"""Blueprint importer"""

from contextlib import contextmanager
from copy import deepcopy
from typing import Any

from dacite.config import Config
from dacite.core import from_dict
from dacite.exceptions import DaciteError
from deepmerge import always_merger
from django.contrib.auth.models import Permission
from django.contrib.contenttypes.models import ContentType
from django.core.exceptions import FieldError
from django.db.models import Model
from django.db.models.query_utils import Q
from django.db.transaction import atomic
from django.db.utils import IntegrityError
from guardian.models import UserObjectPermission
from guardian.shortcuts import assign_perm
from rest_framework.exceptions import ValidationError
from rest_framework.serializers import BaseSerializer, Serializer
from structlog.stdlib import BoundLogger, get_logger
from yaml import load

from authentik.blueprints.v1.common import (
    Blueprint,
    BlueprintEntry,
    BlueprintEntryDesiredState,
    BlueprintEntryState,
    BlueprintLoader,
    EntryInvalidError,
)
from authentik.blueprints.v1.meta.registry import BaseMetaModel, registry
from authentik.core.models import (
    AuthenticatedSession,
    GroupSourceConnection,
    PropertyMapping,
    Provider,
    Session,
    Source,
    User,
    UserSourceConnection,
)
from authentik.enterprise.license import LicenseKey
from authentik.enterprise.models import LicenseUsage
from authentik.enterprise.providers.google_workspace.models import (
    GoogleWorkspaceProviderGroup,
    GoogleWorkspaceProviderUser,
)
from authentik.enterprise.providers.microsoft_entra.models import (
    MicrosoftEntraProviderGroup,
    MicrosoftEntraProviderUser,
)
from authentik.enterprise.providers.ssf.models import StreamEvent
from authentik.enterprise.stages.authenticator_endpoint_gdtc.models import (
    EndpointDevice,
    EndpointDeviceConnection,
)
from authentik.events.logs import LogEvent, capture_logs
from authentik.events.models import SystemTask
from authentik.events.utils import cleanse_dict
from authentik.flows.models import FlowToken, Stage
from authentik.lib.models import SerializerModel
from authentik.lib.sentry import SentryIgnoredException
from authentik.lib.utils.reflection import get_apps
from authentik.outposts.models import OutpostServiceConnection
from authentik.policies.models import Policy, PolicyBindingModel
from authentik.policies.reputation.models import Reputation
from authentik.providers.oauth2.models import (
    AccessToken,
    AuthorizationCode,
    DeviceToken,
    RefreshToken,
)
from authentik.providers.rac.models import ConnectionToken
from authentik.providers.scim.models import SCIMProviderGroup, SCIMProviderUser
from authentik.rbac.models import Role
from authentik.sources.scim.models import SCIMSourceGroup, SCIMSourceUser
from authentik.stages.authenticator_webauthn.models import WebAuthnDeviceType
from authentik.tenants.models import Tenant

# Context set when the serializer is created in a blueprint context
# Update website/docs/customize/blueprints/v1/models.md when used
SERIALIZER_CONTEXT_BLUEPRINT = "blueprint_entry"


def excluded_models() -> list[type[Model]]:
    """Return a list of all excluded models that shouldn't be exposed via API
    or other means (internal only, base classes, non-used objects, etc)"""

    from django.contrib.auth.models import Group as DjangoGroup
    from django.contrib.auth.models import User as DjangoUser

