# Copyright 2008 Nanorex, Inc.  See LICENSE file for details. 
"""

@author: Ninad
@copyright: 2008 Nanorex, Inc.  See LICENSE file for details.
@version: $Id$

History:
2008-08-06: refactored Break and Join Strands commands to create this new class

TODO:
"""


import foundation.env as env
from commands.BuildAtoms.BuildAtoms_Command import BuildAtoms_Command
from utilities.exception_classes import AbstractMethod
from utilities.constants import CL_SUBCOMMAND

_superclass = BuildAtoms_Command

class BreakOrJoinStrands_Command(BuildAtoms_Command):
    """
    A superclass for Break Strands and Join Strands commands
    """   
    
    #Temporary attr 'command_porting_status. See baseCommand for details.
    command_porting_status = "PARTIAL: 2008-0--05: needs PM_class refactoring"
    
    command_level = CL_SUBCOMMAND
        # Note: maybe this should be CL_ABSTRACT so it's correct for *this* class,
        # which each subclass of this class specifying command_level = CL_SUBCOMMAND.
        # For now, this doesn't matter, since this command's name is in
        # _KLUGE_ABSTRACT_CLASSNAMES in FeatureDescriptor.py, and since
        # that code doesn't yet pay attention to CL_ABSTRACT anyway.
        # [bruce 080905 comment]
    command_parent = 'BUILD_DNA'
    
    command_can_be_suspended = False
    command_should_resume_prevMode = True 
    command_has_its_own_PM = True
    
    flyoutToolbar = None      
    
    
        
    def _createPropMgrObject(self):
        """
        Overrides superclass method and also raises an abstract method. 
        Break and join strands must override this method in order to create their
        own PM  objects. 
        """
        raise AbstractMethod()      
    
    def _get_init_gui_flyout_action_string(self):
        raise AbstractMethod
    
    
    def init_gui(self):
        self.command_enter_misc_actions()
        self.command_enter_PM() 
        self.command_enter_flyout()
        
    def restore_gui(self):
        """
        Do changes to the GUI while exiting this mode. This includes closing 
        this mode's property manager, updating the command toolbar etc. 
        @see: L{self.init_gui}
        """
        self.command_exit_misc_actions()
        self.command_exit_flyout()
        self.command_exit_PM()
    
                
    def command_enter_flyout(self):
        """
        Overrides superclass method. See superclass for documentation.
        """        
        self.flyoutToolbar = None
        actionText = self._get_init_gui_flyout_action_string()
        self._init_gui_flyout_action(str(actionText))
            
    def command_exit_flyout(self):
        """
        Overrides superclass method. See superclass for documentation.
        """
        pass
        
    def command_enter_misc_actions(self):
        """
        Overrides superclass method. See superclass for documentation.
        """
        pass
    
    def command_exit_misc_action(self):
        """
        Overrides superclass method. See superclass for documentation.
        """
        pass      
    
    def keep_empty_group(self, group):
        """
        Returns True if the empty group should not be automatically deleted.
        otherwise returns False. The default implementation always returns
        False. Subclasses should override this method if it needs to keep the
        empty group for some reasons. Note that this method will only get called
        when a group has a class constant autdelete_when_empty set to True.
        (and as of 2008-03-06, it is proposed that dna_updater calls this method
        when needed.
        @see: Command.keep_empty_group() which is overridden here.
        """

        bool_keep = _superclass.keep_empty_group(self, group)

        if not bool_keep:
            #Lets just not delete *ANY* DnaGroup while in BreakStrands_Command
            #Although BreakStrands command can only be accessed through
            #BuildDna_EditCommand, it could happen (due to a bug) that the
            #previous command is not BuildDna_Editcommand. So bool_keep
            #in that case will return False propmting dna updater to even delete
            #the empty DnaGroup (if it becomes empty for some reasons) of the
            #BuildDna command. To avoid this ,this method will instruct
            # to keep all instances of DnaGroup even when they might be empty.
            if isinstance(group, self.assy.DnaGroup):
                bool_keep = True
            
        return bool_keep