from __future__ import annotations

from datetime import datetime, timezone
from decimal import Decimal
from enum import Enum

from sqlalchemy import CheckConstraint, DateTime, Enum as SqlEnum, ForeignKey, Numeric
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.models.base import Base


class OrderStatusEnum(str, Enum):
    pending = "pending"
    paid = "paid"


class Order(Base):
    __tablename__ = "orders"
    __table_args__ = (
        CheckConstraint("total_amount >= 0", name="ck_orders_total_amount_non_negative"),
    )

    id: Mapped[int] = mapped_column(primary_key=True)
    user_id: Mapped[int] = mapped_column(ForeignKey("users.id"), nullable=False, index=True)
    total_amount: Mapped[Decimal] = mapped_column(Numeric(10, 2), nullable=False)
    status: Mapped[OrderStatusEnum] = mapped_column(
        SqlEnum(OrderStatusEnum, native_enum=False),
        default=OrderStatusEnum.pending,
        nullable=False,
    )
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        default=lambda: datetime.now(timezone.utc),
        nullable=False,
    )
    paid_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)

    user = relationship("User", back_populates="orders")
    items = relationship(
        "OrderItem",
        back_populates="order",
        cascade="all, delete-orphan",
        lazy="selectin",
    )