/* Copyright (C) 2000, 2001, 2002, 2003, 2004 Shawn Betts <sabetts@vcn.bc.ca>
 *
 * This file is part of ratpoison.
 *
 * ratpoison is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * ratpoison is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this software; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307 USA
 *
 *
 * Functions for handling window splitting and tiling.
 */

#include <unistd.h>
#include <string.h>

#include "ratpoison.h"

#define VERTICALLY 0
#define HORIZONTALLY 1

static rp_screen *frames_screen(rp_frame *);

static void
update_last_access (rp_frame *frame)
{
  static int counter = 0;

  frame->last_access = counter;
  counter++;
}

rp_frame *
current_frame (void)
{
  rp_screen *s = current_screen();
  return screen_get_frame (s, s->current_frame);
}

int
num_frames (rp_screen *s)
{
 int count = 0;
 rp_frame *cur;

 list_for_each_entry (cur, &s->frames, node)
   {
     count++;
   }

 return count;
}

void
cleanup_frame (rp_frame *frame)
{
  rp_window *last_win;
  rp_window *win;
  rp_screen *screen;
  screen = frames_screen(frame);

  win = find_window_other (screen);
  if (win == NULL)
    {
      set_frames_window (frame, NULL);
      return;
    }

  last_win = set_frames_window (frame, win);

  maximize (win);
  unhide_window (win);


  if (!window_is_transient (win))
    hide_others (win);
}

rp_window *
set_frames_window (rp_frame *frame, rp_window *win)
{
  int last_win;

  last_win = frame->win_number;
  if (win)
    {
      frame->win_number = win->number;
      win->frame_number = frame->number;

      /* We need to make sure that win and frame are on the same screen,
       * since with Xinerama, windows can move from one screen to another.
       */
      win->scr = frames_screen(frame);
    }
  else
    {
      frame->win_number = EMPTY;
    }

  return find_window_number (last_win);
}

static rp_screen *
frames_screen (rp_frame *frame)
{
  int i;
  rp_frame *cur;

  for (i=0; i<num_screens; i++)
    list_for_each_entry (cur, &screens[i].frames, node)
      {
        if (frame == cur)
          return &screens[i];
      }

  /* This SHOULD be impossible to get to. FIXME: It'll crash higher up if we
     return NULL. */
  return NULL;
}

void
maximize_all_windows_in_frame (rp_frame *frame)
{
  rp_window *win;

  list_for_each_entry (win, &rp_mapped_window, node)
    {
      if (win->frame_number == frame->number)
        {
          maximize (win);
        }
    }
}

/* Make the frame occupy the entire screen */
static void
maximize_frame (rp_frame *frame)
{
  rp_screen *s = frames_screen (frame);

  frame->x = defaults.padding_left;
  frame->y = defaults.padding_top;

  frame->width = screen_width (s);
  frame->height = screen_height (s);
}

/* Create a full screen frame */
static void
create_initial_frame (rp_screen *screen)
{
  rp_frame *frame;

  frame = frame_new (screen);
  screen->current_frame = frame->number;
  list_add_tail (&frame->node, &screen->frames);

  update_last_access (frame);

  maximize_frame (frame);
  set_frames_window (frame, NULL);
}

void
init_frame_lists (void)
{
  int i;

  for (i=0; i<num_screens; i++)
    init_frame_list (&screens[i]);
}

void
init_frame_list (rp_screen *screen)
{
  INIT_LIST_HEAD (&screen->frames);

  create_initial_frame(screen);
}

rp_frame *
find_last_frame (void)
{
  rp_frame *cur, *last = NULL;
  int last_access = -1;
  int i;

  for (i=0; i<num_screens; i++)
    {
      rp_screen *s = &screens[i];

      list_for_each_entry (cur, &s->frames, node)
        {
          if (cur->number != current_screen()->current_frame
              && cur->last_access > last_access)
            {
              last_access = cur->last_access;
              last = cur;
            }
        }
    }

  return last;
}

/* Return the frame that contains the window. */
rp_frame *
find_windows_frame (rp_window *win)
{
  rp_screen *s;
  rp_frame *cur;

  s = win->scr;

  list_for_each_entry (cur, &s->frames, node)
    {
      if (cur->win_number == win->number) return cur;
    }

  return NULL;
}

rp_frame *
find_frame_next (rp_frame *frame)
{
  if (frame == NULL) return NULL;
  return list_next_entry (frame, &frames_screen (frame)->frames, node);
}

