/*

Copyright (C) 2012-2019 Richard Crozier
Copyright (C) 2013-2019 Torsten <mttl@mailbox.org>

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 <QAction>
#include <QDesktopWidget>
#include <QHBoxLayout>
#include <QLabel>
#include <QSettings>
#include <QStyle>
#include <QToolBar>

#include "resource-manager.h"
#include "octave-dock-widget.h"

namespace octave
{
  label_dock_widget::label_dock_widget (QWidget *p)
    : QDockWidget (p), m_default_float_button (nullptr),
      m_default_close_button (nullptr)
  {
    QStyle *st = style ();
    m_icon_size = 0.75*st->pixelMetric (QStyle::PM_SmallIconSize);

    // keep track of the original buttons on the default title bar,
    // the button further left is considered "float"
    QList<QAbstractButton *> buttonlist = findChildren<QAbstractButton *> ();
    if (buttonlist.size () == 2)
      {
        if (buttonlist.at (0)->x () < buttonlist.at (1)->x ())
          {
            m_default_float_button = buttonlist.at (0);
            m_default_close_button = buttonlist.at (1);
          }
        else
          {
            m_default_float_button = buttonlist.at (1);
            m_default_close_button = buttonlist.at (0);
          }
      }

    // the custom (extra) title bar of the widget
    m_title_widget = new QWidget ();

    m_dock_action = new QAction
      (QIcon (":/actions/icons/widget-undock.png"), "", this);
    m_dock_action->setToolTip (tr ("Undock widget"));
    m_dock_button = new QToolButton (m_title_widget);
    m_dock_button->setDefaultAction (m_dock_action);
    m_dock_button->setFocusPolicy (Qt::NoFocus);
    m_dock_button->setIconSize (QSize (m_icon_size,m_icon_size));

    m_close_action = new QAction
      (QIcon (":/actions/icons/widget-close.png"), "", this);
    m_close_action->setToolTip (tr ("Close widget"));
    m_close_button = new QToolButton (m_title_widget);
    m_close_button->setDefaultAction (m_close_action);
    m_close_button->setFocusPolicy (Qt::NoFocus);
    m_close_button->setIconSize (QSize (m_icon_size,m_icon_size));

    QString css_button = QString ("QToolButton {background: transparent; border: 0px;}");
    m_dock_button->setStyleSheet (css_button);
    m_close_button->setStyleSheet (css_button);

    QHBoxLayout *h_layout = new QHBoxLayout ();
    h_layout->addStretch (100);
    h_layout->addWidget (m_dock_button);
    h_layout->addWidget (m_close_button);
    h_layout->setSpacing (10);
    h_layout->setContentsMargins (5,2,2,2);

    m_title_widget->setLayout (h_layout);

    // copy & paste handling
    connect (p, SIGNAL (copyClipboard_signal ()),
             this, SLOT (copyClipboard ()));
    connect (p, SIGNAL (pasteClipboard_signal ()),
             this, SLOT (pasteClipboard ()));
    connect (p, SIGNAL (selectAll_signal ()),
             this, SLOT (selectAll ()));
    // undo handling
    connect (p, SIGNAL (undo_signal ()), this, SLOT (do_undo ()));
  }

  // set the title in the dockwidgets title bar
  void
  label_dock_widget::set_title (const QString& title)
  {
    QHBoxLayout *h_layout
      = static_cast<QHBoxLayout *> (m_title_widget->layout ());
    QLabel *label = new QLabel (title, m_title_widget);
    label->setStyleSheet ("background-color: transparent;");
    h_layout->insertWidget (0,label);
    setTitleBarWidget (m_title_widget);
    setWindowTitle (title);
  }


