/* GTK - The GIMP Toolkit

 * 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, write to the

 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

 * Boston, MA 02111-1307, USA.

 */

/*

 * Modified by the GTK+ Team and others 1997-2001.  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 "gtktextview.h"

#include "gtktextutil.h"

#define GTK_TEXT_USE_INTERNAL_UNSUPPORTED_API

#include "gtktextdisplay.h"

#include "gtktextbuffer.h"

#include "gtkmenuitem.h"

#include "gtkintl.h"

#include "gtkalias.h"

#define DRAG_ICON_MAX_WIDTH 250

#define DRAG_ICON_MAX_HEIGHT 250

#define DRAG_ICON_LAYOUT_BORDER 5

#define DRAG_ICON_MAX_LINES 7

#define ELLIPSIS_CHARACTER "\xe2\x80\xa6"

typedef struct _GtkUnicodeMenuEntry GtkUnicodeMenuEntry;

typedef struct _GtkTextUtilCallbackInfo GtkTextUtilCallbackInfo;

struct _GtkUnicodeMenuEntry {

  const char *label;

  gunichar ch;

};

struct _GtkTextUtilCallbackInfo

{

  GtkTextUtilCharChosenFunc func;

  gpointer data;

};

static const GtkUnicodeMenuEntry bidi_menu_entries[] = {

  { N_("LRM _Left-to-right mark"), 0x200E },

  { N_("RLM _Right-to-left mark"), 0x200F },

  { N_("LRE Left-to-right _embedding"), 0x202A },

  { N_("RLE Right-to-left e_mbedding"), 0x202B },

  { N_("LRO Left-to-right _override"), 0x202D },

  { N_("RLO Right-to-left o_verride"), 0x202E },

  { N_("PDF _Pop directional formatting"), 0x202C },

  { N_("ZWS _Zero width space"), 0x200B },

  { N_("ZWJ Zero width _joiner"), 0x200D },

  { N_("ZWNJ Zero width _non-joiner"), 0x200C }

};

static GtkTextUtilCallbackInfo *

callback_info_new (GtkTextUtilCharChosenFunc  func,

                   gpointer                   data)

{

  GtkTextUtilCallbackInfo *info;

  info = g_slice_new (GtkTextUtilCallbackInfo);

  info->func = func;

  info->data = data;

  return info;

}

static void

callback_info_free (GtkTextUtilCallbackInfo *info)

{

  g_slice_free (GtkTextUtilCallbackInfo, info);

}

static void

activate_cb (GtkWidget *menu_item,

             gpointer   data)

{

  GtkUnicodeMenuEntry *entry;

  GtkTextUtilCallbackInfo *info = data;

  char buf[7];

  entry = g_object_get_data (G_OBJECT (menu_item), "gtk-unicode-menu-entry");

  buf[g_unichar_to_utf8 (entry->ch, buf)] = '\0';

  (* info->func) (buf, info->data);

}

/*

 * _gtk_text_util_append_special_char_menuitems

 * @menushell: a #GtkMenuShell

 * @callback:  call this when an item is chosen

 * @data: data for callback

 * 

 * Add menuitems for various bidi control characters  to a menu;

 * the menuitems, when selected, will call the given function

 * with the chosen character.

 *

 * This function is private/internal in GTK 2.0, the functionality may

 * become public sometime, but it probably needs more thought first.

 * e.g. maybe there should be a way to just get the list of items,

 * instead of requiring the menu items to be created.

 */

void

_gtk_text_util_append_special_char_menuitems (GtkMenuShell              *menushell,

                                              GtkTextUtilCharChosenFunc  func,

                                              gpointer                   data)

{

  int i;

  for (i = 0; i < G_N_ELEMENTS (bidi_menu_entries); i++)

    {

      GtkWidget *menuitem;

      GtkTextUtilCallbackInfo *info;

      info = callback_info_new (func, data);

      menuitem = gtk_menu_item_new_with_mnemonic (_(bidi_menu_entries[i].label));

      g_object_set_data (G_OBJECT (menuitem), I_("gtk-unicode-menu-entry"),

                         (gpointer)&bidi_menu_entries[i]);

      g_signal_connect_data (menuitem, "activate",

                             G_CALLBACK (activate_cb),

                             info, (GClosureNotify) callback_info_free, 0);

      gtk_widget_show (menuitem);

      gtk_menu_shell_append (menushell, menuitem);

