from datetime import datetime

from sqlalchemy import Column, DateTime, Float, ForeignKey, Integer, String, Text
from sqlalchemy.orm import relationship

from .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, nullable=True)
    created_at = Column(DateTime, default=datetime.utcnow)

    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), nullable=True)
    email = Column(String(100), nullable=True)
    phone = Column(String(20), nullable=True)
    address = Column(Text, nullable=True)
    created_at = Column(DateTime, default=datetime.utcnow)

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

class InventoryItem(Base):
    __tablename__ = "inventory_items"

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

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