from django.db import models
import markdown
from django.template import Template
from django.utils.functional import cached_property

class Tag(models.Model):
    __yamdl__ = True

    slug = models.SlugField(max_length=128, primary_key=True)

    content = models.TextField()


class Page(models.Model):
    __yamdl__ = True

    _template_cache = {}

    title = models.CharField(max_length=255)

    raw_content = models.TextField()
    content = models.TextField()
    slug = models.CharField(max_length=128, unique=True, db_index=True, default=None, null=True)

    tags = models.ManyToManyField(Tag)

    @classmethod
    def from_yaml(cls, **data):
        tags = data.pop("tags", None)

        content = data.pop("content")
        data["raw_content"] = content
        data["content"] = markdown.markdown(content)

        instance = cls.objects.create(**data)

        if tags:
            instance.tags.set(tags)

        return instance

    @cached_property
    def content_template(self):
        if (cached_template := self._template_cache.get(self.slug)) is None:
            cached_template = self._template_cache[self.slug] = Template(self.content, name=self.slug)
        return cached_template