from sqlalchemy import Text, Integer, ForeignKey
from sqlalchemy.orm import Mapped, mapped_column, relationship as sa_relationship
from datetime import datetime
from typing import Optional
from app.database import Base


class TaskComment(Base):
    __tablename__ = "task_comments"

    id: Mapped[int] = mapped_column(primary_key=True, index=True)
    task_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("project_tasks.id", ondelete="CASCADE"), nullable=False, index=True
    )
    user_id: Mapped[Optional[int]] = mapped_column(
        Integer, ForeignKey("users.id", ondelete="SET NULL"), nullable=True
    )
    content: Mapped[str] = mapped_column(Text, nullable=False)
    created_at: Mapped[datetime] = mapped_column(default=datetime.now)

    # Relationships — lazy="raise" to prevent N+1 (mirrors CalendarMember pattern)
    task: Mapped["ProjectTask"] = sa_relationship(back_populates="comments", lazy="raise")
    user: Mapped[Optional["User"]] = sa_relationship(lazy="raise")