/*
  This file is part of KOrganizer.

  Copyright (c) 2008 Thomas Thrainer <tom_t@gmx.at>

  This program 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 2 of the License, or
  (at your option) any later version.

  This program 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 this program; if not, write to the Free Software Foundation, Inc.,
  51 Franklin Street, Fifth Floor,
  Boston, MA 02110-1301, USA.

  As a special exception, permission is given to link this program
  with any edition of Qt, and distribute the resulting executable,
  without including the source code for Qt in the source distribution.
*/

#include "todoviewview.h"

#include <KLocalizedString>
#include <KMenu>

#include <QAction>
#include <QContextMenuEvent>
#include <QEvent>
#include <QHeaderView>
#include <QMouseEvent>

TodoViewView::TodoViewView( QWidget *parent )
  : QTreeView( parent ), mHeaderPopup( 0 ), mIgnoreNextMouseRelease( false )
{
  header()->installEventFilter( this );
  setAlternatingRowColors( true );
  connect( &mExpandTimer, SIGNAL(timeout()), SLOT(expandParent()) );
  mExpandTimer.setInterval( 1000 );
  header()->setStretchLastSection( false );
}

bool TodoViewView::isEditing( const QModelIndex &index ) const
{
  return state() & QAbstractItemView::EditingState &&
         currentIndex() == index;
}

bool TodoViewView::eventFilter( QObject *watched, QEvent *event )
{
  Q_UNUSED( watched );
  if ( event->type() == QEvent::ContextMenu ) {
    QContextMenuEvent *e = static_cast<QContextMenuEvent *>( event );

    if ( !mHeaderPopup ) {
      mHeaderPopup = new KMenu( this );
      mHeaderPopup->addTitle( i18n( "View Columns" ) );
      // First entry can't be disabled
      for ( int i = 1; i < model()->columnCount(); ++i ) {
        QAction *tmp =
          mHeaderPopup->addAction( model()->headerData( i, Qt::Horizontal ).toString() );
        tmp->setData( QVariant( i ) );
        tmp->setCheckable( true );
        mColumnActions << tmp;
      }

      connect( mHeaderPopup, SIGNAL(triggered(QAction*)),
               this, SLOT(toggleColumnHidden(QAction*)) );
    }

    foreach ( QAction *action, mColumnActions ) {
      int column = action->data().toInt();
      action->setChecked( !isColumnHidden( column ) );
    }

    mHeaderPopup->popup( mapToGlobal( e->pos() ) );
    return true;
  }

  return false;
}

void TodoViewView::toggleColumnHidden( QAction *action )
{
  if ( action->isChecked() ) {
    showColumn( action->data().toInt() );
  } else {
    hideColumn( action->data().toInt() );
  }

  emit visibleColumnCountChanged();
}

QModelIndex TodoViewView::moveCursor( CursorAction cursorAction,
                                      Qt::KeyboardModifiers modifiers )
{
  QModelIndex current = currentIndex();
  if ( !current.isValid() ) {
    return QTreeView::moveCursor( cursorAction, modifiers );
  }

  switch ( cursorAction ) {
    case MoveNext:
    {
      // try to find an editable item right of the current one
      QModelIndex tmp = getNextEditableIndex(
        current.sibling( current.row(), current.column() + 1 ), 1 );
      if ( tmp.isValid() ) {
        return tmp;
      }

      // check if the current item is expanded, and find an editable item
      // just below it if so
      current = current.sibling( current.row(), 0 );
      if ( isExpanded( current ) ) {
        tmp = getNextEditableIndex( current.child( 0, 0 ), 1 );
        if ( tmp.isValid() ) {
          return tmp;
        }
      }

      // find an editable item in the item below the currently edited one
      tmp = getNextEditableIndex( current.sibling( current.row() + 1, 0 ), 1 );
      if ( tmp.isValid() ) {
        return tmp;
      }

      // step back a hierarchy level, and search for an editable item there
      while ( current.isValid() ) {
        current = current.parent();
        tmp = getNextEditableIndex( current.sibling( current.row() + 1, 0 ), 1 );
        if ( tmp.isValid() ) {
          return tmp;
        }
      }
      return QModelIndex();
    }
    case MovePrevious:
    {
      // try to find an editable item left of the current one
      QModelIndex tmp = getNextEditableIndex(
        current.sibling( current.row(), current.column() - 1 ), -1 );
      if ( tmp.isValid() ) {
        return tmp;
      }

      int lastCol = model()->columnCount( QModelIndex() ) - 1;

      // search on top of the item, also include expanded items
      tmp = current.sibling( current.row() - 1, 0 );
      while ( tmp.isValid() && isExpanded( tmp ) ) {
        tmp = tmp.child( model()->rowCount( tmp ) - 1, 0 );
      }
      if ( tmp.isValid() ) {
        tmp = getNextEditableIndex( tmp.sibling( tmp.row(), lastCol ), -1 );
        if ( tmp.isValid() ) {
          return tmp;
        }
      }

      // step back a hierarchy level, and search for an editable item there
      current = current.parent();
      return getNextEditableIndex( current.sibling( current.row(), lastCol ), -1 );
    }
    default:
      break;
  }

  return QTreeView::moveCursor( cursorAction, modifiers );
}

QModelIndex TodoViewView::getNextEditableIndex( const QModelIndex &cur, int inc )
{
  if ( !cur.isValid() ) {
    return QModelIndex();
  }

  QModelIndex tmp;
  int colCount = model()->columnCount( QModelIndex() );
  int end = inc == 1 ? colCount : -1;

  for ( int c = cur.column(); c != end; c += inc ) {
    tmp = cur.sibling( cur.row(), c );
    if ( ( tmp.flags() & Qt::ItemIsEditable ) && !isIndexHidden( tmp ) ) {
      return tmp;
    }
  }
  return QModelIndex();
}

void TodoViewView::mouseReleaseEvent ( QMouseEvent *event )
{
  mExpandTimer.stop();

  if ( mIgnoreNextMouseRelease ) {
    mIgnoreNextMouseRelease = false;
    return;
  }

  if ( !indexAt( event->pos() ).isValid() ) {
    clearSelection();
    event->accept();
  } else {
    QTreeView::mouseReleaseEvent( event );
  }
}

void TodoViewView::mouseMoveEvent( QMouseEvent *event )
{
  mExpandTimer.stop();
  QTreeView::mouseMoveEvent( event );
}

void TodoViewView::mousePressEvent( QMouseEvent *event )
{
  mExpandTimer.stop();
  QModelIndex index = indexAt( event->pos() );
  if ( index.isValid() && event->button() == Qt::LeftButton ) {
    mExpandTimer.start();
  }

  QTreeView::mousePressEvent( event );
}

void TodoViewView::expandParent()
{
  QModelIndex index = indexAt( viewport()->mapFromGlobal( QCursor::pos() ) );
  if ( index.isValid() ) {
    mIgnoreNextMouseRelease = true;
    QKeyEvent keyEvent = QKeyEvent( QEvent::KeyPress, Qt::Key_Asterisk, Qt::NoModifier );
    QTreeView::keyPressEvent( &keyEvent );
  }
}