import logging
from typing import Any, Mapping
from urllib.parse import urljoin

import orjson
import requests
from django.conf import settings
from django.db.models import QuerySet
from django.utils.timezone import now as timezone_now
from django.utils.translation import gettext as _
from pydantic import UUID4, BaseModel, ConfigDict, Field, Json, field_validator

from analytics.lib.counts import LOGGING_COUNT_STAT_PROPERTIES_NOT_SENT_TO_BOUNCER
from analytics.models import InstallationCount, RealmCount
from version import API_FEATURE_LEVEL, ZULIP_MERGE_BASE, ZULIP_VERSION
from zerver.actions.realm_settings import (
    do_set_push_notifications_enabled_end_timestamp,
    do_set_realm_property,
)
from zerver.lib import redis_utils
from zerver.lib.exceptions import (
    JsonableError,
    MissingRemoteRealmError,
    RemoteRealmServerMismatchError,
)
from zerver.lib.outgoing_http import OutgoingSession
from zerver.lib.queue import queue_event_on_commit
from zerver.lib.redis_utils import get_redis_client
from zerver.models import Realm, RealmAuditLog
from zerver.models.realms import OrgTypeEnum

redis_client = get_redis_client()


class PushBouncerSession(OutgoingSession):
    def __init__(self, timeout: int = 15) -> None:
        super().__init__(role="push_bouncer", timeout=timeout)


class PushNotificationBouncerError(Exception):
    pass


class PushNotificationBouncerRetryLaterError(JsonableError):
    http_status_code = 502


class PushNotificationBouncerServerError(PushNotificationBouncerRetryLaterError):
    http_status_code = 502


class RealmCountDataForAnalytics(BaseModel):
    property: str
    realm: int
    id: int
    end_time: float
    subgroup: str | None
    value: int


class InstallationCountDataForAnalytics(BaseModel):
    property: str
    id: int
    end_time: float
    subgroup: str | None
    value: int


class RealmAuditLogDataForAnalytics(BaseModel):
    id: int
    realm: int
    event_time: float
    backfilled: bool
    extra_data: str | dict[str, Any] | None
    event_type: int


class RealmDataForAnalytics(BaseModel):
    model_config = ConfigDict(extra="forbid")

    id: int
    host: str
    url: str
    name: str = ""
    org_type: int = 0
    date_created: float
    deactivated: bool
    is_system_bot_realm: bool = False

    authentication_methods: dict[str, bool] = Field(default_factory=dict)

    uuid: UUID4
    uuid_owner_secret: str

    @field_validator("org_type")
    @classmethod
    def check_is_allowed_value(cls, value: int) -> int:
        if value not in [org_type.value for org_type in OrgTypeEnum]:
            raise ValueError("Not a valid org_type value")

        return value


class AnalyticsRequest(BaseModel):
    realm_counts: Json[list[RealmCountDataForAnalytics]]
    installation_counts: Json[list[InstallationCountDataForAnalytics]]
    realmauditlog_rows: Json[list[RealmAuditLogDataForAnalytics]] | None = None
    realms: Json[list[RealmDataForAnalytics]]
    version: Json[str] | None
    merge_base: Json[str] | None
    api_feature_level: Json[int] | None


class UserDataForRemoteBilling(BaseModel):
    uuid: UUID4
    email: str
    full_name: str


def send_to_push_bouncer(
    method: str,
    endpoint: str,
    post_data: bytes | Mapping[str, str | int | None | bytes],
    extra_headers: Mapping[str, str] = {},
) -> dict[str, object]:
    """While it does actually send the notice, this function has a lot of
    code and comments around error handling for the push notifications
    bouncer.  There are several classes of failures, each with its own
    potential solution:

    * Network errors with requests.request.  We raise an exception to signal
      it to the callers.

    * 500 errors from the push bouncer or other unexpected responses;
      we don't try to parse the response, but do make clear the cause.

    * 400 errors from the push bouncer.  Here there are 2 categories:
      Our server failed to connect to the push bouncer (should throw)
      vs. client-side errors like an invalid token.

