/*
 * Copyright (C) 2005-2018 Paul Davis <paul@linuxaudiosystems.com>
 * Copyright (C) 2005 Taybin Rutkin <taybin@taybin.com>
 * Copyright (C) 2006-2012 David Robillard <d@drobilla.net>
 * Copyright (C) 2008 Hans Baier <hansfbaier@googlemail.com>
 * Copyright (C) 2009-2012 Carl Hetherington <carl@carlh.net>
 * Copyright (C) 2013-2019 Robin Gareus <robin@gareus.org>
 * Copyright (C) 2015-2016 Tim Mayberry <mojofunk@gmail.com>
 * Copyright (C) 2015-2017 Nick Mainsbridge <mainsbridge@gmail.com>
 * Copyright (C) 2015-2019 Ben Loftis <ben@harrisonconsoles.com>
 *
 * 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 2 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, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <typeinfo>

#include "ardour/audio_track.h"
#include "ardour/midi_track.h"
#include "ardour/midi_region.h"
#include "ardour/profile.h"
#include "ardour/region_factory.h"

#include "canvas/canvas.h"
#include "canvas/text.h"
#include "canvas/scroll_group.h"

#include "editor.h"
#include "editor_sections.h"
#include "keyboard.h"
#include "public_editor.h"
#include "audio_region_view.h"
#include "audio_streamview.h"
#include "audio_time_axis.h"
#include "region_gain_line.h"
#include "automation_line.h"
#include "automation_time_axis.h"
#include "automation_line.h"
#include "control_point.h"
#include "editor_drag.h"
#include "midi_time_axis.h"
#include "editor_regions.h"
#include "editor_sources.h"
#include "ui_config.h"
#include "verbose_cursor.h"

#include "pbd/i18n.h"

using namespace std;
using namespace ARDOUR;
using namespace PBD;
using namespace Gtk;
using namespace ArdourCanvas;

using Gtkmm2ext::Keyboard;

bool
Editor::track_canvas_scroll (GdkEventScroll* ev)
{
	int direction = ev->direction;

	/* this event arrives without transformation by the canvas, so we have
	 * to transform the coordinates to be able to look things up.
	 */

	Duple event_coords = _track_canvas->window_to_canvas (Duple (ev->x, ev->y));

	switch (direction) {
	case GDK_SCROLL_UP:
		if (Keyboard::modifier_state_equals (ev->state, Keyboard::ScrollZoomHorizontalModifier)) {
			temporal_zoom_step_mouse_focus (false);
			return true;
		} else if (Keyboard::modifier_state_equals (ev->state, Keyboard::ScrollHorizontalModifier)) {
			scroll_left_step ();
			return true;
		} else if (Keyboard::modifier_state_equals (ev->state, Keyboard::ScrollZoomVerticalModifier)) {
			if (!current_stepping_trackview) {
				step_timeout = Glib::signal_timeout().connect (sigc::mem_fun(*this, &Editor::track_height_step_timeout), 500);
				std::pair<TimeAxisView*, int> const p = trackview_by_y_position (event_coords.y, false);
				current_stepping_trackview = p.first;
				if (!current_stepping_trackview) {
					return false;
				}
			}
			last_track_height_step_timestamp = get_microseconds();
			current_stepping_trackview->step_height (false);
			return true;
		} else {
			scroll_up_one_track ();
			return true;
		}
		break;

	case GDK_SCROLL_DOWN:
		if (Keyboard::modifier_state_equals (ev->state, Keyboard::ScrollZoomHorizontalModifier)) {
			temporal_zoom_step_mouse_focus (true);
			return true;
		} else if (Keyboard::modifier_state_equals (ev->state, Keyboard::ScrollHorizontalModifier)) {
			scroll_right_step ();
			return true;
		} else if (Keyboard::modifier_state_equals (ev->state, Keyboard::ScrollZoomVerticalModifier)) {
			if (!current_stepping_trackview) {
				step_timeout = Glib::signal_timeout().connect (sigc::mem_fun(*this, &Editor::track_height_step_timeout), 500);
				std::pair<TimeAxisView*, int> const p = trackview_by_y_position (event_coords.y, false);
				current_stepping_trackview = p.first;
				if (!current_stepping_trackview) {
					return false;
				}
			}
			last_track_height_step_timestamp = get_microseconds();
			current_stepping_trackview->step_height (true);
			return true;
		} else {
			scroll_down_one_track ();
			return true;
		}
		break;

	case GDK_SCROLL_LEFT:
		scroll_left_step ();
		return true;
		break;

	case GDK_SCROLL_RIGHT:
		scroll_right_step ();
		return true;
		break;

	default:
		/* what? */
		break;
	}

	return false;
}

bool
Editor::canvas_scroll_event (GdkEventScroll *event, bool from_canvas)
{
	if (from_canvas) {
		boost::optional<ArdourCanvas::Rect> rulers = _time_markers_group->bounding_box();
		if (rulers && rulers->contains (Duple (event->x, event->y))) {
			return canvas_ruler_event ((GdkEvent*) event, timecode_ruler, TimecodeRulerItem);
		}
	}

	_track_canvas->grab_focus();
	return track_canvas_scroll (event);
}

bool
Editor::track_canvas_button_press_event (GdkEventButton *event)
{
	_track_canvas->grab_focus();
	if (!internal_editing() && !Keyboard::is_context_menu_event (event)) {
		begin_reversible_selection_op (X_("Clear Selection Click (track canvas)"));
		selection->clear ();
		commit_reversible_selection_op();
	}
	return false;
}

bool
Editor::track_canvas_button_release_event (GdkEventButton *event)
{
	if (!Keyboard::is_context_menu_event (event)) {
		if (_drags->active ()) {

			GdkEvent copy = *((GdkEvent*) event);
			Duple winpos = Duple (event->x, event->y);
			Duple where = _track_canvas->window_to_canvas (winpos);

			copy.button.x = where.x;
			copy.button.y = where.y;

