"""
SQLAlchemy JSON Encoder.

JSON Encoder for query objects returned from SQLAlchemy. Since some common
data types from databases are not JSON serializable, this encoder returns
str of unsupported types.
"""

from datetime import datetime
from decimal import Decimal
import json

from sqlalchemy.orm.state import InstanceState


class SQLAlchemyJSONEncoder(json.JSONEncoder):
    """JSON encoder class for use in SQLAlchemy."""

    def default(self, obj):
        """Encode data object.

        Args:
            obj (object): data object to serialize for JSON.

        Returns:
            str: JSON representation of object.
        """
        if isinstance(obj, datetime):
            return str(obj)
        elif isinstance(obj, Decimal):
            return str(obj)
        elif isinstance(obj, InstanceState):
            return str(obj)
        return json.JSONEncoder.default(self, obj)