////////////////////////////////////////////////////////////////////////
//
// 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 <QApplication>
#include <QClipboard>
#include <QCompleter>
#include <QLabel>
#include <QMenu>
#include <QScrollBar>
#include <QVBoxLayout>

#include "gui-preferences-cs.h"
#include "gui-preferences-global.h"
#include "gui-preferences-hw.h"
#include "gui-settings.h"
#include "history-dock-widget.h"
#include "octave-qobject.h"

#include "cmd-hist.h"

#include "error.h"

namespace octave
{
  history_dock_widget::history_dock_widget (QWidget *p, base_qobject& oct_qobj)
    : octave_dock_widget ("HistoryDockWidget", p, oct_qobj)
  {
    setStatusTip (tr ("Browse and search the command history."));

    construct ();

    if (! p)
      make_window ();
  }

  void history_dock_widget::set_history (const QStringList& hist)
  {
    m_history_model->setStringList (hist);
    m_history_list_view->scrollToBottom ();
  }

  void history_dock_widget::append_history (const QString& hist_entry)
  {
    QStringList lst = m_history_model->stringList ();
    lst.append (hist_entry);

    QScrollBar *scroll_bar = m_history_list_view->verticalScrollBar ();

    bool at_bottom = scroll_bar->maximum () - scroll_bar->value () < 1;

    m_history_model->setStringList (lst);

    // Scroll if slider position at bottom.
    if (at_bottom)
      m_history_list_view->scrollToBottom ();
  }

  void history_dock_widget::clear_history (void)
  {
    m_history_model->setStringList (QStringList ());
  }

  void history_dock_widget::save_settings (void)
  {
    gui_settings settings;

    settings.setValue (hw_filter_active.key, m_filter_checkbox->isChecked ());
    settings.setValue (hw_filter_shown.key, m_filter_shown);

    QStringList mru;
    for (int i = 0; i < m_filter->count (); i++)
      mru.append (m_filter->itemText (i));
    settings.setValue (hw_mru_list.key, mru);

    settings.sync ();

    octave_dock_widget::save_settings ();
  }

  void history_dock_widget::update_filter_history (void)
  {
    QString text = m_filter->currentText ();   // get current text
    int index = m_filter->findText (text);     // and its actual index

    if (index > -1)
      m_filter->removeItem (index);    // remove if already existing

    m_filter->insertItem (0, text);    // (re)insert at beginning
    m_filter->setCurrentIndex (0);
  }

  void history_dock_widget::set_filter_focus (bool focus)
  {
    if (focus)
      {
        m_filter->setFocus ();
        setFocusProxy (m_filter);
      }
    else
      {
        m_history_list_view->setFocus ();
        setFocusProxy (m_history_list_view);
      }
  }

  void history_dock_widget::filter_activate (bool state)
  {
    m_filter->setEnabled (state);
    m_sort_filter_proxy_model.setDynamicSortFilter (state);

    if (state)
      m_sort_filter_proxy_model.setFilterWildcard (m_filter->currentText ());
    else
      m_sort_filter_proxy_model.setFilterWildcard (QString ());

    set_filter_focus (state);
  }

  void history_dock_widget::ctxMenu (const QPoint& xpos)
  {
    QMenu menu (this);

    QModelIndex index = m_history_list_view->indexAt (xpos);

    if (index.isValid () && index.column () == 0)
      {
        resource_manager& rmgr = m_octave_qobj.get_resource_manager ();

        menu.addAction (rmgr.icon ("edit-copy"), tr ("Copy"), this,
                        &history_dock_widget::handle_contextmenu_copy);
        menu.addAction (tr ("Evaluate"), this,
                        &history_dock_widget::handle_contextmenu_evaluate);
        menu.addAction (rmgr.icon ("document-new"), tr ("Create script"), this,
                        &history_dock_widget::handle_contextmenu_create_script);
      }
    if (m_filter_shown)
      menu.addAction (tr ("Hide filter"), this,
                      &history_dock_widget::handle_contextmenu_filter);
    else
      menu.addAction (tr ("Show filter"), this,
                      &history_dock_widget::handle_contextmenu_filter);

    menu.exec (m_history_list_view->mapToGlobal (xpos));
  }

  void history_dock_widget::handle_double_click (QModelIndex modelIndex)
  {
    emit command_double_clicked (modelIndex.data ().toString ());
  }

  void history_dock_widget::handle_contextmenu_copy (bool)
  {
    QString text;
    QItemSelectionModel *selectionModel = m_history_list_view->selectionModel ();
    QModelIndexList rows = selectionModel->selectedRows ();
    bool prev_valid_row = false;
    for (auto it = rows.begin (); it != rows.end (); it++)
      {
        if ((*it).isValid ())
          {
            if (prev_valid_row)
              text += '\n';
            text += (*it).data ().toString ();
            prev_valid_row = true;
          }
      }
    QApplication::clipboard ()->setText (text);
  }

  void history_dock_widget::handle_contextmenu_evaluate (bool)
  {
    QItemSelectionModel *selectionModel = m_history_list_view->selectionModel ();
    QModelIndexList rows = selectionModel->selectedRows ();
    for (auto it = rows.begin () ; it != rows.end (); it++)
      {
        if ((*it).isValid ())
          emit command_double_clicked ((*it).data ().toString ());
      }
  }

  void history_dock_widget::handle_contextmenu_create_script (bool)
  {
    QString text;
    QItemSelectionModel *selectionModel = m_history_list_view->selectionModel ();
    QModelIndexList rows = selectionModel->selectedRows ();

