/* GAIL - The GNOME Accessibility Implementation Library
 * Copyright 2001 Sun Microsystems Inc.
 *
 * This program 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.
 *
 * This program 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 Lesser General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <gtk/gtk.h>
#include <libgnomecanvas/libgnomecanvas.h>
#include "gailcanvasitem.h"
#include "gailcanvastext.h"
#include <libgail-util/gail-util.h>

struct _GailCanvasText
{
  GailCanvasItem parent;
  GailTextUtil *textutil;
};

static void           gail_canvas_text_text_interface_init (AtkTextIface        *iface);
static gchar *         gail_canvas_text_get_text            (AtkText             *text,
                                                            gint                start_offset,
                                                            gint                end_offset);
static gchar *         gail_canvas_text_get_text_after_offset
                                                           (AtkText             *text,
                                                            gint                offset,
                                                            AtkTextBoundary     boundary_type,
                                                            gint                *start_offset,
                                                            gint                *end_offset);
static gchar *         gail_canvas_text_get_text_at_offset  (AtkText             *text,
                                                            gint                offset,
                                                            AtkTextBoundary     boundary_type,
                                                            gint                *start_offset,
                                                            gint                *end_offset);
static gchar *         gail_canvas_text_get_text_before_offset
                                                           (AtkText             *text,
                                                            gint                offset,
                                                            AtkTextBoundary     boundary_type,
                                                            gint                *start_offset,
                                                            gint                *end_offset);
static gunichar       gail_canvas_text_get_character_at_offset
                                                            (AtkText            *text,
                                                             gint               offset);
static gint           gail_canvas_text_get_character_count  (AtkText            *text);
static gint           gail_canvas_text_get_caret_offset     (AtkText            *text);
static gboolean       gail_canvas_text_set_caret_offset     (AtkText            *text,
                                                             gint               offset);
static gint           gail_canvas_text_get_offset_at_point  (AtkText            *text,
                                                             gint               x,
                                                             gint               y,
                                                             AtkCoordType       coords);
static void           gail_canvas_text_get_character_extents (AtkText           *text,
                                                              gint              offset,
                                                              gint              *x,
                                                              gint              *y,
                                                              gint              *width,
                                                              gint              *height,
                                                              AtkCoordType      coords);
static AtkAttributeSet *
                      gail_canvas_text_get_run_attributes    (AtkText           *text,
                                                              gint              offset,
                                                              gint              *start_offset,
                                                              gint              *end_offset);
static AtkAttributeSet *
                      gail_canvas_text_get_default_attributes (AtkText          *text);
static gint           gail_canvas_text_get_n_selections      (AtkText           *text);
static gchar *         gail_canvas_text_get_selection         (AtkText           *text,
                                                              gint              selection_num,
                                                              gint              *start_pos,
                                                              gint              *end_pos);
static gboolean       gail_canvas_text_add_selection         (AtkText           *text,
                                                              gint              start_pos,
                                                              gint              end_pos);
static gboolean       gail_canvas_text_remove_selection      (AtkText           *text,
                                                              gint              selection_num);
static gboolean       gail_canvas_text_set_selection         (AtkText           *text,
                                                              gint              selection_num,
                                                              gint              start_pos,
                                                              gint              end_pos);
static gchar *         get_text_near_offset                   (AtkText           *text,
                                                              GailOffsetType    function,
                                                              AtkTextBoundary   boundary_type,
                                                              gint              offset,
                                                              gint              *start_offset,
                                                              gint              *end_offset);

G_DEFINE_TYPE_WITH_CODE (GailCanvasText,
			gail_canvas_text,
			GAIL_TYPE_CANVAS_ITEM,
			G_IMPLEMENT_INTERFACE (ATK_TYPE_TEXT,
					       gail_canvas_text_text_interface_init);)

static void
gail_canvas_text_init (GailCanvasText *foo)
{
  ;
}

AtkObject *
gail_canvas_text_new (GObject *obj)
{
  gpointer object;
  AtkObject *atk_object;
  GailCanvasText *gail_text;

  g_return_val_if_fail (GNOME_IS_CANVAS_ITEM (obj), NULL);
  object = g_object_new (GAIL_TYPE_CANVAS_TEXT, NULL);
  atk_object = ATK_OBJECT (object);
  gail_text = GAIL_CANVAS_TEXT (object);

  atk_object_initialize (atk_object, obj);
  gail_text->textutil = gail_text_util_new ();

  if (GNOME_IS_CANVAS_TEXT (obj))
    {
      gail_text_util_text_setup (gail_text->textutil,
				   GNOME_CANVAS_TEXT (obj)->text);
    }

