import hashlib
from django.template import TemplateDoesNotExist
from django.template.loaders.base import Loader
from django.core.cache import cache
 
class CachedNamespaceLoader(Loader):
    def __init__(self, engine, dirs, namespaces):
        super().__init__(engine, dirs)
        self.namespaces = namespaces or {}
        self._template_cache = {}
 
 
    def get_template_sources(self, template_name):
        namespace, _, template = template_name.partition(':')
        if namespace in self.namespaces:
            base_dirs = self.namespaces[namespace]
            for dir in base_dirs:
                try:
                    yield self.get_template_path(f'{template}', dir)
                except FileNotFoundError:
                    continue
 
    def get_contents(self, origin):
        cache_key = f'template:{hashlib.md5(origin.name.encode()).hexdigest()}'
        template_source = cache.get(cache_key)
        if template_source is None:
            template_source = super().get_contents(origin)
            cache.set(cache_key, template_source, timeout=3600)
        return template_source
 
    def get_template_path(self, template_name, dir):
        path = f'{dir}/{template_name}'
        if not os.path.exists(path):
            raise FileNotFoundError(f'Template {path} not found')
        return path