from datetime import datetime, timezone
from enum import Enum

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

from .base import Base, TimestampMixin, UUIDMixin


class GuestStatus(str, Enum):
    INVITED = "invited"  # Initial state when guest is added
    PENDING = "pending"  # Invitation sent, waiting for response
    CONFIRMED = "confirmed"  # RSVP confirmed attendance
    DECLINED = "declined"  # RSVP declined attendance
    WAITLISTED = "waitlisted"  # On waitlist if event is at capacity
    CANCELLED = "cancelled"  # Guest cancelled after initial confirmation


class Guest(Base, UUIDMixin, TimestampMixin):
    __tablename__ = 'guests'

    # Foreign Keys
    event_id = Column(UUID(as_uuid=True), ForeignKey('events.id'), nullable=False)
    invited_by = Column(UUID(as_uuid=True), ForeignKey('users.id'), nullable=False)
    user_id = Column(UUID(as_uuid=True), ForeignKey('users.id'))  # Optional, if guest is a registered user

    # Guest Information
    full_name = Column(String, nullable=False)
    email = Column(String)
    phone = Column(String)
    invitation_code = Column(String, unique=True, nullable=False)

    # Guest Status
    status = Column(SQLEnum(GuestStatus), nullable=False, default=GuestStatus.INVITED)
    max_additional_guests = Column(Integer, default=0)
    actual_additional_guests = Column(Integer, default=0)

    # Tracking
    invitation_sent_at = Column(DateTime(timezone=True))
    last_reminded_at = Column(DateTime(timezone=True))
    response_date = Column(DateTime(timezone=True))

    # Additional Information
    dietary_restrictions = Column(String)
    notes = Column(String)
    custom_fields = Column(JSONB)

    # Access Management
    is_blocked = Column(Boolean, default=False)
    can_bring_guests = Column(Boolean, default=False)

    # Relationships
    event = relationship("Event", back_populates="guests")
    inviter = relationship("User", foreign_keys=[invited_by])
    user = relationship("User", foreign_keys=[user_id])
    rsvp = relationship("RSVP", back_populates="guest", uselist=False)
    gifts = relationship("GiftItem", secondary="guest_gifts", back_populates="reserved_by")

    __table_args__ = (
        UniqueConstraint('event_id', 'email', name='uq_event_guest_email'),
    )

    def __repr__(self):
        return f"<Guest {self.full_name} ({self.status.value})>"

    @property
    def total_guests(self):
        """Total number of guests including additional guests"""
        return 1 + (self.actual_additional_guests or 0)

    @property
    def has_responded(self):
        """Check if guest has responded to invitation"""
        return self.status in (GuestStatus.CONFIRMED, GuestStatus.DECLINED)

    def update_status(self, new_status: GuestStatus):
        """Update guest status and record response date"""
        self.status = new_status
        if new_status in (GuestStatus.CONFIRMED, GuestStatus.DECLINED):
            self.response_date = datetime.now(timezone.utc)


# Association table for guest gifts (many-to-many relationship)
guest_gifts = Table(
    'guest_gifts',
    Base.metadata,
    Column('guest_id', UUID(as_uuid=True), ForeignKey('guests.id'), primary_key=True),
    Column('gift_id', UUID(as_uuid=True), ForeignKey('gift_items.id'), primary_key=True),
    Column('reserved_at', DateTime(timezone=True), default=lambda: datetime.now(timezone.utc)),
    Column('notes', String),
)