from sqlalchemy import Column, Integer, String, Float, DateTime, ForeignKey
from sqlalchemy.sql import func
from .database import Base

class Drug(Base):
    __tablename__ = "drugs"

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


class DrugVariant(Base):
    __tablename__ = "drug_variants"

    id = Column(Integer, primary_key=True, index=True)
    drug_id = Column(Integer, ForeignKey("drugs.id"), nullable=False)
    strength = Column(String, nullable=False)  # e.g., "5.4mg", "16mg", "100ml"
    quantity = Column(Float, nullable=False, default=0)
    unit = Column(String, nullable=False, default="units")  # tablets, bottles, ml, etc
    low_stock_threshold = Column(Float, nullable=False, default=10)
    created_at = Column(DateTime(timezone=True), server_default=func.now())
    updated_at = Column(DateTime(timezone=True), onupdate=func.now(), server_default=func.now())


class Dispensing(Base):
    __tablename__ = "dispensings"

    id = Column(Integer, primary_key=True, index=True)
    drug_variant_id = Column(Integer, ForeignKey("drug_variants.id"), nullable=False)
    quantity = Column(Float, nullable=False)
    animal_name = Column(String, nullable=False)  # Name/ID of the animal
    user_name = Column(String, nullable=False)  # User who dispensed
    dispensed_at = Column(DateTime(timezone=True), server_default=func.now(), index=True)
    notes = Column(String, nullable=True)