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


def get_snowflake_cursor():
    """This function sets up the Snowflake connection."""
    snowflake_private_key_path = os.environ.get('SNOWFLAKE_PRIVATE_KEY_PATH', '')
    snowflake_key_passphrase = os.environ.get('SNOWFLAKE_KEY_PASSPHRASE', '')

    with open(snowflake_private_key_path, 'rb') as key:
        p_key = serialization.load_pem_private_key(
            key.read(),
            password=snowflake_key_passphrase.encode(),
            backend=default_backend()
        )

    private_key = p_key.private_bytes(
        encoding=serialization.Encoding.DER,
        format=serialization.PrivateFormat.PKCS8,
        encryption_algorithm=serialization.NoEncryption())

    # Snowflake connection parameters
    snowflake_db_config = {
        'user': os.environ.get('SNOWFLAKE_USER'),
        'private_key': private_key,
        'account': os.environ.get('SNOWFLAKE_ACCOUNT'),
        'role': os.environ.get('SNOWFLAKE_ROLE'),
        'warehouse': os.environ.get('SNOWFLAKE_WAREHOUSE'),
        'db': os.environ.get('SNOWFLAKE_DATABASE'),
        'schema': os.environ.get('SNOWFLAKE_SCHEMA')
    }

    # Connect to Snowflake
    conn = snowflake.connector.connect(
        **snowflake_db_config
    )
    return conn