#
# Gramps - a GTK+/GNOME based genealogy program
#
# Copyright (C) 2010  Nick Hall
#
# 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#

# $Id$

"""
TagBase class for Gramps.
"""
#-------------------------------------------------------------------------
#
# TagBase class
#
#-------------------------------------------------------------------------
class TagBase(object):
    """
    Base class for tag-aware objects.
    """

    def __init__(self, source=None):
        """
        Initialize a TagBase. 
        
        If the source is not None, then object is initialized from values of 
        the source object.

        :param source: Object used to initialize the new object
        :type source: TagBase
        """
        if source:
            self.tag_list = list(source.tag_list)
        else:
            self.tag_list = []

    def serialize(self):
        """
        Convert the object to a serialized tuple of data.
        """
        return self.tag_list

    def to_struct(self):
        """
        Convert the data held in this object to a structure (eg,
        struct) that represents all the data elements.
        
        This method is used to recursively convert the object into a
        self-documenting form that can easily be used for various
        purposes, including diffs and queries.

        These structures may be primitive Python types (string,
        integer, boolean, etc.) or complex Python types (lists,
        tuples, or dicts). If the return type is a dict, then the keys
        of the dict match the fieldname of the object. If the return
        struct (or value of a dict key) is a list, then it is a list
        of structs. Otherwise, the struct is just the value of the
        attribute.

        :returns: Returns a struct containing the data of the object.
        :rtype: list
        """
        return self.tag_list

    def unserialize(self, data):
        """
        Convert a serialized tuple of data to an object.
        """
        self.tag_list = data
        return self

    def add_tag(self, tag):
        """
        Add the tag to the object's list of tags.

        :param tag: unicode tag to add.
        :type tag: unicode
        """
        if tag not in self.tag_list:
            self.tag_list.append(tag)

    def remove_tag(self, tag):
        """
        Remove the specified tag from the tag list.
        
        If the tag does not exist in the list, the operation has no effect.

        :param tag: tag to remove from the list.
        :type tag: unicode

        :returns: True if the tag was removed, False if it was not in the list.
        :rtype: bool
        """
        if tag in self.tag_list:
            self.tag_list.remove(tag)
            return True
        else:
            return False

    def get_tag_list(self):
        """
        Return the list of tags associated with the object.
        
        :returns: Returns the list of tags.
        :rtype: list
        """
        return self.tag_list

    def set_tag_list(self, tag_list):
        """
        Assign the passed list to the objects's list of tags.

        :param tag_list: List of tags to ba associated with the object.
        :type tag_list: list
        """
        self.tag_list = tag_list

    def get_referenced_tag_handles(self):
        """
        Return the list of (classname, handle) tuples for all referenced tags.
        
        This method should be used to get the :class:`~gen.lib.tag.Tag` portion
        of the list by objects that store tag lists.
        
        :returns: List of (classname, handle) tuples for referenced objects.
        :rtype: list
        """
        return [('Tag', handle) for handle in self.tag_list]

    def _merge_tag_list(self, acquisition):
        """
        Merge the list of tag from acquisition with our own.

        :param acquisition: The tag list of this object will be merged with
            the current tag list.
        :rtype acquisition: TagBase
        """
        for addendum in acquisition.get_tag_list():
            self.add_tag(addendum)

    def replace_tag_references(self, old_handle, new_handle):
        """
        Replace references to note handles in the list of this object and
        merge equivalent entries.

        :param old_handle: The note handle to be replaced.
        :type old_handle: str
        :param new_handle: The note handle to replace the old one with.
        :type new_handle: str
        """
        refs_list = self.tag_list[:]
        new_ref = None
        if new_handle in self.tag_list:
            new_ref = new_handle
        n_replace = refs_list.count(old_handle)
        for ix_replace in range(n_replace):
            idx = refs_list.index(old_handle)
            if new_ref:
                self.tag_list.pop(idx)
                refs_list.pop(idx)
            else:
                self.tag_list[idx] = new_handle

