/* This file is part of the KDE libraries
  Copyright (C) 2003 Stephan Binner <binner@kde.org>
  Copyright (C) 2003 Zack Rusin <zack@kde.org>
  Copyright (C) 2009 Urs Wolfer <uwolfer @ kde.org>

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Library General Public
  License as published by the Free Software Foundation; either
  version 2 of the License, or (at your option) any later version.

  This library 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
  Library General Public License for more details.

  You should have received a copy of the GNU Library General Public License
  along with this library; see the file COPYING.LIB.  If not, write to
  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  Boston, MA 02110-1301, USA.
*/

#include "ktabwidget.h"

#include <QtGui/QApplication>
#include <QtGui/QDragMoveEvent>
#include <QtGui/QDropEvent>
#include <QtGui/QMouseEvent>
#include <QtGui/QStyle>
#include <QtGui/QStyleOption>
#include <QtGui/QTextDocument>
#include <QtGui/QWheelEvent>
#include <QtCore/QList>

#include <ksharedconfig.h>
#include <kiconloader.h>
#include <kstringhandler.h>
#include <kdebug.h>

#include <ktabbar.h>

#include <kconfiggroup.h>

class KTabWidget::Private
{
  public:
    enum {
        ResizeEnabled = 0,
        ResizeDisabled,
        ResizeLater
    } m_resizeSuspend;

    Private( KTabWidget *parent )
      : m_resizeSuspend(ResizeEnabled),
        m_parent( parent ),
        m_automaticResizeTabs( false ),
        m_tabBarHidden( false )
    {

      KConfigGroup cg(KGlobal::config(), "General");
      m_maxLength = cg.readEntry("MaximumTabLength", 30);
      m_minLength = cg.readEntry("MinimumTabLength", 3);
      Q_ASSERT(m_maxLength >= m_minLength);
      m_currentTabLength = m_minLength;
    }

    KTabWidget *m_parent;
    bool m_automaticResizeTabs;
    bool m_tabBarHidden;
    int m_maxLength;
    int m_minLength;
    int m_currentTabLength;

    //holds the full names of the tab, otherwise all we
    //know about is the shortened name
    QStringList m_tabNames;

    bool isEmptyTabbarSpace( const QPoint & )  const;
    void resizeTabs( int changedTabIndex = -1 );
    void updateTab( int index );
    void removeTab( int index );

    void slotTabMoved( int from, int to );
};

bool KTabWidget::Private::isEmptyTabbarSpace( const QPoint &point ) const
{
    if (m_parent->count() == 0) {
        return true;
    }
    if (m_parent->tabBar()->isHidden()) {
        return false;
    }
  QSize size( m_parent->tabBar()->sizeHint() );
  if ( ( m_parent->tabPosition() == QTabWidget::North && point.y() < size.height() ) ||
       ( m_parent->tabPosition() == QTabWidget::South && point.y() > (m_parent->height() - size.height() ) ) ) {

    QWidget *rightcorner = m_parent->cornerWidget( Qt::TopRightCorner );
    if ( rightcorner && rightcorner->isVisible() ) {
      if ( point.x() >= m_parent->width()-rightcorner->width() )
        return false;
    }

    QWidget *leftcorner = m_parent->cornerWidget( Qt::TopLeftCorner );
    if ( leftcorner && leftcorner->isVisible() ) {
      if ( point.x() <= leftcorner->width() )
        return false;
    }

    for ( int i = 0; i < m_parent->count(); ++i )
      if ( m_parent->tabBar()->tabRect( i ).contains( m_parent->tabBar()->mapFromParent( point ) ) )
        return false;

    return true;
  }

  return false;
}

void KTabWidget::Private::removeTab( int index )
{
  // prevent cascading resize slowness, not to mention crashes due to tab count()
  // and m_tabNames.count() being out of sync!
  m_resizeSuspend = ResizeDisabled;