    """
    assert settings.PUSH_NOTIFICATION_BOUNCER_URL is not None
    assert settings.ZULIP_ORG_ID is not None
    assert settings.ZULIP_ORG_KEY is not None
    url = urljoin(settings.PUSH_NOTIFICATION_BOUNCER_URL, "/api/v1/remotes/" + endpoint)
    api_auth = requests.auth.HTTPBasicAuth(settings.ZULIP_ORG_ID, settings.ZULIP_ORG_KEY)

    headers = {"User-agent": f"ZulipServer/{ZULIP_VERSION}"}
    headers.update(extra_headers)

    if endpoint == "server/analytics":
        # Uploading audit log and/or analytics data can require the
        # bouncer to do a significant chunk of work in a few
        # situations; since this occurs in background jobs, set a long
        # timeout.
        session = PushBouncerSession(timeout=90)
    else:
        session = PushBouncerSession()

    try:
        res = session.request(
            method,
            url,
            data=post_data,
            auth=api_auth,
            verify=True,
            headers=headers,
        )
    except (
        requests.exceptions.Timeout,
        requests.exceptions.SSLError,
        requests.exceptions.ConnectionError,
    ) as e:
        raise PushNotificationBouncerRetryLaterError(
            f"{type(e).__name__} while trying to connect to push notification bouncer"
        )

    if res.status_code >= 500:
        # 5xx's should be resolved by the people who run the push
        # notification bouncer service, and they'll get an appropriate
        # error notification from the server. We raise an exception to signal
        # to the callers that the attempt failed and they can retry.
        error_msg = f"Received {res.status_code} from push notification bouncer"
        logging.warning(error_msg)
        raise PushNotificationBouncerServerError(error_msg)
    elif res.status_code >= 400:
        # If JSON parsing errors, just let that exception happen
        result_dict = orjson.loads(res.content)
        msg = result_dict["msg"]
        if "code" in result_dict and result_dict["code"] == "INVALID_ZULIP_SERVER":
            # Invalid Zulip server credentials should email this server's admins
            raise PushNotificationBouncerError(
                _("Push notifications bouncer error: {error}").format(error=msg)
            )
        elif "code" in result_dict and result_dict["code"] == "PUSH_NOTIFICATIONS_DISALLOWED":
            from zerver.lib.push_notifications import PushNotificationsDisallowedByBouncerError

            raise PushNotificationsDisallowedByBouncerError(reason=msg)
        elif (
            endpoint == "push/test_notification"
            and "code" in result_dict
            and result_dict["code"] == "INVALID_REMOTE_PUSH_DEVICE_TOKEN"
        ):
            # This error from the notification debugging endpoint should just be directly
            # communicated to the device.
            # TODO: Extend this to use a more general mechanism when we add more such error responses.
            from zerver.lib.push_notifications import InvalidRemotePushDeviceTokenError

            raise InvalidRemotePushDeviceTokenError
        elif (
            endpoint == "server/billing"
            and "code" in result_dict
            and result_dict["code"] == "MISSING_REMOTE_REALM"
        ):  # nocoverage
            # The callers requesting this endpoint want the exception to propagate
            # so they can catch it.
            raise MissingRemoteRealmError
        elif (
            endpoint == "server/billing"
            and "code" in result_dict
            and result_dict["code"] == "REMOTE_REALM_SERVER_MISMATCH_ERROR"
        ):  # nocoverage
            # The callers requesting this endpoint want the exception to propagate
            # so they can catch it.
            raise RemoteRealmServerMismatchError
        else:
            # But most other errors coming from the push bouncer
            # server are client errors (e.g. never-registered token)
            # and should be handled as such.
            raise JsonableError(msg)
    elif res.status_code != 200:
        # Anything else is unexpected and likely suggests a bug in
        # this version of Zulip, so we throw an exception that will
        # email the server admins.
        raise PushNotificationBouncerError(
            f"Push notification bouncer returned unexpected status code {res.status_code}"
        )

    # If we don't throw an exception, it's a successful bounce!
    return orjson.loads(res.content)


def send_json_to_push_bouncer(
    method: str, endpoint: str, post_data: Mapping[str, object]
) -> dict[str, object]:
    return send_to_push_bouncer(
        method,
        endpoint,
        orjson.dumps(post_data),
        extra_headers={"Content-type": "application/json"},
    )


PUSH_NOTIFICATIONS_RECENTLY_WORKING_REDIS_KEY = "push_notifications_recently_working_ts"


def record_push_notifications_recently_working() -> None:
    # Record the timestamp in redis, marking that push notifications
    # were working as of this moment.

