import uuid
from sqlalchemy import Column, TIMESTAMP, ForeignKey, UniqueConstraint
from sqlalchemy.dialects.postgresql import UUID
from sqlalchemy.sql import func
from app.db.engine import Base


class SessionPatientMap(Base):
    __tablename__ = "session_patient_map"

    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    session_id = Column(UUID(as_uuid=True), ForeignKey("intake_session.id", ondelete="CASCADE"), nullable=False)
    patient_id = Column(UUID(as_uuid=True), ForeignKey("patient.id", ondelete="CASCADE"), nullable=False)
    created_at = Column(TIMESTAMP(timezone=True), server_default=func.now(), nullable=False)

    __table_args__ = (
        UniqueConstraint("session_id", "patient_id", name="uq_session_patient"),
    )