/* GDK - The GIMP Drawing Kit
 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
 */

/*
 * Modified by the GTK+ Team and others 1997-2000.  See the AUTHORS
 * file for a list of people on the GTK+ Team.  See the ChangeLog
 * files for a list of changes.  These files are distributed with
 * GTK+ at ftp://ftp.gtk.org/pub/gtk/. 
 */

#include "config.h"

#include "gdksurfaceimpl.h"

#include "gdkinternals.h"


G_DEFINE_TYPE (GdkSurfaceImpl, gdk_surface_impl, G_TYPE_OBJECT);

static gboolean
gdk_surface_impl_beep (GdkSurface *surface)
{
  /* FALSE means surfaces can't beep, so the display will be
   * made to beep instead. */
  return FALSE;
}

static GdkDisplay *
get_display_for_surface (GdkSurface *primary,
                        GdkSurface *secondary)
{
  GdkDisplay *display = gdk_surface_get_display (primary);

  if (display)
    return display;

  display = gdk_surface_get_display (secondary);

  if (display)
    return display;

  g_warning ("no display for surface, using default");
  return gdk_display_get_default ();
}

static GdkMonitor *
get_monitor_for_rect (GdkDisplay         *display,
                      const GdkRectangle *rect)
{
  gint biggest_area = G_MININT;
  GdkMonitor *best_monitor = NULL;
  GdkMonitor *monitor;
  GdkRectangle workarea;
  GdkRectangle intersection;
  gint x;
  gint y;
  gint i;

  for (i = 0; i < gdk_display_get_n_monitors (display); i++)
    {
      monitor = gdk_display_get_monitor (display, i);
      gdk_monitor_get_workarea (monitor, &workarea);

      if (gdk_rectangle_intersect (&workarea, rect, &intersection))
        {
          if (intersection.width * intersection.height > biggest_area)
            {
              biggest_area = intersection.width * intersection.height;
              best_monitor = monitor;
            }
        }
    }

  if (best_monitor)
    return best_monitor;

  x = rect->x + rect->width / 2;
  y = rect->y + rect->height / 2;

  return gdk_display_get_monitor_at_point (display, x, y);
}

static gint
get_anchor_x_sign (GdkGravity anchor)
{
  switch (anchor)
    {
    case GDK_GRAVITY_STATIC:
    case GDK_GRAVITY_NORTH_WEST:
    case GDK_GRAVITY_WEST:
    case GDK_GRAVITY_SOUTH_WEST:
      return -1;

    default:
    case GDK_GRAVITY_NORTH:
    case GDK_GRAVITY_CENTER:
    case GDK_GRAVITY_SOUTH:
      return 0;

    case GDK_GRAVITY_NORTH_EAST:
    case GDK_GRAVITY_EAST:
    case GDK_GRAVITY_SOUTH_EAST:
      return 1;
    }
}

static gint
get_anchor_y_sign (GdkGravity anchor)
{
  switch (anchor)
    {
    case GDK_GRAVITY_STATIC:
    case GDK_GRAVITY_NORTH_WEST:
    case GDK_GRAVITY_NORTH:
    case GDK_GRAVITY_NORTH_EAST:
      return -1;

    default:
    case GDK_GRAVITY_WEST:
    case GDK_GRAVITY_CENTER:
    case GDK_GRAVITY_EAST:
      return 0;

    case GDK_GRAVITY_SOUTH_WEST:
    case GDK_GRAVITY_SOUTH:
    case GDK_GRAVITY_SOUTH_EAST:
      return 1;
    }
}

static gint
maybe_flip_position (gint      bounds_pos,
                     gint      bounds_size,
                     gint      rect_pos,
                     gint      rect_size,
                     gint      surface_size,
                     gint      rect_sign,
                     gint      surface_sign,
                     gint      offset,
                     gboolean  flip,
                     gboolean *flipped)
{
  gint primary;
  gint secondary;

  *flipped = FALSE;
  primary = rect_pos + (1 + rect_sign) * rect_size / 2 + offset - (1 + surface_sign) * surface_size / 2;

  if (!flip || (primary >= bounds_pos && primary + surface_size <= bounds_pos + bounds_size))
    return primary;

  *flipped = TRUE;
  secondary = rect_pos + (1 - rect_sign) * rect_size / 2 - offset - (1 - surface_sign) * surface_size / 2;

  if (secondary >= bounds_pos && secondary + surface_size <= bounds_pos + bounds_size)
    return secondary;

  *flipped = FALSE;
  return primary;
}

static GdkSurface *
traverse_to_toplevel (GdkSurface *surface,
                      gint       x,
                      gint       y,
                      gint      *toplevel_x,
                      gint      *toplevel_y)
{
  GdkSurface *parent;
  gdouble xf = x;
  gdouble yf = y;

  while ((parent = surface->parent) != NULL)
    {
      gdk_surface_coords_to_parent (surface, xf, yf, &xf, &yf);
      surface = parent;
    }

