import warnings
from typing import Optional

from golem.core.utilities.random import RandomStateHandler
from golem.utilities.requirements_notificator import warn_requirement

try:
    import cudf
    import cuml
    from cuml import Ridge, LogisticRegression, Lasso, ElasticNet, \
        MBSGDClassifier, MBSGDRegressor, CD
    from cuml.ensemble import RandomForestClassifier, RandomForestRegressor
    from cuml.svm import SVC
    from cuml.neighbors import KNeighborsClassifier as CuMlknnClassifier, \
        KNeighborsRegressor as CuMlknnRegressor
    from cuml import LinearRegression as CuMlLinReg, SGD as CuMlSGD, \
        MultinomialNB as CuMlMultinomialNB
except ModuleNotFoundError:
    warn_requirement('cudf / cuml', 'cudf / cuml')
    cudf = None
    cuml = None

from fedot.core.data.data import InputData, OutputData
from fedot.core.operations.evaluation.evaluation_interfaces import SkLearnEvaluationStrategy
from fedot.core.repository.operation_types_repository import OperationTypesRepository
from fedot.core.repository.tasks import TaskTypesEnum


class CuMLEvaluationStrategy(SkLearnEvaluationStrategy):
    """
    This class defines the certain operation implementation for the GPU-based CuML operations
    defined in operation repository
    :param str operation_type: str type of the operation defined in operation or
    data operation repositories
    :param dict params: hyperparameters to fit the operation with
    """
    try:
        __operations_by_types = {
            'ridge': Ridge,
            'lasso': Lasso,
            'logit': LogisticRegression,
            'linear': CuMlLinReg,
            'rf': RandomForestClassifier,
            'rfr': RandomForestRegressor,
            'svc': SVC,
            'knn': CuMlknnClassifier,
            'knnreg': CuMlknnRegressor,
            'sgd': CuMlSGD,
            'multinb': CuMlMultinomialNB,
            'elasticnet': ElasticNet,
            'mbsgdclass': MBSGDClassifier,
            'mbsgdcregr': MBSGDRegressor,
            'cd': CD
        }
    except NameError:
        # if cuML not installed
        __operations_by_types = {}

    def __init__(self, operation_type: str, params: Optional[dict] = None):
        super().__init__(operation_type, params)
        self.operation_impl = self._convert_to_operation(operation_type)
        cuml.set_global_output_type('numpy')

    def fit(self, train_data: InputData):
        """
        This method is used for operation training with the data provided
        :param InputData train_data: data used for operation training
        :return: trained cuML operation
        """
        warnings.filterwarnings("ignore", category=RuntimeWarning)
        operation_implementation = self.operation_impl(**self.params_for_fit.to_dict())

        # If model doesn't support multi-output and current task is ts_forecasting
        current_task = train_data.task.task_type
        models_repo = OperationTypesRepository()
        non_multi_models = models_repo.suitable_operation(task_type=current_task,
                                                          tags=['non_multi'])
        is_model_not_support_multi = self.operation_type in non_multi_models
        features = cudf.DataFrame(train_data.features.astype('float32'))
        target = cudf.Series(train_data.target.flatten().astype('float32'))

        if is_model_not_support_multi and current_task == TaskTypesEnum.ts_forecasting:
            raise NotImplementedError('Not supported for GPU yet')
            # TODO Manually wrap the regressor into multi-output model
        else:
            with RandomStateHandler():
                operation_implementation.fit(features, target)
        return operation_implementation

    def predict(self, trained_operation, predict_data: InputData) -> OutputData:
        """
        This method used for prediction of the target data during predict stage.
        :param trained_operation: operation object
        :param predict_data: data to predict
        :return OutputData: passed data with new predicted target
        """
        raise NotImplementedError()

    def _convert_to_operation(self, operation_type: str):
        if operation_type in self.__operations_by_types.keys():
            return self.__operations_by_types[operation_type]
        else:
            raise ValueError(f'Impossible to obtain cuML strategy for {operation_type}')