    return (
        # Django only classes
        DjangoUser,
        DjangoGroup,
        ContentType,
        Permission,
        UserObjectPermission,
        # Base classes
        Provider,
        Source,
        PropertyMapping,
        UserSourceConnection,
        GroupSourceConnection,
        Stage,
        OutpostServiceConnection,
        Policy,
        PolicyBindingModel,
        # Classes that have other dependencies
        Session,
        AuthenticatedSession,
        # Classes which are only internally managed
        # FIXME: these shouldn't need to be explicitly listed, but rather based off of a mixin
        FlowToken,
        LicenseUsage,
        SCIMProviderGroup,
        SCIMProviderUser,
        Tenant,
        SystemTask,
        ConnectionToken,
        AuthorizationCode,
        AccessToken,
        RefreshToken,
        Reputation,
        WebAuthnDeviceType,
        SCIMSourceUser,
        SCIMSourceGroup,
        GoogleWorkspaceProviderUser,
        GoogleWorkspaceProviderGroup,
        MicrosoftEntraProviderUser,
        MicrosoftEntraProviderGroup,
        EndpointDevice,
        EndpointDeviceConnection,
        DeviceToken,
        StreamEvent,
    )


def is_model_allowed(model: type[Model]) -> bool:
    """Check if model is allowed"""
    return model not in excluded_models() and issubclass(model, SerializerModel | BaseMetaModel)


class DoRollback(SentryIgnoredException):
    """Exception to trigger a rollback"""


@contextmanager
def transaction_rollback():
    """Enters an atomic transaction and always triggers a rollback at the end of the block."""
    try:
        with atomic():
            yield
            raise DoRollback()
    except DoRollback:
        pass


def rbac_models() -> dict:
    models = {}
    for app in get_apps():
        for model in app.get_models():
            if not is_model_allowed(model):
                continue
            models[model._meta.model_name] = app.label
    return models


class Importer:
    """Import Blueprint from raw dict or YAML/JSON"""

    logger: BoundLogger
    _import: Blueprint

    def __init__(self, blueprint: Blueprint, context: dict | None = None):
        self.__pk_map: dict[Any, Model] = {}
        self._import = blueprint
        self.logger = get_logger()
        ctx = self.default_context()
        always_merger.merge(ctx, self._import.context)
        if context:
            always_merger.merge(ctx, context)
        self._import.context = ctx

    def default_context(self):
        """Default context"""
        return {
            "goauthentik.io/enterprise/licensed": LicenseKey.get_total().status().is_valid,
            "goauthentik.io/rbac/models": rbac_models(),
        }

    @staticmethod
    def from_string(yaml_input: str, context: dict | None = None) -> "Importer":
        """Parse YAML string and create blueprint importer from it"""
        import_dict = load(yaml_input, BlueprintLoader)
        try:
            _import = from_dict(
                Blueprint, import_dict, config=Config(cast=[BlueprintEntryDesiredState])
            )
        except DaciteError as exc:
            raise EntryInvalidError from exc
        return Importer(_import, context)

    @property
    def blueprint(self) -> Blueprint:
        """Get imported blueprint"""
        return self._import

    def __update_pks_for_attrs(self, attrs: dict[str, Any]) -> dict[str, Any]:
        """Replace any value if it is a known primary key of an other object"""

        def updater(value) -> Any:
            if value in self.__pk_map:
                self.logger.debug("Updating reference in entry", value=value)
                return self.__pk_map[value]
            return value

        for key, value in attrs.items():
            try:
                if isinstance(value, dict):
                    for _, _inner_key in enumerate(value):
                        value[_inner_key] = updater(value[_inner_key])
                elif isinstance(value, list):
                    for idx, _inner_value in enumerate(value):
                        attrs[key][idx] = updater(_inner_value)
                else:
                    attrs[key] = updater(value)
            except TypeError:
                continue
        return attrs

    def __query_from_identifier(self, attrs: dict[str, Any]) -> Q:
        """Generate an or'd query from all identifiers in an entry"""
        # Since identifiers can also be pk-references to other objects (see FlowStageBinding)
        # we have to ensure those references are also replaced
        main_query = Q()
        if "pk" in attrs:
            main_query = Q(pk=attrs["pk"])
        sub_query = Q()
        for identifier, value in attrs.items():
            if identifier == "pk":
                continue
            if isinstance(value, dict):
                sub_query &= Q(**{f"{identifier}__contains": value})
            else:
                sub_query &= Q(**{identifier: value})

