/*
 *	subtitleeditor -- a tool to create or edit subtitle
 *
 *	https://kitone.github.io/subtitleeditor/
 *	https://github.com/kitone/subtitleeditor/
 *
 *	Copyright @ 2005-2012, kitone
 *
 *	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/>.
 */
 
#include <extension/action.h>
#include <i18n.h>
#include <debug.h>

class ExtendLengthPlugin : public Action
{
public:

	ExtendLengthPlugin()
	{
		activate();
		update_ui();
	}

	~ExtendLengthPlugin()
	{
		deactivate();
	}

	/*
	 *
	 */
	void activate()
	{
		se_debug(SE_DEBUG_PLUGINS);

		// actions
		action_group = Gtk::ActionGroup::create("ExtendLengthPlugin");

		action_group->add(
				Gtk::Action::create("extend-length", _("_Extend Length Forward"), _("Extend the length of selected subtitles to the start time of the next")),
					sigc::mem_fun(*this, &ExtendLengthPlugin::on_extend_length_fwd));

		action_group->add(
				Gtk::Action::create("extend-length-bwd", _("E_xtend Length Backwards"), _("Extend the length of selected subtitles backwards to the end time of the previous")),
					sigc::mem_fun(*this, &ExtendLengthPlugin::on_extend_length_bwd));
		// ui
		Glib::RefPtr<Gtk::UIManager> ui = get_ui_manager();

		ui_id = ui->new_merge_id();

		ui->insert_action_group(action_group);

		ui->add_ui(ui_id, "/menubar/menu-timings/extend-length", "extend-length", "extend-length");
		ui->add_ui(ui_id, "/menubar/menu-timings/extend-length-bwd", "extend-length-bwd", "extend-length-bwd");
	}

	/*
	 *
	 */
	void deactivate()
	{
		se_debug(SE_DEBUG_PLUGINS);

		Glib::RefPtr<Gtk::UIManager> ui = get_ui_manager();

		ui->remove_ui(ui_id);
		ui->remove_action_group(action_group);
	}

	/*
	 *
	 */
	void update_ui()
	{
		se_debug(SE_DEBUG_PLUGINS);

		bool visible = (get_current_document() != NULL);

		action_group->get_action("extend-length")->set_sensitive(visible);
		action_group->get_action("extend-length-bwd")->set_sensitive(visible);
	}

protected:

	/*
	 *
	 */
	void on_extend_length_fwd()
	{
		se_debug(SE_DEBUG_PLUGINS);

		execute(true);
	}

	/*
	 *
	 */
	void on_extend_length_bwd()
	{
		se_debug(SE_DEBUG_PLUGINS);

		execute(false);
	}

	/*
	 *
	 */
	bool execute(bool forward)
	{
		se_debug(SE_DEBUG_PLUGINS);

		Document *doc = get_current_document();

		g_return_val_if_fail(doc, false);

		Subtitles subtitles = doc->subtitles();

		std::vector<Subtitle> selection = subtitles.get_selection();

		if(selection.empty())
		{
			doc->flash_message(_("Please select at least 1 subtitle."));
			return false;
		}

		SubtitleTime gap( get_config().get_value_int("timing", "min-gap-between-subtitles") );

		doc->start_command(_("Extend lenght"));

		if( forward )	// extend length forward, i.e. keep start and move end
		{
			for(unsigned int i=0; i< selection.size(); ++i)
			{
				Subtitle &sub = selection[i];
				Subtitle next = subtitles.get_next(sub);
				if(next)
				{
					SubtitleTime time = next.get_start() - gap;
					sub.set_end(time);
				}
			}
		}
		else // extend length backwards, i.e. keep end and move start
		{
			for( int i = selection.size() - 1; i >= 0 ; --i)
			{
				Subtitle &sub = selection[i];
				Subtitle prev = subtitles.get_previous(sub);
				if(prev)
				{
					SubtitleTime endtime = sub.get_end();
					SubtitleTime starttime = prev.get_end() + gap;
					//NOTE: we cannot just call sub.set_start() because it automatically shifts the end to preserve duration
					sub.set_start_and_end( starttime, endtime );
				}
			}
		}
		doc->emit_signal("subtitle-time-changed");
		doc->finish_command();

		return true;
	}
	
protected:
	Gtk::UIManager::ui_merge_id ui_id;
	Glib::RefPtr<Gtk::ActionGroup> action_group;
};

REGISTER_EXTENSION(ExtendLengthPlugin)