			_drags->end_grab (&copy);
		}
	}
	return false;
}

bool
Editor::track_canvas_motion_notify_event (GdkEventMotion */*event*/)
{
	int x, y;
	/* keep those motion events coming */
	_track_canvas->get_pointer (x, y);
	return false;
}

bool
Editor::typed_event (ArdourCanvas::Item* item, GdkEvent *event, ItemType type)
{
	if (!session () || session()->loading () || session()->deletion_in_progress ()) {
		return false;
	}

	gint ret = FALSE;

	switch (event->type) {
	case GDK_BUTTON_PRESS:
	case GDK_2BUTTON_PRESS:
	case GDK_3BUTTON_PRESS:
		ret = button_press_handler (item, event, type);
		break;
	case GDK_BUTTON_RELEASE:
		ret = button_release_handler (item, event, type);
		break;
	case GDK_MOTION_NOTIFY:
		ret = motion_handler (item, event);
		break;

	case GDK_ENTER_NOTIFY:
		ret = enter_handler (item, event, type);
		break;

	case GDK_LEAVE_NOTIFY:
		ret = leave_handler (item, event, type);
		break;

	case GDK_KEY_PRESS:
		ret = key_press_handler (item, event, type);
		break;

	case GDK_KEY_RELEASE:
		ret = key_release_handler (item, event, type);
		break;

	default:
		break;
	}
	return ret;
}

bool
Editor::canvas_region_view_event (GdkEvent *event, ArdourCanvas::Item* item, RegionView *rv)
{
	bool ret = false;

	if (!rv->sensitive ()) {
		return false;
	}

	switch (event->type) {
	case GDK_BUTTON_PRESS:
	case GDK_2BUTTON_PRESS:
	case GDK_3BUTTON_PRESS:
		clicked_regionview = rv;
		clicked_control_point = 0;
		clicked_axisview = &rv->get_time_axis_view();
		clicked_routeview = dynamic_cast<RouteTimeAxisView*>(clicked_axisview);
		ret = button_press_handler (item, event, RegionItem);
		break;

	case GDK_BUTTON_RELEASE:
		ret = button_release_handler (item, event, RegionItem);
		break;

	case GDK_MOTION_NOTIFY:
		ret = motion_handler (item, event);
		break;

	case GDK_ENTER_NOTIFY:
		set_entered_regionview (rv);
		ret = enter_handler (item, event, RegionItem);
		break;

	case GDK_LEAVE_NOTIFY:
		if (event->crossing.detail != GDK_NOTIFY_INFERIOR) {
			set_entered_regionview (0);
			ret = leave_handler (item, event, RegionItem);
		}
		break;

	default:
		break;
	}

	return ret;
}

bool
Editor::canvas_wave_view_event (GdkEvent *event, ArdourCanvas::Item* item, RegionView* rv)
{
	/* we only care about enter events here, required for mouse/cursor
	 * tracking. there is a non-linear (non-child/non-parent) relationship
	 * between various components of a regionview and so when we leave one
	 * of them (e.g. a trim handle) and enter another (e.g. the waveview)
	 * no other items get notified. enter/leave handling does not propagate
	 * in the same way as other events, so we need to catch this because
	 * entering (and leaving) the waveview is equivalent to
	 * entering/leaving the regionview (which is why it is passed in as a
	 * third argument).
	 *
	 * And in fact, we really only care about enter events.
	 */

	bool ret = false;

	if (!rv->sensitive ()) {
		return false;
	}

	switch (event->type) {
	case GDK_ENTER_NOTIFY:
		set_entered_regionview (rv);
		ret = enter_handler (item, event, WaveItem);
		break;

	default:
		break;
	}

	return ret;
}


bool
Editor::canvas_stream_view_event (GdkEvent *event, ArdourCanvas::Item* item, RouteTimeAxisView *tv)
{
	bool ret = FALSE;

	switch (event->type) {
	case GDK_BUTTON_PRESS:
	case GDK_2BUTTON_PRESS:
	case GDK_3BUTTON_PRESS:
		clicked_regionview = 0;
		clicked_control_point = 0;
		clicked_axisview = tv;
		clicked_routeview = dynamic_cast<RouteTimeAxisView*>(clicked_axisview);
		ret = button_press_handler (item, event, StreamItem);
		break;

	case GDK_BUTTON_RELEASE:
		ret = button_release_handler (item, event, StreamItem);
		break;

	case GDK_MOTION_NOTIFY:
		ret = motion_handler (item, event);
		break;

	case GDK_ENTER_NOTIFY:
		set_entered_track (tv);
		ret = enter_handler (item, event, StreamItem);
		break;

	case GDK_LEAVE_NOTIFY:
		if (event->crossing.detail != GDK_NOTIFY_INFERIOR) {
			set_entered_track (0);
		}
		ret = leave_handler (item, event, StreamItem);
		break;

	default:
		break;
	}

	return ret;
}

bool
Editor::canvas_automation_track_event (GdkEvent *event, ArdourCanvas::Item* item, AutomationTimeAxisView *atv)
{
	if (atv->parameter().type() == MidiVelocityAutomation) {
		/* no event handling for velocity tracks until we can make the
		   automation control affect note velocity.
		*/
		return false;
	}

	bool ret = false;

	switch (event->type) {
	case GDK_BUTTON_PRESS:
	case GDK_2BUTTON_PRESS:
	case GDK_3BUTTON_PRESS:
		clicked_regionview = 0;
		clicked_control_point = 0;
		clicked_axisview = atv;
		clicked_routeview = 0;
		ret = button_press_handler (item, event, AutomationTrackItem);
		break;

	case GDK_BUTTON_RELEASE:
		ret = button_release_handler (item, event, AutomationTrackItem);
		break;