rp_frame *
find_frame_prev (rp_frame *frame)
{
  if (frame == NULL) return NULL;
  return list_prev_entry (frame, &frames_screen (frame)->frames, node);
}

rp_window *
current_window (void)
{
  return find_window_number (current_frame()->win_number);
}

static int
window_fits_in_frame (rp_window *win, rp_frame *frame)
{
  /* If the window has minimum size hints, make sure they are smaller
     than the frame. */
  if (win->hints->flags & PMinSize)
    {
      if (win->hints->min_width > frame->width
          ||
          win->hints->min_height > frame->height)
        {
          return 0;
        }
    }

  return 1;
}

/* Search the list of mapped windows for a window that will fit in the
   specified frame. */
rp_window *
find_window_for_frame (rp_frame *frame)
{
  rp_screen *s = frames_screen (frame);
  int last_access = 0;
  rp_window_elem *most_recent = NULL;
  rp_window_elem *cur;

  list_for_each_entry (cur, &rp_current_group->mapped_windows, node)
    {
      if ((cur->win->scr == s || rp_have_xinerama)
          && cur->win != current_window()
          && !find_windows_frame (cur->win)
          && cur->win->last_access >= last_access
          && window_fits_in_frame (cur->win, frame)
          && cur->win->frame_number == EMPTY)
        {
          most_recent = cur;
          last_access = cur->win->last_access;
        }
    }

  if (most_recent)
    return most_recent->win;

  return NULL;
}

/* Splits the frame in 2. if way is 0 then split vertically otherwise
   split it horizontally. */
static void
split_frame (rp_frame *frame, int way, int pixels)
{
  rp_screen *s;
  rp_window *win;
  rp_frame *new_frame;

  s = frames_screen (frame);

  /* Make our new frame. */
  new_frame = frame_new (s);

  /* Add the frame to the frameset. */
  list_add (&new_frame->node, &current_frame()->node);

  set_frames_window (new_frame, NULL);

  if (way == HORIZONTALLY)
    {
      new_frame->x = frame->x;
      new_frame->y = frame->y + pixels;
      new_frame->width = frame->width;
      new_frame->height = frame->height - pixels;

      frame->height = pixels;
    }
  else
    {
      new_frame->x = frame->x + pixels;
      new_frame->y = frame->y;
      new_frame->width = frame->width - pixels;
      new_frame->height = frame->height;

      frame->width = pixels;
    }

  win = find_window_for_frame (new_frame);
  if (win)
    {
      PRINT_DEBUG (("Found a window for the frame!\n"));

      set_frames_window (new_frame, win);

      maximize (win);
      unhide_window (win);
      XRaiseWindow (dpy, win->w);
    }
  else
    {
      PRINT_DEBUG (("No window fits the frame.\n"));

      set_frames_window (new_frame, NULL);
    }

  /* resize the existing frame */
  if (frame->win_number != EMPTY)
    {
      maximize_all_windows_in_frame (frame);
      XRaiseWindow (dpy, find_window_number (frame->win_number)->w);
    }

  update_bar (s);
  show_frame_indicator();
}

/* Splits the window vertically leaving the original with 'pixels'
   pixels . */
void
v_split_frame (rp_frame *frame, int pixels)
{
  split_frame (frame, VERTICALLY, pixels);
}

/* Splits the frame horizontally leaving the original with 'pixels'
   pixels . */
void
h_split_frame (rp_frame *frame, int pixels)
{
  split_frame (frame, HORIZONTALLY, pixels);
}

void
remove_all_splits (void)
{
  struct list_head *tmp, *iter;
  rp_screen *s = current_screen();
  rp_frame *frame;
  rp_window *win;

  /* Hide all the windows not in the current frame. */
  list_for_each_entry (win, &rp_mapped_window, node)
    {
      if (win->frame_number != s->current_frame && win->scr == s)
        hide_window (win);
    }

  /* Delete all the frames except the current one. */
  list_for_each_safe_entry (frame, iter, tmp, &s->frames, node)
    {
      if (frame->number != s->current_frame)
        {
          list_del (&frame->node);
          frame_free (s, frame);
        }
    }

  /* Maximize the frame and the windows in the frame. */
  maximize_frame (current_frame());
  maximize_all_windows_in_frame (current_frame());
}

/* Shrink the size of the frame to fit it's current window. */
void
resize_shrink_to_window (rp_frame *frame)
{
  rp_window *win;

  if (frame->win_number == EMPTY) return;

  win = find_window_number (frame->win_number);

  resize_frame_horizontally (frame, win->width + win->border*2 - frame->width);
  resize_frame_vertically (frame, win->height + win->border*2 - frame->height);
}

