/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8; coding: utf-8 -*-

 * gtksourcegutterrendererlines.c

 * This file is part of GtkSourceView

 *

 * Copyright (C) 2010 - Jesse van den Kieboom

 *

 * GtkSourceView 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 2.1 of the License, or (at your option) any later version.

 *

 * GtkSourceView 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

 */

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif

#include "gtksourcegutterrendererlines.h"

#include "gtksourceview.h"

struct _GtkSourceGutterRendererLinesPrivate

{

	gint num_line_digits;

	gint prev_line_num;

	guint cursor_visible : 1;

};

G_DEFINE_TYPE_WITH_PRIVATE (GtkSourceGutterRendererLines, gtk_source_gutter_renderer_lines, GTK_SOURCE_TYPE_GUTTER_RENDERER_TEXT)

static GtkTextBuffer *

get_buffer (GtkSourceGutterRendererLines *renderer)

{

	GtkTextView *view;

	view = gtk_source_gutter_renderer_get_view (GTK_SOURCE_GUTTER_RENDERER (renderer));

	return view != NULL ? gtk_text_view_get_buffer (view) : NULL;

}

static inline gint

count_num_digits (gint num_lines)

{

	if (num_lines < 100)

	{

		return 2;

	}

	else if (num_lines < 1000)

	{

		return 3;

	}

	else if (num_lines < 10000)

	{

		return 4;

	}

	else if (num_lines < 100000)

	{

		return 5;

	}

	else if (num_lines < 1000000)

	{

		return 6;

	}

	else

	{

		return 10;

	}

}

static void

recalculate_size (GtkSourceGutterRendererLines *renderer)

{

	gint num_lines;

	gint num_digits = 0;

	GtkTextBuffer *buffer;

	buffer = get_buffer (renderer);

	num_lines = gtk_text_buffer_get_line_count (buffer);

	num_digits = count_num_digits (num_lines);

	if (num_digits != renderer->priv->num_line_digits)

	{

		gchar markup[24];

		gint size;

		renderer->priv->num_line_digits = num_digits;

		num_lines = MAX (num_lines, 99);

		g_snprintf (markup, sizeof markup, "%d", num_lines);

		gtk_source_gutter_renderer_text_measure_markup (GTK_SOURCE_GUTTER_RENDERER_TEXT (renderer),

		                                                markup,

		                                                &size,

		                                                NULL);

		gtk_source_gutter_renderer_set_size (GTK_SOURCE_GUTTER_RENDERER (renderer),

		                                     size);

	}

}

static void

on_buffer_changed (GtkSourceBuffer              *buffer,

                   GtkSourceGutterRendererLines *renderer)

{

	recalculate_size (renderer);

}

static void

gutter_renderer_change_buffer (GtkSourceGutterRenderer *renderer,

                               GtkTextBuffer           *old_buffer)

{

	GtkSourceGutterRendererLines *lines = GTK_SOURCE_GUTTER_RENDERER_LINES (renderer);

	GtkTextBuffer *buffer;

	if (old_buffer != NULL)

	{

		g_signal_handlers_disconnect_by_func (old_buffer,

						      on_buffer_changed,

						      lines);

	}

	buffer = get_buffer (lines);

	if (buffer != NULL)

	{

		g_signal_connect_object (buffer,

					 "changed",

					 G_CALLBACK (on_buffer_changed),

					 lines,

					 0);

		recalculate_size (lines);

	}

	lines->priv->prev_line_num = 0;

	if (GTK_SOURCE_GUTTER_RENDERER_CLASS (gtk_source_gutter_renderer_lines_parent_class)->change_buffer != NULL)

	{

		GTK_SOURCE_GUTTER_RENDERER_CLASS (gtk_source_gutter_renderer_lines_parent_class)->change_buffer (renderer,

														 old_buffer);

	}

}

static void

on_view_style_updated (GtkTextView                  *view,

		       GtkSourceGutterRendererLines *renderer)

{

	/* Force to recalculate the size. */

	renderer->priv->num_line_digits = -1;

	recalculate_size (renderer);

}

static void

on_view_notify_cursor_visible (GtkTextView                  *view,

                               GParamSpec                   *pspec,

                               GtkSourceGutterRendererLines *renderer)

{

	renderer->priv->cursor_visible = gtk_text_view_get_cursor_visible (view);

}

static void

gutter_renderer_change_view (GtkSourceGutterRenderer *renderer,

			     GtkTextView             *old_view)

{

	GtkTextView *new_view;

	if (old_view != NULL)