	case GDK_MOTION_NOTIFY:
		ret = motion_handler (item, event);
		break;

	case GDK_ENTER_NOTIFY:
		ret = enter_handler (item, event, AutomationTrackItem);
		break;

	case GDK_LEAVE_NOTIFY:
		ret = leave_handler (item, event, AutomationTrackItem);
		break;

	case GDK_KEY_PRESS:
		if (_drags->active()) {
			return _drags->mid_drag_key_event (&event->key);
		}
		break;

	case GDK_KEY_RELEASE:
		if (_drags->active()) {
			return _drags->mid_drag_key_event (&event->key);
		}
		break;

	default:
		break;
	}

	return ret;
}

bool
Editor::canvas_start_xfade_event (GdkEvent *event, ArdourCanvas::Item* item, AudioRegionView *rv)
{
	if (!rv->sensitive()) {
		return false;
	}

	switch (event->type) {
	case GDK_BUTTON_PRESS:
		clicked_regionview = rv;
		clicked_control_point = 0;
		clicked_axisview = &rv->get_time_axis_view();
		clicked_routeview = dynamic_cast<RouteTimeAxisView*>(clicked_axisview);
		if (event->button.button == 3) {
			return button_press_handler (item, event, StartCrossFadeItem);
		}
		break;

	case GDK_BUTTON_RELEASE:
		if (event->button.button == 3) {
			return button_release_handler (item, event, StartCrossFadeItem);
		}
		break;

	default:
		break;

	}

	/* In Mixbus, the crossfade area is used to trim the region while leaving the fade anchor intact (see preserve_fade_anchor)*/
	/* however in A3 this feature is unfinished, and it might be better to do it with a modifier-trim instead, anyway */
	/* if we return RegionItem here then we avoid the issue until it is resolved later */
	return typed_event (item, event, RegionItem); // StartCrossFadeItem);
}

bool
Editor::canvas_end_xfade_event (GdkEvent *event, ArdourCanvas::Item* item, AudioRegionView *rv)
{
	if (!rv->sensitive()) {
		return false;
	}

	switch (event->type) {
	case GDK_BUTTON_PRESS:
		clicked_regionview = rv;
		clicked_control_point = 0;
		clicked_axisview = &rv->get_time_axis_view();
		clicked_routeview = dynamic_cast<RouteTimeAxisView*>(clicked_axisview);
		if (event->button.button == 3) {
			return button_press_handler (item, event, EndCrossFadeItem);
		}
		break;

	case GDK_BUTTON_RELEASE:
		if (event->button.button == 3) {
			return button_release_handler (item, event, EndCrossFadeItem);
		}
		break;

	default:
		break;

	}

	/* In Mixbus, the crossfade area is used to trim the region while leaving the fade anchor intact (see preserve_fade_anchor)*/
	/* however in A3 this feature is unfinished, and it might be better to do it with a modifier-trim instead, anyway */
	/* if we return RegionItem here then we avoid the issue until it is resolved later */
	return typed_event (item, event, RegionItem); // EndCrossFadeItem);
}

bool
Editor::canvas_fade_in_event (GdkEvent *event, ArdourCanvas::Item* item, AudioRegionView *rv)
{
	/* we handle only button 3 press/release events */

	if (!rv->sensitive()) {
		return false;
	}

	switch (event->type) {
	case GDK_BUTTON_PRESS:
		clicked_regionview = rv;
		clicked_control_point = 0;
		clicked_axisview = &rv->get_time_axis_view();
		clicked_routeview = dynamic_cast<RouteTimeAxisView*>(clicked_axisview);
		if (event->button.button == 3) {
			return button_press_handler (item, event, FadeInItem);
		}
		break;

	case GDK_BUTTON_RELEASE:
		if (event->button.button == 3) {
			return button_release_handler (item, event, FadeInItem);
		}
		break;

	default:
		break;

	}

	/* proxy for the regionview, except enter/leave events */

	if (event->type == GDK_ENTER_NOTIFY || event->type == GDK_LEAVE_NOTIFY) {
		return true;
	} else {
		return canvas_region_view_event (event, rv->get_canvas_group(), rv);
	}
}

bool
Editor::canvas_fade_in_handle_event (GdkEvent *event, ArdourCanvas::Item* item, AudioRegionView *rv, bool trim)
{
	bool ret = false;

	if (!rv->sensitive()) {
		return false;
	}

	switch (event->type) {
	case GDK_BUTTON_PRESS:
	case GDK_2BUTTON_PRESS:
	case GDK_3BUTTON_PRESS:
		clicked_regionview = rv;
		clicked_control_point = 0;
		clicked_axisview = &rv->get_time_axis_view();
		clicked_routeview = dynamic_cast<RouteTimeAxisView*>(clicked_axisview);
		ret = button_press_handler (item, event, trim ? FadeInTrimHandleItem : FadeInHandleItem);
		break;

	case GDK_BUTTON_RELEASE:
		ret = button_release_handler (item, event, trim ? FadeInTrimHandleItem : FadeInHandleItem);
		break;

	case GDK_MOTION_NOTIFY:
		ret = motion_handler (item, event);
		break;

	case GDK_ENTER_NOTIFY:
		ret = enter_handler (item, event, trim ? FadeInTrimHandleItem : FadeInHandleItem);
		break;

	case GDK_LEAVE_NOTIFY:
		ret = leave_handler (item, event, trim ? FadeInTrimHandleItem : FadeInHandleItem);
		break;

	default:
		break;
	}

	return ret;
}

bool
Editor::canvas_fade_out_event (GdkEvent *event, ArdourCanvas::Item* item, AudioRegionView *rv)
{
	/* we handle only button 3 press/release events */

	if (!rv->sensitive()) {
		return false;
	}

	switch (event->type) {
	case GDK_BUTTON_PRESS:
		clicked_regionview = rv;
		clicked_control_point = 0;
		clicked_axisview = &rv->get_time_axis_view();
		clicked_routeview = dynamic_cast<RouteTimeAxisView*>(clicked_axisview);
		if (event->button.button == 3) {
			return button_press_handler (item, event, FadeOutItem);
		}
		break;

	case GDK_BUTTON_RELEASE:
		if (event->button.button == 3) {
			return button_release_handler (item, event, FadeOutItem);
		}
		break;

	default:
		break;