/* resize_frame is a generic frame resizer that can resize vertically,
   horizontally, to the right, to the left, etc. It all depends on the
   functions passed to it. Returns -1 if the resize failed, 0 for
   success. */
static int
resize_frame (rp_frame *frame, rp_frame *pusher, int diff,
              int (*c1)(rp_frame *), int (c2)(rp_frame *),
              int (*c3)(rp_frame *), int (c4)(rp_frame *),
              void (*resize1)(rp_frame *, int),
              void (*resize2)(rp_frame *, int),
              int (*resize3)(rp_frame *, rp_frame *, int))
{
  rp_screen *s = frames_screen (frame);
  rp_frame *cur;

  /* Loop through the frames and determine which ones are affected by
     resizing frame. */
  list_for_each_entry (cur, &s->frames, node)
    {
      if (cur == frame || cur == pusher) continue;
      /* If cur is touching frame along the axis that is being
         moved then this frame is affected by the resize. */
      if ((*c1)(cur) == (*c3)(frame))
        {
          /* If the frame can't get any smaller, then fail. */
          if (diff > 0
              && abs ((*c3)(cur) - (*c1)(cur)) - diff <= defaults.window_border_width * 2)
            return -1;
          /* Test for this circumstance:
             --+
             | |+-+
             |f||c|
             | |+-+
             --+

             In this case, resizing cur will not affect any other
             frames, so just do the resize.
          */
          if (((*c2)(cur) >= (*c2)(frame))
              && (*c4)(cur) <= (*c4)(frame))
            {
              (*resize2)(cur, -diff);
              maximize_all_windows_in_frame (cur);
            }
          /* Otherwise, cur's corners are either strictly outside
             frame's corners, or one of them is inside and the other
             isn't. In either of these cases, resizing cur will affect
             other adjacent frames, so find them and resize them first
             (recursive step) and then resize cur. */
          else if (((*c2)(cur) < (*c2)(frame)
                    && (*c4)(cur) > (*c4)(frame))
                   || ((*c2)(cur) >= (*c2)(frame)
                       && (*c2)(cur) < (*c4)(frame))
                   || ((*c4)(cur) > (*c2)(frame)
                       && (*c4)(cur) <= (*c4)(frame)))
            {
              /* Attempt to resize cur. */
              if (resize3 (cur, frame, -diff) == -1)
                return -1;
            }
        }
    }

  /* Finally, resize the frame and the windows inside. */
  (*resize1) (frame, diff);
  maximize_all_windows_in_frame (frame);

  return 0;
}

static int resize_frame_bottom (rp_frame *frame, rp_frame *pusher, int diff);
static int resize_frame_top (rp_frame *frame, rp_frame *pusher, int diff);
static int resize_frame_left (rp_frame *frame, rp_frame *pusher, int diff);
static int resize_frame_right (rp_frame *frame, rp_frame *pusher, int diff);

/* Resize frame by moving it's right side. */
static int
resize_frame_right (rp_frame *frame, rp_frame *pusher, int diff)
{
  return resize_frame (frame, pusher, diff,
                       frame_left, frame_top, frame_right, frame_bottom,
                       frame_resize_right, frame_resize_left, resize_frame_left);
}

/* Resize frame by moving it's left side. */
static int
resize_frame_left (rp_frame *frame, rp_frame *pusher, int diff)
{
  return resize_frame (frame, pusher, diff,
                       frame_right, frame_top, frame_left, frame_bottom,
                       frame_resize_left, frame_resize_right, resize_frame_right);
}

/* Resize frame by moving it's top side. */
static int
resize_frame_top (rp_frame *frame, rp_frame *pusher, int diff)
{
  return resize_frame (frame, pusher, diff,
                       frame_bottom, frame_left, frame_top, frame_right,
                       frame_resize_up, frame_resize_down, resize_frame_bottom);
}

/* Resize frame by moving it's bottom side. */
static int
resize_frame_bottom (rp_frame *frame, rp_frame *pusher, int diff)
{
  return resize_frame (frame, pusher, diff,
                       frame_top, frame_left, frame_bottom, frame_right,
                       frame_resize_down, frame_resize_up, resize_frame_top);
}