	{

		g_signal_handlers_disconnect_by_func (old_view,

						      on_view_style_updated,

						      renderer);

		g_signal_handlers_disconnect_by_func (old_view,

						      on_view_notify_cursor_visible,

						      renderer);

	}

	new_view = gtk_source_gutter_renderer_get_view (renderer);

	if (new_view != NULL)

	{

		g_signal_connect_object (new_view,

					 "style-updated",

					 G_CALLBACK (on_view_style_updated),

					 renderer,

					 0);

		g_signal_connect_object (new_view,

					 "notify::cursor-visible",

					 G_CALLBACK (on_view_notify_cursor_visible),

					 renderer,

					 0);

		GTK_SOURCE_GUTTER_RENDERER_LINES (renderer)->priv->cursor_visible = gtk_text_view_get_cursor_visible (new_view);

	}

	if (GTK_SOURCE_GUTTER_RENDERER_CLASS (gtk_source_gutter_renderer_lines_parent_class)->change_view != NULL)

	{

		GTK_SOURCE_GUTTER_RENDERER_CLASS (gtk_source_gutter_renderer_lines_parent_class)->change_view (renderer,

													       old_view);

	}

}

static void

gutter_renderer_query_data (GtkSourceGutterRenderer      *renderer,

                            GtkTextIter                  *start,

                            GtkTextIter                  *end,

                            GtkSourceGutterRendererState  state)

{

	GtkSourceGutterRendererLines *lines = GTK_SOURCE_GUTTER_RENDERER_LINES (renderer);

	gchar text[24];

	gint line;

	gint len;

	gboolean current_line;

	line = gtk_text_iter_get_line (start) + 1;

	current_line = (state & GTK_SOURCE_GUTTER_RENDERER_STATE_CURSOR) &&

	               lines->priv->cursor_visible;

	if (current_line)

	{

		len = g_snprintf (text, sizeof text, "%d", line);

	}

	else

	{

		len = g_snprintf (text, sizeof text, "%d", line);

	}

	gtk_source_gutter_renderer_text_set_markup (GTK_SOURCE_GUTTER_RENDERER_TEXT (renderer),

	                                            text,

	                                            len);

}

static gint

get_last_visible_line_number (GtkSourceGutterRendererLines *lines)

{

	GtkTextView *view;

	GdkRectangle visible_rect;

	GtkTextIter iter;

	view = gtk_source_gutter_renderer_get_view (GTK_SOURCE_GUTTER_RENDERER (lines));

	gtk_text_view_get_visible_rect (view, &visible_rect);

	gtk_text_view_get_line_at_y (view,

				     &iter,

				     visible_rect.y + visible_rect.height,

				     NULL);

	gtk_text_iter_forward_line (&iter);

	return gtk_text_iter_get_line (&iter);

}

static void

gutter_renderer_end (GtkSourceGutterRenderer *renderer)

{

	GtkSourceGutterRendererLines *lines = GTK_SOURCE_GUTTER_RENDERER_LINES (renderer);

	GtkTextBuffer *buffer = get_buffer (lines);

	if (buffer != NULL)

	{

		gint line_num = get_last_visible_line_number (lines);

		/* When the text is modified in a GtkTextBuffer, GtkTextView tries to

		 * redraw the smallest required region. But the information displayed in

		 * the gutter may become invalid in a bigger region.

		 * See https://bugzilla.gnome.org/show_bug.cgi?id=732418 for an example

		 * where line numbers are not updated correctly when splitting a wrapped

		 * line.

		 * The performances should not be a big problem here. Correctness is

		 * more important than performances. It just triggers a second

		 * draw.

		 * The queue_draw() is called in gutter_renderer_end(), because

		 * the first draw is anyway needed to avoid flickering (if the

		 * first draw is not done, there will be a white region in the

		 * gutter during one frame).

		 * Another solution that has better performances is to compare

		 * the total number of lines in the buffer, instead of the last

		 * visible line. But it has the drawback that the gutter is

		 * continuously redrawn during file loading.

		 *

		 * FIXME A better solution would be to add a vfunc in the

		 * GutterRenderer so that the Gutter can ask each renderer for

		 * the invalidation region, before drawing. So that only one

		 * draw is needed, and the solution would be more generic (if

		 * other renderers also need a different invalidation region

		 * than the GtkTextView). But the GutterRendererClass doesn't

		 * have padding for future expansion, so it must wait for

		 * GtkSourceView 4.

