first upload

backend/app/database.py

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+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker, declarative_base
+import os
+
+DATABASE_URL = os.getenv("DATABASE_URL", "sqlite:///./drugs.db")
+
+# For SQLite, ensure the directory exists
+if "sqlite" in DATABASE_URL:
+    # Extract path from sqlite:/// URL
+    db_path = DATABASE_URL.replace("sqlite:///", "")
+    os.makedirs(os.path.dirname(db_path) or ".", exist_ok=True)
+
+engine = create_engine(
+    DATABASE_URL,
+    connect_args={"check_same_thread": False} if "sqlite" in DATABASE_URL else {}
+)
+
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+Base = declarative_base()
+
+# Drop and recreate all tables (for development only)
+Base.metadata.drop_all(bind=engine)
+Base.metadata.create_all(bind=engine)
+
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

backend/app/main.py

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+from fastapi import FastAPI, Depends, HTTPException, APIRouter
+from fastapi.middleware.cors import CORSMiddleware
+from sqlalchemy.orm import Session
+from typing import List, Optional
+from datetime import datetime
+from .database import engine, get_db, Base
+from .models import Drug, DrugVariant, Dispensing
+from pydantic import BaseModel
+
+# Create tables
+Base.metadata.create_all(bind=engine)
+
+app = FastAPI(title="Drug Inventory API")
+
+# CORS middleware for frontend
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],  # In production, restrict this
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Create a router with /api prefix
+router = APIRouter(prefix="/api")
+
+# Pydantic schemas
+class DrugCreate(BaseModel):
+    name: str
+    description: str = None
+
+class DrugUpdate(BaseModel):
+    name: str = None
+    description: str = None
+
+class DrugResponse(BaseModel):
+    id: int
+    name: str
+    description: str = None
+    
+    class Config:
+        from_attributes = True
+
+class DrugVariantCreate(BaseModel):
+    strength: str
+    quantity: float
+    unit: str = "units"
+    low_stock_threshold: float = 10
+
+class DrugVariantUpdate(BaseModel):
+    strength: str = None
+    quantity: float = None
+    unit: str = None
+    low_stock_threshold: float = None
+
+class DrugVariantResponse(BaseModel):
+    id: int
+    drug_id: int
+    strength: str
+    quantity: float
+    unit: str
+    low_stock_threshold: float
+    
+    class Config:
+        from_attributes = True
+
+class DrugWithVariantsResponse(BaseModel):
+    id: int
+    name: str
+    description: str = None
+    variants: List[DrugVariantResponse] = []
+    
+    class Config:
+        from_attributes = True
+
+class DispensingCreate(BaseModel):
+    drug_variant_id: int
+    quantity: float
+    animal_name: str
+    user_name: str
+    notes: Optional[str] = None
+
+class DispensingResponse(BaseModel):
+    id: int
+    drug_variant_id: int
+    quantity: float
+    animal_name: str
+    user_name: str
+    notes: Optional[str] = None
+    dispensed_at: datetime
+    
+    class Config:
+        from_attributes = True
+
+# Routes
+@router.get("/")
+def read_root():
+    return {"message": "Drug Inventory API"}
+
+@router.get("/drugs", response_model=List[DrugWithVariantsResponse])
+def list_drugs(db: Session = Depends(get_db)):
+    """Get all drugs with their variants"""
+    drugs = db.query(Drug).all()
+    result = []
+    for drug in drugs:
+        variants = db.query(DrugVariant).filter(DrugVariant.drug_id == drug.id).all()
+        drug_dict = drug.__dict__.copy()
+        drug_dict['variants'] = variants
+        result.append(drug_dict)
+    return result
+
+@router.get("/drugs/low-stock", response_model=List[DrugWithVariantsResponse])
+def low_stock_drugs(db: Session = Depends(get_db)):
+    """Get drugs with low stock variants"""
+    # Get variants that are low on stock
+    low_stock_variants = db.query(DrugVariant).filter(
+        DrugVariant.quantity <= DrugVariant.low_stock_threshold
+    ).all()
+    
+    # Get unique drug IDs