  *toplevel_x = (gint) xf;
  *toplevel_y = (gint) yf;
  return surface;
}

static void
gdk_surface_impl_move_to_rect (GdkSurface          *surface,
                              const GdkRectangle *rect,
                              GdkGravity          rect_anchor,
                              GdkGravity          surface_anchor,
                              GdkAnchorHints      anchor_hints,
                              gint                rect_anchor_dx,
                              gint                rect_anchor_dy)
{
  GdkSurface *transient_for_toplevel;
  GdkDisplay *display;
  GdkMonitor *monitor;
  GdkRectangle bounds;
  GdkRectangle root_rect = *rect;
  GdkRectangle flipped_rect;
  GdkRectangle final_rect;
  gboolean flipped_x;
  gboolean flipped_y;

  /*
   * First translate the anchor rect to toplevel coordinates. This is needed
   * because not all backends will be able to get root coordinates for
   * non-toplevel surfaces.
   */
  transient_for_toplevel = traverse_to_toplevel (surface->transient_for,
                                                 root_rect.x,
                                                 root_rect.y,
                                                 &root_rect.x,
                                                 &root_rect.y);

  gdk_surface_get_root_coords (transient_for_toplevel,
                              root_rect.x,
                              root_rect.y,
                              &root_rect.x,
                              &root_rect.y);

  display = get_display_for_surface (surface, surface->transient_for);
  monitor = get_monitor_for_rect (display, &root_rect);
  gdk_monitor_get_workarea (monitor, &bounds);

  flipped_rect.width = surface->width - surface->shadow_left - surface->shadow_right;
  flipped_rect.height = surface->height - surface->shadow_top - surface->shadow_bottom;
  flipped_rect.x = maybe_flip_position (bounds.x,
                                        bounds.width,
                                        root_rect.x,
                                        root_rect.width,
                                        flipped_rect.width,
                                        get_anchor_x_sign (rect_anchor),
                                        get_anchor_x_sign (surface_anchor),
                                        rect_anchor_dx,
                                        anchor_hints & GDK_ANCHOR_FLIP_X,
                                        &flipped_x);
  flipped_rect.y = maybe_flip_position (bounds.y,
                                        bounds.height,
                                        root_rect.y,
                                        root_rect.height,
                                        flipped_rect.height,
                                        get_anchor_y_sign (rect_anchor),
                                        get_anchor_y_sign (surface_anchor),
                                        rect_anchor_dy,
                                        anchor_hints & GDK_ANCHOR_FLIP_Y,
                                        &flipped_y);

  final_rect = flipped_rect;

  if (anchor_hints & GDK_ANCHOR_SLIDE_X)
    {
      if (final_rect.x + final_rect.width > bounds.x + bounds.width)
        final_rect.x = bounds.x + bounds.width - final_rect.width;

      if (final_rect.x < bounds.x)
        final_rect.x = bounds.x;
    }

  if (anchor_hints & GDK_ANCHOR_SLIDE_Y)
    {
      if (final_rect.y + final_rect.height > bounds.y + bounds.height)
        final_rect.y = bounds.y + bounds.height - final_rect.height;

      if (final_rect.y < bounds.y)
        final_rect.y = bounds.y;
    }

  if (anchor_hints & GDK_ANCHOR_RESIZE_X)
    {
      if (final_rect.x < bounds.x)
        {
          final_rect.width -= bounds.x - final_rect.x;
          final_rect.x = bounds.x;
        }

      if (final_rect.x + final_rect.width > bounds.x + bounds.width)
        final_rect.width = bounds.x + bounds.width - final_rect.x;
    }

  if (anchor_hints & GDK_ANCHOR_RESIZE_Y)
    {
      if (final_rect.y < bounds.y)
        {
          final_rect.height -= bounds.y - final_rect.y;
          final_rect.y = bounds.y;
        }

      if (final_rect.y + final_rect.height > bounds.y + bounds.height)
        final_rect.height = bounds.y + bounds.height - final_rect.y;
    }

  flipped_rect.x -= surface->shadow_left;
  flipped_rect.y -= surface->shadow_top;
  flipped_rect.width += surface->shadow_left + surface->shadow_right;
  flipped_rect.height += surface->shadow_top + surface->shadow_bottom;

  final_rect.x -= surface->shadow_left;
  final_rect.y -= surface->shadow_top;
  final_rect.width += surface->shadow_left + surface->shadow_right;
  final_rect.height += surface->shadow_top + surface->shadow_bottom;

  if (final_rect.width != surface->width || final_rect.height != surface->height)
    gdk_surface_move_resize (surface, final_rect.x, final_rect.y, final_rect.width, final_rect.height);
  else
    gdk_surface_move (surface, final_rect.x, final_rect.y);

  g_signal_emit_by_name (surface,
                         "moved-to-rect",
                         &flipped_rect,
                         &final_rect,
                         flipped_x,
                         flipped_y);
}

static void
gdk_surface_impl_class_init (GdkSurfaceImplClass *impl_class)
{
  impl_class->beep = gdk_surface_impl_beep;
  impl_class->move_to_rect = gdk_surface_impl_move_to_rect;
}

static void
gdk_surface_impl_init (GdkSurfaceImpl *impl)
{
}