	}

	/* proxy for the regionview, except enter/leave events */

	if (event->type == GDK_ENTER_NOTIFY || event->type == GDK_LEAVE_NOTIFY) {
		return true;
	} else {
		return canvas_region_view_event (event, rv->get_canvas_group(), rv);
	}
}

bool
Editor::canvas_fade_out_handle_event (GdkEvent *event, ArdourCanvas::Item* item, AudioRegionView *rv, bool trim)
{
	bool ret = false;

	if (!rv->sensitive()) {
		return false;
	}

	switch (event->type) {
	case GDK_BUTTON_PRESS:
	case GDK_2BUTTON_PRESS:
	case GDK_3BUTTON_PRESS:
		clicked_regionview = rv;
		clicked_control_point = 0;
		clicked_axisview = &rv->get_time_axis_view();
		clicked_routeview = dynamic_cast<RouteTimeAxisView*>(clicked_axisview);
		ret = button_press_handler (item, event, trim ? FadeOutTrimHandleItem : FadeOutHandleItem);
		break;

	case GDK_BUTTON_RELEASE:
		ret = button_release_handler (item, event, trim ? FadeOutTrimHandleItem : FadeOutHandleItem);
		break;

	case GDK_MOTION_NOTIFY:
		ret = motion_handler (item, event);
		break;

	case GDK_ENTER_NOTIFY:
		ret = enter_handler (item, event, trim ? FadeOutTrimHandleItem : FadeOutHandleItem);
		break;

	case GDK_LEAVE_NOTIFY:
		ret = leave_handler (item, event, trim ? FadeOutTrimHandleItem : FadeOutHandleItem);
		break;

	default:
		break;
	}

	return ret;
}

struct DescendingRegionLayerSorter {
	bool operator()(std::shared_ptr<Region> a, std::shared_ptr<Region> b) {
		return a->layer() > b->layer();
	}
};

bool
Editor::canvas_control_point_event (GdkEvent *event, ArdourCanvas::Item* item, ControlPoint* cp)
{
	switch (event->type) {
	case GDK_BUTTON_PRESS:
	case GDK_2BUTTON_PRESS:
	case GDK_3BUTTON_PRESS:
		clicked_control_point = cp;
		clicked_axisview = &cp->line().trackview;
		clicked_routeview = dynamic_cast<RouteTimeAxisView*>(clicked_axisview);
		clicked_regionview = 0;
		break;
	default:
		break;
	}

	return typed_event (item, event, ControlPointItem);
}

bool
Editor::canvas_velocity_event (GdkEvent *event, ArdourCanvas::Item* item)
{
	return typed_event (item, event, VelocityItem);
}

bool
Editor::canvas_velocity_base_event (GdkEvent *event, ArdourCanvas::Item* item)
{
	return typed_event (item, event, VelocityBaseItem);
}

bool
Editor::canvas_line_event (GdkEvent *event, ArdourCanvas::Item* item, AutomationLine* al)
{
	ItemType type;
	RegionFxLine* rfl;
	if ((rfl = dynamic_cast<RegionFxLine*> (al)) != 0) {
		type = GainLineItem;
		if (event->type == GDK_BUTTON_PRESS) {
			clicked_regionview = &rfl->region_view ();
		}
	} else {
		type = AutomationLineItem;
		if (event->type == GDK_BUTTON_PRESS) {
			clicked_regionview = 0;
		}
	}

	clicked_control_point = 0;
	clicked_axisview = &al->trackview;
	clicked_routeview = dynamic_cast<RouteTimeAxisView*>(clicked_axisview);

	return typed_event (item, event, type);
}

bool
Editor::canvas_selection_rect_event (GdkEvent *event, ArdourCanvas::Item* item, SelectionRect* rect)
{
	bool ret = false;

	switch (event->type) {
	case GDK_BUTTON_PRESS:
	case GDK_2BUTTON_PRESS:
	case GDK_3BUTTON_PRESS:
		clicked_selection = rect->id;
		ret = button_press_handler (item, event, SelectionItem);
		break;
	case GDK_BUTTON_RELEASE:
		ret = button_release_handler (item, event, SelectionItem);
		break;
	case GDK_MOTION_NOTIFY:
		ret = motion_handler (item, event);
		break;
		/* Don't need these at the moment. */
	case GDK_ENTER_NOTIFY:
		ret = enter_handler (item, event, SelectionItem);
		break;

	case GDK_LEAVE_NOTIFY:
		ret = leave_handler (item, event, SelectionItem);
		break;

	default:
		break;
	}

	return ret;
}

bool
Editor::canvas_selection_start_trim_event (GdkEvent *event, ArdourCanvas::Item* item, SelectionRect* rect)
{
	bool ret = false;

	switch (event->type) {
	case GDK_BUTTON_PRESS:
	case GDK_2BUTTON_PRESS:
	case GDK_3BUTTON_PRESS:
		clicked_selection = rect->id;
		ret = button_press_handler (item, event, StartSelectionTrimItem);
		break;
	case GDK_BUTTON_RELEASE:
		ret = button_release_handler (item, event, StartSelectionTrimItem);
		break;
	case GDK_MOTION_NOTIFY:
		ret = motion_handler (item, event);
		break;
	case GDK_ENTER_NOTIFY:
		ret = enter_handler (item, event, StartSelectionTrimItem);
		break;

	case GDK_LEAVE_NOTIFY:
		ret = leave_handler (item, event, StartSelectionTrimItem);
		break;