  // Need to do this here, rather than in tabRemoved().  Calling
  // QTabWidget::removeTab() below may cause a relayout of the tab bar, which
  // will call resizeTabs() immediately.  If m_automaticResizeTabs is true,
  // that will use the m_tabNames[] list before it has been updated to reflect
  // the new tab arrangement.  See bug 190528.
  m_tabNames.removeAt( index );

  m_parent->QTabWidget::removeTab( index );

  const bool doResize = (m_resizeSuspend == ResizeLater) || m_automaticResizeTabs;
  m_resizeSuspend = ResizeEnabled;
  if (doResize) {
    resizeTabs();
  }

}

void KTabWidget::Private::resizeTabs( int changeTabIndex )
{
    if (m_resizeSuspend != ResizeEnabled) {
        m_resizeSuspend = ResizeLater;
        return;
    }

    int newTabLength = m_maxLength;

    if (m_automaticResizeTabs) {
        // Calculate new max length
        int lcw = 0, rcw = 0;

        const int tabBarHeight = m_parent->tabBar()->sizeHint().height();
        if (m_parent->cornerWidget(Qt::TopLeftCorner) &&
            m_parent->cornerWidget( Qt::TopLeftCorner )->isVisible()) {
            lcw = qMax(m_parent->cornerWidget(Qt::TopLeftCorner)->width(), tabBarHeight);
        }
        if (m_parent->cornerWidget(Qt::TopRightCorner) &&
            m_parent->cornerWidget(Qt::TopRightCorner)->isVisible()) {
            rcw = qMax( m_parent->cornerWidget(Qt::TopRightCorner)->width(), tabBarHeight);
        }

        const int maxTabBarWidth = m_parent->width() - lcw - rcw;

        // binary search for the best fitting tab title length; some wiggling was
        // required to make this behave in the face of rounding.
        int newTabLengthHi = m_maxLength + 1;
        int newTabLengthLo = m_minLength;
        int prevTabLengthMid = -1;
        while (true) {
            int newTabLengthMid = (newTabLengthHi + newTabLengthLo) / 2;
            if (prevTabLengthMid == newTabLengthMid) {
                // no change, we're stuck due to rounding.
                break;
            }
            prevTabLengthMid = newTabLengthMid;

            if (m_parent->tabBarWidthForMaxChars(newTabLengthMid) > maxTabBarWidth) {
                newTabLengthHi = newTabLengthMid;
            } else {
                newTabLengthLo = newTabLengthMid;
            }
        }
        newTabLength = qMin(newTabLengthLo, m_maxLength);
    }

    // Update hinted or all tabs
    if (m_currentTabLength != newTabLength) {
        m_currentTabLength = newTabLength;
        for (int i = 0; i < m_parent->count(); i++) {
            updateTab(i);
        }
    } else if (changeTabIndex != -1) {
        updateTab(changeTabIndex);
    }
}

void KTabWidget::Private::updateTab( int index )
{
  QString title = m_automaticResizeTabs ? m_tabNames[ index ] : m_parent->QTabWidget::tabText( index );
  m_parent->setTabToolTip( index, QString() );

  if ( title.length() > m_currentTabLength ) {
    QString toolTipText = title;
    // Remove '&'s, which are indicators for keyboard shortcuts in tab titles. "&&" is replaced by '&'.
    for ( int i = toolTipText.indexOf( '&' ); i >= 0 && i < toolTipText.length(); i = toolTipText.indexOf( '&', i + 1 ) )
      toolTipText.remove( i, 1 );

    if ( Qt::mightBeRichText( toolTipText ) )
      m_parent->setTabToolTip( index, Qt::escape( toolTipText ) );
    else
      m_parent->setTabToolTip( index, toolTipText );
  }

  title = KStringHandler::rsqueeze( title, m_currentTabLength ).leftJustified( m_minLength, ' ' );

  if ( m_parent->QTabWidget::tabText( index ) != title )
    m_parent->QTabWidget::setTabText( index, title );
}

void KTabWidget::Private::slotTabMoved(int from, int to)
{
    /* called from Qt slot when Qt has moved the tab, so we only
       need to adjust the m_tabNames list */
    if (m_automaticResizeTabs) {
        QString movedName = m_tabNames.takeAt(from);
        m_tabNames.insert(to, movedName);
    }
}

