#
# Copyright (c) 2020 Cord Technologies Limited
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import dataclasses
import logging
from typing import TypeVar, Type, List

import requests
import requests.exceptions
from requests import Session, Timeout
from requests.adapters import HTTPAdapter
from requests.packages.urllib3.util import Retry

from cord.configs import BaseConfig
from cord.exceptions import *
from cord.http.error_utils import check_error_response
from cord.http.query_methods import QueryMethods
from cord.http.request import Request


class Querier:
    """ Querier for DB get/post requests. """
    T = TypeVar('T')

    def __init__(self, config: BaseConfig):
        self._config = config

    def basic_getter(self, db_object_type: Type[T], uid=None, payload=None) -> T:
        """ Single DB object getter. """
        request = self.request(
            QueryMethods.GET,
            db_object_type,
            uid,
            self._config.read_timeout,
            payload=payload
        )
        res = self.execute(request)
        if res:
            if dataclasses.is_dataclass(db_object_type):
                return db_object_type(**res)
            else:
                return db_object_type(res)
        else:
            raise ResourceNotFoundError("Resource not found.")

    def get_multiple(self, object_type: Type[T], uid=None, payload=None) -> List[T]:
        request = self.request(
            QueryMethods.GET,
            object_type,
            uid,
            self._config.read_timeout,
            payload=payload
        )
        result = self.execute(request)

        if result is not None:
            return [object_type(**item) for item in result]
        else:
            raise ResourceNotFoundError(f"[{object_type}] not found for query with uid=[{uid}] and payload=[{payload}]")

    def basic_delete(self, db_object_type: Type[T], uid=None):
        """ Single DB object getter. """
        request = self.request(
            QueryMethods.DELETE,
            db_object_type,
            uid,
            self._config.read_timeout,
        )

        self.execute(request)

    def basic_setter(self, db_object_type: Type[T], uid, payload):
        """ Single DB object setter. """
        request = self.request(
            QueryMethods.POST,
            db_object_type,
            uid,
            self._config.write_timeout,
            payload=payload,
        )

        res = self.execute(request)

        if res:
            return res
        else:
            raise RequestException("Setting %s with uid %s failed." % (db_object_type, uid))

    def basic_put(self, db_object_type, uid, payload):
        """ Single DB object put request. """
        request = self.request(
            QueryMethods.PUT,
            db_object_type,
            uid,
            self._config.write_timeout,
            payload=payload,
        )

        res = self.execute(request)

        if res:
            return res
        else:
            raise RequestException("Setting %s with uid %s failed." % (db_object_type, uid))

    def request(self, method, db_object_type: Type[T], uid, timeout, payload=None):
        request = Request(method, db_object_type, uid, timeout, self._config.connect_timeout, payload)

        request.headers = self._config.define_headers(request.data)
        return request

    def execute(self, request):
        """ Execute a request. """
        logging.info("Request: %s", (request.data[:100] + '..') if len(request.data) > 100 else request.data)

        session = Session()
        session.mount("https://", HTTPAdapter(max_retries=Retry(connect=0)))

        req = requests.Request(
            method=request.http_method,
            url=self._config.endpoint,
            headers=request.headers,
            data=request.data,
        ).prepare()

        timeouts = (request.connect_timeout, request.timeout)

        try:
            res = session.send(req, timeout=timeouts)
        except Timeout as e:
            raise TimeOutError(str(e))
        except RequestException as e:
            raise RequestException(str(e))
        except Exception as e:
            raise UnknownException(str(e))

        try:
            res_json = res.json()
        except Exception:
            raise CordException("Error parsing JSON response: %s" % res.text)

        if res_json.get("status") != requests.codes.ok:
            response = res_json.get("response")
            extra_payload = res_json.get("payload")
            check_error_response(response, extra_payload)

        session.close()

        return res_json.get("response")
