/*
 * This file is part of Tepl, a text editor library.
 *
 * From gedit-view.c:
 * Copyright 1998, 1999 - Alex Roberts, Evan Lawrence
 * Copyright 2000, 2002 - Chema Celorio, Paolo Maggi
 * Copyright 2003-2005 - Paolo Maggi
 *
 * Copyright 2016 - Sébastien Wilmet <swilmet@gnome.org>
 *
 * Tepl 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.
 *
 * Tepl 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/>.
 */

#include "tepl-view.h"
#include "tepl-buffer.h"

/**
 * SECTION:view
 * @Short_description: Widget that displays a TeplBuffer
 * @Title: TeplView
 *
 * #TeplView is a subclass of #GtkSourceView, to add more features useful for a
 * text editor.
 */

#define SCROLL_MARGIN 0.02

G_DEFINE_TYPE (TeplView, tepl_view, GTK_SOURCE_TYPE_VIEW)

static GtkTextBuffer *
tepl_view_create_buffer (GtkTextView *view)
{
	return GTK_TEXT_BUFFER (tepl_buffer_new ());
}

static void
tepl_view_class_init (TeplViewClass *klass)
{
	GtkTextViewClass *text_view_class = GTK_TEXT_VIEW_CLASS (klass);

	text_view_class->create_buffer = tepl_view_create_buffer;
}

static void
tepl_view_init (TeplView *view)
{
}

/**
 * tepl_view_new:
 *
 * Returns: a new #TeplView.
 * Since: 1.0
 */
GtkWidget *
tepl_view_new (void)
{
	return g_object_new (TEPL_TYPE_VIEW, NULL);
}

/**
 * tepl_view_cut_clipboard:
 * @view: a #TeplView.
 *
 * Cuts the clipboard and then scrolls to the cursor position.
 *
 * Since: 1.0
 */
void
tepl_view_cut_clipboard (TeplView *view)
{
	GtkTextBuffer *buffer;
	GtkClipboard *clipboard;

	g_return_if_fail (TEPL_IS_VIEW (view));

	buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (view));

	clipboard = gtk_widget_get_clipboard (GTK_WIDGET (view),
					      GDK_SELECTION_CLIPBOARD);

	gtk_text_buffer_cut_clipboard (buffer,
				       clipboard,
				       gtk_text_view_get_editable (GTK_TEXT_VIEW (view)));

	gtk_text_view_scroll_to_mark (GTK_TEXT_VIEW (view),
				      gtk_text_buffer_get_insert (buffer),
				      SCROLL_MARGIN,
				      FALSE,
				      0.0,
				      0.0);
}

/**
 * tepl_view_copy_clipboard:
 * @view: a #TeplView.
 *
 * Copies the clipboard.
 *
 * Since: 1.0
 */
void
tepl_view_copy_clipboard (TeplView *view)
{
	GtkTextBuffer *buffer;
	GtkClipboard *clipboard;

	g_return_if_fail (TEPL_IS_VIEW (view));

	buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (view));

	clipboard = gtk_widget_get_clipboard (GTK_WIDGET (view),
					      GDK_SELECTION_CLIPBOARD);

	gtk_text_buffer_copy_clipboard (buffer, clipboard);

	/* On copy do not scroll, we are already on screen. */
}

/**
 * tepl_view_paste_clipboard:
 * @view: a #TeplView.
 *
 * Pastes the clipboard and then scrolls to the cursor position.
 *
 * Since: 1.0
 */
void
tepl_view_paste_clipboard (TeplView *view)
{
	GtkTextBuffer *buffer;
	GtkClipboard *clipboard;

	g_return_if_fail (TEPL_IS_VIEW (view));

	buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (view));

	clipboard = gtk_widget_get_clipboard (GTK_WIDGET (view),
					      GDK_SELECTION_CLIPBOARD);

	gtk_text_buffer_paste_clipboard (buffer,
					 clipboard,
					 NULL,
					 gtk_text_view_get_editable (GTK_TEXT_VIEW (view)));

	gtk_text_view_scroll_to_mark (GTK_TEXT_VIEW (view),
				      gtk_text_buffer_get_insert (buffer),
				      SCROLL_MARGIN,
				      FALSE,
				      0.0,
				      0.0);
}

/**
 * tepl_view_delete_selection:
 * @view: a #TeplView.
 *
 * Deletes the text currently selected in the #GtkTextBuffer associated
 * to the view and then scrolls to the cursor position.
 *
 * Since: 1.0
 */
void
tepl_view_delete_selection (TeplView *view)
{
	GtkTextBuffer *buffer;

	g_return_if_fail (TEPL_IS_VIEW (view));

	buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (view));

	gtk_text_buffer_delete_selection (buffer,
					  TRUE,
					  gtk_text_view_get_editable (GTK_TEXT_VIEW (view)));

	gtk_text_view_scroll_to_mark (GTK_TEXT_VIEW (view),
				      gtk_text_buffer_get_insert (buffer),
				      SCROLL_MARGIN,
				      FALSE,
				      0.0,
				      0.0);
}