KTabWidget::KTabWidget( QWidget *parent, Qt::WindowFlags flags )
  : QTabWidget( parent ),
    d( new Private( this ) )
{
  setWindowFlags( flags );
  setTabBar( new KTabBar( this ) );
  setObjectName( "tabbar" );
  setAcceptDrops( true );

  connect(tabBar(), SIGNAL(contextMenu(int,QPoint)), SLOT(contextMenu(int,QPoint)));
  connect(tabBar(), SIGNAL(tabDoubleClicked(int)), SLOT(mouseDoubleClick(int)));
  connect(tabBar(), SIGNAL(newTabRequest()), this, SIGNAL(mouseDoubleClick())); // #185487
  connect(tabBar(), SIGNAL(mouseMiddleClick(int)), SLOT(mouseMiddleClick(int)));
  connect(tabBar(), SIGNAL(initiateDrag(int)), SLOT(initiateDrag(int)));
  connect(tabBar(), SIGNAL(testCanDecode(const QDragMoveEvent*,bool&)), SIGNAL(testCanDecode(const QDragMoveEvent*,bool&)));
  connect(tabBar(), SIGNAL(receivedDropEvent(int,QDropEvent*)), SLOT(receivedDropEvent(int,QDropEvent*)));
  connect(tabBar(), SIGNAL(moveTab(int,int)), SLOT(moveTab(int,int)));
  connect(tabBar(), SIGNAL(tabMoved(int,int)), SLOT(slotTabMoved(int,int)));
  connect(tabBar(), SIGNAL(tabCloseRequested(int)), SLOT(closeRequest(int)));
}

KTabWidget::~KTabWidget()
{
  delete d;
}

/*void KTabWidget::insertTab( QWidget *child, const QString &label, int index )
{
  QTabWidget::insertTab( child, label, index );
}

void KTabWidget::insertTab( QWidget *child, const QIcon& iconset, const QString &label, int index )
{
  QTabWidget::insertTab( child, iconset, label, index );
}

void KTabWidget::insertTab( QWidget *child, QTab *tab, int index )
{
  QTabWidget::insertTab( child, tab, index);
  if ( d->m_automaticResizeTabs ) {
    if ( index < 0 || index >= count() ) {
      d->m_tabNames.append( tab->text() );
      d->resizeTabs( d->m_tabNames.count()-1 );
    }
    else {
      d->m_tabNames.insert( d->m_tabNames.at( index ), tab->text() );
      d->resizeTabs( index );
    }
  }
}*/

void KTabWidget::setTabBarHidden( bool hide )
{
  if (hide == isTabBarHidden())
    return;

  QWidget *rightcorner = cornerWidget( Qt::TopRightCorner );
  QWidget *leftcorner = cornerWidget( Qt::TopLeftCorner );

  d->m_tabBarHidden = hide;
  if ( hide ) {
    if ( leftcorner ) leftcorner->hide();
    if ( rightcorner ) rightcorner->hide();
    tabBar()->hide();
  } else {
    tabBar()->show();
    if ( leftcorner ) leftcorner->show();
    if ( rightcorner ) rightcorner->show();
  }
}

bool KTabWidget::isTabBarHidden() const
{
  return d->m_tabBarHidden;
}

void KTabWidget::setTabTextColor( int index, const QColor& color )
{
  tabBar()->setTabTextColor( index, color );
}

QColor KTabWidget::tabTextColor( int index ) const
{
  return tabBar()->tabTextColor( index );
}

