from datetime import datetime, timedelta, timezone

import jwt
from flask import current_app


class BaseBearerToken:
    ENCODING_ALGORITHM = "RS256"
    DEFAULT_TIME_TO_LIVE = 60 * 5

    def __init__(self, ttl):
        self._ttl = ttl

    def claimset_at(self, now):
        claimset = self.durable_claims.copy()
        ts_now = now.timestamp()
        ts_exp = (now + timedelta(seconds=self.ttl)).timestamp()
        claimset["iss"] = current_app.config["JWT_TOKEN_ISS"]
        claimset["iat"] = int(ts_now)
        claimset["exp"] = int(ts_exp)
        claimset["nbf"] = int(ts_now)
        return claimset

    def encode_at(self, datetime):
        private_key = current_app.config["DNA_IDENTITY_PRIVATE_KEY"]
        headers = {}
        kid = current_app.config.get("JWT_TOKEN_KID")
        if kid:
            headers["kid"] = kid
        return jwt.encode(
            self.claimset_at(datetime),
            private_key,
            self.ENCODING_ALGORITHM,
            headers=headers,
        )

    def encode(self):
        return self.encode_at(datetime.now(timezone.utc))

    @property
    def ttl(self):
        return self._ttl or self.DEFAULT_TIME_TO_LIVE

    @property
    def durable_claims(self):
        return {}


class DNABearerToken(BaseBearerToken):
    def __init__(self, dna_account, resource_group=None, ttl=None):
        self._dna_account = dna_account
        self._resource_group = resource_group
        super().__init__(ttl)

    @property
    def dna_account(self):
        return self._dna_account

    @property
    def durable_claims(self):
        return self._dna_account.serialize_claims(self._resource_group)

    @property
    def token_length(self):
        return len(self.encode().encode("utf-8"))


class M2MBearerToken(BaseBearerToken):
    DEFAULT_TIME_TO_LIVE = 60 * 60 * 24

    def __init__(self, application, ttl=None):
        self._application = application
        super().__init__(ttl)

    @property
    def application(self):
        return self._application

    @property
    def durable_claims(self):
        return self._application.serialize_claims()

    @property
    def ttl(self):
        return self._ttl or self._application.ttl or self.DEFAULT_TIME_TO_LIVE