/*
 * Copyright (C) 2012-2017 Robin Haberkorn
 *
 * This program 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 3 of the License, or
 * (at your option) any later version.
 *
 * 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 General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

requires 2.0.20

%ctop{
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <string.h>

#include <glib/gprintf.h>

#include <gdk/gdk.h>

/*
 * NOTE: These definitions are also in sciteco.h,
 * but we cannot include them from a plain C file.
 */
#define IS_CTL(C)	((C) < ' ')
#define CTL_ECHO(C)	((C) | 0x40)
#define CTL_KEY_ESC	27

#define GDK_TO_PANGO_COLOR(X) \
	((guint16)((X) * G_MAXUINT16))
%}

%h{
#include <gtk/gtk.h>
%}

class Gtk:Canonicalized:Label from Gtk:Label {
	private PangoColor fg;
	private guint16 fg_alpha;
	private PangoColor bg;
	private guint16 bg_alpha;

	override (Gtk:Widget) void
	style_updated(Gtk:Widget *widget)
	{
		Self *self = SELF(widget);

		GtkStyleContext *style;
		GdkRGBA normal_color;

		PARENT_HANDLER(widget);
		style = gtk_widget_get_style_context(widget);

		gtk_style_context_get_color(style, GTK_STATE_NORMAL, &normal_color);
		self->_priv->bg.red   = GDK_TO_PANGO_COLOR(normal_color.red);
		self->_priv->bg.green = GDK_TO_PANGO_COLOR(normal_color.green);
		self->_priv->bg.blue  = GDK_TO_PANGO_COLOR(normal_color.blue);
		self->_priv->bg_alpha = GDK_TO_PANGO_COLOR(normal_color.alpha);

		/*
		 * If Pango does not support transparent foregrounds,
		 * it will at least use a high-contrast foreground.
		 * NOTE: It would be very hard to get an appropriate background
		 * color even if Gtk supports it since the label itself may
		 * not have one but one of its parents.
		 * FIXME: We may want to honour the background color,
		 * so we can at least get decent reverse text when setting
		 * the background color in the CSS.
		 */
		self->_priv->fg.red   = G_MAXUINT16 - self->_priv->bg.red;
		self->_priv->fg.green = G_MAXUINT16 - self->_priv->bg.green;
		self->_priv->fg.blue  = G_MAXUINT16 - self->_priv->bg.blue;
		/* try hard to get a transparent foreground anyway */
		self->_priv->fg_alpha = G_MAXUINT16;
	}

	public GtkWidget *
	new(const gchar *str)
	{
		Self *widget = GET_NEW;

		self_set_text(widget, str);

		return GTK_WIDGET(widget);
	}

	private void
	add_highlight_attribs(Pango:Attr:List *attribs,
	                      Pango:Color *fg, guint16 fg_alpha,
	                      Pango:Color *bg, guint16 bg_alpha,
	                      guint index, gsize len)
	{
		PangoAttribute *attr;

#if PANGO_VERSION_CHECK(1,38,0)
		attr = pango_attr_foreground_alpha_new(fg_alpha);
		attr->start_index = index;
		attr->end_index = index + len;
		pango_attr_list_insert(attribs, attr);

		attr = pango_attr_background_alpha_new(bg_alpha);
		attr->start_index = index;
		attr->end_index = index + len;
		pango_attr_list_insert(attribs, attr);
#endif

		attr = pango_attr_foreground_new(fg->red, fg->green, fg->blue);
		attr->start_index = index;
		attr->end_index = index + len;
		pango_attr_list_insert(attribs, attr);

		attr = pango_attr_background_new(bg->red, bg->green, bg->blue);
		attr->start_index = index;
		attr->end_index = index + len;
		pango_attr_list_insert(attribs, attr);
	}

	public void
	parse_string(const gchar *str, gssize len,
	             Pango:Color *fg, guint16 fg_alpha,
	             Pango:Color *bg, guint16 bg_alpha,
	             Pango:Attr:List **attribs, gchar **text)
	{
		gsize text_len = 1; /* for trailing 0 */
		gint index = 0;

		if (len < 0)
			len = strlen(str);

		/*
		 * Approximate size of unformatted text.
		 */
		for (gint i = 0; i < len; i++)
			text_len += IS_CTL(str[i]) ? 3 : 1;

		*attribs = pango_attr_list_new();
		*text = g_malloc(text_len);

		while (len > 0) {
			/*
			 * NOTE: This mapping is similar to
			 * View::set_presentations()
			 */
			switch (*str) {
			case CTL_KEY_ESC:
				self_add_highlight_attribs(*attribs,
				                           fg, fg_alpha,
				                           bg, bg_alpha,
				                           index, 1);
				(*text)[index++] = '$';
				break;
			case '\r':
				self_add_highlight_attribs(*attribs,
				                           fg, fg_alpha,
				                           bg, bg_alpha,
				                           index, 2);
				(*text)[index++] = 'C';
				(*text)[index++] = 'R';
				break;
			case '\n':
				self_add_highlight_attribs(*attribs,
				                           fg, fg_alpha,
				                           bg, bg_alpha,
				                           index, 2);
				(*text)[index++] = 'L';
				(*text)[index++] = 'F';
				break;
			case '\t':
				self_add_highlight_attribs(*attribs,
				                           fg, fg_alpha,
				                           bg, bg_alpha,
				                           index, 3);
				(*text)[index++] = 'T';
				(*text)[index++] = 'A';
				(*text)[index++] = 'B';
				break;
			default:
				if (IS_CTL(*str)) {
					self_add_highlight_attribs(*attribs,
					                           fg, fg_alpha,
					                           bg, bg_alpha,
					                           index, 2);
					(*text)[index++] = '^';
					(*text)[index++] = CTL_ECHO(*str);
				} else {
					(*text)[index++] = *str;
				}
				break;
			}

			str++;
			len--;
		}

		/* null-terminate generated text */
		(*text)[index] = '\0';
	}

	public void
	set_text(self, const gchar *str)
	{
		PangoAttrList *attribs = NULL;
		gchar *plaintext = NULL;

		if (str)
			self_parse_string(str, -1,
			                  &self->_priv->fg, self->_priv->fg_alpha,
			                  &self->_priv->bg, self->_priv->bg_alpha,
			                  &attribs, &plaintext);

		gtk_label_set_attributes(GTK_LABEL(self), attribs);
		pango_attr_list_unref(attribs);
		gtk_label_set_text(GTK_LABEL(self), plaintext);
		g_free(plaintext);
	}
}