#include "e.h"

static void _e_xinerama_clean(void);
static void _e_xinerama_update(void);
static int  _e_xinerama_cb_screen_sort(const void *data1, const void *data2);

static Eina_List *all_screens = NULL;
static Eina_List *chosen_screens = NULL;
static Eina_List *fake_screens = NULL;

EINTERN int
e_xinerama_init(void)
{
   _e_xinerama_update();
   return 1;
}

EINTERN int
e_xinerama_shutdown(void)
{
   _e_xinerama_clean();
   return 1;
}

EAPI void
e_xinerama_update(void)
{
   _e_xinerama_clean();
   _e_xinerama_update();
}

EAPI const Eina_List *
e_xinerama_screens_get(void)
{
   if (fake_screens) return fake_screens;
   return chosen_screens;
}

EAPI const Eina_List *
e_xinerama_screens_all_get(void)
{
   if (fake_screens) return fake_screens;
   return all_screens;
}

EAPI void
e_xinerama_fake_screen_add(int x, int y, int w, int h)
{
   E_Screen *scr;

   scr = E_NEW(E_Screen, 1);
   scr->screen = eina_list_count(fake_screens);
   scr->escreen = scr->screen;
   scr->x = x;
   scr->y = y;
   scr->w = w;
   scr->h = h;
   fake_screens = eina_list_append(fake_screens, scr);
}

/* local subsystem functions */
static void
_e_xinerama_clean(void)
{
   E_FREE_LIST(all_screens, E_FREE);
   chosen_screens = eina_list_free(chosen_screens);
   E_FREE_LIST(fake_screens, E_FREE);
}

static void
_e_xinerama_update(void)
{
   int n;
   Ecore_X_Window *roots;
   Eina_List *l;
   E_Screen *scr;

   roots = ecore_x_window_root_list(&n);
   if (roots)
     {
        int i;
        int rw, rh;
        Ecore_X_Window root;

        /* more than 1 root window - xinerama wont be active */
        if (n > 1)
          {
             free(roots);
             return;
          }
        /* first (and only) root window */
        root = roots[0];
        free(roots);
        /* get root size */
        ecore_x_window_size_get(root, &rw, &rh);
        /* get number of xinerama screens */
        n = ecore_x_xinerama_screen_count_get();
        if (n < 1)
          {
             E_Screen *screen;

             screen = E_NEW(E_Screen, 1);
             screen->screen = 0;
             screen->escreen = screen->screen;
             screen->x = 0;
             screen->y = 0;
             screen->w = rw;
             screen->h = rh;
             all_screens = eina_list_append(all_screens, screen);
          }
        else
          {
             for (i = 0; i < n; i++)
               {
                  int x, y, w, h;

                  /* get each xinerama screen geometry */
                  if (ecore_x_xinerama_screen_geometry_get(i, &x, &y, &w, &h))
                    {
                       E_Screen *screen;

                       INF("E17 INIT: XINERAMA SCREEN: [%i][%i], %ix%i+%i+%i",
                              i, i, w, h, x, y);
                       /* add it to our list */
                       screen = E_NEW(E_Screen, 1);
                       screen->screen = i;
                       screen->escreen = screen->screen;
                       screen->x = x;
                       screen->y = y;
                       screen->w = w;
                       screen->h = h;
                       all_screens = eina_list_append(all_screens, screen);
                    }
               }
          }
     }
   /* now go through all_screens... and build a list of chosen screens */
   EINA_LIST_FOREACH (all_screens, l, scr)
     {
        Eina_List *ll;
        E_Screen *scr2;
        int add = 1;
        Eina_List *removes;

        removes = NULL;
        /* does this screen intersect with any we have chosen? */
        EINA_LIST_FOREACH(chosen_screens, ll, scr2)
          {
             /* if they intersect */
             if (E_INTERSECTS(scr->x, scr->y, scr->w, scr->h,
                              scr2->x, scr2->y, scr2->w, scr2->h))
               {
                  int sz, sz2;

                  /* calculate pixel area */
                  sz = scr->w * scr->h;
                  sz2 = scr2->w * scr2->h;
                  /* if the one we already have is bigger, DONT add the new */
                  if (sz > sz2)
                    removes = eina_list_append(removes, scr2);
                  /* add the old to a list to remove */
                  else
                    add = 0;
               }
          }
        /* if there are screens to remove - remove them */
        EINA_LIST_FREE(removes, scr2)
          {
             chosen_screens = eina_list_remove(chosen_screens, scr2);
          }
        /* if this screen is to be added, add it */
        if (add)
          chosen_screens = eina_list_append(chosen_screens, scr);
     }
   chosen_screens = eina_list_sort(chosen_screens,
                                   eina_list_count(chosen_screens),
                                   _e_xinerama_cb_screen_sort);
   INF("======================= screens:");
   n = 0;
   EINA_LIST_FOREACH(chosen_screens, l, scr)
     {
        scr->escreen = n;
        INF("E17 INIT: XINERAMA CHOSEN: [%i][%i], %ix%i+%i+%i",
               scr->screen, scr->escreen, scr->w, scr->h, scr->x, scr->y);
        n++;
     }
}

static int
_e_xinerama_cb_screen_sort(const void *data1, const void *data2)
{
   const E_Screen *scr, *scr2;
   int dif;

   scr = data1;
   scr2 = data2;
   if (scr->x != scr2->x)
     return scr->x - scr2->x;
   else if (scr->y != scr2->y)
     return scr->y - scr2->y;
   else
     {
        dif = (scr2->w * scr2->h) - (scr->w * scr->h);
        if (dif == 0) return scr->screen - scr2->screen;
     }
   return dif;
}