#  Copyright 2021 Collate
#  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.

"""
Workflow related configurations and utilities
"""
import importlib
import logging
from typing import Type, TypeVar

from metadata.generated.schema.metadataIngestion.workflow import (
    OpenMetadataServerConfig,
)
from metadata.generated.schema.metadataIngestion.workflow import Source as SourceConfig
from metadata.ingestion.api.common import DynamicTypedConfig
from metadata.ingestion.api.processor import Processor
from metadata.ingestion.api.sink import Sink
from metadata.ingestion.api.source import Source

logger = logging.getLogger("Config")

T = TypeVar("T")


def fetch_type_class(_type: str, is_file: bool):
    """
    Helper function to build the path for
    dynamic imports
    """
    if is_file:
        return _type.replace("-", "_")
    else:
        return "".join([i.title() for i in _type.replace("-", "_").split("_")])


def get_class(key: str) -> Type[T]:
    """
    Given an import key, import the class and return it
    """
    if key.find(".") >= 0:
        # If the key contains a dot, we treat it as an import path and attempt
        # to load it dynamically.
        module_name, class_name = key.rsplit(".", 1)
        my_class = getattr(importlib.import_module(module_name), class_name)
        return my_class


def get_ingestion_source(
    source_type: str,
    source_config: SourceConfig,
    metadata_config: OpenMetadataServerConfig,
) -> Source:
    """
    Import the required source class and configure it.

    :param source_type: Type specified in the config, e.g., redshift
    :param source_config: Specific source configurations, such as the host
    :param metadata_config: Metadata server configurations
    """

    source_class = get_class(
        "metadata.ingestion.source.{}.{}Source".format(
            fetch_type_class(source_type, is_file=True),
            fetch_type_class(source_type, is_file=False),
        )
    )
    source: Source = source_class.create(source_config.dict(), metadata_config)
    logger.debug(f"Source type:{source_type},{source_class} configured")

    source.prepare()
    logger.debug(f"Source type:{source_type},{source_class} prepared")

    return source


def get_sink(
    sink_type: str,
    sink_config: DynamicTypedConfig,
    metadata_config: OpenMetadataServerConfig,
    _from: str = "ingestion",
) -> Sink:
    """
    Helps us to fetch and importing the sink class.

    By default, we will pick it up from `ingestion`.

    :param sink_type: Type specified in the config, e.g., metadata-rest
    :param sink_config: Specific sink configurations, such as the host
    :param metadata_config: Metadata server configurations
    :param _from: From where do we load the sink class. Ingestion by default.
    """
    sink_class = get_class(
        "metadata.{}.sink.{}.{}Sink".format(
            _from,
            fetch_type_class(sink_type, is_file=True),
            fetch_type_class(sink_type, is_file=False),
        )
    )

    sink: Sink = sink_class.create(
        sink_config.dict().get("config", {}), metadata_config
    )

    logger.debug(f"Sink type: {sink_type}, {sink_class} configured")

    return sink


def get_processor(
    processor_type: str,
    processor_config: DynamicTypedConfig,
    metadata_config: OpenMetadataServerConfig,
    _from: str = "ingestion",
    **kwargs,
) -> Processor:
    """
    Helps us to fetch and import the Processor class.

    By default, we will pick it up from `ingestion`

    We allow to pass any other specific object we may require.
    E.g., for the ORM Profiler we need a Session to reach
    the source tables.

    :param processor_type: Type specified in the config, e.g., metadata-rest
    :param processor_config: Specific Processor configurations, such as the profiler and tests
    :param metadata_config: Metadata server configurations
    :param _from: From where do we load the sink class. Ingestion by default.
    """
    processor_class = get_class(
        "metadata.{}.processor.{}.{}Processor".format(
            _from,
            fetch_type_class(processor_type, is_file=True),
            fetch_type_class(processor_type, is_file=False),
        )
    )

    processor: Processor = processor_class.create(
        processor_config.dict().get("config", {}), metadata_config, **kwargs
    )

    logger.debug(f"Sink type: {processor_type}, {processor_class} configured")

    return processor