	default:
		break;
	}

	return ret;
}

bool
Editor::canvas_selection_end_trim_event (GdkEvent *event, ArdourCanvas::Item* item, SelectionRect* rect)
{
	bool ret = false;

	switch (event->type) {
	case GDK_BUTTON_PRESS:
	case GDK_2BUTTON_PRESS:
	case GDK_3BUTTON_PRESS:
		clicked_selection = rect->id;
		ret = button_press_handler (item, event, EndSelectionTrimItem);
		break;
	case GDK_BUTTON_RELEASE:
		ret = button_release_handler (item, event, EndSelectionTrimItem);
		break;
	case GDK_MOTION_NOTIFY:
		ret = motion_handler (item, event);
		break;
	case GDK_ENTER_NOTIFY:
		ret = enter_handler (item, event, EndSelectionTrimItem);
		break;

	case GDK_LEAVE_NOTIFY:
		ret = leave_handler (item, event, EndSelectionTrimItem);
		break;

	default:
		break;
	}

	return ret;
}

bool
Editor::canvas_frame_handle_event (GdkEvent* event, ArdourCanvas::Item* item, RegionView* rv)
{
	bool ret = false;

	/* frame handles are not active when in internal edit mode, because actual notes
	   might be in the area occupied by the handle - we want them to be editable as normal.
	*/

	if (internal_editing() || !rv->sensitive()) {
		return false;
	}

	/* NOTE: frame handles pretend to be the colored trim bar from an event handling
	   perspective. XXX change this ??
	*/

	ItemType type;

	if (item->get_data ("isleft")) {
		type = LeftFrameHandle;
	} else {
		type = RightFrameHandle;
	}

	switch (event->type) {
	case GDK_BUTTON_PRESS:
	case GDK_2BUTTON_PRESS:
	case GDK_3BUTTON_PRESS:
		clicked_regionview = rv;
		clicked_control_point = 0;
		clicked_axisview = &clicked_regionview->get_time_axis_view();
		clicked_routeview = dynamic_cast<RouteTimeAxisView*>(clicked_axisview);
		ret = button_press_handler (item, event, type);
		break;
	case GDK_BUTTON_RELEASE:
		ret = button_release_handler (item, event, type);
		break;
	case GDK_MOTION_NOTIFY:
		ret = motion_handler (item, event);
		break;
	case GDK_ENTER_NOTIFY:
		ret = enter_handler (item, event, type);
		break;

	case GDK_LEAVE_NOTIFY:
		ret = leave_handler (item, event, type);
		break;

	default:
		break;
	}

	return ret;
}


bool
Editor::canvas_region_view_name_highlight_event (GdkEvent* event, ArdourCanvas::Item* item, RegionView* rv)
{
	bool ret = false;

	if (!rv->sensitive()) {
		return false;
	}

	switch (event->type) {
	case GDK_BUTTON_PRESS:
	case GDK_2BUTTON_PRESS:
	case GDK_3BUTTON_PRESS:
		clicked_regionview = rv;
		clicked_control_point = 0;
		clicked_axisview = &clicked_regionview->get_time_axis_view();
		clicked_routeview = dynamic_cast<RouteTimeAxisView*>(clicked_axisview);
		ret = button_press_handler (item, event, RegionViewNameHighlight);
		break;
	case GDK_BUTTON_RELEASE:
		ret = button_release_handler (item, event, RegionViewNameHighlight);
		break;
	case GDK_MOTION_NOTIFY:
		motion_handler (item, event);
		ret = true; // force this to avoid propagating the event into the regionview
		break;
	case GDK_ENTER_NOTIFY:
		ret = enter_handler (item, event, RegionViewNameHighlight);
		break;

	case GDK_LEAVE_NOTIFY:
		ret = leave_handler (item, event, RegionViewNameHighlight);
		break;

	default:
		break;
	}

	return ret;
}

bool
Editor::canvas_region_view_name_event (GdkEvent *event, ArdourCanvas::Item* item, RegionView* rv)
{
	bool ret = false;

	if (!rv->sensitive()) {
		return false;
	}

	switch (event->type) {
	case GDK_BUTTON_PRESS:
	case GDK_2BUTTON_PRESS:
	case GDK_3BUTTON_PRESS:
		clicked_regionview = rv;
		clicked_control_point = 0;
		clicked_axisview = &clicked_regionview->get_time_axis_view();
		clicked_routeview = dynamic_cast<RouteTimeAxisView*>(clicked_axisview);
		ret = button_press_handler (item, event, RegionViewName);
		break;
	case GDK_BUTTON_RELEASE:
		ret = button_release_handler (item, event, RegionViewName);
		break;
	case GDK_MOTION_NOTIFY:
		ret = motion_handler (item, event);
		break;
	case GDK_ENTER_NOTIFY:
		ret = enter_handler (item, event, RegionViewName);
		break;

	case GDK_LEAVE_NOTIFY:
		ret = leave_handler (item, event, RegionViewName);
		break;

	default:
		break;
	}

	return ret;
}

bool
Editor::canvas_feature_line_event (GdkEvent *event, ArdourCanvas::Item* item, RegionView*)
{
	bool ret = false;

	switch (event->type) {
	case GDK_BUTTON_PRESS:
	case GDK_2BUTTON_PRESS:
	case GDK_3BUTTON_PRESS:
		clicked_regionview = 0;
		clicked_control_point = 0;
		clicked_axisview = 0;
		clicked_routeview = 0; //dynamic_cast<RouteTimeAxisView*>(clicked_axisview);
		ret = button_press_handler (item, event, FeatureLineItem);
		break;

	case GDK_BUTTON_RELEASE:
		ret = button_release_handler (item, event, FeatureLineItem);
		break;

	case GDK_MOTION_NOTIFY:
		ret = motion_handler (item, event);
		break;