/**
 * tepl_view_select_all:
 * @view: a #TeplView.
 *
 * Selects all the text.
 *
 * Since: 1.0
 */
void
tepl_view_select_all (TeplView *view)
{
	GtkTextBuffer *buffer;
	GtkTextIter start;
	GtkTextIter end;

	g_return_if_fail (TEPL_IS_VIEW (view));

	buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (view));

	gtk_text_buffer_get_bounds (buffer, &start, &end);
	gtk_text_buffer_select_range (buffer, &start, &end);
}

/**
 * tepl_view_scroll_to_cursor:
 * @view: a #TeplView.
 *
 * Scrolls the @view to the cursor position.
 *
 * Since: 1.0
 */
void
tepl_view_scroll_to_cursor (TeplView *view)
{
	GtkTextBuffer *buffer;

	g_return_if_fail (TEPL_IS_VIEW (view));

	buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (view));

	gtk_text_view_scroll_to_mark (GTK_TEXT_VIEW (view),
				      gtk_text_buffer_get_insert (buffer),
				      0.25,
				      FALSE,
				      0.0,
				      0.0);
}

/**
 * tepl_view_goto_line:
 * @view: a #TeplView.
 * @line: a line number, counting from 0.
 *
 * Places the cursor at the position returned by
 * gtk_text_buffer_get_iter_at_line(), and scrolls to that position.
 *
 * Returns: %TRUE if the cursor has been moved exactly to @line, %FALSE if that
 *   line didn't exist.
 * Since: 2.0
 */
gboolean
tepl_view_goto_line (TeplView *view,
		     gint      line)
{
	GtkTextBuffer *buffer;
	GtkTextIter iter;
	gboolean line_exists;

	g_return_val_if_fail (TEPL_IS_VIEW (view), FALSE);

	buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (view));

	gtk_text_buffer_get_iter_at_line (buffer, &iter, line);
	line_exists = gtk_text_iter_get_line (&iter) == line;

	gtk_text_buffer_place_cursor (buffer, &iter);
	tepl_view_scroll_to_cursor (view);

	return line_exists;
}

/**
 * tepl_view_goto_line_offset:
 * @view: a #TeplView.
 * @line: a line number, counting from 0.
 * @line_offset: the line offset, in characters (not bytes).
 *
 * Places the cursor at the position returned by
 * gtk_text_buffer_get_iter_at_line_offset(), and scrolls to that position.
 *
 * Returns: %TRUE if the cursor has been moved exactly to @line and
 *   @line_offset, %FALSE if that position didn't exist.
 * Since: 2.0
 */
gboolean
tepl_view_goto_line_offset (TeplView *view,
			    gint      line,
			    gint      line_offset)
{
	GtkTextBuffer *buffer;
	GtkTextIter iter;
	gboolean pos_exists;

	g_return_val_if_fail (TEPL_IS_VIEW (view), FALSE);

	buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (view));

	gtk_text_buffer_get_iter_at_line_offset (buffer,
						 &iter,
						 line,
						 line_offset);

	pos_exists = (gtk_text_iter_get_line (&iter) == line &&
		      gtk_text_iter_get_line_offset (&iter) == line_offset);

	gtk_text_buffer_place_cursor (buffer, &iter);
	tepl_view_scroll_to_cursor (view);

	return pos_exists;
}

/**
 * tepl_view_select_lines:
 * @view: a #TeplView.
 * @start_line: start of the region to select.
 * @end_line: end of the region to select.
 *
 * Selects the lines between @start_line and @end_line included, counting from
 * zero. And then scrolls to the cursor.
 *
 * Possible use-case: line numbers coming from a compilation output, to go to
 * the place where a warning or error occurred.
 *
 * Since: 2.0
 */
void
tepl_view_select_lines (TeplView *view,
			gint      start_line,
			gint      end_line)
{
	GtkTextBuffer *buffer;
	GtkTextIter start_iter;
	GtkTextIter end_iter;

	g_return_if_fail (TEPL_IS_VIEW (view));

	if (end_line < start_line)
	{
		gint start_line_copy;

		/* Swap start_line and end_line */
		start_line_copy = start_line;
		start_line = end_line;
		end_line = start_line_copy;
	}

	buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (view));

	gtk_text_buffer_get_iter_at_line (buffer, &start_iter, start_line);
	gtk_text_buffer_get_iter_at_line (buffer, &end_iter, end_line);

	if (!gtk_text_iter_ends_line (&end_iter))
	{
		gtk_text_iter_forward_to_line_end (&end_iter);
	}

	gtk_text_buffer_select_range (buffer, &start_iter, &end_iter);

	tepl_view_scroll_to_cursor (view);
}