/* Resize frame diff pixels by expanding it to the right. If the frame
   is against the right side of the screen, expand it to the left. */
void
resize_frame_horizontally (rp_frame *frame, int diff)
{
  int (*resize_fn)(rp_frame *, rp_frame*, int);
  struct list_head *l;
  rp_screen *s = frames_screen (frame);

  if (num_frames (s) < 2 || diff == 0)
    return;

  if (frame_width (frame) + diff <= defaults.window_border_width * 2)
    return;

  /* Find out which resize function to use. */
  if (frame_right (frame) < screen_right (s))
    {
      resize_fn = resize_frame_right;
    }
  else if (frame_left (frame) > screen_left (s))
    {
      resize_fn = resize_frame_left;
    }
  else
    {
      return;
    }

  /* Copy the frameset. If the resize fails, then we restore the
     original one. */
  l = screen_copy_frameset (s);

  if ((*resize_fn) (frame, NULL, diff) == -1)
    {
      screen_restore_frameset (s, l);
    }
  else
    {
      frameset_free (l);
    }

  /* It's our responsibility to free this. */
  free (l);
}

/* Resize frame diff pixels by expanding it down. If the frame is
   against the bottom of the screen, expand it up. */
void
resize_frame_vertically (rp_frame *frame, int diff)
{
  int (*resize_fn)(rp_frame *, rp_frame*, int);
  struct list_head *l;
  rp_screen *s = frames_screen (frame);

  if (num_frames (s) < 2 || diff == 0)
    return;

  if (frame_height (frame) + diff <= defaults.window_border_width * 2)
    return;

  /* Find out which resize function to use. */
  if (frame_bottom (frame) < screen_bottom (s))
    {
      resize_fn = resize_frame_bottom;
    }
  else if (frame_top (frame) > screen_top (s))
    {
      resize_fn = resize_frame_top;
    }
  else
    {
      return;
    }

  /* Copy the frameset. If the resize fails, then we restore the
     original one. */
  l = screen_copy_frameset (s);

  if ((*resize_fn) (frame, NULL, diff) == -1)
    {
      screen_restore_frameset (s, l);
    }
  else
    {
      frameset_free (l);
    }

  /* It's our responsibility to free this. */
  free (l);
}

static int
frame_is_below (rp_frame *src, rp_frame *frame)
{
  if (frame->y > src->y) return 1;
  return 0;
}

static int
frame_is_above (rp_frame *src, rp_frame *frame)
{
  if (frame->y < src->y) return 1;
  return 0;
}

static int
frame_is_left (rp_frame *src, rp_frame *frame)
{
  if (frame->x < src->x) return 1;
  return 0;
}

static int
frame_is_right (rp_frame *src, rp_frame *frame)
{
  if (frame->x > src->x) return 1;
  return 0;
}

static int
total_frame_area (rp_screen *s)
{
  int area = 0;
  rp_frame *cur;

  list_for_each_entry (cur, &s->frames, node)
    {
      area += cur->width * cur->height;
    }

  return area;
}

/* Return 1 if frames f1 and f2 overlap */
static int
frames_overlap (rp_frame *f1, rp_frame *f2)
{
  if (f1->x >= f2->x + f2->width
      || f1->y >= f2->y + f2->height
      || f2->x >= f1->x + f1->width
      || f2->y >= f1->y + f1->height)
    {
      return 0;
    }
  return 1;
}

/* Return 1 if w's frame overlaps any other window's frame */
static int
frame_overlaps (rp_frame *frame)
{
  rp_screen *s;
  rp_frame *cur;

  s = frames_screen (frame);

  list_for_each_entry (cur, &s->frames, node)
    {
      if (cur != frame && frames_overlap (cur, frame))
        {
          return 1;
        }
    }
  return 0;
}

void
remove_frame (rp_frame *frame)
{
  rp_screen *s;
  int area;
  rp_frame *cur;
  rp_window *win;

  if (frame == NULL) return;

  s = frames_screen (frame);

  area = total_frame_area(s);
  PRINT_DEBUG (("Total Area: %d\n", area));

  list_del (&frame->node);
  win = find_window_number (frame->win_number);
  hide_window (win);
  hide_others (win);

  list_for_each_entry (cur, &s->frames, node)
    {
      rp_frame tmp_frame;
      int fits = 0;

/*       if (cur->win_number != EMPTY) */
/*      { */
/*        PRINT_DEBUG (("Trying frame containing window '%s'\n", window_name (cur->win))); */
/*      } */
/*       else */
/*      { */
/*        PRINT_DEBUG (("Trying some empty frame\n")); */
/*      } */

