class Book(db.Model):
    title = db.StringProperty(required=True)
    author = db.StringProperty(required=True)
    created = db.DateTimeProperty(auto_now_add=True)

    # Get all the Chapters for a book
    def getChapters(self):
        key = self.chapterMemkey()
        chapters = memcache.get(key)
        if chapters is None:
            logging.info('DB access for key %s.', key)
            chapters = Chapter.all().ancestor(self).order("number").fetch(100)
            if not memcache.set(key, chapters, 300):
                logging.error('Memcache set failed for Chapters.')
        else:
            logging.info('Memcache for key %s.', key)
        return chapters

class Chapter(db.Model):
    """ All chapters that a book have """
    title = db.StringProperty(required=True)
    number = db.IntegerProperty(default=1)
    created = db.DateTimeProperty(auto_now_add=True)

    book = db.ReferenceProperty(Book,
                                required=True,
                                collection_name='chapters')

    # Search by Book (parent)
    @classmethod
    def byBook(cls, book, limit=100):
        chapter = book.getChapters()
        return chapter

    # Search by id
    @classmethod
    def byId(cls, id, book):
        return Chapter.get_by_id(long(id), parent=book)

class Vote(db.Model):
    """ All votes that a book-chapter have """
    chapterNumber = db.IntegerProperty(required=True)
    option = db.IntegerProperty(default=1)
    value = db.IntegerProperty(default=1)

    book = db.ReferenceProperty(Book,
                                required=True,
                                collection_name='book_votes')
    chapter = db.ReferenceProperty(Chapter,
                                   required=True,
                                   collection_name='chapter_votes')

    # --------------------------
    # ClassMethods for the class
    # --------------------------

    # Search by Book (parent)
    @classmethod
    def byBook(cls, book, limit=100):
        vote = book.getVotes()
        return vote

    # Search by id
    @classmethod
    def byId(cls, id, book):
        return Vote.get_by_id(long(id), parent=book)

@classmethod
def byChapter(cls, chapter, limit=100):
    vote = chapter.getVotes()
    return vote