#ifndef KDE_NO_DEPRECATED
void KTabWidget::setTabReorderingEnabled( bool on)
{
  static_cast<KTabBar*>(tabBar())->setTabReorderingEnabled( on );
}
#endif

#ifndef KDE_NO_DEPRECATED
bool KTabWidget::isTabReorderingEnabled() const
{
  return static_cast<KTabBar*>(tabBar())->isTabReorderingEnabled();
}
#endif

#ifndef KDE_NO_DEPRECATED
void KTabWidget::setTabCloseActivatePrevious( bool previous)
{
  static_cast<KTabBar*>(tabBar())->setTabCloseActivatePrevious( previous );
}
#endif

#ifndef KDE_NO_DEPRECATED
bool KTabWidget::tabCloseActivatePrevious() const
{
  return static_cast<KTabBar*>(tabBar())->tabCloseActivatePrevious();
}
#endif

int KTabWidget::tabBarWidthForMaxChars( int maxLength )
{
  int hframe, overlap;
  hframe  = tabBar()->style()->pixelMetric( QStyle::PM_TabBarTabHSpace, 0L, tabBar() );
  overlap = tabBar()->style()->pixelMetric( QStyle::PM_TabBarTabOverlap, 0L, tabBar() );

  const QFontMetrics fm = tabBar()->fontMetrics();
  int x = 0;
  for ( int i = 0; i < count(); ++i ) {
    QString newTitle = d->m_tabNames.value( i );
    newTitle = KStringHandler::rsqueeze( newTitle, maxLength ).leftJustified( d->m_minLength, ' ' );

    int lw = fm.width( newTitle );
    int iw = 0;
    if ( !tabBar()->tabIcon( i ).isNull() ) {
      iw = tabBar()->tabIcon( i ).pixmap( style()->pixelMetric( QStyle::PM_SmallIconSize ), QIcon::Normal ).width() + 4;
    }
#ifndef KDE_NO_DEPRECATED
    if ( isCloseButtonEnabled() ) {
      // FIXME: how to get the size of the close button directly from the tabBar()?
      iw += KIconLoader::SizeSmall * 3 / 2;
    }
#endif
    x += ( tabBar()->style()->sizeFromContents( QStyle::CT_TabBarTab, 0L,
         QSize( qMax( lw + hframe + iw, QApplication::globalStrut().width() ), 0 ),
         this ) ).width();
  }

  return x;
}

QString KTabWidget::tabText( int index ) const
{
    if ( d->m_automaticResizeTabs ) {
        if (index >= 0 && index < count()) {
            if (index >= d->m_tabNames.count()) {
                // Ooops, the tab exists, but tabInserted wasn't called yet.
                // This can happen when inserting the first tab,
                // and calling tabText from slotCurrentChanged,
                // see KTabWidget_UnitTest.
                const_cast<KTabWidget*>(this)->tabInserted(index);
            }
            return d->m_tabNames[ index ];
        }
        else
            return QString();
    }
    else
        return QTabWidget::tabText( index );
}

void KTabWidget::setTabText( int index, const QString &text )
{
  if (text == tabText(index))
    return;

  if ( d->m_automaticResizeTabs ) {

    tabBar()->setUpdatesEnabled(false); //no flicker

    QTabWidget::setTabText( index, text );

    if ( index != -1 ) {
        if (index >= d->m_tabNames.count()) {
            kWarning(240) << "setTabText(" << index << ") called but d->m_tabNames has only" << d->m_tabNames.count() << "entries";
            while (index >= d->m_tabNames.count()) {
                d->m_tabNames.append(QString());
            }
        }
      d->m_tabNames[ index ] = text;
      d->resizeTabs( index );
    }

    tabBar()->setUpdatesEnabled(true);