      /* Backup the frame */
      memcpy (&tmp_frame, cur, sizeof (rp_frame));

      if (frame_is_below (frame, cur)
          || frame_is_above (frame, cur))
        {
          if (frame_is_below (frame, cur))
            cur->y = frame->y;
          cur->height += frame->height;
        }

      PRINT_DEBUG (("Attempting vertical Frame y=%d height=%d\n", cur->y, cur->height));
      PRINT_DEBUG (("New Total Area: %d\n", total_frame_area(s)));

      /* If the area is bigger than before, the frame takes up too
         much space. If the current frame and the deleted frame DON'T
         overlap then the current window took up just the right amount
         of space but didn't take up the space left behind by the
         deleted window. If any active frames overlap, it could have
         taken up the right amount of space, overlaps with the deleted
         frame but obviously didn't fit. */
      if (total_frame_area(s) > area || !frames_overlap (cur, frame) || frame_overlaps (cur))
        {
          PRINT_DEBUG (("Didn't fit vertically\n"));

          /* Restore the current window's frame */
          memcpy (cur, &tmp_frame, sizeof (rp_frame));
        }
      else
        {
          PRINT_DEBUG (("It fit vertically!!\n"));

          /* update the frame backup */
          memcpy (&tmp_frame, cur, sizeof (rp_frame));
          fits = 1;
        }

      if (frame_is_left (frame, cur)
          || frame_is_right (frame, cur))
        {
          if (frame_is_right (frame, cur))
            cur->x = frame->x;
          cur->width += frame->width;
        }

      PRINT_DEBUG (("Attempting horizontal Frame x=%d width=%d\n", cur->x, cur->width));
      PRINT_DEBUG (("New Total Area: %d\n", total_frame_area(s)));

      /* Same test as the vertical test, above. */
      if (total_frame_area(s) > area || !frames_overlap (cur, frame) || frame_overlaps (cur))
        {
          PRINT_DEBUG (("Didn't fit horizontally\n"));

          /* Restore the current window's frame */
          memcpy (cur, &tmp_frame, sizeof (rp_frame));
        }
      else
        {
          PRINT_DEBUG (("It fit horizontally!!\n"));
          fits = 1;
        }

      if (fits)
        {
          /* The current frame fits into the new space so keep its
             new frame parameters and maximize the window to fit
             the new frame size. */
          if (cur->win_number != EMPTY)
            {
              win = find_window_number (cur->win_number);
              maximize_all_windows_in_frame (cur);
              XRaiseWindow (dpy, win->w);
            }
        }
      else
        {
          memcpy (cur, &tmp_frame, sizeof (rp_frame));
        }
    }

  frame_free (s, frame);
}

/* Switch the input focus to another frame, and therefore a different
   window. */
void
set_active_frame (rp_frame *frame)
{
  rp_screen *old_s = current_screen();
  rp_screen *s = frames_screen (frame);
  int old = current_screen()->current_frame;
  rp_window *win, *old_win;
  rp_frame *old_frame;

  win = find_window_number (frame->win_number);
  old_frame = current_frame();
  if (old_frame)
    {
      old_win = find_window_number (old_frame->win_number);
    }
  else
    {
      old_win = NULL;
    }

  /* Make the switch */
  give_window_focus (win, old_win);
  update_last_access (frame);
  s->current_frame = frame->number;

  /* If frame->win == NULL, then rp_current_screen is not updated. */
  rp_current_screen = s->xine_screen_num;

  update_bar (s);

  /* Possibly show the frame indicator. */
  if ((old != s->current_frame && num_frames(s) > 1)
      || s != old_s)
    {
      show_frame_indicator();

      /* run the frame switch hook. We call it in here because this is
         when a frame switch ACTUALLY (for sure) happens. */
      hook_run (&rp_switch_frame_hook);
    }

  /* If the frame has no window to give focus to, give the key window
     focus. */
  if(frame->win_number == EMPTY)
    {
      set_window_focus (s->key_window);
    }
}

void
exchange_with_frame (rp_screen *s, rp_frame *cur, rp_frame *frame)
{
  rp_window *win,*last_win;

  /* As a frame does not tell which screen it belongs to,
   * we could only make sure the frames are not on different
   * screens when xinerama is not available, if both have
   * windows in it. As this is not enough the caller will
   * have to check this. As I only plan to implement 
   * exchange_{left,right,up,down}, this will be a nop...*/
  if (frame == NULL || frame == cur) return;

  /* Exchange the windows in the frames */
  win = find_window_number (cur->win_number);
  last_win = set_frames_window (frame, win);
  set_frames_window (cur, last_win);