+    drug_ids = list(set(v.drug_id for v in low_stock_variants))
+    drugs = db.query(Drug).filter(Drug.id.in_(drug_ids)).all()
+    
+    result = []
+    for drug in drugs:
+        variants = [v for v in low_stock_variants if v.drug_id == drug.id]
+        drug_dict = drug.__dict__.copy()
+        drug_dict['variants'] = variants
+        result.append(drug_dict)
+    return result
+
+@router.get("/drugs/{drug_id}", response_model=DrugWithVariantsResponse)
+def get_drug(drug_id: int, db: Session = Depends(get_db)):
+    """Get a specific drug with its variants"""
+    drug = db.query(Drug).filter(Drug.id == drug_id).first()
+    if not drug:
+        raise HTTPException(status_code=404, detail="Drug not found")
+    
+    variants = db.query(DrugVariant).filter(DrugVariant.drug_id == drug.id).all()
+    drug_dict = drug.__dict__.copy()
+    drug_dict['variants'] = variants
+    return drug_dict
+
+@router.post("/drugs", response_model=DrugWithVariantsResponse)
+def create_drug(drug: DrugCreate, db: Session = Depends(get_db)):
+    """Create a new drug"""
+    # Check if drug name already exists
+    existing = db.query(Drug).filter(Drug.name == drug.name).first()
+    if existing:
+        raise HTTPException(status_code=400, detail="Drug with this name already exists")
+    
+    db_drug = Drug(name=drug.name, description=drug.description)
+    db.add(db_drug)
+    db.commit()
+    db.refresh(db_drug)
+    
+    # Return drug with empty variants list
+    drug_dict = db_drug.__dict__.copy()
+    drug_dict['variants'] = []
+    return drug_dict
+
+@router.put("/drugs/{drug_id}", response_model=DrugWithVariantsResponse)
+def update_drug(drug_id: int, drug_update: DrugUpdate, db: Session = Depends(get_db)):
+    """Update a drug"""
+    drug = db.query(Drug).filter(Drug.id == drug_id).first()
+    if not drug:
+        raise HTTPException(status_code=404, detail="Drug not found")
+    
+    for field, value in drug_update.dict(exclude_unset=True).items():
+        setattr(drug, field, value)
+    
+    db.commit()
+    db.refresh(drug)
+    
+    variants = db.query(DrugVariant).filter(DrugVariant.drug_id == drug.id).all()
+    drug_dict = drug.__dict__.copy()
+    drug_dict['variants'] = variants
+    return drug_dict
+
+@router.delete("/drugs/{drug_id}")
+def delete_drug(drug_id: int, db: Session = Depends(get_db)):
+    """Delete a drug and all its variants"""
+    drug = db.query(Drug).filter(Drug.id == drug_id).first()
+    if not drug:
+        raise HTTPException(status_code=404, detail="Drug not found")
+    
+    # Delete all variants first
+    db.query(DrugVariant).filter(DrugVariant.drug_id == drug_id).delete()
+    # Delete the drug
+    db.delete(drug)
+    db.commit()
+    
+    return {"message": "Drug and all variants deleted successfully"}
+
+# Drug Variant endpoints
+@router.post("/drugs/{drug_id}/variants", response_model=DrugVariantResponse)
+def create_drug_variant(drug_id: int, variant: DrugVariantCreate, db: Session = Depends(get_db)):
+    """Create a new variant for a drug"""
+    # Check if drug exists
+    drug = db.query(Drug).filter(Drug.id == drug_id).first()
+    if not drug:
+        raise HTTPException(status_code=404, detail="Drug not found")
+    
+    # Check if variant with same strength already exists for this drug
+    existing = db.query(DrugVariant).filter(
+        DrugVariant.drug_id == drug_id,
+        DrugVariant.strength == variant.strength
+    ).first()
+    if existing:
+        raise HTTPException(status_code=400, detail="Variant with this strength already exists for this drug")
+    
+    db_variant = DrugVariant(
+        drug_id=drug_id,
+        strength=variant.strength,
+        quantity=variant.quantity,
+        unit=variant.unit,
+        low_stock_threshold=variant.low_stock_threshold
+    )
+    db.add(db_variant)
+    db.commit()
+    db.refresh(db_variant)
+    return db_variant
+
+@router.get("/variants/{variant_id}", response_model=DrugVariantResponse)
+def get_drug_variant(variant_id: int, db: Session = Depends(get_db)):
