from base64 import urlsafe_b64encode
from hashlib import sha3_512
from pathlib import Path
from secrets import token_urlsafe

from falcon.constants import MEDIA_JS
from jinja2 import Environment, FileSystemLoader


class CryptResource:
    @staticmethod
    def scramble(secret, value):
        h = sha3_512()
        h.update(f"{secret}{value}".encode())
        return urlsafe_b64encode(h.digest()).rstrip(b'=').decode('ascii')

    def __init__(self, secret=None):
        self.current_hubapp = "first"
        self.secret = secret or token_urlsafe(64)
        self.master_uri = f"/{self.scramble(self.secret, 'index.html')}"
        self.master_js_uri = f"/{self.scramble(self.secret, 'master.js')}"
        hubapp_dir = Path(__file__).parents[1] / "hubapps" / self.current_hubapp
        self.env = Environment(loader=FileSystemLoader(hubapp_dir))
        with open(hubapp_dir / "index.js", "rb") as fh:
            self._index_js = fh.read()
        with open(hubapp_dir / "master.js", "rb") as fh:
            self._master_js = fh.read()

    async def on_get(self, req, resp):
        resp.data = self.env.get_template("index.html.j2").render({}).encode()

    async def on_get_index_js(self, req, resp):
        resp.data = self.env.get_template("index.js").render({}).encode()

    async def on_get_master(self, req, resp):
        resp.data = self.env.get_template("master.html.j2").render({"master_js": self.master_js_uri}).encode()

    async def on_get_master_js(self, req, resp):
        resp.data = self._master_js
        resp.content_type = MEDIA_JS

    def register_on(self, app):
        app.add_route("/", self)
        app.add_route("/index.js", self, suffix="index_js")
        app.add_route(self.master_uri, self, suffix="master")
        app.add_route(self.master_js_uri, self, suffix="master_js")