  atk_object->role = ATK_ROLE_TEXT;
  return atk_object;
}

static void
gail_canvas_text_class_init (GailCanvasTextClass *klass)
{
}

static void
gail_canvas_text_text_interface_init (AtkTextIface *iface)
{
  g_return_if_fail (iface != NULL);

  iface->get_text = gail_canvas_text_get_text;
  iface->get_text_after_offset = gail_canvas_text_get_text_after_offset;
  iface->get_text_at_offset = gail_canvas_text_get_text_at_offset;
  iface->get_text_before_offset = gail_canvas_text_get_text_before_offset;
  iface->get_character_at_offset = gail_canvas_text_get_character_at_offset;
  iface->get_character_count = gail_canvas_text_get_character_count;
  iface->get_caret_offset = gail_canvas_text_get_caret_offset;
  iface->set_caret_offset = gail_canvas_text_set_caret_offset;
  iface->get_offset_at_point = gail_canvas_text_get_offset_at_point;
  iface->get_character_extents = gail_canvas_text_get_character_extents;
  iface->get_n_selections = gail_canvas_text_get_n_selections;
  iface->get_selection = gail_canvas_text_get_selection;
  iface->add_selection = gail_canvas_text_add_selection;
  iface->remove_selection = gail_canvas_text_remove_selection;
  iface->set_selection = gail_canvas_text_set_selection;
  iface->get_run_attributes = gail_canvas_text_get_run_attributes;
  iface->get_default_attributes = gail_canvas_text_get_default_attributes;
}

static gchar *
gail_canvas_text_get_text (AtkText *text,
                           gint start_offset,
                           gint end_offset)
{
  GailCanvasText *gail_text;
  GtkTextBuffer *buffer;
  GtkTextIter start, end;

  g_return_val_if_fail (GAIL_IS_CANVAS_TEXT (text), NULL);
  gail_text = GAIL_CANVAS_TEXT (text);
  g_return_val_if_fail (gail_text->textutil, NULL);

  buffer = gail_text->textutil->buffer;
  gtk_text_buffer_get_iter_at_offset (buffer, &start, start_offset);
  gtk_text_buffer_get_iter_at_offset (buffer, &end, end_offset);

  return gtk_text_buffer_get_text (buffer, &start, &end, FALSE);
}

static gchar *
gail_canvas_text_get_text_after_offset (AtkText *text,
                                        gint offset,
                                        AtkTextBoundary boundary_type,
                                        gint *start_offset,
                                        gint *end_offset)
{
  return get_text_near_offset (text, GAIL_AFTER_OFFSET,
			       boundary_type, offset,
			       start_offset, end_offset);
}

static gchar *
gail_canvas_text_get_text_at_offset (AtkText *text,
                                     gint offset,
                                     AtkTextBoundary boundary_type,
                                     gint *start_offset,
                                     gint *end_offset)
{
  return get_text_near_offset (text, GAIL_AT_OFFSET,
			       boundary_type, offset,
			       start_offset, end_offset);
}

static gchar *
gail_canvas_text_get_text_before_offset (AtkText *text,
                                         gint offset,
                                         AtkTextBoundary boundary_type,
                                         gint *start_offset,
                                         gint *end_offset)
{
  return get_text_near_offset (text, GAIL_BEFORE_OFFSET,
			       boundary_type, offset,
			       start_offset, end_offset);
}

static gunichar
gail_canvas_text_get_character_at_offset (AtkText *text,
                                          gint offset)
{
  GailCanvasText *gail_item;
  GtkTextIter start, end;
  GtkTextBuffer *buffer;
  gchar *string;
  gchar *index;
  gunichar unichar;

  g_return_val_if_fail (GAIL_IS_CANVAS_TEXT (text), '\0');
  gail_item = GAIL_CANVAS_TEXT (text);
  buffer = gail_item->textutil->buffer;
  if (offset >= gtk_text_buffer_get_char_count (buffer))
    return '\0';

  gtk_text_buffer_get_start_iter (buffer, &start);
  gtk_text_buffer_get_end_iter (buffer, &end);
  string = gtk_text_buffer_get_text (buffer, &start, &end, FALSE);
  index = g_utf8_offset_to_pointer (string, offset);

  unichar = g_utf8_get_char (index);
  g_free (string);
  return unichar;
}

static gint
gail_canvas_text_get_character_count (AtkText *text)
{
  GtkTextBuffer *buffer;
  GailCanvasText *gail_text;