  static QString
  qdockwidget_css (const QString& close_icon, const QString& close_tooltip,
                   const QString& float_icon, const QString& float_tooltip,
                   int icon_size, const QString& titlebar_foreground,
                   const QString& titlebar_background)
  {
    return QString ("QDockWidget\n"
                    "{\n"
                    "%6"
                    "  border: none;\n"
                    "  titlebar-close-icon: url(%1);\n"
                    "  titlebar-normal-icon: url(%2);\n"
                    "}\n"
                    "\n"
                    "QDockWidget::close-button, QDockWidget::float-button\n"
                    "{\n"
                    "  border: none;\n"
                    "  icon-size: %3px;\n"
                    "}\n"
                    "\n"
                    "QAbstractButton#qt_dockwidget_closebutton\n"
                    "{\n"
                    "  qproperty-toolTip: \"%4\";\n"
                    "}\n"
                    "\n"
                    "QAbstractButton#qt_dockwidget_floatbutton\n"
                    "{\n"
                    "  qproperty-toolTip: \"%5\";\n"
                    "}\n"
                    "\n"
                    "QDockWidget::title {\n"
                    "  text-align: left;\n"
                    "%7"
                    "  padding-left: 1px;\n"
                    "}\n"
                    "\n"
                    "QDockWidget::close-button\n"
                    "{\n"
                    "  right: %8px;\n"
                    "  top: 3px;\n"
                    "}\n"
                    "\n"
                    "QDockWidget::float-button\n"
                    "{\n"
                    "  right: %9px;\n"
                    "  top: 3px;\n"
                    "}\n"
                    ).arg (close_icon).arg (float_icon).arg (icon_size)
                     .arg (close_tooltip).arg (float_tooltip)
                     .arg (titlebar_foreground). arg (titlebar_background)
                     .arg ((icon_size*2)/3). arg((icon_size*7)/3);
  }

  octave_dock_widget::octave_dock_widget (const QString& obj_name, QWidget *p)
    : label_dock_widget (p), m_recent_float_geom (), m_recent_dock_geom (),
      m_waiting_for_mouse_button_release (false)
  {
    setObjectName (obj_name);

    m_parent = static_cast<QMainWindow *> (p);     // store main window
    m_predecessor_widget = nullptr;

    connect (this, SIGNAL (topLevelChanged (bool)),
             this, SLOT (toplevel_change (bool)));
    connect (this, SIGNAL (visibilityChanged (bool)),
             this, SLOT (handle_visibility_changed (bool)));

    connect (p, SIGNAL (settings_changed (const QSettings*)),
             this, SLOT (handle_settings (const QSettings*)));

    connect (p, SIGNAL (active_dock_changed (octave_dock_widget*,
                                             octave_dock_widget*)),
             this, SLOT (handle_active_dock_changed (octave_dock_widget*,
                                                     octave_dock_widget*)));

    connect (this, SIGNAL (request_queue_cmd (octave_cmd*)),
             p, SLOT (queue_cmd (octave_cmd*)));

    if (m_default_float_button != nullptr)
      {
        disconnect (m_default_float_button, 0, 0, 0);
        connect (m_default_float_button, SIGNAL (clicked (bool)),
                 this, SLOT (make_window (bool)));
      }
    connect (this, SIGNAL (queue_make_window (bool)),
             this, SLOT (make_window (bool)), Qt::QueuedConnection);
    connect (this, SIGNAL (queue_make_widget ()),
             this, SLOT (make_widget ()), Qt::QueuedConnection);

    connect (m_dock_action, SIGNAL (triggered (bool)),
             this, SLOT (make_window (bool)));
    connect (m_close_action, SIGNAL (triggered (bool)),
             this, SLOT (change_visibility (bool)));

    m_close_action->setToolTip (tr ("Hide widget"));

    setStyleSheet (qdockwidget_css (QString (":/actions/icons/widget-close.png"),
                                    QString ("Close widget"),
                                    QString (":/actions/icons/widget-undock.png"),
                                    QString ("Undock widget"),
                                    m_icon_size,
                                    QString (""),
                                    QString ("")));
    if (widget ())
      widget ()->setToolTip (QString (""));

    m_icon_color = "";
    m_title_3d = 50;

    installEventFilter (this);

    setFocusPolicy (Qt::StrongFocus);

    setFeatures (QDockWidget::AllDockWidgetFeatures);

    handle_settings (resource_manager::get_settings ());
  }

  // connect signal visibility changed to related slot (called from main-window)
  void
  octave_dock_widget::connect_visibility_changed (void)
  {
    connect (this, SIGNAL (visibilityChanged (bool)),
             this, SLOT (handle_visibility (bool)));
    emit active_changed (isVisible ());  // emit once for init of window menu
  }

  // make the widget floating
  void
  octave_dock_widget::make_window (bool widget_was_dragged)
  {
    bool vis = isVisible ();

    // prevent follow-up calls by clearing state variable
    m_waiting_for_mouse_button_release = false;

    set_focus_predecessor ();  // set focus previously active widget if tabbed

    // Before unparenting, get current geometry for restoring if dragged
    QRect geom = geometry ();

    // the widget has to be reparented (parent = 0), preferably
    // from a non-toplevel widget otherwise may not have full
    // decorations, e.g., no taskbar icon and always in front
    if (isFloating ())
      setFloating (false);

