from datetime import datetime, timezone
from enum import Enum
from typing import TYPE_CHECKING, List, Optional

from sqlalchemy import Column, UniqueConstraint
from sqlalchemy import Enum as SAEnum
from sqlmodel import Field, Relationship, SQLModel

from app.models.order_line import OrderLinePublic

if TYPE_CHECKING:
    from app.models.order_line import OrderLine
    from app.models.participant import Participant
    from app.models.purchase_round import PurchaseRound


class PaymentStatus(str, Enum):
    UNPAID = "unpaid"
    PAID = "paid"


class OrderBase(SQLModel):
    payment_status: PaymentStatus = Field(
        default=PaymentStatus.UNPAID,
        sa_column=Column(
            SAEnum(
                PaymentStatus,
                name="payment_status",
                native_enum=False,
                values_callable=lambda enum_cls: [member.value for member in enum_cls],
            ),
            nullable=False,
        ),
    )
    paid_at: Optional[datetime] = Field(default=None)
    created_at: datetime = Field(default_factory=lambda: datetime.now(timezone.utc))


class Order(OrderBase, table=True):
    __tablename__ = "orders"
    __table_args__ = (UniqueConstraint("purchase_round_id", "order_number", name="uq_order_round_order_number"),)

    id: Optional[int] = Field(default=None, primary_key=True)
    participant_id: int = Field(foreign_key="participant.id", ondelete="CASCADE")
    purchase_round_id: int = Field(foreign_key="purchase_round.id", ondelete="CASCADE")
    order_number: int = Field()

    participant: "Participant" = Relationship(back_populates="orders")
    purchase_round: "PurchaseRound" = Relationship(back_populates="orders")
    order_lines: List["OrderLine"] = Relationship(
        back_populates="order", sa_relationship_kwargs={"cascade": "all, delete-orphan"}
    )


class OrderPublic(OrderBase):
    id: int
    participant_id: int
    purchase_round_id: int
    order_number: int


class OrderConfirmation(OrderPublic):
    order_lines: List[OrderLinePublic]