        return main_query | sub_query

    def _validate_single(self, entry: BlueprintEntry) -> BaseSerializer | None:  # noqa: PLR0915
        """Validate a single entry"""
        if not entry.check_all_conditions_match(self._import):
            self.logger.debug("One or more conditions of this entry are not fulfilled, skipping")
            return None

        model_app_label, model_name = entry.get_model(self._import).split(".")
        try:
            model: type[SerializerModel] = registry.get_model(model_app_label, model_name)
        except LookupError as exc:
            raise EntryInvalidError.from_entry(exc, entry) from exc
        # Don't use isinstance since we don't want to check for inheritance
        if not is_model_allowed(model):
            raise EntryInvalidError.from_entry(f"Model {model} not allowed", entry)
        if issubclass(model, BaseMetaModel):
            serializer_class: type[Serializer] = model.serializer()
            serializer = serializer_class(
                data=entry.get_attrs(self._import),
                context={
                    SERIALIZER_CONTEXT_BLUEPRINT: entry,
                },
            )
            try:
                serializer.is_valid(raise_exception=True)
            except ValidationError as exc:
                raise EntryInvalidError.from_entry(
                    f"Serializer errors {serializer.errors}",
                    validation_error=exc,
                    entry=entry,
                ) from exc
            return serializer

        # If we try to validate without referencing a possible instance
        # we'll get a duplicate error, hence we load the model here and return
        # the full serializer for later usage
        # Because a model might have multiple unique columns, we chain all identifiers together
        # to create an OR query.
        updated_identifiers = self.__update_pks_for_attrs(entry.get_identifiers(self._import))
        for key, value in list(updated_identifiers.items()):
            if isinstance(value, dict) and "pk" in value:
                del updated_identifiers[key]
                updated_identifiers[f"{key}"] = value["pk"]

        query = self.__query_from_identifier(updated_identifiers)
        if not query:
            raise EntryInvalidError.from_entry("No or invalid identifiers", entry)

        try:
            existing_models = model.objects.filter(query)
        except FieldError as exc:
            raise EntryInvalidError.from_entry(f"Invalid identifier field: {exc}", entry) from exc

        serializer_kwargs = {}
        model_instance = existing_models.first()
        if (
            not isinstance(model(), BaseMetaModel)
            and model_instance
            and entry.state != BlueprintEntryDesiredState.MUST_CREATED
        ):
            self.logger.debug(
                "Initialise serializer with instance",
                model=model,
                instance=model_instance,
                pk=model_instance.pk,
            )
            serializer_kwargs["instance"] = model_instance
            serializer_kwargs["partial"] = True
        elif model_instance and entry.state == BlueprintEntryDesiredState.MUST_CREATED:
            msg = (
                f"State is set to {BlueprintEntryDesiredState.MUST_CREATED.value} "
                "and object exists already",
            )
            raise EntryInvalidError.from_entry(
                ValidationError({k: msg for k in entry.identifiers.keys()}, "unique"),
                entry,
            )
        else:
            self.logger.debug(
                "Initialised new serializer instance",
                model=model,
                **cleanse_dict(updated_identifiers),
            )
            model_instance = model()
            # pk needs to be set on the model instance otherwise a new one will be generated
            if "pk" in updated_identifiers:
                model_instance.pk = updated_identifiers["pk"]
            serializer_kwargs["instance"] = model_instance
        try:
            full_data = self.__update_pks_for_attrs(entry.get_attrs(self._import))
        except ValueError as exc:
            raise EntryInvalidError.from_entry(exc, entry) from exc
        always_merger.merge(full_data, updated_identifiers)
        serializer_kwargs["data"] = full_data

