from sqlalchemy import (
    Boolean, CheckConstraint, DateTime, Integer, ForeignKey, Index,
    String, UniqueConstraint, func,
)
from sqlalchemy.orm import Mapped, mapped_column, relationship
from datetime import datetime
from typing import Optional
from app.database import Base


class CalendarMember(Base):
    __tablename__ = "calendar_members"
    __table_args__ = (
        UniqueConstraint("calendar_id", "user_id", name="uq_calendar_members_cal_user"),
        CheckConstraint(
            "permission IN ('read_only', 'create_modify', 'full_access')",
            name="ck_calendar_members_permission",
        ),
        CheckConstraint(
            "status IN ('pending', 'accepted', 'rejected')",
            name="ck_calendar_members_status",
        ),
        Index("ix_calendar_members_user_id", "user_id"),
        Index("ix_calendar_members_calendar_id", "calendar_id"),
        Index("ix_calendar_members_status", "status"),
    )

    id: Mapped[int] = mapped_column(primary_key=True, index=True)
    calendar_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("calendars.id", ondelete="CASCADE"), nullable=False
    )
    user_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False
    )
    invited_by: Mapped[Optional[int]] = mapped_column(
        Integer, ForeignKey("users.id", ondelete="SET NULL"), nullable=True
    )
    permission: Mapped[str] = mapped_column(String(20), nullable=False)
    can_add_others: Mapped[bool] = mapped_column(
        Boolean, default=False, server_default="false"
    )
    local_color: Mapped[Optional[str]] = mapped_column(String(20), nullable=True)
    status: Mapped[str] = mapped_column(String(20), nullable=False, default="pending")
    invited_at: Mapped[datetime] = mapped_column(
        DateTime, default=func.now(), server_default=func.now()
    )
    accepted_at: Mapped[Optional[datetime]] = mapped_column(DateTime, nullable=True)

    calendar: Mapped["Calendar"] = relationship(back_populates="members", lazy="raise")
    user: Mapped["User"] = relationship(foreign_keys=[user_id], lazy="raise")
    inviter: Mapped[Optional["User"]] = relationship(
        foreign_keys=[invited_by], lazy="raise"
    )