// Remove after thorough testing 3/20/18    m_parent->removeDockWidget (this);

    setParent (0, Qt::CustomizeWindowHint | Qt::WindowTitleHint |
               Qt::WindowMinMaxButtonsHint | Qt::WindowCloseButtonHint | Qt::Window);

    // restore the last geometry when floating only if we have not dragged
    // the window outside the main window
    if (! widget_was_dragged)
      geom = m_recent_float_geom.isNull () ? QRect (50,100,480,480)
                                           : m_recent_float_geom;
    setGeometry (geom);

    // adjust the (un)dock icon
    if (titleBarWidget ())
      {
        m_dock_action->setIcon (QIcon (":/actions/icons/widget-dock"
                                       + m_icon_color + ".png"));
        m_dock_action->setToolTip (tr ("Dock widget"));
        disconnect (m_dock_action, 0, this, 0);
        connect (m_dock_action, SIGNAL (triggered (bool)),
                 this, SLOT (make_widget (bool)));
      }
    else
      {
        disconnect (m_default_float_button, 0, this, 0);
        connect (m_default_float_button, SIGNAL (clicked (bool)),
                 this, SLOT (make_widget (bool)));
      }

    raise ();
    activateWindow ();

    if (vis)
    {
      show ();
      focus ();
      set_style (true);
    }
  }

  // dock the widget
  void
  octave_dock_widget::make_widget (bool)
  {
    bool vis = isVisible ();

    // Since floating widget has no parent, we have to read it
    QSettings *settings = resource_manager::get_settings ();

    settings->setValue ("MainWindow/windowState", m_parent->saveState ());
    // Stay window, otherwise will bounce back to window by default because
    // there is no layout information for this widget in the saved settings.
    setParent (m_parent, Qt::Window);
    m_parent->addDockWidget (Qt::BottomDockWidgetArea, this);
    // recover old window states, hide and re-show new added widget
    m_parent->restoreState (settings->value ("MainWindow/windowState").toByteArray ());
    setFloating (false);

    // adjust the (un)dock icon
    if (titleBarWidget ())
      {
        m_dock_action->setIcon (QIcon (":/actions/icons/widget-undock"
                                       + m_icon_color + ".png"));
        m_dock_action->setToolTip (tr ("Undock widget"));
        disconnect (m_dock_action, 0, this, 0);
        connect (m_dock_action, SIGNAL (triggered (bool)),
                 this, SLOT (make_window (bool)));
      }
    else
      {
        disconnect (m_default_float_button, 0, this, 0);
        connect (m_default_float_button, SIGNAL (clicked (bool)),
                 this, SLOT (make_window (bool)));
      }

    raise ();
    QApplication::setActiveWindow (this);

    if (vis)
      {
        show ();
        focus ();
        set_style (true);
      }
  }

  // dock the widget
  void
  octave_dock_widget::default_dock (bool)
  {
    setFloating (false);
  }

  // set the widget which previously had focus when tabified
  void
  octave_dock_widget::set_predecessor_widget (octave_dock_widget *prev_widget)
  {
    m_predecessor_widget = prev_widget;
  }

  // close event
  void
  octave_dock_widget::closeEvent (QCloseEvent *e)
  {
    emit active_changed (false);
    set_focus_predecessor ();
    QDockWidget::closeEvent (e);
  }

  // get focus widget
  QWidget *
  octave_dock_widget::focusWidget (void)
  {
    QWidget *w = QApplication::focusWidget ();
    if (w && w->focusProxy ()) w = w->focusProxy ();
    return w;
  }

  bool
  octave_dock_widget::event (QEvent *event)
  {
    // low-level check of whether docked-widget became a window via
    // double-click or via drag-and-drop
    if ( (event->type () == QEvent::MouseButtonDblClick && ! isFloating ())
        || (event->type () == QEvent::ActivationChange && m_waiting_for_mouse_button_release))
      {
        bool retval = QDockWidget::event (event);
        if (isFloating () && parent () != 0)
          {
            m_waiting_for_mouse_button_release = false;
            emit queue_make_window (event->type () != QEvent::MouseButtonDblClick);
          }
        return retval;
      }

    return QDockWidget::event (event);
  }

  void
  octave_dock_widget::handle_settings (const QSettings *settings)
  {
    m_custom_style
      = settings->value ("DockWidgets/widget_title_custom_style",false).toBool ();

    m_title_3d
      = settings->value ("DockWidgets/widget_title_3d",50).toInt ();

