"""Serve files directly from the ContentsManager."""

# Copyright (c) Jupyter Development Team.
# Distributed under the terms of the Modified BSD License.

import mimetypes
import json
from base64 import decodebytes
from tornado import gen, web
from jupyter_server.base.handlers import JupyterHandler
from jupyter_server.utils import maybe_future


class FilesHandler(JupyterHandler):
    """serve files via ContentsManager

    Normally used when ContentsManager is not a FileContentsManager.

    FileContentsManager subclasses use AuthenticatedFilesHandler by default,
    a subclass of StaticFileHandler.
    """

    @property
    def content_security_policy(self):
        # In case we're serving HTML/SVG, confine any Javascript to a unique
        # origin so it can't interact with the notebook server.
        return (
            super(FilesHandler, self).content_security_policy
            + "; sandbox allow-scripts"
        )

    @web.authenticated
    def head(self, path):
        self.get(path, include_body=False)

    @web.authenticated
    @gen.coroutine
    def get(self, path, include_body=True):
        cm = self.contents_manager

        if cm.is_hidden(path) and not cm.allow_hidden:
            self.log.info("Refusing to serve hidden file, via 404 Error")
            raise web.HTTPError(404)

        path = path.strip("/")
        if "/" in path:
            _, name = path.rsplit("/", 1)
        else:
            name = path

        model = yield maybe_future(cm.get(path, type="file", content=include_body))

        if self.get_argument("download", False):
            self.set_attachment_header(name)

        # get mimetype from filename
        if name.lower().endswith(".ipynb"):
            self.set_header("Content-Type", "application/x-ipynb+json")
        else:
            cur_mime = mimetypes.guess_type(name)[0]
            if cur_mime == "text/plain":
                self.set_header("Content-Type", "text/plain; charset=UTF-8")
            elif cur_mime is not None:
                self.set_header("Content-Type", cur_mime)
            else:
                if model["format"] == "base64":
                    self.set_header("Content-Type", "application/octet-stream")
                else:
                    self.set_header("Content-Type", "text/plain; charset=UTF-8")

        if include_body:
            if model["format"] == "base64":
                b64_bytes = model["content"].encode("ascii")
                self.write(decodebytes(b64_bytes))
            elif model["format"] == "json":
                self.write(json.dumps(model["content"]))
            else:
                self.write(model["content"])
            self.flush()


default_handlers = []