  g_return_val_if_fail (GAIL_IS_CANVAS_TEXT (text), 0);
  gail_text = GAIL_CANVAS_TEXT (text);
  g_return_val_if_fail (gail_text->textutil, 0);
  buffer = gail_text->textutil->buffer;
  return gtk_text_buffer_get_char_count (buffer);
}

static gint
gail_canvas_text_get_caret_offset (AtkText *text)
{
  GailCanvasText *gail_text;
  GtkTextBuffer *buffer;
  GtkTextMark *cursor_mark;
  GtkTextIter cursor_itr;

  g_return_val_if_fail (GAIL_IS_CANVAS_TEXT (text), 0);
  gail_text = GAIL_CANVAS_TEXT (text);
  g_return_val_if_fail (gail_text->textutil, 0);
  buffer = gail_text->textutil->buffer;
  cursor_mark = gtk_text_buffer_get_insert (buffer);
  gtk_text_buffer_get_iter_at_mark (buffer, &cursor_itr, cursor_mark);
  return gtk_text_iter_get_offset (&cursor_itr);
}

static gboolean
gail_canvas_text_set_caret_offset (AtkText *text,
                                   gint offset)
{
  GailCanvasText *gail_text;
  GtkTextBuffer *buffer;
  GtkTextIter pos_itr;

  g_return_val_if_fail (GAIL_IS_CANVAS_TEXT (text), FALSE);
  gail_text = GAIL_CANVAS_TEXT (text);
  g_return_val_if_fail (gail_text->textutil, FALSE);
  buffer = gail_text->textutil->buffer;
  gtk_text_buffer_get_iter_at_offset (buffer,  &pos_itr, offset);
  gtk_text_buffer_move_mark_by_name (buffer, "insert", &pos_itr);
  return TRUE;
}

static gint
gail_canvas_text_get_offset_at_point (AtkText *text,
                                      gint x,
                                      gint y,
                                      AtkCoordType coords)
{
  return -1;
}

static void
gail_canvas_text_get_character_extents (AtkText *text,
                                        gint offset,
                                        gint *x,
                                        gint *y,
                                        gint *width,
                                        gint *height,
                                        AtkCoordType coords)
{
  return;
}

static AtkAttributeSet *
gail_canvas_text_get_run_attributes (AtkText *text,
                                     gint offset,
                                     gint *start_offset,
                                     gint *end_offset)
{
  GailCanvasText *gail_text;

  g_return_val_if_fail (GAIL_IS_CANVAS_TEXT (text), NULL);
  gail_text = GAIL_CANVAS_TEXT (text);
  g_return_val_if_fail (gail_text->textutil, NULL);

  return gail_misc_buffer_get_run_attributes (gail_text->textutil->buffer,
					      offset, start_offset, end_offset);
}

static AtkAttributeSet *
gail_canvas_text_get_default_attributes (AtkText *text)
{
  return NULL;
}

static gint
gail_canvas_text_get_n_selections (AtkText *text)
{
  GailCanvasText *gail_text;
  GtkTextBuffer *buffer;
  GtkTextIter start, end;
  gint select_start, select_end;

  g_return_val_if_fail (GAIL_IS_CANVAS_TEXT (text), -1);
  gail_text = GAIL_CANVAS_TEXT (text);
  g_return_val_if_fail (gail_text->textutil, -1);
  buffer = gail_text->textutil->buffer;

  gtk_text_buffer_get_selection_bounds (buffer, &start, &end);
  select_start = gtk_text_iter_get_offset (&start);
  select_end = gtk_text_iter_get_offset (&end);

  if (select_start != select_end)
     return 1;
  else
     return 0;
}

static gchar *
gail_canvas_text_get_selection (AtkText *text,
                                gint selection_num,
                                gint *start_pos,
                                gint *end_pos)
{
  GailCanvasText *gail_text;
  GtkTextBuffer *buffer;
  GtkTextIter start, end;

 /* Only let the user get the selection if one is set, and if the
  * selection_num is 0.
  */
  if (selection_num != 0)
     return NULL;

  g_return_val_if_fail (GAIL_IS_CANVAS_TEXT (text), NULL);
  gail_text = GAIL_CANVAS_TEXT (text);
  g_return_val_if_fail (gail_text->textutil, NULL);
  buffer = gail_text->textutil->buffer;

  gtk_text_buffer_get_selection_bounds (buffer, &start, &end);
  *start_pos = gtk_text_iter_get_offset (&start);
  *end_pos = gtk_text_iter_get_offset (&end);

  if (*start_pos != *end_pos)
    return gtk_text_buffer_get_text (buffer, &start, &end, FALSE);
  else
    return NULL;
}