    QColor default_var = QColor (0,0,0);
    m_fg_color = settings->value ("DockWidgets/title_fg_color",
                                  default_var).value<QColor> ();
    default_var = QColor (0,0,0);
    m_fg_color_active = settings->value ("DockWidgets/title_fg_color_active",
                                         default_var).value<QColor> ();

    default_var = QColor (255,255,255);
    m_bg_color = settings->value ("DockWidgets/title_bg_color",
                                  default_var).value<QColor> ();
    default_var = QColor (192,192,192);
    m_bg_color_active = settings->value ("DockWidgets/title_bg_color_active",
                                         default_var).value<QColor> ();

    QColor bcol (m_bg_color);
    QColor bcola (m_bg_color_active);

    if (! m_custom_style)
      {
        bcol = QWidget::palette ().color (m_title_widget->backgroundRole ());
        bcola = bcol;
      }

    int r, g, b;
    bcol.getRgb (&r, &g, &b);
    if (r+g+b < 400)
      m_icon_color = "-light";
    else
      m_icon_color = "";

    bcola.getRgb (&r, &g, &b);
    if (r+g+b < 400)
      m_icon_color_active = "-light";
    else
      m_icon_color_active = "";

    QRect available_size = QApplication::desktop ()->availableGeometry (m_parent);
    int x1, y1, x2, y2;
    available_size.getCoords (&x1, &y1, &x2, &y2);
    QRect default_size = QRect (x1+16, y1+32, x2/3, 2*y2/3);

    m_recent_float_geom = settings->value ("DockWidgets/" + objectName ()
                                           + "_floating_geometry",
                                           default_size).toRect ();

    QWidget dummy;
    dummy.setGeometry (m_recent_float_geom);

    if (QApplication::desktop ()->screenNumber (&dummy) == -1)
      m_recent_float_geom = default_size;

    m_recent_dock_geom = settings->value ("DockWidgets/" + objectName (),
                                          QByteArray ()).toByteArray ();

    notice_settings (settings);  // call individual handler

    set_style (false);
  }

  void
  octave_dock_widget::handle_active_dock_changed (octave_dock_widget *w_old,
                                                  octave_dock_widget *w_new)
  {
    if (m_custom_style && this == w_old)
      {
        set_style (false);
        update ();
      }

    if (m_custom_style && this == w_new)
      {
        set_style (true);
        update ();
      }
  }

  void
  octave_dock_widget::save_settings (void)
  {
    // save state of this dock-widget
    QString name = objectName ();
    QSettings *settings = resource_manager::get_settings ();

    if (! settings)
      return;

    store_geometry ();

    settings->beginGroup ("DockWidgets");

    // conditional needed?
    if (! m_recent_float_geom.isNull ())
      settings->setValue (name + "_floating_geometry", m_recent_float_geom);

    if (! m_recent_dock_geom.isEmpty ())
      settings->setValue (name, m_recent_dock_geom);
    settings->setValue (name+"Visible", isVisible ()); // store visibility
    settings->setValue (name+"Floating", isFloating ()); // store floating
    settings->setValue (name+"_minimized", isMinimized ()); // store minimized

    settings->endGroup ();
    settings->sync ();
  }

  bool octave_dock_widget::eventFilter (QObject *obj, QEvent *e)
  {
    if (e->type () == QEvent::NonClientAreaMouseButtonDblClick)
      {
        e->ignore (); // ignore double clicks into window decoration elements
        return true;
      }

    return QDockWidget::eventFilter (obj,e);
  }

  void
  octave_dock_widget::store_geometry (void)
  {
    if (isFloating ())
      {
        if (! parent ())
          m_recent_float_geom = geometry ();
      }
    else
      {
        m_recent_dock_geom = saveGeometry ();
      }
  }

  void
  octave_dock_widget::moveEvent (QMoveEvent *event)
  {
    store_geometry ();

    QDockWidget::moveEvent (event);
  }

  void
  octave_dock_widget::resizeEvent (QResizeEvent *event)
  {
    store_geometry ();

    QDockWidget::resizeEvent (event);
  }

  // slot for hiding the widget
  void
  octave_dock_widget::change_visibility (bool)
  {
    setVisible (false);
    emit active_changed (false);
  }

  void
  octave_dock_widget::toplevel_change (bool toplevel)
  {
    QObject *dockobj;
    const char *docksig;

    if (titleBarWidget ())
      {
        dockobj = m_dock_action;
        docksig = SIGNAL (triggered (bool));
      }
    else
      {
        dockobj = m_default_float_button;
        docksig = SIGNAL (clicked (bool));
      }

    if (toplevel)
      {
        // This is a fallback in case the attempt to create a floated
        // top-level window fails and the QDockWidget remains a child
        // of the QMainWindow.
        connect (dockobj, docksig, this, SLOT (default_dock (bool)));