  } else {
    QTabWidget::setTabText( index, text );
  }
}


void KTabWidget::dragEnterEvent( QDragEnterEvent *event )
{
  if ( d->isEmptyTabbarSpace( event->pos() ) ) {
    bool accept = false;
    // The receivers of the testCanDecode() signal has to adjust
    // 'accept' accordingly.
    emit testCanDecode( event, accept);

    event->setAccepted( accept );
    return;
  }

  QTabWidget::dragEnterEvent( event );
}

void KTabWidget::dragMoveEvent( QDragMoveEvent *event )
{
  if ( d->isEmptyTabbarSpace( event->pos() ) ) {
    bool accept = false;
    // The receivers of the testCanDecode() signal has to adjust
    // 'accept' accordingly.
    emit testCanDecode( event, accept);

    event->setAccepted( accept );
    return;
  }

  QTabWidget::dragMoveEvent( event );
}

void KTabWidget::dropEvent( QDropEvent *event )
{
  if ( d->isEmptyTabbarSpace( event->pos() ) ) {
    emit ( receivedDropEvent( event ) );
    return;
  }

  QTabWidget::dropEvent( event );
}

#ifndef QT_NO_WHEELEVENT
void KTabWidget::wheelEvent( QWheelEvent *event )
{
  if ( d->isEmptyTabbarSpace( event->pos() ) )
    QCoreApplication::sendEvent( tabBar(), event );
  else
    QTabWidget::wheelEvent( event );
}

void KTabWidget::wheelDelta( int delta )
{
  if ( count() < 2 )
    return;

  int page = currentIndex();
  if ( delta < 0 )
     page = (page + 1) % count();
  else {
    page--;
    if ( page < 0 )
      page = count() - 1;
  }
  setCurrentIndex( page );
}
#endif

void KTabWidget::mouseDoubleClickEvent( QMouseEvent *event )
{
  if ( event->button() != Qt::LeftButton )
    return;

  if ( d->isEmptyTabbarSpace( event->pos() ) ) {
    emit( mouseDoubleClick() );
    return;
  }

  QTabWidget::mouseDoubleClickEvent( event );
}

void KTabWidget::mousePressEvent( QMouseEvent *event )
{
  if ( event->button() == Qt::RightButton ) {
    if ( d->isEmptyTabbarSpace( event->pos() ) ) {
      emit( contextMenu( mapToGlobal( event->pos() ) ) );
      return;
    }
  }

  QTabWidget::mousePressEvent( event );
}

void KTabWidget::mouseReleaseEvent( QMouseEvent *event )
{
  if ( event->button() == Qt::MidButton ) {
    if ( d->isEmptyTabbarSpace( event->pos() ) ) {
      emit( mouseMiddleClick() );
      return;
    }
  }

  QTabWidget::mouseReleaseEvent( event );
}

void KTabWidget::receivedDropEvent( int index, QDropEvent *event )
{
  emit( receivedDropEvent( widget( index ), event ) );
}

void KTabWidget::initiateDrag( int index )
{
  emit( initiateDrag( widget( index ) ) );
}

void KTabWidget::contextMenu( int index, const QPoint &point )
{
  emit( contextMenu( widget( index ), point ) );
}

void KTabWidget::mouseDoubleClick( int index )
{
  emit( mouseDoubleClick( widget( index ) ) );
}

void KTabWidget::mouseMiddleClick( int index )
{
  emit( mouseMiddleClick( widget( index ) ) );
}

void KTabWidget::moveTab( int from, int to )
{
  setUpdatesEnabled(false);

  const QString tablabel = tabText( from );
  QWidget *w = widget( from );
  const QColor color = tabTextColor( from );
  const QIcon tabiconset = tabIcon( from );
  const QString tabtooltip = tabToolTip( from );
  const bool current = ( from == currentIndex() );
  const bool enabled = isTabEnabled( from );

  const bool blocked = blockSignals( true );

  QWidget *fw = QApplication::focusWidget();

  removeTab( from );
  insertTab( to, w, tablabel );

