from django.http import HttpResponse, HttpResponseNotAllowed
import ujson

from typing import Optional, Any, Dict, List, Text
from zerver.lib.str_utils import force_bytes
from zerver.lib.exceptions import JsonableError

class HttpResponseUnauthorized(HttpResponse):
    status_code = 401

    def __init__(self, realm, www_authenticate=None):
        # type: (Text, Optional[Text]) -> None
        HttpResponse.__init__(self)
        if www_authenticate is None:
            self["WWW-Authenticate"] = 'Basic realm="%s"' % (realm,)
        elif www_authenticate == "session":
            self["WWW-Authenticate"] = 'Session realm="%s"' % (realm,)
        else:
            raise AssertionError("Invalid www_authenticate value!")

def json_unauthorized(message, www_authenticate=None):
    # type: (Text, Optional[Text]) -> HttpResponse
    resp = HttpResponseUnauthorized("zulip", www_authenticate=www_authenticate)
    resp.content = force_bytes(ujson.dumps({"result": "error",
                                            "msg": message}) + "\n")
    return resp

def json_method_not_allowed(methods):
    # type: (List[Text]) -> HttpResponseNotAllowed
    resp = HttpResponseNotAllowed(methods)
    resp.content = force_bytes(ujson.dumps({"result": "error",
                                            "msg": "Method Not Allowed",
                                            "allowed_methods": methods}))
    return resp

def json_response(res_type="success", msg="", data=None, status=200):
    # type: (Text, Text, Optional[Dict[str, Any]], int) -> HttpResponse
    content = {"result": res_type, "msg": msg}
    if data is not None:
        content.update(data)
    return HttpResponse(content=ujson.dumps(content) + "\n",
                        content_type='application/json', status=status)

def json_success(data=None):
    # type: (Optional[Dict[str, Any]]) -> HttpResponse
    return json_response(data=data)

def json_response_from_error(exception):
    # type: (JsonableError) -> HttpResponse
    '''
    This should only be needed in middleware; in app code, just raise.

    When app code raises a JsonableError, the JsonErrorHandler
    middleware takes care of transforming it into a response by
    calling this function.
    '''
    return json_response('error',
                         msg=exception.msg,
                         data=exception.data,
                         status=exception.http_status_code)

def json_error(msg, data=None, status=400):
    # type: (Text, Optional[Dict[str, Any]], int) -> HttpResponse
    return json_response(res_type="error", msg=msg, data=data, status=status)