# -*- coding: utf-8 -*-

# Copyright (c) 2009 - 2013 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing specialized tree views. 
"""

from PyQt4.QtCore import Qt
from PyQt4.QtGui import QTreeView, QItemSelectionModel

class E4TreeView(QTreeView):
    """
    Class implementing a tree view supporting removal of entries.
    """
    def keyPressEvent(self, evt):
        """
        Protected method implementing special key handling.
        
        @param evt reference to the event (QKeyEvent)
        """
        if evt.key() in [Qt.Key_Delete, Qt.Key_Backspace] and \
           self.model() is not None:
            self.removeSelected()
            evt.setAccepted(True)
        else:
            QTreeView.keyPressEvent(self, evt)
    
    def removeSelected(self):
        """
        Public method to remove the selected entries.
        """
        if self.model() is None or \
           self.selectionModel() is None or \
           not self.selectionModel().hasSelection():
            # no models available or nothing selected
            return
        
        selectedRows = self.selectionModel().selectedRows()
        for idx in reversed(sorted(selectedRows)):
            self.model().removeRow(idx.row(), idx.parent())
    
    def removeAll(self):
        """
        Public method to clear the view.
        """
        if self.model() is not None:
            self.model().removeRows(0, self.model().rowCount(self.rootIndex()), 
                                    self.rootIndex())