	case GDK_ENTER_NOTIFY:
		ret = enter_handler (item, event, FeatureLineItem);
		break;

	case GDK_LEAVE_NOTIFY:
		ret = leave_handler (item, event, FeatureLineItem);
		break;

	default:
		break;
	}

	return ret;
}

bool
Editor::canvas_marker_event (GdkEvent *event, ArdourCanvas::Item* item, ArdourMarker* /*marker*/)
{
	return typed_event (item, event, MarkerItem);
}

bool
Editor::canvas_selection_marker_event (GdkEvent *event, ArdourCanvas::Item* item)
{
	return typed_event (item, event, SelectionMarkerItem);
}

bool
Editor::canvas_videotl_bar_event (GdkEvent *event, ArdourCanvas::Item* item)
{
	return typed_event (item, event, VideoBarItem);
}

bool
Editor::canvas_tempo_marker_event (GdkEvent *event, ArdourCanvas::Item* item, TempoMarker* marker)
{
	return typed_event (item, event, TempoMarkerItem);
}

bool
Editor::canvas_tempo_curve_event (GdkEvent *event, ArdourCanvas::Item* item, TempoCurve* /*marker*/)
{
	return typed_event (item, event, TempoCurveItem);
}

bool
Editor::canvas_meter_marker_event (GdkEvent *event, ArdourCanvas::Item* item, MeterMarker* /*marker*/)
{
	return typed_event (item, event, MeterMarkerItem);
}

bool
Editor::canvas_bbt_marker_event (GdkEvent *event, ArdourCanvas::Item* item, BBTMarker* /*marker*/)
{
	return typed_event (item, event, BBTMarkerItem);
}

bool
Editor::canvas_ruler_event (GdkEvent *event, ArdourCanvas::Item* item, ItemType type)
{
	bool handled = false;

	if (event->type == GDK_SCROLL) {

		/* scroll events in the rulers are handled a little differently from
		   scrolling elsewhere in the canvas.
		*/

		switch (event->scroll.direction) {
		case GDK_SCROLL_UP:
			if (Keyboard::modifier_state_equals (event->scroll.state, Keyboard::ScrollHorizontalModifier)) {
				scroll_left_step ();
			} else if (UIConfiguration::instance().get_use_mouse_position_as_zoom_focus_on_scroll()) {
				temporal_zoom_step_mouse_focus (false);
			} else if (Keyboard::modifier_state_equals (event->scroll.state, Keyboard::PrimaryModifier)) {
				temporal_zoom_step_mouse_focus (false);
			} else {
				temporal_zoom_step (false);
			}
			handled = true;
			break;

		case GDK_SCROLL_DOWN:
			if (Keyboard::modifier_state_equals (event->scroll.state, Keyboard::ScrollHorizontalModifier)) {
				scroll_right_step ();
			} else if (UIConfiguration::instance().get_use_mouse_position_as_zoom_focus_on_scroll()) {
				temporal_zoom_step_mouse_focus (true);
			} else if (Keyboard::modifier_state_equals (event->scroll.state, Keyboard::PrimaryModifier)) {
				temporal_zoom_step_mouse_focus (true);
			} else {
				temporal_zoom_step (true);
			}
			handled = true;
			break;

		case GDK_SCROLL_LEFT:
			scroll_left_half_page ();
			handled = true;
			break;

		case GDK_SCROLL_RIGHT:
			scroll_right_half_page ();
			handled = true;
			break;

		default:
			/* what? */
			break;
		}
		return handled;
	}

	return typed_event (item, event, type);
}

bool
Editor::canvas_ruler_bar_event (GdkEvent *event, ArdourCanvas::Item* item, ItemType type, std::string const& color_name)
{
	/* XXX consolidate with Editor::canvas_ruler_event ? */

	switch (event->type) {
	case GDK_ENTER_NOTIFY:
		if (event->crossing.detail != GDK_NOTIFY_INFERIOR) {
			item->set_fill_color (Gtkmm2ext::HSV(UIConfiguration::instance().color_mod (color_name, "marker bar")).lighter(0.20).color());
		}
		break;
	case GDK_LEAVE_NOTIFY:
		if (event->crossing.detail != GDK_NOTIFY_INFERIOR) {
			item->set_fill_color (UIConfiguration::instance().color_mod (color_name, "marker bar"));
		}
		break;
	default:
		break;
	};

	return typed_event (item, event, type);
}

bool
Editor::section_rect_event (GdkEvent* ev, Location* loc, ArdourCanvas::Rectangle* rect, std::string color)
{
	switch (ev->type) {
		case GDK_ENTER_NOTIFY:
			if (UIConfiguration::instance ().get_widget_prelight ()) {
				rect->set_fill_color (Gtkmm2ext::HSV (UIConfiguration::instance().color (color)).lighter (0.25));
				return true;
			}
			break;
		case GDK_LEAVE_NOTIFY:
			if (UIConfiguration::instance ().get_widget_prelight ()) {
				rect->set_fill_color (UIConfiguration::instance().color (color));
				return true;
			}
			break;
		case GDK_BUTTON_PRESS:
			if (Keyboard::modifier_state_equals (ev->button.state, Keyboard::PrimaryModifier)) {
				/* used to add markers */
				return false;
			}
			if (ev->button.button == 1) {
				_session->request_locate (loc->start().samples());
			}
			return true;
		case GDK_2BUTTON_PRESS:
		case GDK_3BUTTON_PRESS:
			if (Keyboard::modifier_state_equals (ev->button.state, Keyboard::PrimaryModifier)) {
				return false;
			}
			if (ev->button.button == 1) {
				assert (find_location_markers (loc));
				rename_marker (find_location_markers (loc)->start);
				return true;
			}
			break;
		case GDK_BUTTON_RELEASE:
			if (Keyboard::is_context_menu_event (&ev->button)) {
				using namespace Menu_Helpers;