    bool prev_valid_row = false;
    for (auto it = rows.begin (); it != rows.end (); it++)
      {
        if ((*it).isValid ())
          {
            if (prev_valid_row)
              text += '\n';
            text += (*it).data ().toString ();
            prev_valid_row = true;
          }
      }

    if (text.length () > 0)
      emit command_create_script (text);
  }

  void history_dock_widget::handle_contextmenu_filter (void)
  {
    m_filter_shown = ! m_filter_shown;
    m_filter_widget->setVisible (m_filter_shown);

    set_filter_focus (m_filter_shown && m_filter_checkbox->isChecked ()) ;
  }

  void history_dock_widget::copyClipboard (void)
  {
    if (m_history_list_view->hasFocus ())
      handle_contextmenu_copy (true);
    if (m_filter->lineEdit ()->hasFocus ()
        && m_filter->lineEdit ()->hasSelectedText ())
      {
        QClipboard *clipboard = QApplication::clipboard ();
        clipboard->setText (m_filter->lineEdit ()->selectedText ());
      }
  }

  void history_dock_widget::pasteClipboard (void)
  {
    if (m_filter->lineEdit ()->hasFocus ())
      {
        QClipboard *clipboard = QApplication::clipboard ();
        QString str = clipboard->text ();
        if (str.length () > 0)
          m_filter->lineEdit ()->insert (str);
      }
  }

  void history_dock_widget::selectAll (void)
  {
    if (m_filter->lineEdit ()->hasFocus ())
      m_filter->lineEdit ()->selectAll ();

    if (m_history_list_view->hasFocus ())
      m_history_list_view->selectAll ();
  }

  void history_dock_widget::handle_visibility (bool visible)
  {
    octave_dock_widget::handle_visibility (visible);

    if (visible)
      {
        int filter_state = m_filter_checkbox->isChecked ();
        filter_activate (filter_state);
      }
  }

  void history_dock_widget::construct (void)
  {
    m_history_model = new QStringListModel ();
    m_sort_filter_proxy_model.setSourceModel (m_history_model);
    m_history_list_view = new QListView (this);
    m_history_list_view->setModel (&m_sort_filter_proxy_model);
    m_history_list_view->setAlternatingRowColors (true);
    m_history_list_view->setEditTriggers (QAbstractItemView::NoEditTriggers);
    m_history_list_view->setStatusTip
      (tr ("Double-click a command to transfer it to the Command Window."));
    m_history_list_view->setSelectionMode (QAbstractItemView::ExtendedSelection);
    m_history_list_view->setContextMenuPolicy (Qt::CustomContextMenu);
    connect (m_history_list_view, &QListView::customContextMenuRequested,
             this, &history_dock_widget::ctxMenu);

    m_filter = new QComboBox (this);
    m_filter->setToolTip (tr ("Enter text to filter the command history"));
    m_filter->setEditable (true);
    m_filter->setMaxCount (MaxFilterHistory);
    m_filter->setInsertPolicy (QComboBox::NoInsert);
    m_filter->setSizeAdjustPolicy
      (QComboBox::AdjustToMinimumContentsLengthWithIcon);
    QSizePolicy sizePol (QSizePolicy::Expanding, QSizePolicy::Preferred);
    m_filter->setSizePolicy (sizePol);
    m_filter->completer ()->setCaseSensitivity (Qt::CaseSensitive);

    QLabel *filter_label = new QLabel (tr ("Filter"));

    m_filter_checkbox = new QCheckBox ();

    set_title (tr ("Command History"));
    setWidget (new QWidget ());

    m_filter_widget = new QWidget (this);
    QHBoxLayout *filter_layout = new QHBoxLayout ();
    filter_layout->addWidget (filter_label);
    filter_layout->addWidget (m_filter_checkbox);
    filter_layout->addWidget (m_filter);
    filter_layout->setMargin(0);
    m_filter_widget->setLayout (filter_layout);

    QVBoxLayout *hist_layout = new QVBoxLayout ();
    hist_layout->addWidget (m_filter_widget);
    hist_layout->addWidget (m_history_list_view);

    hist_layout->setMargin (2);
    hist_layout->setSpacing (0);
    widget ()->setLayout (hist_layout);

    // Init state of the filter

    gui_settings settings;

    m_filter_shown = settings.value (hw_filter_shown).toBool ();
    m_filter_widget->setVisible (m_filter_shown);

    m_filter->addItems (settings.value (hw_mru_list).toStringList ());

    bool filter_state = settings.value (hw_filter_active).toBool ();
    m_filter_checkbox->setChecked (filter_state);
    filter_activate (filter_state);

    // Connect signals and slots
    connect (m_filter, &QComboBox::editTextChanged,
             &m_sort_filter_proxy_model,
             &QSortFilterProxyModel::setFilterWildcard);
    connect (m_filter_checkbox, &QCheckBox::toggled,
             this, &history_dock_widget::filter_activate);
    connect (m_filter->lineEdit (), &QLineEdit::editingFinished,
             this, &history_dock_widget::update_filter_history);

    connect (m_history_list_view, &QListView::doubleClicked,
             this, &history_dock_widget::handle_double_click);

    m_history_list_view->setTextElideMode (Qt::ElideRight);
  }

  void history_dock_widget::notice_settings (void)
  {
    gui_settings settings;

    QFont font = QFont ();

    font.setStyleHint (QFont::TypeWriter);
    QString default_font = settings.value (global_mono_font).toString ();

    font.setFamily (settings.value (cs_font.key, default_font).toString ());
    font.setPointSize (settings.value (cs_font_size).toInt ());

    m_history_list_view->setFont (font);
  }

}