  // Don't lose focus due to moving the tab (#159295)
  // (removeTab hides the widget, which gives focus to the "next in chain", could be anything)
  if (w->isAncestorOf(fw)) {
      fw->setFocus();
  }

  setTabIcon( to, tabiconset );
  setTabText( to, tablabel );
  setTabToolTip( to, tabtooltip );
  setTabTextColor( to, color );
  if ( current )
    setCurrentIndex( to );
  setTabEnabled( to, enabled );
  if ( d->m_automaticResizeTabs ) {
    d->resizeTabs( to );
  }
  blockSignals( blocked );

  setUpdatesEnabled(true);

#ifndef KDE_NO_DEPRECATED
  emit ( movedTab( from, to ) );
#endif
}

void KTabWidget::removePage( QWidget *widget )
{
  // not just calling removeTab() because that one is also virtual.
  const int index = indexOf(widget);
  if ( d->m_automaticResizeTabs ) {
    setUpdatesEnabled(false);
    d->removeTab(index);
    setUpdatesEnabled(true);
  } else {
    d->removeTab(index);
  }
}

void KTabWidget::removeTab( int index )
{
  if ( d->m_automaticResizeTabs ) {
    const bool wasUpdatesEnabled = updatesEnabled();
    setUpdatesEnabled(false);
    d->removeTab( index );
    setUpdatesEnabled(wasUpdatesEnabled);
  } else {
    d->removeTab( index );
  }
}

#ifndef KDE_NO_DEPRECATED
void KTabWidget::setHoverCloseButton( bool button )
{
  // deprecated
  setTabsClosable( button );
}
#endif

#ifndef KDE_NO_DEPRECATED
bool KTabWidget::hoverCloseButton() const
{
  // deprecated
  return false;
}
#endif

#ifndef KDE_NO_DEPRECATED
void KTabWidget::setHoverCloseButtonDelayed( bool delayed )
{
  // deprecated
  Q_UNUSED( delayed );
}
#endif

#ifndef KDE_NO_DEPRECATED
bool KTabWidget::hoverCloseButtonDelayed() const
{
  // deprecated
  return tabsClosable();
}
#endif

#ifndef KDE_NO_DEPRECATED
void KTabWidget::setCloseButtonEnabled( bool enable )
{
  static_cast<KTabBar*>( tabBar() )->setTabsClosable( enable );
}
#endif

#ifndef KDE_NO_DEPRECATED
bool KTabWidget::isCloseButtonEnabled() const
{
  return static_cast<KTabBar*>( tabBar() )->tabsClosable();
}
#endif

void KTabWidget::setAutomaticResizeTabs( bool enabled )
{
  if ( d->m_automaticResizeTabs == enabled )
    return;

  setUpdatesEnabled(false);

  d->m_automaticResizeTabs = enabled;
  if ( enabled ) {
    d->m_tabNames.clear();
    for ( int i = 0; i < count(); ++i )
      d->m_tabNames.append( tabBar()->tabText( i ) );
  } else
    for ( int i = 0; i < count(); ++i )
      tabBar()->setTabText( i, d->m_tabNames[ i ] );

  d->resizeTabs();

  setUpdatesEnabled(true);
}

bool KTabWidget::automaticResizeTabs() const
{
  return d->m_automaticResizeTabs;
}

void KTabWidget::closeRequest( int index )
{
  emit( closeRequest( widget( index ) ) );
}

void KTabWidget::resizeEvent( QResizeEvent *event )
{
  QTabWidget::resizeEvent( event );
  d->resizeTabs();
}

void KTabWidget::tabInserted( int idx )
{
   d->m_tabNames.insert( idx, tabBar()->tabText( idx ) );
}

void KTabWidget::tabRemoved( int idx )
{
  Q_UNUSED(idx)
// d->m_tabNames is now updated in KTabWidget::Private::removeTab()
}

/* This function is kept only for BC reasons, it is not useful anymore */
#ifndef KDE_NO_DEPRECATED
void KTabWidget::currentChanged( int )
{
}
#endif

#include "ktabwidget.moc"