from datetime import datetime, timezone
from enum import Enum

from sqlalchemy import (
    Column, String, ForeignKey, UniqueConstraint,
    Integer, DateTime, Enum as SQLEnum
)
from sqlalchemy.dialects.postgresql import UUID, JSONB
from sqlalchemy.orm import relationship

from .base import Base, TimestampMixin, UUIDMixin


class RSVPStatus(str, Enum):
    ATTENDING = "attending"
    NOT_ATTENDING = "not_attending"
    MAYBE = "maybe"


class RSVP(Base, UUIDMixin, TimestampMixin):
    __tablename__ = 'rsvps'

    # Foreign Keys
    event_id = Column(UUID(as_uuid=True), ForeignKey('events.id'), nullable=False)
    guest_id = Column(UUID(as_uuid=True), ForeignKey('guests.id'), nullable=False)

    # RSVP Details
    status = Column(SQLEnum(RSVPStatus), nullable=False)
    number_of_guests = Column(Integer, default=1, nullable=False)
    response_message = Column(String)

    # Additional Information
    dietary_requirements = Column(String)
    additional_info = Column(JSONB)

    # Tracking
    response_date = Column(DateTime(timezone=True),
                           default=lambda: datetime.now(timezone.utc),
                           nullable=False)
    last_updated = Column(DateTime(timezone=True),
                          default=lambda: datetime.now(timezone.utc),
                          onupdate=lambda: datetime.now(timezone.utc))

    # Relationships
    event = relationship("Event", back_populates="rsvps")
    guest = relationship("Guest", back_populates="rsvp")

    # Ensure one RSVP per guest per event
    __table_args__ = (
        UniqueConstraint('event_id', 'guest_id', name='uq_event_guest_rsvp'),
    )

    def __repr__(self):
        return f"<RSVP guest_id={self.guest_id} status={self.status.value}>"

    @property
    def is_attending(self) -> bool:
        """Check if the RSVP indicates attendance"""
        return self.status == RSVPStatus.ATTENDING

    def update_status(self, new_status: RSVPStatus, guests_count: int = None):
        """
        Update RSVP status and optionally number of guests
        """
        self.status = new_status
        if guests_count is not None:
            self.number_of_guests = max(1, guests_count)  # Ensure at least 1 guest
        self.last_updated = datetime.now(timezone.utc)