  /* Make sure the windows comes up full screen */
  if (last_win)
    maximize (last_win);
  if (win)
    {
    maximize (win);
    /* Make sure the program bar is always on the top */
    update_window_names (win->scr, defaults.window_fmt);
  }

  /* Make the switch */
  update_last_access (frame);

  if (s->current_frame == cur->number)
    {
      s->current_frame = frame->number;
      /* mark it as active */
      show_frame_indicator();
    }

  update_bar (s);


  XSync (dpy, False);

  hook_run (&rp_switch_frame_hook);

  /* FIXME: Remaining problems:
   *  - if one of the window is transient, the windows in the
   *  background could cause problems.
   *
   *  - how to implement correct mouse-warping?
   *  (is it needed at all?)
   */
}


void
blank_frame (rp_frame *frame)
{
  rp_screen *s;
  rp_window *win;

  if (frame->win_number == EMPTY) return;

  s = frames_screen (frame);

  win = find_window_number (frame->win_number);
  hide_window (win);
  hide_others (win);

  set_frames_window (frame, NULL);

  update_bar (s);

  /* Give the key window focus. */
  set_window_focus (frames_screen(frame)->key_window);
}

void
hide_frame_indicator (void)
{
  int i;
  for (i=0; i<num_screens; i++)
    XUnmapWindow (dpy, screens[i].frame_window);
}

void
show_frame_indicator (void)
{
  hide_frame_indicator ();
  show_frame_message (MESSAGE_FRAME_STRING);
  alarm (defaults.frame_indicator_timeout);
}

void
show_frame_message (char *msg)
{
  rp_screen *s = current_screen ();
  int width, height;
  rp_frame *frame;

  frame = current_frame();

  width = defaults.bar_x_padding * 2 + XmbTextEscapement (defaults.font, msg, strlen (msg));
  height = (FONT_HEIGHT (defaults.font) + defaults.bar_y_padding * 2);

  /* We don't want another frame indicator to be displayed on another
   * screen at the same time, so we hide it before bringing it back again.
   */
  hide_frame_indicator ();

  XMoveResizeWindow (dpy, s->frame_window,
                     s->left + frame->x + frame->width / 2 - width / 2,
                     s->top + frame->y + frame->height / 2 - height / 2,
                     width, height);

  XMapRaised (dpy, s->frame_window);
  XClearWindow (dpy, s->frame_window);
  XSync (dpy, False);

  XmbDrawString (dpy, s->frame_window, defaults.font, s->normal_gc,
		 defaults.bar_x_padding,
		 defaults.bar_y_padding + rp_font_ascent,
		 msg, strlen (msg));
}

rp_frame *
find_frame_up (rp_frame *frame)
{
  rp_screen *s = frames_screen (frame);
  rp_frame *cur;

  list_for_each_entry (cur, &s->frames, node)
    {
      if (frame->y == cur->y + cur->height)
        {
          if (frame->x >= cur->x && frame->x < cur->x + cur->width)
            return cur;
        }
    }

  return NULL;
}

rp_frame *
find_frame_down (rp_frame *frame)
{
  rp_screen *s = frames_screen (frame);
  rp_frame *cur;

  list_for_each_entry (cur, &s->frames, node)
    {
      if (frame->y + frame->height == cur->y)
        {
          if (frame->x >= cur->x && frame->x < cur->x + cur->width)
            return cur;
        }
    }

  return NULL;
}

rp_frame *
find_frame_left (rp_frame *frame)
{
  rp_screen *s = frames_screen (frame);
  rp_frame *cur;

  list_for_each_entry (cur, &s->frames, node)
    {
      if (frame->x == cur->x + cur->width)
        {
          if (frame->y >= cur->y && frame->y < cur->y + cur->height)
            return cur;
        }
    }

  return NULL;
}

rp_frame *
find_frame_right (rp_frame *frame)
{
  rp_screen *s = frames_screen (frame);
  rp_frame *cur;

  list_for_each_entry (cur, &s->frames, node)
    {
      if (frame->x + frame->width == cur->x)
        {
          if (frame->y >= cur->y && frame->y < cur->y + cur->height)
            return cur;
        }
    }

  return NULL;
}

rp_frame *
find_frame_number (int num)
{
  int i;
  rp_frame *cur;

  for (i=0; i<num_screens; i++)
    {
      rp_screen *s = &screens[i];

      list_for_each_entry (cur, &s->frames, node)
        {
          if (cur->number == num)
            return cur;
        }
    }

  return NULL;
}