"""
Tool_OCR - Base Schema with UTC Datetime Serialization

All datetime fields stored in the database are in UTC (using datetime.utcnow()).
This base class ensures proper serialization with 'Z' suffix to indicate UTC,
allowing frontend to correctly convert to local timezone.
"""

from datetime import datetime
from typing import Any
from pydantic import BaseModel, ConfigDict


def serialize_datetime_utc(dt: datetime) -> str:
    """Serialize datetime to ISO format with UTC indicator (Z suffix).

    Database stores all times in UTC without timezone info (naive datetime).
    This serializer adds the 'Z' suffix to indicate UTC, enabling proper
    timezone conversion in the frontend.
    """
    if dt is None:
        return None
    # Ensure ISO format with 'Z' suffix for UTC
    return dt.isoformat() + 'Z'


class UTCDatetimeBaseModel(BaseModel):
    """Base model that serializes all datetime fields with UTC indicator.

    Use this as base class for any response schema containing datetime fields
    to ensure consistent timezone handling across the API.
    """
    model_config = ConfigDict(
        from_attributes=True,
        json_encoders={
            datetime: serialize_datetime_utc
        }
    )