from sqlalchemy import Column, String, Boolean, Integer, Numeric, ForeignKey
from sqlalchemy.orm import relationship
from app.core.database.db_session import Base

class Part(Base):
    __tablename__ = "parts"

    part_id = Column(String(26), primary_key=True)
    sku = Column(String(100), unique=True, nullable=False)
    name = Column(String(255), nullable=False)
    cost_price = Column(Numeric(10, 2), nullable=False)
    low_stock_alert = Column(Integer, default=3)
    supplier = Column(String(255), nullable=True)
    barcode = Column(String(100), unique=True, nullable=True)
    is_active = Column(Boolean, default=True)

    compatibilities = relationship("PartDeviceCompatibility", back_populates="part", cascade="all, delete-orphan")
    bom_variants = relationship("RepairVariantPart", back_populates="part", cascade="all, delete-orphan")

class PartDeviceCompatibility(Base):
    __tablename__ = "part_device_compatibility"

    id = Column(String(26), primary_key=True)
    part_id = Column(String(26), ForeignKey("parts.part_id", ondelete="CASCADE"), nullable=False)
    model_id = Column(String(26), nullable=False)

    part = relationship("Part", back_populates="compatibilities")
    model = relationship("DeviceModel", primaryjoin="DeviceModel.model_id == PartDeviceCompatibility.model_id", foreign_keys=[model_id])

class RepairVariantPart(Base):
    __tablename__ = "repair_variant_parts"

    id = Column(String(26), primary_key=True)
    variant_id = Column(String(26), ForeignKey("repair_variants.variant_id", ondelete="CASCADE"), nullable=False)
    part_id = Column(String(26), ForeignKey("parts.part_id", ondelete="RESTRICT"), nullable=False)
    quantity = Column(Integer, default=1, nullable=False)

    variant = relationship("RepairVariant", back_populates="bom_parts")
    part = relationship("Part", back_populates="bom_variants")