static gboolean
gail_canvas_text_add_selection (AtkText *text,
                                gint start_pos,
                                gint end_pos)
{
  GailCanvasText *gail_text;
  GtkTextBuffer *buffer;
  GtkTextIter pos_itr;
  GtkTextIter start, end;
  gint select_start, select_end;

  g_return_val_if_fail (GAIL_IS_CANVAS_TEXT (text), FALSE);
  gail_text = GAIL_CANVAS_TEXT (text);
  g_return_val_if_fail (gail_text->textutil, FALSE);
  buffer = gail_text->textutil->buffer;

  gtk_text_buffer_get_selection_bounds (buffer, &start, &end);
  select_start = gtk_text_iter_get_offset (&start);
  select_end = gtk_text_iter_get_offset (&end);

 /* If there is already a selection, then don't allow another to be added,
  * since GtkTextView only supports one selected region.
  */
  if (select_start == select_end)
    {
      gtk_text_buffer_get_iter_at_offset (buffer,  &pos_itr, start_pos);
      gtk_text_buffer_move_mark_by_name (buffer, "insert", &pos_itr);
      gtk_text_buffer_get_iter_at_offset (buffer,  &pos_itr, end_pos);
      gtk_text_buffer_move_mark_by_name (buffer, "selection_bound", &pos_itr);
      return TRUE;
    }
  else
    return FALSE;
}

static gboolean
gail_canvas_text_remove_selection (AtkText *text,
                                 gint selection_num)
{
  GailCanvasText *gail_text;
  GtkTextBuffer *buffer;
  GtkTextMark *cursor_mark;
  GtkTextIter cursor_itr;
  GtkTextIter start, end;
  gint select_start, select_end;

  if (selection_num != 0)
     return FALSE;

  g_return_val_if_fail (GAIL_IS_CANVAS_TEXT (text), FALSE);
  gail_text = GAIL_CANVAS_TEXT (text);
  g_return_val_if_fail (gail_text->textutil, FALSE);
  buffer = gail_text->textutil->buffer;

  gtk_text_buffer_get_selection_bounds (buffer, &start, &end);
  select_start = gtk_text_iter_get_offset (&start);
  select_end = gtk_text_iter_get_offset (&end);

  if (select_start != select_end)
    {
     /* Setting the start & end of the selected region to the caret position
      * turns off the selection.
      */
      cursor_mark = gtk_text_buffer_get_insert (buffer);
      gtk_text_buffer_get_iter_at_mark (buffer, &cursor_itr, cursor_mark);
      gtk_text_buffer_move_mark_by_name (buffer, "insert", &cursor_itr);
      gtk_text_buffer_move_mark_by_name (buffer, "selection_bound", &cursor_itr);
      return TRUE;
    }
  else
    return FALSE;
}

static gboolean
gail_canvas_text_set_selection (AtkText *text,
                              gint selection_num,
                              gint start_pos,
                              gint end_pos)
{
  GailCanvasText *gail_text;
  GtkTextBuffer *buffer;
  GtkTextIter pos_itr;
  GtkTextIter start, end;
  gint select_start, select_end;

 /* Only let the user move the selection if one is set, and if the
  * selection_num is 0
  */
  if (selection_num != 0)
     return FALSE;

  g_return_val_if_fail (GAIL_IS_CANVAS_TEXT (text), FALSE);
  gail_text = GAIL_CANVAS_TEXT (text);
  g_return_val_if_fail (gail_text->textutil, FALSE);
  buffer = gail_text->textutil->buffer;

  gtk_text_buffer_get_selection_bounds (buffer, &start, &end);
  select_start = gtk_text_iter_get_offset (&start);
  select_end = gtk_text_iter_get_offset (&end);

  if (select_start != select_end)
    {
      gtk_text_buffer_get_iter_at_offset (buffer,  &pos_itr, start_pos);
      gtk_text_buffer_move_mark_by_name (buffer, "insert", &pos_itr);
      gtk_text_buffer_get_iter_at_offset (buffer,  &pos_itr, end_pos);
      gtk_text_buffer_move_mark_by_name (buffer, "selection_bound", &pos_itr);
      return TRUE;
    }
  else
    return FALSE;
}

static gchar *
get_text_near_offset (AtkText *text,
                      GailOffsetType function,
                      AtkTextBoundary boundary_type,
                      gint offset,
                      gint *start_offset,
                      gint *end_offset)
{
  return gail_text_util_get_text (GAIL_CANVAS_TEXT (text)->textutil, NULL,
				  function, boundary_type, offset,
				  start_offset, end_offset);
}