				/* find section */
				timepos_t start (loc->start ());
				timepos_t end;
				Location* l = _session->locations()->section_at (start, start, end);
				assert (l);

				timepos_t where (canvas_event_time (ev));
				snap_to (where, Temporal::RoundNearest);

				section_box_menu.set_name ("ArdourContextMenu");
				MenuList& items (section_box_menu.items());
				items.clear ();

				items.push_back (MenuElem (_("New Arrangement Marker"), sigc::bind (sigc::mem_fun(*this, &Editor::mouse_add_new_marker), where, Location::Flags(Location::IsMark | Location::IsSection), 0)));
				items.push_back (MenuElem (_("Select Arrangement Section"), sigc::bind (sigc::mem_fun(*_sections, &EditorSections::select), l)));
#if 0
				items.push_back (SeparatorElem());
				add_section_context_items (items);   //TODO: section_context_items needs to be modified to operate on the marker you clicked on, not the range selection (which might not exist)
#endif

				section_box_menu.popup (ev->button.button, ev->button.time);
				return true;
			}
			break;
		default:
			break;
	}
	return false;
}

bool
Editor::canvas_playhead_cursor_event (GdkEvent *event, ArdourCanvas::Item* item)
{
	return typed_event (item, event, PlayheadCursorItem);
}

bool
Editor::canvas_section_box_event (GdkEvent *event)
{
	switch (event->type) {
		case GDK_BUTTON_PRESS:
			if (!Keyboard::modifier_state_equals (event->button.state, Keyboard::PrimaryModifier)
			   && event->button.button == 1) {
				_drags->set (new CursorDrag (this, *_playhead_cursor, false), event);
			}
			/*fallthrough*/
		case GDK_2BUTTON_PRESS:
			/*fallthrough*/
		case GDK_3BUTTON_PRESS:
			return !Keyboard::modifier_state_equals (event->button.state, Keyboard::PrimaryModifier);
		case GDK_BUTTON_RELEASE:
			if (Keyboard::is_context_menu_event (&event->button)) {
				section_box_menu.set_name ("ArdourContextMenu");
				Gtk::Menu_Helpers::MenuList& items (section_box_menu.items());
				items.clear ();
				add_section_context_items (items);
				section_box_menu.popup (event->button.button, event->button.time);
				return true;
			}
			return false;
		default:
			break;
	}
	return false;
}

bool
Editor::canvas_note_event (GdkEvent *event, ArdourCanvas::Item* item)
{
	if (!internal_editing()) {
		return false;
	}

	return typed_event (item, event, NoteItem);
}

bool
Editor::canvas_drop_zone_event (GdkEvent* event)
{
	GdkEventScroll scroll;
	ArdourCanvas::Duple winpos;

	switch (event->type) {
	case GDK_BUTTON_RELEASE:
		if (event->button.button == 1) {
			begin_reversible_selection_op (X_("Nowhere Click"));
			selection->clear_objects ();
			selection->clear_tracks ();
			commit_reversible_selection_op ();
		}
		break;

	case GDK_SCROLL:
		/* convert coordinates back into window space so that
		 * we can just call canvas_scroll_event().
		 */
		winpos = _track_canvas->canvas_to_window (Duple (event->scroll.x, event->scroll.y));
		scroll = event->scroll;
		scroll.x = winpos.x;
		scroll.y = winpos.y;
		return canvas_scroll_event (&scroll, true);
		break;

	case GDK_ENTER_NOTIFY:
		return typed_event (_canvas_drop_zone, event, DropZoneItem);

	case GDK_LEAVE_NOTIFY:
		return typed_event (_canvas_drop_zone, event, DropZoneItem);

	case GDK_MOTION_NOTIFY:
		return motion_handler (_canvas_drop_zone, event);
		break;

	default:
		break;
	}

	return true;
}

bool
Editor::canvas_grid_zone_event (GdkEvent* event)
{
	GdkEventScroll scroll;
	ArdourCanvas::Duple winpos;


	switch (event->type) {

		case GDK_BUTTON_PRESS:
			if (event->button.button == 1) {
				choose_mapping_drag (_canvas_grid_zone, event);
			}
			break;

		case GDK_BUTTON_RELEASE:
			return typed_event (_canvas_grid_zone, event, GridZoneItem);
			break;

		case GDK_SCROLL:
			/* convert coordinates back into window space so that
			 * we can just call canvas_scroll_event().
			 */
			winpos   = _track_canvas->canvas_to_window (Duple (event->scroll.x, event->scroll.y));
			scroll   = event->scroll;
			scroll.x = winpos.x;
			scroll.y = winpos.y;
			return canvas_scroll_event (&scroll, true);
			break;

		case GDK_ENTER_NOTIFY:
			return typed_event (_canvas_grid_zone, event, GridZoneItem);

		case GDK_LEAVE_NOTIFY:
			return typed_event (_canvas_grid_zone, event, GridZoneItem);

		case GDK_MOTION_NOTIFY:
			return motion_handler (_canvas_grid_zone, event);
			break;

		default:
			break;
	}

	return true;
}

bool
Editor::track_canvas_drag_motion (Glib::RefPtr<Gdk::DragContext> const& context, int x, int y, guint time)
{
	std::shared_ptr<Region> region;
	std::shared_ptr<Region> region_copy;
	RouteTimeAxisView* rtav;
	GdkEvent event;
	double px;
	double py;

	string target = _track_canvas->drag_dest_find_target (context, _track_canvas->drag_dest_get_target_list());

	if (target.empty()) {
		return false;
	}

	event.type = GDK_MOTION_NOTIFY;
	event.button.x = x;
	event.button.y = y;
	/* assume we're dragging with button 1 */
	event.motion.state = Gdk::BUTTON1_MASK;