    }

}

static void

append_n_lines (GString *str, const gchar *text, GSList *lines, gint n_lines)

{

  PangoLayoutLine *line;

  gint i;

  for (i = 0; i < n_lines; i++)

    {

      line = lines->data;

      g_string_append_len (str, &text[line->start_index], line->length);

      lines = lines->next;

    }

}

static void

limit_layout_lines (PangoLayout *layout)

{

  const gchar *text;

  GString     *str;

  GSList      *lines, *elem;

  gint         n_lines;

  n_lines = pango_layout_get_line_count (layout);

  if (n_lines >= DRAG_ICON_MAX_LINES)

    {

      text  = pango_layout_get_text (layout);

      str   = g_string_new (NULL);

      lines = pango_layout_get_lines_readonly (layout);

      /* get first lines */

      elem = lines;

      append_n_lines (str, text, elem,

                      DRAG_ICON_MAX_LINES / 2);

      g_string_append (str, "\n" ELLIPSIS_CHARACTER "\n");

      /* get last lines */

      elem = g_slist_nth (lines, n_lines - DRAG_ICON_MAX_LINES / 2);

      append_n_lines (str, text, elem,

                      DRAG_ICON_MAX_LINES / 2);

      pango_layout_set_text (layout, str->str, -1);

      g_string_free (str, TRUE);

    }

}

/*

 * _gtk_text_util_create_drag_icon

 * @widget: #GtkWidget to extract the pango context

 * @text: a #gchar to render the icon

 * @len: length of @text, or -1 for NUL-terminated text

 *

 * Creates a drag and drop icon from @text.

 *

 * Returns: a #GdkPixmap to use as DND icon

 */

GdkPixmap *

_gtk_text_util_create_drag_icon (GtkWidget *widget, 

                                 gchar     *text,

                                 gsize      len)

{

  GdkDrawable  *drawable = NULL;

  PangoContext *context;

  PangoLayout  *layout;

  cairo_t      *cr;

  gint          pixmap_height, pixmap_width;

  gint          layout_width, layout_height;

  g_return_val_if_fail (widget != NULL, NULL);

  g_return_val_if_fail (text != NULL, NULL);

  context = gtk_widget_get_pango_context (widget);

  layout  = pango_layout_new (context);

  pango_layout_set_text (layout, text, len);

  pango_layout_set_wrap (layout, PANGO_WRAP_WORD_CHAR);

  pango_layout_get_size (layout, &layout_width, &layout_height);

  layout_width = MIN (layout_width, DRAG_ICON_MAX_WIDTH * PANGO_SCALE);

  pango_layout_set_width (layout, layout_width);

  limit_layout_lines (layout);

  /* get again layout extents, they may have changed */

  pango_layout_get_size (layout, &layout_width, &layout_height);

  pixmap_width  = layout_width  / PANGO_SCALE + DRAG_ICON_LAYOUT_BORDER * 2;

  pixmap_height = layout_height / PANGO_SCALE + DRAG_ICON_LAYOUT_BORDER * 2;

  drawable = gdk_pixmap_new (widget->window,

                             pixmap_width  + 2,

                             pixmap_height + 2,

                             -1);

  cr = gdk_cairo_create (drawable);

  gdk_cairo_set_source_color (cr, &widget->style->base [gtk_widget_get_state (widget)]);

  cairo_paint (cr);

  gdk_cairo_set_source_color (cr, &widget->style->text [gtk_widget_get_state (widget)]);

  cairo_move_to (cr, 1 + DRAG_ICON_LAYOUT_BORDER, 1 + DRAG_ICON_LAYOUT_BORDER);

  pango_cairo_show_layout (cr, layout);

  cairo_set_source_rgb (cr, 0, 0, 0);

  cairo_rectangle (cr, 0.5, 0.5, pixmap_width + 1, pixmap_height + 1);

  cairo_set_line_width (cr, 1.0);

  cairo_stroke (cr);

  cairo_destroy (cr);

  g_object_unref (layout);

  return drawable;

}

static void

gtk_text_view_set_attributes_from_style (GtkTextView        *text_view,

                                         GtkTextAttributes  *values,

                                         GtkStyle           *style)

{

  values->appearance.bg_color = style->base[GTK_STATE_NORMAL];

  values->appearance.fg_color = style->text[GTK_STATE_NORMAL];

  if (values->font)

    pango_font_description_free (values->font);

  values->font = pango_font_description_copy (style->font_desc);