        // Could be dragging window, so must wait until there is a
        // change in focus.
        if (parent () != 0)
          m_waiting_for_mouse_button_release = true;
      }
    else
      {
        // If a drag-and-drop within the QMainWindow occurred, want to remain a widget.
        m_waiting_for_mouse_button_release = false;

        // Making into a widget immediately will mangle the double-click
        // status and cause problems on followup button clicks.
        if (parent () == 0)
          emit queue_make_widget ();
      }
  }

  void
  octave_dock_widget::set_style (bool active)
  {
    QString css_foreground;
    QString css_background;
    QString css_button;
    QString dock_icon;

    QString icon_col = m_icon_color;

    QString close_tooltip = "Close widget";
    QString dock_tooltip;

    if (isFloating ())
      {
        dock_icon = "widget-dock";
        dock_tooltip = "Dock widget";
      }
    else
      {
        dock_icon = "widget-undock";
        dock_tooltip = "Undock widget";
      }

#if defined (Q_OS_MAC)
    QString alignment = "center";
#else
    QString alignment = "center left";
#endif
    if (m_custom_style)
      {

        QColor bg_col, fg_col;

        if (active)
          {
            bg_col = m_bg_color_active;
            fg_col = m_fg_color_active;
            icon_col = m_icon_color_active;
          }
        else
          {
            bg_col = m_bg_color;
            fg_col = m_fg_color;
            icon_col = m_icon_color;
          }

        QColor bg_col_top, bg_col_bottom;
        if (m_title_3d > 0)
          {
            bg_col_top = bg_col.lighter (100 + m_title_3d);
            bg_col_bottom = bg_col.darker (100 + m_title_3d);
          }
        else
          {
            bg_col_top = bg_col.darker (100 - m_title_3d);
            bg_col_bottom = bg_col.lighter (100 - m_title_3d);
          }

        css_foreground = QString ("  color: %1;\n").arg (fg_col.name ());

        css_background =
          QString ("  background: qlineargradient(x1: 0, y1: 0, x2: 0, y2: 1,"
                   " stop: 0 %1, stop: 0.60 %2, stop: 0.95 %2 stop: 1.0 %3);\n").
          arg (bg_col_top.name ()).
          arg (bg_col.name ()).
          arg (bg_col_bottom.name ());
      }
    else
      {
        css_foreground = QString ("");
        css_background = QString ("");
      }

    QString full_dock_icon = ":/actions/icons/" + dock_icon + icon_col + ".png";
    QString full_close_icon = ":/actions/icons/widget-close" + icon_col + ".png";
    if (titleBarWidget ())
      {
        titleBarWidget ()->setStyleSheet (css_foreground + css_background);
        css_button = QString ("QToolButton {background: transparent; border: 0px;}");
        m_dock_button->setStyleSheet (css_button);
        m_close_button->setStyleSheet (css_button);
        m_dock_action->setIcon (QIcon (full_dock_icon));
        m_close_action->setIcon (QIcon (full_close_icon));
      }
    else
      {
        setStyleSheet (qdockwidget_css (full_close_icon,
                                        close_tooltip,
                                        full_dock_icon,
                                        dock_tooltip,
                                        m_icon_size,
                                        css_foreground,
                                        css_background));
      }
  }

  // set focus to previously active widget in tabbed widget stack
  void
  octave_dock_widget::set_focus_predecessor (void)
  {
    // only != 0 if widget was tabbed
    if (m_predecessor_widget && m_predecessor_widget->isVisible ())
      m_predecessor_widget->focus ();

    m_predecessor_widget = nullptr;
    // FIXME: Until cset bda0c5b38bda, the wrong keys "Dockwidget/..." were used
    // here.  This had no effect in Qt4, but does in Qt5.  In the following, the
    // four incorrect keys are updated if still present in the settings files.
    // The keys are also used in the settings dialog, but
    // octave_dock_widget::handle_settings is already called at program start.
    // These tests can be removed in a future version of Octave (version 6).
    resource_manager::update_settings_key ("Dockwidgets/title_bg_color",
                                           "DockWidgets/title_bg_color");
    resource_manager::update_settings_key ("Dockwidgets/title_bg_color_active",
                                           "DockWidgets/title_bg_color_active");
    resource_manager::update_settings_key ("Dockwidgets/title_fg_color",
                                           "DockWidgets/title_fg_color");
    resource_manager::update_settings_key ("Dockwidgets/title_fg_color_active",
                                           "DockWidgets/title_fg_color_active");
  }
}