#include <glib/gi18n.h>

#include <2geom/bezier-curve.h>

#include "desktop.h"

#include "ui/tool/control-point-selection.h"

#include "ui/tool/curve-drag-point.h"

#include "ui/tool/event-utils.h"

#include "ui/tool/multi-path-manipulator.h"

#include "ui/tool/path-manipulator.h"

#include "ui/tool/node.h"

namespace Inkscape {

namespace UI {

bool CurveDragPoint::_drags_stroke = false;

bool CurveDragPoint::_segment_was_degenerate = false;

CurveDragPoint::CurveDragPoint(PathManipulator &pm)

: ControlPoint(pm._multi_path_manipulator._path_data.node_data.desktop, Geom::Point(),

Gtk::ANCHOR_CENTER, SP_CTRL_SHAPE_CIRCLE, 1.0, &invisible_cset,

pm._multi_path_manipulator._path_data.dragpoint_group)

, _pm(pm)

{

setVisible(false);

}

bool CurveDragPoint::_eventHandler(SPEventContext *event_context, GdkEvent *event)

{

// do not process any events when the manipulator is empty

if (_pm.empty()) {

setVisible(false);

return false;

}

return ControlPoint::_eventHandler(event_context, event);

}

bool CurveDragPoint::grabbed(GdkEventMotion */*event*/)

{

_pm._selection.hideTransformHandles();

NodeList::iterator second = first.next();

// move the handles to 1/3 the length of the segment for line segments

if (first->front()->isDegenerate() && second->back()->isDegenerate()) {

_segment_was_degenerate = true;

// delta is a vector equal 1/3 of distance from first to second

Geom::Point delta = (second->position() - first->position()) / 3.0;

first->front()->move(first->front()->position() + delta);

second->back()->move(second->back()->position() - delta);

_pm.update();

} else {

_segment_was_degenerate = false;

}

return false;

}

void CurveDragPoint::dragged(Geom::Point &new_pos, GdkEventMotion *event)

{

NodeList::iterator second = first.next();

// special cancel handling - retract handles when if the segment was degenerate

if (_is_drag_cancelled(event) && _segment_was_degenerate) {

first->front()->retract();

second->back()->retract();

_pm.update();

return;

}

// Magic Bezier Drag Equations follow!

// "weight" describes how the influence of the drag should be distributed

// among the handles; 0 = front handle only, 1 = back handle only.

double weight, t = _t;

if (t <= 1.0 / 6.0) weight = 0;

else if (t <= 0.5) weight = (pow((6 * t - 1) / 2.0, 3)) / 2;

else if (t <= 5.0 / 6.0) weight = (1 - pow((6 * (1-t) - 1) / 2.0, 3)) / 2 + 0.5;

else weight = 1;

Geom::Point delta = new_pos - position();

Geom::Point offset0 = ((1-weight)/(3*t*(1-t)*(1-t))) * delta;

Geom::Point offset1 = (weight/(3*t*t*(1-t))) * delta;

first->front()->move(first->front()->position() + offset0);

second->back()->move(second->back()->position() + offset1);

_pm.update();

}

void CurveDragPoint::ungrabbed(GdkEventButton *)

{

_pm._updateDragPoint(_desktop->d2w(position()));

_pm._commit(_("Drag curve"));

_pm._selection.restoreTransformHandles();

}

bool CurveDragPoint::clicked(GdkEventButton *event)

{

// This check is probably redundant

if (!first || event->button != 1) return false;

// the next iterator can be invalid if we click very near the end of path

NodeList::iterator second = first.next();

if (!second) return false;

// insert nodes on Ctrl+Alt+click

if (held_control(*event) && held_alt(*event)) {

_insertNode(false);

return true;

}

if (held_shift(*event)) {

// if both nodes of the segment are selected, deselect;

// otherwise add to selection

if (first->selected() && second->selected()) {

_pm._selection.erase(first.ptr());

_pm._selection.erase(second.ptr());

} else {

_pm._selection.insert(first.ptr());

_pm._selection.insert(second.ptr());

}

} else {

// without Shift, take selection

_pm._selection.clear();

_pm._selection.insert(first.ptr());

_pm._selection.insert(second.ptr());

}

return true;

}

bool CurveDragPoint::doubleclicked(GdkEventButton *event)

{

if (event->button != 1 || !first || !first.next()) return false;

_insertNode(true);

return true;

}

void CurveDragPoint::_insertNode(bool take_selection)

{

// The purpose of this call is to make way for the just created node.

// Otherwise clicks on the new node would only work after the user moves the mouse a bit.

// PathManipulator will restore visibility when necessary.

setVisible(false);

NodeList::iterator inserted = _pm.subdivideSegment(first, _t);

if (take_selection) {

_pm._selection.clear();

}

_pm._selection.insert(inserted.ptr());

_pm.update(true);

_pm._commit(_("Add node"));

}

Glib::ustring CurveDragPoint::_getTip(unsigned state)

{

if (_pm.empty()) return "";

if (!first || !first.next()) return "";

bool linear = first->front()->isDegenerate() && first.next()->back()->isDegenerate();

if (state_held_shift(state)) {

return C_("Path segment tip",

"<b>Shift</b>: click to toggle segment selection");

}

if (state_held_control(state) && state_held_alt(state)) {

return C_("Path segment tip",

"<b>Ctrl+Alt</b>: click to insert a node");

}

if (linear) {

return C_("Path segment tip",

"<b>Linear segment</b>: drag to convert to a Bezier segment, "

"doubleclick to insert node, click to select (more: Shift, Ctrl+Alt)");

} else {

return C_("Path segment tip",

"<b>Bezier segment</b>: drag to shape the segment, doubleclick to insert node, "

"click to select (more: Shift, Ctrl+Alt)");

}

}

} // namespace UI

} // namespace Inkscape