"""Snowflake connector module."""
import os

from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import serialization
from snowflake import connector

import config


def get_sf_private_key(secrets_manager_client):
    """Return Snowflake private_key.

    Returns:
        str: Snowflake private_key.
    """
    private_key_string = secrets_manager_client.get_cred('SNOWFLAKE_KEY')
    private_key = None
    if private_key_string:
        private_key = serialization.load_pem_private_key(
            bytes(private_key_string, 'utf8'),
            password=None,
            backend=default_backend()
        )

    return private_key


def get_sf_connection(secrets_manager_client):
    """Return Snowflake connection."""
    return connector.connect(
        user=os.environ.get('SNOWFLAKE_USER'),
        account=os.environ.get('SNOWFLAKE_ACCOUNT'),
        warehouse=os.environ.get('SNOWFLAKE_WAREHOUSE'),
        database=os.environ.get('SNOWFLAKE_DATABASE'),
        schema=os.environ.get('SNOWFLAKE_SCHEMA'),
        role=os.environ.get('SNOWFLAKE_ROLE'),
        private_key=get_sf_private_key(secrets_manager_client)
    )


def execute_snowflake_query(query: str, params: dict) -> list[dict]:
    """Extract data from Snowflake.

    Args:
        query (str): SQL statement for extracting data from Snowflake.
        params (dict): For formatting the query.

    Returns:
        List: List of tuples or empty list.
    """
    with get_sf_connection(config.secrets_manager_client_lambda) as connection:
        with connection.cursor(connector.DictCursor) as cursor:
            return cursor.execute(query, params).fetchall()