# Copyright 2023 Google LLC
#
# 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.

"""Imported models."""

from __future__ import annotations

import typing
from typing import Mapping, Optional

from google.cloud import bigquery

from bigframes.core.logging import log_adapter
from bigframes.ml import base, core, globals, utils
import bigframes.pandas as bpd
import bigframes.session


@log_adapter.class_logger
class TensorFlowModel(base.Predictor):
    """Imported TensorFlow model.

    Args:
        model_path (str):
            Cloud Storage path that holds the model files.
        session (BigQuery Session):
            BQ session to create the model.
    """

    def __init__(
        self,
        model_path: str,
        *,
        session: Optional[bigframes.session.Session] = None,
    ):
        self.session = session or bpd.get_global_session()
        self.model_path = model_path
        self._bqml_model: Optional[core.BqmlModel] = None
        self._bqml_model_factory = globals.bqml_model_factory()

    def _create_bqml_model(self):
        options = {"model_type": "TENSORFLOW", "model_path": self.model_path}
        return self._bqml_model_factory.create_imported_model(
            session=self.session, options=options
        )

    @classmethod
    def _from_bq(
        cls, session: bigframes.session.Session, bq_model: bigquery.Model
    ) -> TensorFlowModel:
        assert bq_model.model_type == "TENSORFLOW"

        model = cls(session=session, model_path="")
        model._bqml_model = core.BqmlModel(session, bq_model)
        return model

    def predict(self, X: utils.ArrayType) -> bpd.DataFrame:
        """Predict the result from input DataFrame.

        Args:
            X (bigframes.dataframe.DataFrame or bigframes.series.Series or pandas.core.frame.DataFrame or pandas.core.series.Series):
                Input DataFrame. Schema is defined by the model.

        Returns:
            bigframes.dataframe.DataFrame: Output DataFrame. Schema is defined by the model."""

        if not self._bqml_model:
            if self.model_path is None:
                raise ValueError("Model GCS path must be provided.")
            self._bqml_model = self._create_bqml_model()
        self._bqml_model = typing.cast(core.BqmlModel, self._bqml_model)

        (X,) = utils.batch_convert_to_dataframe(X)

        return self._bqml_model.predict(X)

    def to_gbq(self, model_name: str, replace: bool = False) -> TensorFlowModel:
        """Save the model to BigQuery.

        Args:
            model_name (str):
                The name of the model.
            replace (bool, default False):
                 Default to False.

        Returns:
            TensorFlowModel: Saved model."""
        if not self._bqml_model:
            if self.model_path is None:
                raise ValueError("Model GCS path must be provided.")
            self._bqml_model = self._create_bqml_model()
        self._bqml_model = typing.cast(core.BqmlModel, self._bqml_model)

        new_model = self._bqml_model.copy(model_name, replace)
        return new_model.session.read_gbq_model(model_name)


@log_adapter.class_logger
class ONNXModel(base.Predictor):
    """Imported Open Neural Network Exchange (ONNX) model.

    Args:
        model_path (str):
            Cloud Storage path that holds the model files.
        session (BigQuery Session):
            BQ session to create the model.
    """

    def __init__(
        self,
        model_path: str,
        *,
        session: Optional[bigframes.session.Session] = None,
    ):
        self.session = session or bpd.get_global_session()
        self.model_path = model_path
        self._bqml_model: Optional[core.BqmlModel] = None
        self._bqml_model_factory = globals.bqml_model_factory()

    def _create_bqml_model(self):
        options = {"model_type": "ONNX", "model_path": self.model_path}
        return self._bqml_model_factory.create_imported_model(
            session=self.session, options=options
        )

    @classmethod
    def _from_bq(
        cls, session: bigframes.session.Session, bq_model: bigquery.Model
    ) -> ONNXModel:
        assert bq_model.model_type == "ONNX"

        model = cls(session=session, model_path="")
        model._bqml_model = core.BqmlModel(session, bq_model)
        return model

    def predict(self, X: utils.ArrayType) -> bpd.DataFrame:
        """Predict the result from input DataFrame.

        Args:
            X (bigframes.dataframe.DataFrame or bigframes.series.Series or pandas.core.frame.DataFrame or pandas.core.series.Series):
                Input DataFrame or Series. Schema is defined by the model.

        Returns:
            bigframes.dataframe.DataFrame: Output DataFrame, schema is defined by the model."""

        if not self._bqml_model:
            if self.model_path is None:
                raise ValueError("Model GCS path must be provided.")
            self._bqml_model = self._create_bqml_model()
        self._bqml_model = typing.cast(core.BqmlModel, self._bqml_model)

        (X,) = utils.batch_convert_to_dataframe(X, session=self._bqml_model.session)

        return self._bqml_model.predict(X)

    def to_gbq(self, model_name: str, replace: bool = False) -> ONNXModel:
        """Save the model to BigQuery.

