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


class IntakeSession(Base):
    __tablename__ = "intake_session"

    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    patient_id = Column(UUID(as_uuid=True), ForeignKey("patient.id", ondelete="CASCADE"), nullable=False, unique=True)
    department_id = Column(UUID(as_uuid=True), ForeignKey("mstr_department.id"), nullable=False)
    status = Column(String(30), nullable=False, default="ACTIVE")
    started_at = Column(TIMESTAMP(timezone=True), server_default=func.now(), nullable=False)
    completed_at = Column(TIMESTAMP(timezone=True), nullable=True)
    pending_question = Column(Text, nullable=True)
    created_at = Column(TIMESTAMP(timezone=True), server_default=func.now(), nullable=False)
    __table_args__ = (
        Index("sessions_status_idx", "department_id", "status"),
    )


class SessionContributor(Base):
    __tablename__ = "session_contributor"

    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)
    staff_id = Column(UUID(as_uuid=True), ForeignKey("user.id"), nullable=False)
    sequence_number = Column(SmallInteger, nullable=False)
    joined_at = Column(TIMESTAMP(timezone=True), server_default=func.now(), nullable=False)

    __table_args__ = (
        UniqueConstraint("session_id", "staff_id", name="uq_contributor_session_staff"),
        Index("contributors_session_idx", "session_id", "sequence_number"),
    )