    redis_key = redis_utils.REDIS_KEY_PREFIX + PUSH_NOTIFICATIONS_RECENTLY_WORKING_REDIS_KEY
    # Keep this record around for 24h in case it's useful for debugging.
    redis_client.set(redis_key, str(timezone_now().timestamp()), ex=60 * 60 * 24)


def check_push_notifications_recently_working() -> bool:
    # Check in redis whether push notifications were working in the last hour.
    redis_key = redis_utils.REDIS_KEY_PREFIX + PUSH_NOTIFICATIONS_RECENTLY_WORKING_REDIS_KEY
    timestamp = redis_client.get(redis_key)
    if timestamp is None:
        return False

    # If the timestamp is within the last hour, we consider push notifications to be working.
    return timezone_now().timestamp() - float(timestamp) < 60 * 60


def maybe_mark_pushes_disabled(
    e: JsonableError | orjson.JSONDecodeError, logger: logging.Logger
) -> None:
    if isinstance(e, PushNotificationBouncerServerError):
        # We don't fall through and deactivate the flag, since this is
        # not under the control of the caller.
        return

    if isinstance(e, JsonableError):
        logger.warning(e.msg)
    else:
        logger.exception("Exception communicating with %s", settings.PUSH_NOTIFICATION_BOUNCER_URL)

    # An exception was thrown talking to the push bouncer. There may
    # be certain transient failures that we could ignore here -
    # therefore we check whether push notifications were recently working
    # and if so, the error can be treated as transient.
    # Otherwise, the assumed explanation is that there is something wrong
    # either with our credentials being corrupted or our ability to reach the
    # bouncer service over the network, so we move to
    # reporting push notifications as likely not working.
    if check_push_notifications_recently_working():
        # Push notifications were recently observed working, so we
        # assume this is likely a transient failure.
        return

    for realm in Realm.objects.filter(push_notifications_enabled=True):
        do_set_realm_property(realm, "push_notifications_enabled", False, acting_user=None)
        do_set_push_notifications_enabled_end_timestamp(realm, None, acting_user=None)


def build_analytics_data(
    realm_count_query: QuerySet[RealmCount],
    installation_count_query: QuerySet[InstallationCount],
    realmauditlog_query: QuerySet[RealmAuditLog],
) -> tuple[
    list[RealmCountDataForAnalytics],
    list[InstallationCountDataForAnalytics],
    list[RealmAuditLogDataForAnalytics],
]:
    # We limit the batch size on the client side to avoid OOM kills timeouts, etc.
    MAX_CLIENT_BATCH_SIZE = 10000
    realm_count_data = [
        RealmCountDataForAnalytics(
            property=row.property,
            realm=row.realm.id,
            id=row.id,
            end_time=row.end_time.timestamp(),
            subgroup=row.subgroup,
            value=row.value,
        )
        for row in realm_count_query.order_by("id")[0:MAX_CLIENT_BATCH_SIZE]
    ]
    installation_count_data = [
        InstallationCountDataForAnalytics(
            property=row.property,
            id=row.id,
            end_time=row.end_time.timestamp(),
            subgroup=row.subgroup,
            value=row.value,
        )
        for row in installation_count_query.order_by("id")[0:MAX_CLIENT_BATCH_SIZE]
    ]
    zerver_realmauditlog = [
        RealmAuditLogDataForAnalytics(
            id=row.id,
            realm=row.realm.id,
            event_time=row.event_time.timestamp(),
            backfilled=row.backfilled,
            # Note that we don't need to add extra_data_json here because
            # the view remote_server_post_analytics populates extra_data_json
            # from the provided extra_data.
            extra_data=row.extra_data,
            event_type=row.event_type,
        )
        for row in realmauditlog_query.order_by("id")[0:MAX_CLIENT_BATCH_SIZE]
    ]

    return realm_count_data, installation_count_data, zerver_realmauditlog


def get_realms_info_for_push_bouncer(realm_id: int | None = None) -> list[RealmDataForAnalytics]:
    realms = Realm.objects.order_by("id")
    if realm_id is not None:  # nocoverage
        realms = realms.filter(id=realm_id)