}

GdkPixmap *

_gtk_text_util_create_rich_drag_icon (GtkWidget     *widget,

                                      GtkTextBuffer *buffer,

                                      GtkTextIter   *start,

                                      GtkTextIter   *end)

{

  GdkDrawable       *drawable = NULL;

  gint               pixmap_height, pixmap_width;

  gint               layout_width, layout_height;

  GtkTextBuffer     *new_buffer;

  GtkTextLayout     *layout;

  GtkTextAttributes *style;

  PangoContext      *ltr_context, *rtl_context;

  GtkTextIter        iter;

  cairo_t           *cr;

   g_return_val_if_fail (GTK_IS_WIDGET (widget), NULL);

   g_return_val_if_fail (GTK_IS_TEXT_BUFFER (buffer), NULL);

   g_return_val_if_fail (start != NULL, NULL);

   g_return_val_if_fail (end != NULL, NULL);

   new_buffer = gtk_text_buffer_new (gtk_text_buffer_get_tag_table (buffer));

   gtk_text_buffer_get_start_iter (new_buffer, &iter);

   gtk_text_buffer_insert_range (new_buffer, &iter, start, end);

   gtk_text_buffer_get_start_iter (new_buffer, &iter);

   layout = gtk_text_layout_new ();

   ltr_context = gtk_widget_create_pango_context (widget);

   pango_context_set_base_dir (ltr_context, PANGO_DIRECTION_LTR);

   rtl_context = gtk_widget_create_pango_context (widget);

   pango_context_set_base_dir (rtl_context, PANGO_DIRECTION_RTL);

   gtk_text_layout_set_contexts (layout, ltr_context, rtl_context);

   g_object_unref (ltr_context);

   g_object_unref (rtl_context);

   style = gtk_text_attributes_new ();

   layout_width = widget->allocation.width;

   if (GTK_IS_TEXT_VIEW (widget))

     {

       gtk_widget_ensure_style (widget);

       gtk_text_view_set_attributes_from_style (GTK_TEXT_VIEW (widget),

                                                style, widget->style);

       layout_width = layout_width

         - gtk_text_view_get_border_window_size (GTK_TEXT_VIEW (widget), GTK_TEXT_WINDOW_LEFT)

         - gtk_text_view_get_border_window_size (GTK_TEXT_VIEW (widget), GTK_TEXT_WINDOW_RIGHT);

     }

   style->direction = gtk_widget_get_direction (widget);

   style->wrap_mode = PANGO_WRAP_WORD_CHAR;

   gtk_text_layout_set_default_style (layout, style);

   gtk_text_attributes_unref (style);

   gtk_text_layout_set_buffer (layout, new_buffer);

   gtk_text_layout_set_cursor_visible (layout, FALSE);

   gtk_text_layout_set_screen_width (layout, layout_width);

   gtk_text_layout_validate (layout, DRAG_ICON_MAX_HEIGHT);

   gtk_text_layout_get_size (layout, &layout_width, &layout_height);

   layout_width = MIN (layout_width, DRAG_ICON_MAX_WIDTH);

   layout_height = MIN (layout_height, DRAG_ICON_MAX_HEIGHT);

   pixmap_width  = layout_width + DRAG_ICON_LAYOUT_BORDER * 2;

   pixmap_height = layout_height + DRAG_ICON_LAYOUT_BORDER * 2;

   drawable = gdk_pixmap_new (widget->window,

                              pixmap_width  + 2, pixmap_height + 2, -1);

   cr = gdk_cairo_create (drawable);

   gdk_cairo_set_source_color (cr, &widget->style->base [gtk_widget_get_state (widget)]);

   cairo_paint (cr);

   gtk_text_layout_draw (layout, widget, drawable,

                         widget->style->text_gc [gtk_widget_get_state (widget)],

                         - (1 + DRAG_ICON_LAYOUT_BORDER),

                         - (1 + DRAG_ICON_LAYOUT_BORDER),

                         0, 0,

                         pixmap_width, pixmap_height, NULL);

   cairo_set_source_rgb (cr, 0, 0, 0);

   cairo_rectangle (cr, 0.5, 0.5, pixmap_width + 1, pixmap_height + 1);

   cairo_set_line_width (cr, 1.0);

   cairo_stroke (cr);

   cairo_destroy (cr);

   g_object_unref (layout);

   g_object_unref (new_buffer);

   return drawable;

