from datetime import UTC, datetime

from sqlalchemy import event
from sqlmodel import Field, SQLModel


class BaseModel(SQLModel):
    """Base model with common fields for all models."""

    id: int | None = Field(primary_key=True, default=None)

    # timestamps
    created_at: datetime = Field(default_factory=lambda: datetime.now(UTC))
    updated_at: datetime = Field(default_factory=lambda: datetime.now(UTC))


# SQLAlchemy event listener to automatically update updated_at timestamp
@event.listens_for(BaseModel, "before_update", propagate=True)
def update_timestamp(mapper, connection, target):
    """Automatically set updated_at timestamp before update operations."""
    target.updated_at = datetime.now(UTC)