import typing
import jinja2

from starlette.background import BackgroundTask
from starlette.templating import _TemplateResponse


class Jinja2Templates:
    """
    This is a patched version of starlette.templating.Jinja2Templates that
    supports extensions (list of strings) passed to jinja2.Environment
    """

    def __init__(self, directory: str, extensions: typing.List[str] = []) -> None:
        assert jinja2 is not None, "jinja2 must be installed to use Jinja2Templates"
        self.env = self.get_env(directory, extensions)

    def get_env(
        self, directory: str, extensions: typing.List[str] = []
    ) -> "jinja2.Environment":
        @jinja2.contextfunction
        def url_for(context: dict, name: str, **path_params: typing.Any) -> str:
            request = context["request"]
            return request.url_for(name, **path_params)

        loader = jinja2.FileSystemLoader(directory)
        env = jinja2.Environment(loader=loader, extensions=extensions, autoescape=True)
        env.globals["url_for"] = url_for
        return env

    def get_template(self, name: str) -> "jinja2.Template":
        return self.env.get_template(name)

    def TemplateResponse(
        self,
        name: str,
        context: dict,
        status_code: int = 200,
        headers: dict = None,
        media_type: str = None,
        background: BackgroundTask = None,
    ) -> _TemplateResponse:
        if "request" not in context:
            raise ValueError('context must include a "request" key')
        template = self.get_template(name)
        return _TemplateResponse(
            template,
            context,
            status_code=status_code,
            headers=headers,
            media_type=media_type,
            background=background,
        )