}

static gint

layout_get_char_width (PangoLayout *layout)

{

  gint width;

  PangoFontMetrics *metrics;

  const PangoFontDescription *font_desc;

  PangoContext *context = pango_layout_get_context (layout);

  font_desc = pango_layout_get_font_description (layout);

  if (!font_desc)

    font_desc = pango_context_get_font_description (context);

  metrics = pango_context_get_metrics (context, font_desc, NULL);

  width = pango_font_metrics_get_approximate_char_width (metrics);

  pango_font_metrics_unref (metrics);

  return width;

}

/*

 * _gtk_text_util_get_block_cursor_location

 * @layout: a #PangoLayout

 * @index: index at which cursor is located

 * @pos: cursor location

 * @at_line_end: whether cursor is drawn at line end, not over some

 * character

 *

 * Returns: whether cursor should actually be drawn as a rectangle.

 *     It may not be the case if character at index is invisible.

 */

gboolean

_gtk_text_util_get_block_cursor_location (PangoLayout    *layout,

					  gint            index,

					  PangoRectangle *pos,

					  gboolean       *at_line_end)

{

  PangoRectangle strong_pos, weak_pos;

  PangoLayoutLine *layout_line;

  gboolean rtl;

  gint line_no;

  const gchar *text;

  g_return_val_if_fail (layout != NULL, FALSE);

  g_return_val_if_fail (index >= 0, FALSE);

  g_return_val_if_fail (pos != NULL, FALSE);

  pango_layout_index_to_pos (layout, index, pos);

  if (pos->width != 0)

    {

      /* cursor is at some visible character, good */

      if (at_line_end)

	*at_line_end = FALSE;

      if (pos->width < 0)

	{

	  pos->x += pos->width;

	  pos->width = -pos->width;

	}

      return TRUE;

    }

  pango_layout_index_to_line_x (layout, index, FALSE, &line_no, NULL);

  layout_line = pango_layout_get_line_readonly (layout, line_no);

  g_return_val_if_fail (layout_line != NULL, FALSE);

  text = pango_layout_get_text (layout);

  if (index < layout_line->start_index + layout_line->length)

    {

      /* this may be a zero-width character in the middle of the line,

       * or it could be a character where line is wrapped, we do want

       * block cursor in latter case */

      if (g_utf8_next_char (text + index) - text !=

	  layout_line->start_index + layout_line->length)

	{

	  /* zero-width character in the middle of the line, do not

	   * bother with block cursor */

	  return FALSE;

	}

    }

  /* Cursor is at the line end. It may be an empty line, or it could

   * be on the left or on the right depending on text direction, or it

   * even could be in the middle of visual layout in bidi text. */

  pango_layout_get_cursor_pos (layout, index, &strong_pos, &weak_pos);

  if (strong_pos.x != weak_pos.x)

    {

      /* do not show block cursor in this case, since the character typed

       * in may or may not appear at the cursor position */

      return FALSE;

    }

  /* In case when index points to the end of line, pos->x is always most right

   * pixel of the layout line, so we need to correct it for RTL text. */

  if (layout_line->length)

    {

      if (layout_line->resolved_dir == PANGO_DIRECTION_RTL)

	{

	  PangoLayoutIter *iter;

	  PangoRectangle line_rect;

	  gint i;

	  gint left, right;

	  const gchar *p;

	  p = g_utf8_prev_char (text + index);

	  pango_layout_line_index_to_x (layout_line, p - text, FALSE, &left);

	  pango_layout_line_index_to_x (layout_line, p - text, TRUE, &right);

	  pos->x = MIN (left, right);

	  iter = pango_layout_get_iter (layout);

	  for (i = 0; i < line_no; i++)

	    pango_layout_iter_next_line (iter);

	  pango_layout_iter_get_line_extents (iter, NULL, &line_rect);

	  pango_layout_iter_free (iter);

          rtl = TRUE;

	  pos->x += line_rect.x;

	}

      else

	rtl = FALSE;

    }

  else

    {

      PangoContext *context = pango_layout_get_context (layout);

      rtl = pango_context_get_base_dir (context) == PANGO_DIRECTION_RTL;

    }

  pos->width = layout_get_char_width (layout);

  if (rtl)

    pos->x -= pos->width - 1;

  if (at_line_end)

    *at_line_end = TRUE;

  return pos->width != 0;

}