from django.db import models
import markdown
from django.utils.functional import cached_property
from django.template import engines
from django_jinja.backend import Origin

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()
    toc = models.JSONField()
    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)

        md = markdown.Markdown(extensions=["toc"])

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

        data["content"] = md.convert(content)
        data["toc"] = {
            "html": md.toc,
            "tokens": md.toc_tokens
        }

        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] = engines["jinja2"].from_string(self.content)
            cached_template.origin = Origin(name=self.slug, template_name=self.slug)
            cached_template.name = self.slug
        return cached_template