        serializer: Serializer = model().serializer(
            context={
                SERIALIZER_CONTEXT_BLUEPRINT: entry,
            },
            **serializer_kwargs,
        )
        try:
            serializer.is_valid(raise_exception=True)
        except ValidationError as exc:
            raise EntryInvalidError.from_entry(
                f"Serializer errors {serializer.errors}",
                validation_error=exc,
                entry=entry,
                serializer=serializer,
            ) from exc
        return serializer

    def _apply_permissions(self, instance: Model, entry: BlueprintEntry):
        """Apply object-level permissions for an entry"""
        for perm in entry.get_permissions(self._import):
            if perm.user is not None:
                assign_perm(perm.permission, User.objects.get(pk=perm.user), instance)
            if perm.role is not None:
                role = Role.objects.get(pk=perm.role)
                role.assign_permission(perm.permission, obj=instance)

    def apply(self) -> bool:
        """Apply (create/update) models yaml, in database transaction"""
        try:
            with atomic():
                if not self._apply_models():
                    self.logger.debug("Reverting changes due to error")
                    raise IntegrityError
        except IntegrityError:
            return False
        self.logger.debug("Committing changes")
        return True

    def _apply_models(self, raise_errors=False) -> bool:
        """Apply (create/update) models yaml"""
        self.__pk_map = {}
        for entry in self._import.entries:
            model_app_label, model_name = entry.get_model(self._import).split(".")
            try:
                model: type[SerializerModel] = registry.get_model(model_app_label, model_name)
            except LookupError:
                self.logger.warning(
                    "App or Model does not exist", app=model_app_label, model=model_name
                )
                return False
            # Validate each single entry
            serializer = None
            try:
                serializer = self._validate_single(entry)
            except EntryInvalidError as exc:
                # For deleting objects we don't need the serializer to be valid
                if entry.get_state(self._import) == BlueprintEntryDesiredState.ABSENT:
                    serializer = exc.serializer
                else:
                    self.logger.warning(f"Entry invalid: {exc}", entry=entry, error=exc)
                    if raise_errors:
                        raise exc
                    return False
            if not serializer:
                continue

            state = entry.get_state(self._import)
            if state in [
                BlueprintEntryDesiredState.PRESENT,
                BlueprintEntryDesiredState.CREATED,
                BlueprintEntryDesiredState.MUST_CREATED,
            ]:
                instance = serializer.instance
                if (
                    instance
                    and not instance._state.adding
                    and state == BlueprintEntryDesiredState.CREATED
                ):
                    self.logger.debug(
                        "Instance exists, skipping",
                        model=model,
                        instance=instance,
                        pk=instance.pk,
                    )
                else:
                    instance = serializer.save()
                    self.logger.debug("Updated model", model=instance)
                if "pk" in entry.identifiers:
                    self.__pk_map[entry.identifiers["pk"]] = instance.pk
                entry._state = BlueprintEntryState(instance)
                self._apply_permissions(instance, entry)
            elif state == BlueprintEntryDesiredState.ABSENT:
                instance: Model | None = serializer.instance
                if instance.pk:
                    instance.delete()
                    self.logger.debug("Deleted model", mode=instance)
                    continue
                self.logger.debug("Entry to delete with no instance, skipping")
        return True

    def validate(self, raise_validation_errors=False) -> tuple[bool, list[LogEvent]]:
        """Validate loaded blueprint export, ensure all models are allowed
        and serializers have no errors"""
        self.logger.debug("Starting blueprint import validation")
        orig_import = deepcopy(self._import)
        if self._import.version != 1:
            self.logger.warning("Invalid blueprint version")
            return False, [LogEvent("Invalid blueprint version", log_level="warning", logger=None)]
        with (
            transaction_rollback(),
            capture_logs() as logs,
        ):
            successful = self._apply_models(raise_errors=raise_validation_errors)
            if not successful:
                self.logger.warning("Blueprint validation failed")
        self.logger.debug("Finished blueprint import validation")
        self._import = orig_import
        return successful, logs