    realm_info_list = [
        RealmDataForAnalytics(
            id=realm.id,
            uuid=realm.uuid,
            uuid_owner_secret=realm.uuid_owner_secret,
            host=realm.host,
            url=realm.url,
            deactivated=realm.deactivated,
            date_created=realm.date_created.timestamp(),
            org_type=realm.org_type,
            name=realm.name,
            authentication_methods=realm.authentication_methods_dict(),
            is_system_bot_realm=realm.string_id == settings.SYSTEM_BOT_REALM,
        )
        for realm in realms
    ]

    return realm_info_list


def send_server_data_to_push_bouncer(consider_usage_statistics: bool = True) -> None:
    logger = logging.getLogger("zulip.analytics")
    # first, check what's latest
    try:
        result = send_to_push_bouncer("GET", "server/analytics/status", {})
    except (JsonableError, orjson.JSONDecodeError) as e:
        maybe_mark_pushes_disabled(e, logger)
        return

    # Gather only entries with IDs greater than the last ID received by the push bouncer.
    # We don't re-send old data that's already been submitted.
    last_acked_realm_count_id = result["last_realm_count_id"]
    last_acked_installation_count_id = result["last_installation_count_id"]
    last_acked_realmauditlog_id = result["last_realmauditlog_id"]

    if settings.SUBMIT_USAGE_STATISTICS and consider_usage_statistics:
        # Only upload usage statistics, which is relatively expensive,
        # if called from the analytics cron job and the server has
        # uploading such statistics enabled.
        installation_count_query = InstallationCount.objects.filter(
            id__gt=last_acked_installation_count_id
        ).exclude(property__in=LOGGING_COUNT_STAT_PROPERTIES_NOT_SENT_TO_BOUNCER)
        realm_count_query = RealmCount.objects.filter(id__gt=last_acked_realm_count_id).exclude(
            property__in=LOGGING_COUNT_STAT_PROPERTIES_NOT_SENT_TO_BOUNCER
        )
    else:
        installation_count_query = InstallationCount.objects.none()
        realm_count_query = RealmCount.objects.none()

    (realm_count_data, installation_count_data, realmauditlog_data) = build_analytics_data(
        realm_count_query=realm_count_query,
        installation_count_query=installation_count_query,
        realmauditlog_query=RealmAuditLog.objects.filter(
            event_type__in=RealmAuditLog.SYNCED_BILLING_EVENTS, id__gt=last_acked_realmauditlog_id
        ),
    )

    record_count = len(realm_count_data) + len(installation_count_data) + len(realmauditlog_data)
    request = AnalyticsRequest.model_construct(
        realm_counts=realm_count_data,
        installation_counts=installation_count_data,
        realmauditlog_rows=realmauditlog_data,
        realms=get_realms_info_for_push_bouncer(),
        version=ZULIP_VERSION,
        merge_base=ZULIP_MERGE_BASE,
        api_feature_level=API_FEATURE_LEVEL,
    )

    # Send the actual request, and process the response.
    try:
        response = send_to_push_bouncer(
            "POST", "server/analytics", request.model_dump(round_trip=True)
        )
    except (JsonableError, orjson.JSONDecodeError) as e:
        maybe_mark_pushes_disabled(e, logger)
        return

    assert isinstance(response["realms"], dict)  # for mypy
    realms = response["realms"]
    for realm_uuid, data in realms.items():
        try:
            realm = Realm.objects.get(uuid=realm_uuid)
        except Realm.DoesNotExist:
            # This occurs if the installation's database was rebuilt
            # from scratch or a realm was hard-deleted from the local
            # database, after generating secrets and talking to the
            # bouncer.
            logger.warning("Received unexpected realm UUID from bouncer %s", realm_uuid)
            continue

        do_set_realm_property(
            realm, "push_notifications_enabled", data["can_push"], acting_user=None
        )
        do_set_push_notifications_enabled_end_timestamp(
            realm, data["expected_end_timestamp"], acting_user=None
        )

    logger.info("Reported %d records", record_count)


def maybe_enqueue_audit_log_upload(realm: Realm) -> None:
    # Update the push notifications service, either with the fact that
    # the realm now exists or updates to its audit log of users.
    #
    # Done via a queue worker so that networking failures cannot have
    # any impact on the success operation of the local server's
    # ability to do operations that trigger these updates.
    from zerver.lib.push_notifications import uses_notification_bouncer

    if uses_notification_bouncer():
        event = {"type": "push_bouncer_update_for_realm", "realm_id": realm.id}
        queue_event_on_commit("deferred_work", event)