pointer = NULL;
    }

    if ((caps & WL_SEAT_CAPABILITY_KEYBOARD) && !d->keyboard) {
        d->keyboard = wl_seat_get_keyboard(seat);
        wl_keyboard_add_listener(d->keyboard, &keyboard_listener, d);
    } else if (!(caps & WL_SEAT_CAPABILITY_KEYBOARD) && d->keyboard) {
        wl_keyboard_destroy(d->keyboard);
        d->keyboard = NULL;
    }
}

static const struct wl_seat_listener seat_listener = {
    seat_handle_capabilities,
    NULL
};

static void
registry_handle_global(void *data, struct wl_registry *registry,
               uint32_t name, const char *interface, uint32_t version)
{
    struct display *d = (struct display*)data;
    (void)version;

    if (strcmp(interface, "wl_compositor") == 0) {
        d->compositor = (wl_compositor*)wl_registry_bind(registry, name, &wl_compositor_interface, 1);
    } else if (strcmp(interface, "wl_shell") == 0) {
        d->shell = (wl_shell*)wl_registry_bind(registry, name, &wl_shell_interface, 1);
    } else if (strcmp(interface, "wl_seat") == 0) {
        d->seat = (wl_seat*)wl_registry_bind(registry, name,
                       &wl_seat_interface, 1);
        wl_seat_add_listener(d->seat, &seat_listener, d);
    } else if (strcmp(interface, "wl_shm") == 0) {
        d->shm = (wl_shm*)wl_registry_bind(registry, name, &wl_shm_interface, 1);
        d->cursor_theme = wl_cursor_theme_load(NULL, 32, d->shm);
        d->default_cursor =
            wl_cursor_theme_get_cursor(d->cursor_theme, "left_ptr");
    }
}

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

static const struct wl_registry_listener registry_listener = {
    registry_handle_global,
    registry_handle_global_remove
};

void nc_wayland_display_draw(window *pwindow, void *redraw)
{
    struct wl_region *region;

    struct wl_callback_listener frame_listener = {(wayland_egl_t)redraw};

    if (pwindow->opaque || pwindow->fullscreen) {
        region = wl_compositor_create_region(pwindow->display->compositor);
        wl_region_add(region, 0, 0,
                  pwindow->geometry.width,
                  pwindow->geometry.height);
        wl_surface_set_opaque_region(pwindow->surface, region);
        wl_region_destroy(region);
    } else {
        wl_surface_set_opaque_region(pwindow->surface, NULL);
    }

    pwindow->callback = wl_surface_frame(pwindow->surface);
    wl_callback_add_listener(pwindow->callback, &frame_listener, pwindow);

    eglSwapBuffers(pwindow->display->egl.dpy, pwindow->egl_surface);
}

void nc_wayland_display_init(display *pdisplay, void *redraw)
{
    fptr = (wayland_egl_t)redraw;

    pdisplay->display = wl_display_connect(NULL);
    assert(pdisplay->display);

    pdisplay->registry = wl_display_get_registry(pdisplay->display);
    wl_registry_add_listener(pdisplay->registry, &registry_listener, pdisplay);

    wl_display_dispatch(pdisplay->display);

    init_egl(pdisplay, pdisplay->window->opaque);
    create_surface(pdisplay->window);

    pdisplay->cursor_surface =
        wl_compositor_create_surface(pdisplay->compositor);
}

int nc_wayland_display_destroy(display *pdisplay)
{
    destroy_surface(pdisplay->window);
    fini_egl(pdisplay);

    wl_surface_destroy(pdisplay->cursor_surface);
    if (pdisplay->cursor_theme)
        wl_cursor_theme_destroy(pdisplay->cursor_theme);

    if (pdisplay->shell)
        wl_shell_destroy(pdisplay->shell);

    if (pdisplay->compositor)
        wl_compositor_destroy(pdisplay->compositor);

    wl_registry_destroy(pdisplay->registry);
    if(pdisplay->display) {
        wl_display_flush(pdisplay->display);
        wl_display_disconnect(pdisplay->display);
    }

    return 0;
}