	(void) window_event_sample (&event, &px, &py);

	std::pair<TimeAxisView*, int> const tv = trackview_by_y_position (py, false);
	bool can_drop = false;

	if (tv.first != 0) {

		/* over a time axis view of some kind */

		rtav = dynamic_cast<RouteTimeAxisView*> (tv.first);

		if (rtav != 0 && rtav->is_track ()) {
			/* over a track, not a bus */
			can_drop = true;
		}


	} else {
		/* not over a time axis view, so drop is possible */
		can_drop = true;
	}

	if (can_drop) {

		if (target == "x-ardour/region.pbdid") {
			if (tv.first == 0 && pbdid_dragged_dt != DataType::NIL) {
				/* drop to drop-zone */
				context->drag_status (Gdk::ACTION_COPY, time);
				return true;
			}

			if ((pbdid_dragged_dt == DataType::AUDIO && dynamic_cast<AudioTimeAxisView*> (tv.first) != 0) ||
			    (pbdid_dragged_dt == DataType::MIDI  && dynamic_cast<MidiTimeAxisView*> (tv.first) != 0)) {
				/* audio to audio OR MIDI to MIDI */
				context->drag_status (Gdk::ACTION_COPY, time);
				return true;
			}
		} else {
			/* DND originating from outside ardour
			 *
			 * TODO: check if file is audio/midi, allow drops on same track-type only,
			 * currently: if audio is dropped on a midi-track, it is only added to the region-list
			 */
			if (UIConfiguration::instance().get_only_copy_imported_files()) {
				context->drag_status(Gdk::ACTION_COPY, time);
			} else {
				if ((context->get_actions() & (Gdk::ACTION_COPY | Gdk::ACTION_LINK | Gdk::ACTION_MOVE)) == Gdk::ACTION_COPY) {
					context->drag_status(Gdk::ACTION_COPY, time);
				} else {
					context->drag_status(Gdk::ACTION_LINK, time);
				}
			}
			return true;
		}
	}

	/* no drop here */
	context->drag_status (Gdk::DragAction (0), time);
	return false;
}

void
Editor::drop_regions (const Glib::RefPtr<Gdk::DragContext>& /*context*/,
                      int x, int y,
                      const SelectionData& data,
                      guint /*info*/, guint /*time*/)
{
	GdkEvent event;
	double px;
	double py;

	event.type = GDK_MOTION_NOTIFY;
	event.button.x = x;
	event.button.y = y;
	/* assume we're dragging with button 1 */
	event.motion.state = Gdk::BUTTON1_MASK;
	samplepos_t const pos = window_event_sample (&event, &px, &py);

	PBD::ID rid (data.get_data_as_string ());
	std::shared_ptr<Region> region = RegionFactory::region_by_id (rid);

	if (!region) { return; }

	RouteTimeAxisView* rtav = 0;
	std::pair<TimeAxisView*, int> const tv = trackview_by_y_position (py, false);

	if (tv.first != 0) {
		rtav = dynamic_cast<RouteTimeAxisView*> (tv.first);
	} else {
		try {
			if (std::dynamic_pointer_cast<AudioRegion> (region)) {
				uint32_t output_chan = region->sources().size();
				if ((Config->get_output_auto_connect() & AutoConnectMaster) && session()->master_out()) {
					output_chan =  session()->master_out()->n_inputs().n_audio();
				}
				list<std::shared_ptr<AudioTrack> > audio_tracks;
				audio_tracks = session()->new_audio_track (region->sources().size(), output_chan, 0, 1, region->name(), PresentationInfo::max_order);
				rtav = dynamic_cast<RouteTimeAxisView*> (time_axis_view_from_stripable (audio_tracks.front()));
			} else if (std::dynamic_pointer_cast<MidiRegion> (region)) {
				ChanCount one_midi_port (DataType::MIDI, 1);
				list<std::shared_ptr<MidiTrack> > midi_tracks;
				midi_tracks = session()->new_midi_track (one_midi_port, one_midi_port,
				                                         Config->get_strict_io () || Profile->get_mixbus (),
				                                         std::shared_ptr<ARDOUR::PluginInfo>(),
				                                         (ARDOUR::Plugin::PresetRecord*) 0,
				                                         (ARDOUR::RouteGroup*) 0, 1, region->name(), PresentationInfo::max_order, Normal, true);
				rtav = dynamic_cast<RouteTimeAxisView*> (time_axis_view_from_stripable (midi_tracks.front()));
			} else {
				return;
			}
		} catch (...) {
			error << _("Could not create new track after region placed in the drop zone") << endmsg;
			return;
		}
	}

	if (rtav != 0 && rtav->is_track ()) {
		std::shared_ptr<Region> region_copy = RegionFactory::create (region, true);

		if ((std::dynamic_pointer_cast<AudioRegion> (region_copy) != 0 && dynamic_cast<AudioTimeAxisView*> (rtav) != 0) ||
		    (std::dynamic_pointer_cast<MidiRegion> (region_copy) != 0 && dynamic_cast<MidiTimeAxisView*> (rtav) != 0)) {
			_drags->set (new RegionInsertDrag (this, region_copy, rtav, timepos_t (pos), drag_time_domain (region_copy.get())), &event);
			_drags->end_grab (&event);
		}
	}
}

bool
Editor::key_press_handler (ArdourCanvas::Item*, GdkEvent*, ItemType)
{
	return false;
}

bool
Editor::key_release_handler (ArdourCanvas::Item* item, GdkEvent* event, ItemType type)
{

	bool handled = false;

	switch (type) {
	case TempoMarkerItem:
		switch (event->key.keyval) {
		case GDK_Delete:
			remove_tempo_marker (item);
			handled = true;
			break;
		default:
			break;
		}
		break;

	case MeterMarkerItem:
		switch (event->key.keyval) {
		case GDK_Delete:
			remove_meter_marker (item);
			handled = true;
			break;
		default:
			break;
		}
		break;

	default:
		break;
	}

	return handled;
}