"""Station and StationRecipeAssignment models.

A Station represents a physical control point (typically one per tablet/PC).
Recipes are assigned to stations so that each station only sees the products
it is supposed to inspect.
"""
from datetime import datetime
from typing import TYPE_CHECKING, Optional

from sqlalchemy import Boolean, DateTime, ForeignKey, Integer, String, Text, UniqueConstraint, func
from sqlalchemy.orm import Mapped, mapped_column, relationship

from src.backend.database import Base

if TYPE_CHECKING:
    from src.backend.models.orm.recipe import Recipe


class Station(Base):
    __tablename__ = "stations"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    code: Mapped[str] = mapped_column(String(100), nullable=False, index=True)
    name: Mapped[str] = mapped_column(String(255), nullable=False)
    location: Mapped[Optional[str]] = mapped_column(String(255), nullable=True)
    notes: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
    active: Mapped[bool] = mapped_column(Boolean, nullable=False, default=True, index=True)
    created_by: Mapped[int] = mapped_column(Integer, ForeignKey("users.id"), nullable=False)
    created_at: Mapped[datetime] = mapped_column(
        DateTime, nullable=False, server_default=func.now()
    )

    assignments: Mapped[list["StationRecipeAssignment"]] = relationship(
        back_populates="station", cascade="all, delete-orphan", lazy="selectin"
    )

    __table_args__ = (
        UniqueConstraint("code", name="uq_stations_code"),
        {"mysql_engine": "InnoDB", "mysql_charset": "utf8mb4"},
    )

    def __repr__(self) -> str:
        return f"<Station {self.code} '{self.name}'>"


class StationRecipeAssignment(Base):
    __tablename__ = "station_recipe_assignments"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    station_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("stations.id", ondelete="CASCADE"), nullable=False, index=True
    )
    recipe_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("recipes.id", ondelete="CASCADE"), nullable=False, index=True
    )
    assigned_by: Mapped[int] = mapped_column(Integer, ForeignKey("users.id"), nullable=False)
    assigned_at: Mapped[datetime] = mapped_column(
        DateTime, nullable=False, server_default=func.now()
    )

    station: Mapped["Station"] = relationship(back_populates="assignments")
    recipe: Mapped["Recipe"] = relationship(lazy="selectin")

    __table_args__ = (
        UniqueConstraint("station_id", "recipe_id", name="uq_station_recipe"),
        {"mysql_engine": "InnoDB", "mysql_charset": "utf8mb4"},
    )

    def __repr__(self) -> str:
        return f"<StationRecipeAssignment station={self.station_id} recipe={self.recipe_id}>"
