#include <e.h>
#include <Eina.h>
#include <grp.h>
#include <sys/types.h>
#include <pwd.h>
#include <Elput.h>

E_API E_Module_Api e_modapi =
   {
      E_MODULE_API_VERSION,
      "Gesture Recognition"
   };

static Eina_Hash *active_gestures;
static Elput_Manager *manager;

typedef struct {
   Eina_Vector2 pos;
   unsigned int fingers;
   struct {
     Evas_Object *visuals, *win;
   } visuals;
} Swipe_Stats;

static Swipe_Stats*
_find_swipe_gesture_recognizition(Elput_Device *dev)
{
   Swipe_Stats *stats = eina_hash_find(active_gestures, dev);

   return stats;
}

static Swipe_Stats*
_start_swipe_gesture_recognizition(Elput_Device *dev)
{
   Swipe_Stats *stats = _find_swipe_gesture_recognizition(dev);

   if (stats)
     eina_hash_del_by_key(active_gestures, dev);

   stats = calloc(1, sizeof(Swipe_Stats));
   EINA_SAFETY_ON_NULL_RETURN_VAL(stats, NULL);

   if (e_bindings_swipe_available())
     {
        E_Zone *zone = e_zone_current_get();

        stats->visuals.win =  elm_notify_add(zone->base);
        elm_notify_align_set(stats->visuals.win, 0.5, 0.5);
        elm_object_tree_focus_allow_set(stats->visuals.win, EINA_FALSE);
        evas_object_layer_set(stats->visuals.win, E_LAYER_CLIENT_PRIO);
        evas_object_show(stats->visuals.win);

        stats->visuals.visuals = elm_progressbar_add(stats->visuals.win);
        elm_object_text_set(stats->visuals.visuals, "Progress of visuals");
        evas_object_size_hint_min_set(stats->visuals.visuals, 300, 50);
        evas_object_show(stats->visuals.visuals);
        elm_object_content_set(stats->visuals.win, stats->visuals.visuals);
     }


   eina_hash_add(active_gestures, dev, stats);

   return stats;
}

static void
_end_swipe_gesture_recognizition(Elput_Device *dev)
{
   eina_hash_del_by_key(active_gestures, dev);
}

static double
_config_angle(Eina_Vector2 pos)
{
   double res = atan(pos.y/pos.x);

   if (res < 0) res += M_PI;
   if (pos.y < 0) res += M_PI;
   return res;
}

static Eina_Bool
_user_part_of_input(void)
{
   uid_t user = getuid();
   struct passwd *user_pw = getpwuid(user);
   gid_t *gids = NULL;
   int number_of_groups = 0;
   struct group *input_group = getgrnam("input");

   EINA_SAFETY_ON_NULL_RETURN_VAL(user_pw, EINA_FALSE);
   EINA_SAFETY_ON_NULL_RETURN_VAL(input_group, EINA_FALSE);

   if (getgrouplist(user_pw->pw_name, getgid(), NULL, &number_of_groups) != -1)
     {
        ERR("Failed to enumerate groups of user");
        return EINA_FALSE;
     }
   number_of_groups ++;
   gids = alloca((number_of_groups) * sizeof(gid_t));
   if (getgrouplist(user_pw->pw_name, getgid(), gids, &number_of_groups) == -1)
     {
        ERR("Failed to get groups of user");
        return EINA_FALSE;
     }

   for (int i = 0; i < number_of_groups; ++i)
     {
        if (gids[i] == input_group->gr_gid)
          return EINA_TRUE;
     }
   return EINA_FALSE;
}

static void
_stats_free(void *ptr)
{
   Swipe_Stats *stats = ptr;

   evas_object_del(stats->visuals.win);
   free(stats);
}

static void
_begin(void *data EINA_UNUSED, Elput_Device *device, Elput_Swipe_Gesture *gesture)
{
   Swipe_Stats *stats = _start_swipe_gesture_recognizition(device);
   stats->fingers = elput_swipe_finger_count_get(gesture);
   stats->pos.x = stats->pos.y = 0;
}

static void
_update(void *data EINA_UNUSED, Elput_Device *device, Elput_Swipe_Gesture *gesture)
{
   E_Bindings_Swipe_Live_Update live_update = e_bindings_swipe_live_update_hook_get();
   Swipe_Stats *stats = _find_swipe_gesture_recognizition(device);

   stats->pos.x += elput_swipe_dx_get(gesture);
   stats->pos.y += elput_swipe_dy_get(gesture);

   if (live_update)
     {
        live_update(e_bindings_swipe_live_update_hook_data_get(), EINA_FALSE, _config_angle(stats->pos), eina_vector2_length_get(&stats->pos), 0.8, stats->fingers);
     }
   else if (stats->visuals.win)
     {
        Eina_Inarray *res = e_bindings_swipe_find_candidates(E_BINDING_CONTEXT_NONE, _config_angle (stats->pos), eina_vector2_length_get(&stats->pos), stats->fingers);
        E_Binding_Swipe_Candidate *itr;
        double total = 0.0f;
        unsigned int len = 0;

        EINA_INARRAY_FOREACH(res, itr)
          {
             total += itr->acceptance;
             len ++;
          }

        if (len > 0)
          {
             char text_buffer[1000];

             snprintf(text_buffer, sizeof(text_buffer), "%d gestures possible", len);
             elm_progressbar_value_set(stats->visuals.visuals, total/len);
             elm_object_text_set(stats->visuals.visuals, text_buffer);
          }
        else
          {
             elm_progressbar_value_set(stats->visuals.visuals, 0.0f);
             elm_object_text_set(stats->visuals.visuals, "No gesture found");
          }

        eina_inarray_free(res);
     }
}

static void
_end(void *data EINA_UNUSED, Elput_Device *device, Elput_Swipe_Gesture *gesture EINA_UNUSED)
{
   E_Bindings_Swipe_Live_Update live_update = e_bindings_swipe_live_update_hook_get();
   Swipe_Stats *stats = _find_swipe_gesture_recognizition(device);

   if (live_update)
     live_update(e_bindings_swipe_live_update_hook_data_get(), EINA_TRUE, _config_angle(stats->pos), eina_vector2_length_get(&stats->pos), 0.8, stats->fingers);
   else
     e_bindings_swipe_handle(E_BINDING_CONTEXT_NONE, NULL, _config_angle(stats->pos), eina_vector2_length_get(&stats->pos), stats->fingers);

   _end_swipe_gesture_recognizition(device);
}

E_API int
e_modapi_init(E_Module *m EINA_UNUSED)
{
   const char *device = NULL;

   elput_init();

   device = getenv("XDG_SEAT");
   if (!device) device = "seat0";
   manager = elput_manager_connect_gestures(device, 0);
   elput_input_init(manager);

   elput_manager_swipe_gesture_listen(manager, _begin, NULL, _update, NULL, _end, NULL);

   if (!_user_part_of_input())
     {
        e_module_dialog_show(m, "Gesture Recognition", "Your user is not part of the input group, libinput cannot be used.");

        return 0;
     }
   active_gestures = eina_hash_pointer_new(_stats_free);

   return 1;
}

E_API int
e_modapi_shutdown(E_Module *m EINA_UNUSED)
{
   elput_shutdown();
   return 1;
}

E_API int
e_modapi_save(E_Module *m EINA_UNUSED)
{

   return 1;
}