////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2011-2022 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// This file is part of Octave.
//
// Octave 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.
//
// Octave 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 Octave; see the file COPYING.  If not, see
// <https://www.gnu.org/licenses/>.
//
////////////////////////////////////////////////////////////////////////

#if defined (HAVE_CONFIG_H)
#  include "config.h"
#endif

#include <QListWidget>
#include <QEvent>
#include <QMouseEvent>

#include "Container.h"
#include "ListBoxControl.h"
#include "QtHandlesUtils.h"

#include "octave-qobject.h"

OCTAVE_BEGIN_NAMESPACE(octave)

static void
updateSelection (QListWidget *list, const Matrix& value)
{
  octave_idx_type n = value.numel ();
  int lc = list->count ();

  list->clearSelection ();

  for (octave_idx_type i = 0; i < n; i++)
    {
      int idx = octave::math::round (value(i));

      if (1 <= idx && idx <= lc)
        {
          list->item (idx-1)->setSelected (true);
          list->scrollToItem (list->item (idx-1));
          if (i == 0
              && list->selectionMode () == QAbstractItemView::SingleSelection)
            break;
        }
      else
        {
          // Invalid selection.
          list->clearSelection ();
          break;
        }
    }
}

ListBoxControl *
ListBoxControl::create (octave::base_qobject& oct_qobj,
                        octave::interpreter& interp,
                        const graphics_object& go)
{
  Object *parent = parentObject (interp, go);

  if (parent)
    {
      Container *container = parent->innerContainer ();

      if (container)
        return new ListBoxControl (oct_qobj, interp, go,
                                   new QListWidget (container));
    }

  return nullptr;
}

ListBoxControl::ListBoxControl (octave::base_qobject& oct_qobj,
                                octave::interpreter& interp,
                                const graphics_object& go, QListWidget *list)
  : BaseControl (oct_qobj, interp, go, list), m_blockCallback (false),
    m_selectionChanged (false)
{
  uicontrol::properties& up = properties<uicontrol> ();

  list->addItems (Utils::fromStringVector (up.get_string_vector ()));
  if ((up.get_max () - up.get_min ()) > 1)
    list->setSelectionMode (QAbstractItemView::ExtendedSelection);
  else
    list->setSelectionMode (QAbstractItemView::SingleSelection);
  Matrix value = up.get_value ().matrix_value ();
  if (value.numel () > 0)
    {
      octave_idx_type n = value.numel ();
      int lc = list->count ();

      for (octave_idx_type i = 0; i < n; i++)
        {
          int idx = octave::math::round (value(i));

          if (1 <= idx && idx <= lc)
            {
              list->item (idx-1)->setSelected (true);
              list->scrollToItem (list->item (idx-1));
              if (i == 0 && (list->selectionMode ()
                             == QAbstractItemView::SingleSelection))
                break;
            }
        }
    }

  list->viewport ()->installEventFilter (this);

  connect (list, &QListWidget::itemSelectionChanged,
           this, &ListBoxControl::itemSelectionChanged);
  connect (list, &QListWidget::activated,
           this, &ListBoxControl::itemActivated);
  connect (list, &QListWidget::itemPressed,
           this, &ListBoxControl::itemPressed);
}

ListBoxControl::~ListBoxControl (void)
{ }

void
ListBoxControl::update (int pId)
{
  uicontrol::properties& up = properties<uicontrol> ();
  QListWidget *list = qWidget<QListWidget> ();

  switch (pId)
    {
    case uicontrol::properties::ID_STRING:
      m_blockCallback = true;
      list->clear ();
      list->addItems (Utils::fromStringVector (up.get_string_vector ()));
      updateSelection (list, up.get_value ().matrix_value ());
      m_blockCallback = false;
      break;

    case uicontrol::properties::ID_MIN:
    case uicontrol::properties::ID_MAX:
      if ((up.get_max () - up.get_min ()) > 1)
        list->setSelectionMode (QAbstractItemView::ExtendedSelection);
      else
        list->setSelectionMode (QAbstractItemView::SingleSelection);
      break;

    case uicontrol::properties::ID_LISTBOXTOP:
      {
        int idx = octave::math::fix (up.get_listboxtop ());
        if (idx > 0)
          list->scrollToItem (list->item (idx-1),
                              QAbstractItemView::PositionAtTop);
        break;
      }

    case uicontrol::properties::ID_VALUE:
      m_blockCallback = true;
      updateSelection (list, up.get_value ().matrix_value ());
      m_blockCallback = false;
      break;

    default:
      BaseControl::update (pId);
      break;
    }
}

void
ListBoxControl::sendSelectionChange ()
{
  if (! m_blockCallback)
    {
      QListWidget *list = qWidget<QListWidget> ();

      QModelIndexList l = list->selectionModel ()->selectedIndexes ();
      Matrix value (dim_vector (1, l.size ()));
      int i = 0;

      for (const auto& idx : l)
        value(i++) = idx.row () + 1;

      emit gh_set_event (m_handle, "value", octave_value (value), false);
      emit gh_callback_event (m_handle, "callback");
    }

  m_selectionChanged = false;
}

void
ListBoxControl::itemSelectionChanged (void)
{
  if (! m_blockCallback)
    m_selectionChanged = true;
}

void
ListBoxControl::itemActivated (const QModelIndex&)
{
  m_selectionChanged = true;
}
void
ListBoxControl::itemPressed (QListWidgetItem *)
{
  m_selectionChanged = true;
}

bool
ListBoxControl::eventFilter (QObject *watched, QEvent *e)
{
  // listbox change
  if (watched == m_qobject)
    {
      switch (e->type ())
        {
        case QEvent::KeyRelease:
          if (m_selectionChanged)
            sendSelectionChange ();
          m_selectionChanged = false;
          break;

        default:
          break;
        }

      return Object::eventFilter (watched, e);
    }
  // listbox viewport
  else
    {
      bool override_return = false;
      QListWidget *list = qWidget<QListWidget> ();

      switch (e->type ())
        {
        case QEvent::MouseButtonPress:
          {
            QMouseEvent *m = dynamic_cast<QMouseEvent *> (e);

            if (m->button () & Qt::RightButton)
              override_return = true;
            else
              {
                if (! list->indexAt (m->pos ()).isValid ())
                  override_return = true;
                m_selectionChanged = true;
              }
            break;
          }
        case QEvent::MouseButtonRelease:
          {
            QMouseEvent *m = dynamic_cast<QMouseEvent *> (e);

            if (m->button () & Qt::RightButton)
              override_return = true;

            else if (! list->indexAt (m->pos ()).isValid ())
              {
                list->setCurrentRow (list->count () - 1);
                override_return = true;
              }

            if (m_selectionChanged)
              sendSelectionChange ();
            m_selectionChanged = false;

            break;
          }
        default:
          break;

        }
      return BaseControl::eventFilter (watched, e) || override_return;
    }
}

OCTAVE_END_NAMESPACE(octave)