import xml.etree.ElementTree as et

from boards.models import Post

TAG_THREAD = 'thread'


class PostFilter:
    def __init__(self, content=None):
        self.content = content

    def filter(self, posts):
        return posts

    def add_filter(self, model_tag, value):
        return model_tag


class ThreadFilter(PostFilter):
    def filter(self, posts):
        op_id = self.content.text

        op = Post.objects.filter(opening=True, id=op_id).first()
        if op:
            return posts.filter(thread=op.get_thread())
        else:
            return posts.none()

    def add_filter(self, model_tag, value):
        thread_tag = et.SubElement(model_tag, TAG_THREAD)
        thread_tag.text = str(value)