import enum
import uuid
from datetime import date
from decimal import Decimal

from sqlalchemy import Date, ForeignKey, Numeric, String, UniqueConstraint
from sqlalchemy.dialects.postgresql import ENUM as PgEnum, UUID
from sqlalchemy.orm import Mapped, mapped_column

from app.db.base import Base


class ObjektpositionStatus(str, enum.Enum):
    aktiv = "aktiv"
    entfernt = "entfernt"


objektposition_status_pg = PgEnum(
    ObjektpositionStatus, name="objektposition_status", create_type=False
)


class Objektposition(Base):
    """Prompt 10: Ist-Bestand + individuelle Soll-Abweichung je Objekt/Material.
    UUID-PK (Karte 13: sync-relevant, siehe ergebnisse/20_datenbank_schema.md)."""

    __tablename__ = "objektposition"
    __table_args__ = (UniqueConstraint("objekt_id", "material_id"),)

    id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    objekt_id: Mapped[int] = mapped_column(ForeignKey("objekt.id"), nullable=False)
    material_id: Mapped[int] = mapped_column(ForeignKey("material.id"), nullable=False)
    # NULL = Sollmenge folgt dynamisch der aktuellen Vorlagenposition (Prompt 10).
    sollmenge_override: Mapped[Decimal | None] = mapped_column(Numeric)
    ist_status: Mapped[ObjektpositionStatus] = mapped_column(
        objektposition_status_pg, nullable=False, default=ObjektpositionStatus.aktiv
    )
    istmenge: Mapped[Decimal] = mapped_column(Numeric, nullable=False, default=0)
    seriennummer: Mapped[str | None] = mapped_column(String)
    ablaufdatum: Mapped[date | None] = mapped_column(Date)
    chargennummer: Mapped[str | None] = mapped_column(String)