        Args:
            model_name (str):
                The name of the model.
            replace (bool, default False):
                Determine whether to replace if the model already exists. Default to False.

        Returns:
            ONNXModel: Saved model."""
        if not self._bqml_model:
            if self.model_path is None:
                raise ValueError("Model GCS path must be provided.")
            self._bqml_model = self._create_bqml_model()
        self._bqml_model = typing.cast(core.BqmlModel, self._bqml_model)

        new_model = self._bqml_model.copy(model_name, replace)
        return new_model.session.read_gbq_model(model_name)


@log_adapter.class_logger
class XGBoostModel(base.Predictor):
    """Imported XGBoost model.

    .. warning::

        Imported XGBoost models have the several limitations. See:
        https://cloud.google.com/bigquery/docs/reference/standard-sql/bigqueryml-syntax-create-xgboost#limitations

    Args:
        model_path (str):
            Cloud Storage path that holds the model files.
        input (Dict, default None):
            Specify the model input schema information when you
            create the XGBoost model. The input should be the format of
            {field_name: field_type}. Input is optional only if feature_names
            and feature_types are both specified in the model file. Supported types
            are "bool", "string", "int64", "float64", "array<bool>", "array<string>", "array<int64>", "array<float64>".
        output (Dict, default None):
            Specify the model output schema information when you
            create the XGBoost model. The input should be the format of
            {field_name: field_type}. Output is optional only if feature_names
            and feature_types are both specified in the model file. Supported types
            are "bool", "string", "int64", "float64", "array<bool>", "array<string>", "array<int64>", "array<float64>".
        session (BigQuery Session):
            BQ session to create the model.
    """

    def __init__(
        self,
        model_path: str,
        *,
        input: Optional[Mapping[str, str]] = None,
        output: Optional[Mapping[str, str]] = None,
        session: Optional[bigframes.session.Session] = None,
    ):
        self.session = session or bpd.get_global_session()
        self.model_path = model_path
        self.input = input
        self.output = output
        self._bqml_model: Optional[core.BqmlModel] = None
        self._bqml_model_factory = globals.bqml_model_factory()

    def _create_bqml_model(self):
        options = {"model_type": "XGBOOST", "model_path": self.model_path}

        if not self.input and not self.output:
            return self._bqml_model_factory.create_imported_model(
                session=self.session, options=options
            )
        if not self.input or not self.output:
            raise ValueError("input and output must both or neigher be set.")
        self.input = {
            k: utils.standardize_type(v, globals._REMOTE_MODEL_SUPPORTED_DTYPES)
            for k, v in self.input.items()
        }
        self.output = {
            k: utils.standardize_type(v, globals._REMOTE_MODEL_SUPPORTED_DTYPES)
            for k, v in self.output.items()
        }

        return self._bqml_model_factory.create_xgboost_imported_model(
            session=self.session,
            input=self.input,
            output=self.output,
            options=options,
        )

    @classmethod
    def _from_bq(
        cls, session: bigframes.session.Session, bq_model: bigquery.Model
    ) -> XGBoostModel:
        assert bq_model.model_type == "XGBOOST"

        model = cls(session=session, model_path="")
        model._bqml_model = core.BqmlModel(session, bq_model)
        return model

    def predict(self, X: utils.ArrayType) -> bpd.DataFrame:
        """Predict the result from input DataFrame.

        Args:
            X (bigframes.dataframe.DataFrame or bigframes.series.Series or pandas.core.frame.DataFrame or pandas.core.series.Series):
                Input DataFrame or Series. Schema is defined by the model.

        Returns:
            bigframes.dataframe.DataFrame: Output DataFrame. Schema is defined by the model."""

        if not self._bqml_model:
            if self.model_path is None:
                raise ValueError("Model GCS path must be provided.")
            self._bqml_model = self._create_bqml_model()
        self._bqml_model = typing.cast(core.BqmlModel, self._bqml_model)

        (X,) = utils.batch_convert_to_dataframe(X, session=self._bqml_model.session)

        return self._bqml_model.predict(X)

    def to_gbq(self, model_name: str, replace: bool = False) -> XGBoostModel:
        """Save the model to BigQuery.

        Args:
            model_name (str):
                The name of the model.
            replace (bool, default False):
                Determine whether to replace if the model already exists. Default to False.

        Returns:
            XGBoostModel: Saved model."""
        if not self._bqml_model:
            if self.model_path is None:
                raise ValueError("Model GCS path must be provided.")
            self._bqml_model = self._create_bqml_model()
        self._bqml_model = typing.cast(core.BqmlModel, self._bqml_model)

        new_model = self._bqml_model.copy(model_name, replace)
        return new_model.session.read_gbq_model(model_name)
