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

class InventoryType(enum.Enum):
    ink = "ink"
    paper = "paper"
    garment = "garment"
    other = "other"

class InventoryItem(Base):
    __tablename__ = "inventory_items"
    id = Column(Integer, primary_key=True, index=True)
    sku = Column(String(100), unique=True, nullable=True)
    name = Column(String(255), nullable=False)
    type = Column(Enum(InventoryType), nullable=False)
    unit = Column(String(50), nullable=True)
    quantity_on_hand = Column(Float, nullable=False, default=0.0)
    min_threshold = Column(Float, nullable=True)
    location = Column(String(255), nullable=True)
    supplier_id = Column(Integer, ForeignKey("suppliers.id"), nullable=True)
    created_at = Column(DateTime(timezone=True), server_default=func.now())

    movements = relationship("InventoryMovement", back_populates="item")
    reservations = relationship("InventoryReservation", back_populates="item")
    components = relationship("ProductComponent", back_populates="inventory_item")

class InventoryMovement(Base):
    __tablename__ = "inventory_movements"
    id = Column(Integer, primary_key=True, index=True)
    inventory_item_id = Column(Integer, ForeignKey("inventory_items.id"), nullable=False)
    change_qty = Column(Float, nullable=False)
    movement_type = Column(String(50), nullable=False)
    reference_type = Column(String(50), nullable=True)
    reference_id = Column(Integer, nullable=True)
    notes = Column(Text, nullable=True)
    created_at = Column(DateTime(timezone=True), server_default=func.now())

    item = relationship("InventoryItem", back_populates="movements")

class InventoryReservation(Base):
    __tablename__ = "inventory_reservations"
    id = Column(Integer, primary_key=True, index=True)
    order_item_id = Column(Integer, ForeignKey("order_items.id"), nullable=False)
    inventory_item_id = Column(Integer, ForeignKey("inventory_items.id"), nullable=False)
    qty_reserved = Column(Float, nullable=False)
    created_at = Column(DateTime(timezone=True), server_default=func.now())
    released_at = Column(DateTime(timezone=True), nullable=True)
    consumed_at = Column(DateTime(timezone=True), nullable=True)

    item = relationship("InventoryItem", back_populates="reservations")


class Supplier(Base):
    __tablename__ = "suppliers"
    id = Column(Integer, primary_key=True, index=True)
    name = Column(String(255), nullable=False)
    contact_info = Column(Text, nullable=True)
    created_at = Column(DateTime(timezone=True), server_default=func.now())