from sqlalchemy import Column, Integer, String, Float, DateTime, ForeignKey, Text
from sqlalchemy.orm import relationship
from sqlalchemy.sql import func
from app.db.base import Base


class Category(Base):
    __tablename__ = "categories"

    id = Column(Integer, primary_key=True, index=True)
    name = Column(String(100), unique=True, index=True, nullable=False)
    description = Column(Text)
    created_at = Column(DateTime(timezone=True), server_default=func.now())
    updated_at = Column(DateTime(timezone=True), onupdate=func.now())

    items = relationship("InventoryItem", back_populates="category")


class Supplier(Base):
    __tablename__ = "suppliers"

    id = Column(Integer, primary_key=True, index=True)
    name = Column(String(200), unique=True, index=True, nullable=False)
    contact_person = Column(String(100))
    email = Column(String(100))
    phone = Column(String(20))
    address = Column(Text)
    created_at = Column(DateTime(timezone=True), server_default=func.now())
    updated_at = Column(DateTime(timezone=True), onupdate=func.now())

    items = relationship("InventoryItem", back_populates="supplier")


class InventoryItem(Base):
    __tablename__ = "inventory_items"

    id = Column(Integer, primary_key=True, index=True)
    name = Column(String(200), index=True, nullable=False)
    sku = Column(String(50), unique=True, index=True, nullable=False)
    description = Column(Text)
    category_id = Column(Integer, ForeignKey("categories.id"))
    supplier_id = Column(Integer, ForeignKey("suppliers.id"))
    quantity = Column(Integer, default=0)
    min_quantity = Column(Integer, default=0)
    unit_price = Column(Float, nullable=False)
    created_at = Column(DateTime(timezone=True), server_default=func.now())
    updated_at = Column(DateTime(timezone=True), onupdate=func.now())

    category = relationship("Category", back_populates="items")
    supplier = relationship("Supplier", back_populates="items")