#!/usr/bin/env python
#
# classes.py - AuroraTag
# Author: mark grandi
# 6/6/2011
#

from datetime import datetime
from database import Database


class TagCollection:
    ''' class that contains a collection of tags'''

    # set up the table stuff

    def __init__(self):

        # instance variables
        self.tags = []
        self.id = None

    def __iter__(self):

        return self.tags.__iter__()

    def __next__(self):

        return self.tags.__next__()

    def __str__(self):
        ''' toString override'''

        result = ""

        for tag in self.tags:

            result = result + tag + "\n"

        return result


    def numberOfTags(self):
        ''' function that returns the number of tags'''

        return len(self.tags)


    def addTag(self, tagToAdd):
        ''' adds the tag to the collection. Throws a NotTagException if
        you try and add any object except a Tag object to the collection'''

        if not isinstance(tagToAdd, Tag):

            raise NotTagException("You can only add tags to a TagCollection")

        #  add it to our internal list
        self.tags.append(tagToAdd)

    def containsTag(self, tagToCheck):
        ''' returns whether this collection contains the specified tag or not'''
        return  tagToCheck in self.tags





class Tag:
    ''' class that represents a tag'''

    def __init__(self, tagName = ""):
        '''
        init function

        @param tagName - the name of the tag.
        '''

        # instance variables
        self.id = None
        #self.parentId = None
        self.name = tagName
        #self.nestedTags = None
        self.dateCreated = datetime.now()
        self.state = State.NEW

    def __setattr__(self, name, value):
        ''' so i'm defining this method so that it gets called every time
        i set an attribute on this object. All this does is sets the attribute
        normally, and then set the object's state to be dirty if its not already new. '''

        self.__dict__[name] = value

        # set the object state, we do it through __dict__ to not cause an infinite loop
        # self.state = State.DIRTY
        self.__dict__["state"] = State.DIRTY

    def __str__(self):
        ''' toString override'''

        return "<Tag: {}>".format(self.name)

    def __repr__(self):
        return "<Tag: {}>".format(self.name)


class State:
    ''' enum class that represents the state of a tag. '''
    CLEAN = 0
    DIRTY = 1
    NEW = 2



class SingletonException:
    ''' exception that gets called when you try to create another instance of a singleton'''

    pass


class NotTagException(Exception):
    '''exception class that gets raised when you try to add
    a non Tag object to the TagCollection'''

    pass

class NotTagCollectionException(Exception):
    '''exception class that gets raised when you try to save
    a non TagCollection object to the database'''

    pass