import typing

from flask import g

from .. import CortexSearchConfig, init_cortex_search

if typing.TYPE_CHECKING:
    from flask import Flask


class FlaskCortexSearch:
    """Flask extension for integrating CortexSearchClient.

    This extension initializes and manages the Cortex Search client within
    a Flask application context. It reads Snowflake connection settings from
    the Flask application configuration and sets up the search service if
    valid credentials are provided.

    Connects owslogger to include correlation_id in a right way.

    Expected Flask config keys:
        - ``SNOWFLAKE_ACCOUNT``: Snowflake account identifier.
        - ``SNOWFLAKE_USER``: Snowflake username.
        - ``SNOWFLAKE_DATABASE``: Target Snowflake database.
        - ``SNOWFLAKE_SCHEMA``: Target Snowflake schema.
        - ``SNOWFLAKE_CORTEX_SEARCH_SERVICE_NAME``: Name of the Cortex Search service.
        - ``SNOWFLAKE_PRIVATE_KEY_PATH``: Path to the private key file (PEM/P8).
        - ``SNOWFLAKE_PRIVATE_KEY``: Private key content as a string (alternative to path if already parsed).
        - ``SNOWFLAKE_KEY_PASSPHRASE``: Passphrase for the private key, if encrypted.
        - ``SNOWFLAKE_CORTEX_SEARCH_SCORING_CONFIG``: Optional scoring configuration.
        - ``SNOWFLAKE_LOGIN_TIMEOUT``: Optional login timeout in seconds.
        - ``SNOWFLAKE_NETWORK_TIMEOUT``: Optional network timeout in seconds.
    """

    def __init__(self, app: 'Flask | None' = None) -> None:
        if app is not None:
            self.init_app(app)

    def init_app(self, app: 'Flask') -> None:
        """Bind the extension to a Flask application and initialize Cortex Search.

        Initialization is skipped when neither ``SNOWFLAKE_PRIVATE_KEY_PATH``
        nor ``SNOWFLAKE_PRIVATE_KEY`` is set in the app config, allowing the
        application to start without Snowflake credentials in environments where
        the search feature is not required.

        Args:
            app: The Flask application instance to bind this extension to.
        """
        if 'cortex_search' in app.extensions:
            raise RuntimeError('FlaskCortexSearch is already initialised on this app.')
        app.extensions['cortex_search'] = self
        config = app.config
        if config.get('SNOWFLAKE_PRIVATE_KEY_PATH') or config.get(
            'SNOWFLAKE_PRIVATE_KEY'
        ):
            init_cortex_search(
                CortexSearchConfig(
                    SNOWFLAKE_ACCOUNT=config.get('SNOWFLAKE_ACCOUNT'),
                    SNOWFLAKE_USER=config.get('SNOWFLAKE_USER'),
                    SNOWFLAKE_DATABASE=config.get('SNOWFLAKE_DATABASE'),
                    SNOWFLAKE_SCHEMA=config.get('SNOWFLAKE_SCHEMA'),
                    SNOWFLAKE_CORTEX_SEARCH_SERVICE_NAME=config.get(
                        'SNOWFLAKE_CORTEX_SEARCH_SERVICE_NAME'
                    ),
                    SNOWFLAKE_PRIVATE_KEY_PATH=config.get('SNOWFLAKE_PRIVATE_KEY_PATH'),
                    SNOWFLAKE_KEY_PASSPHRASE=config.get('SNOWFLAKE_KEY_PASSPHRASE'),
                    SNOWFLAKE_PRIVATE_KEY=config.get('SNOWFLAKE_PRIVATE_KEY'),
                    SNOWFLAKE_CORTEX_SEARCH_SCORING_CONFIG=config.get(
                        'SNOWFLAKE_CORTEX_SEARCH_SCORING_CONFIG'
                    ),
                    SNOWFLAKE_LOGIN_TIMEOUT=config.get('SNOWFLAKE_LOGIN_TIMEOUT'),
                    SNOWFLAKE_NETWORK_TIMEOUT=config.get('SNOWFLAKE_NETWORK_TIMEOUT'),
                ),
                lambda: getattr(g, 'log', None),
            )