		 */

		if (lines->priv->prev_line_num != line_num)

		{

			lines->priv->prev_line_num = line_num;

			gtk_source_gutter_renderer_queue_draw (renderer);

		}

	}

	if (GTK_SOURCE_GUTTER_RENDERER_CLASS (gtk_source_gutter_renderer_lines_parent_class)->end != NULL)

	{

		GTK_SOURCE_GUTTER_RENDERER_CLASS (gtk_source_gutter_renderer_lines_parent_class)->end (renderer);

	}

}

static void

extend_selection_to_line (GtkSourceGutterRendererLines *renderer,

                          GtkTextIter                  *line_start)

{

	GtkTextIter start;

	GtkTextIter end;

	GtkTextIter line_end;

	GtkTextBuffer *buffer;

	buffer = get_buffer (renderer);

	gtk_text_buffer_get_selection_bounds (buffer,

	                                      &start,

	                                      &end;;

	line_end = *line_start;

	if (!gtk_text_iter_ends_line (&line_end))

	{

		gtk_text_iter_forward_to_line_end (&line_end);

	}

	if (gtk_text_iter_compare (&start, line_start) < 0)

	{

		gtk_text_buffer_select_range (buffer,

		                              &start,

		                              &line_end);

	}

	else if (gtk_text_iter_compare (&end, &line_end) < 0)

	{

		/* if the selection is in this line, extend

		 * the selection to the whole line */

		gtk_text_buffer_select_range (buffer,

		                              &line_end,

		                              line_start);

	}

	else

	{

		gtk_text_buffer_select_range (buffer,

		                              &end,

		                              line_start);

	}

}

static void

select_line (GtkSourceGutterRendererLines *renderer,

             GtkTextIter                  *line_start)

{

	GtkTextIter iter;

	GtkTextBuffer *buffer;

	buffer = get_buffer (renderer);

	iter = *line_start;

	if (!gtk_text_iter_ends_line (&iter))

	{

		gtk_text_iter_forward_to_line_end (&iter);

	}

	/* Select the line, put the cursor at the end of the line */

	gtk_text_buffer_select_range (buffer, &iter, line_start);

}

static void

gutter_renderer_activate (GtkSourceGutterRenderer *renderer,

                          GtkTextIter             *iter,

                          GdkRectangle            *rect,

                          GdkEvent                *event)

{

	GtkSourceGutterRendererLines *lines;

	lines = GTK_SOURCE_GUTTER_RENDERER_LINES (renderer);

	if (event->type == GDK_BUTTON_PRESS && (event->button.button == 1))

	{

		GtkTextBuffer *buffer;

		buffer = get_buffer (lines);

		if ((event->button.state & GDK_CONTROL_MASK) != 0)

		{

			/* Single click + Ctrl -> select the line */

			select_line (lines, iter);

		}

		else if ((event->button.state & GDK_SHIFT_MASK) != 0)

		{

			/* Single click + Shift -> extended current

			   selection to include the clicked line */

			extend_selection_to_line (lines, iter);

		}

		else

		{

			gtk_text_buffer_place_cursor (buffer, iter);

		}

	}

	else if (event->type == GDK_2BUTTON_PRESS && (event->button.button == 1))

	{

		select_line (lines, iter);

	}

}

static gboolean

gutter_renderer_query_activatable (GtkSourceGutterRenderer *renderer,

                                   GtkTextIter             *iter,

                                   GdkRectangle            *area,

                                   GdkEvent                *event)

{

	return get_buffer (GTK_SOURCE_GUTTER_RENDERER_LINES (renderer)) != NULL;

}

static void

gtk_source_gutter_renderer_lines_class_init (GtkSourceGutterRendererLinesClass *klass)

{

	GtkSourceGutterRendererClass *renderer_class = GTK_SOURCE_GUTTER_RENDERER_CLASS (klass);

	renderer_class->query_data = gutter_renderer_query_data;

	renderer_class->end = gutter_renderer_end;

	renderer_class->query_activatable = gutter_renderer_query_activatable;

	renderer_class->activate = gutter_renderer_activate;

	renderer_class->change_buffer = gutter_renderer_change_buffer;

	renderer_class->change_view = gutter_renderer_change_view;

}

static void

gtk_source_gutter_renderer_lines_init (GtkSourceGutterRendererLines *self)

{

	self->priv = gtk_source_gutter_renderer_lines_get_instance_private (self);

}

GtkSourceGutterRenderer *

gtk_source_gutter_renderer_lines_new (void)

{

	return g_object_new (GTK_SOURCE_TYPE_GUTTER_RENDERER_LINES, NULL);

}