+    """Get a specific drug variant"""
+    variant = db.query(DrugVariant).filter(DrugVariant.id == variant_id).first()
+    if not variant:
+        raise HTTPException(status_code=404, detail="Drug variant not found")
+    return variant
+
+@router.put("/variants/{variant_id}", response_model=DrugVariantResponse)
+def update_drug_variant(variant_id: int, variant_update: DrugVariantUpdate, db: Session = Depends(get_db)):
+    """Update a drug variant"""
+    variant = db.query(DrugVariant).filter(DrugVariant.id == variant_id).first()
+    if not variant:
+        raise HTTPException(status_code=404, detail="Drug variant not found")
+    
+    for field, value in variant_update.dict(exclude_unset=True).items():
+        setattr(variant, field, value)
+    
+    db.commit()
+    db.refresh(variant)
+    return variant
+
+@router.delete("/variants/{variant_id}")
+def delete_drug_variant(variant_id: int, db: Session = Depends(get_db)):
+    """Delete a drug variant"""
+    variant = db.query(DrugVariant).filter(DrugVariant.id == variant_id).first()
+    if not variant:
+        raise HTTPException(status_code=404, detail="Drug variant not found")
+    
+    db.delete(variant)
+    db.commit()
+    
+    return {"message": "Drug variant deleted successfully"}
+
+# Dispensing endpoints
+@router.post("/dispense", response_model=DispensingResponse)
+def dispense_drug(dispensing: DispensingCreate, db: Session = Depends(get_db)):
+    """Record a drug dispensing and reduce inventory"""
+    # Check if drug variant exists
+    variant = db.query(DrugVariant).filter(DrugVariant.id == dispensing.drug_variant_id).first()
+    if not variant:
+        raise HTTPException(status_code=404, detail="Drug variant not found")
+    
+    # Check if enough quantity available
+    if variant.quantity < dispensing.quantity:
+        raise HTTPException(
+            status_code=400, 
+            detail=f"Insufficient quantity. Available: {variant.quantity}, Requested: {dispensing.quantity}"
+        )
+    
+    # Reduce variant quantity
+    variant.quantity -= dispensing.quantity
+    db.commit()
+    
+    # Create dispensing record
+    db_dispensing = Dispensing(**dispensing.dict())
+    db.add(db_dispensing)
+    db.commit()
+    db.refresh(db_dispensing)
+    return db_dispensing
+
+@router.get("/dispense/history", response_model=List[DispensingResponse])
+def list_dispensings(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):
+    """Get dispensing records (audit log)"""
+    return db.query(Dispensing).order_by(Dispensing.dispensed_at.desc()).offset(skip).limit(limit).all()
+
+@router.get("/drugs/{drug_id}/dispense/history", response_model=List[DispensingResponse])
+def get_drug_dispensings(drug_id: int, db: Session = Depends(get_db)):
+    """Get dispensing history for a specific drug (all variants)"""
+    # Verify drug exists
+    drug = db.query(Drug).filter(Drug.id == drug_id).first()
+    if not drug:
+        raise HTTPException(status_code=404, detail="Drug not found")
+    
+    # Get all variant IDs for this drug
+    variant_ids = db.query(DrugVariant.id).filter(DrugVariant.drug_id == drug_id).subquery()
+    
+    return db.query(Dispensing).filter(Dispensing.drug_variant_id.in_(variant_ids)).order_by(Dispensing.dispensed_at.desc()).all()
+
+@router.get("/variants/{variant_id}/dispense/history", response_model=List[DispensingResponse])
+def get_variant_dispensings(variant_id: int, db: Session = Depends(get_db)):
+    """Get dispensing history for a specific drug variant"""
+    # Verify variant exists
+    variant = db.query(DrugVariant).filter(DrugVariant.id == variant_id).first()
+    if not variant:
+        raise HTTPException(status_code=404, detail="Drug variant not found")
+    
+    return db.query(Dispensing).filter(Dispensing.drug_variant_id == variant_id).order_by(Dispensing.dispensed_at.desc()).all()
+
+# Include router with /api prefix
+app.include_router(router)

backend/app/models.py

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+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)