app.py

"""
FastAPI Server for Audit Checklist Application
=============================================

This server provides a REST API for managing audit checklists with MongoDB integration.
It supports CRUD operations for checklist data and user management.

Features:
- MongoDB Atlas integration with async Motor driver
- CORS support for React frontend
- Comprehensive error handling
- Health check endpoint
- Environment-based configuration

Author: Audit Checklist Team
Version: 1.0.0
"""

import os
import sys
import base64
from datetime import datetime
from typing import Optional, List, Dict, Any, Union
import logging

# FastAPI imports
from fastapi import FastAPI, HTTPException, status, UploadFile, File
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse

# Pydantic for data validation
from pydantic import BaseModel, Field

# MongoDB async driver
import motor.motor_asyncio
from bson import ObjectId

# Environment variables
from dotenv import load_dotenv

# Load environment variables from .env file
load_dotenv('mongodb.env')

# Configure logging
logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s'
)
logger = logging.getLogger(__name__)

# =============================================================================
# CONFIGURATION AND INITIALIZATION
# =============================================================================

# Environment variables with fallback defaults
MONGODB_URI = os.getenv('MONGODB_URI', 'mongodb://localhost:27017/audit_checklist')
PORT = int(os.getenv('PORT', 8000))  # Hugging Face Spaces uses port 8000
CORS_ORIGIN = os.getenv('CORS_ORIGIN', '*')  # Allow all origins by default for mobile apps

# Initialize FastAPI application
app = FastAPI(
    title="Audit Checklist API",
    description="REST API for managing audit checklists with MongoDB integration",
    version="1.0.0",
    docs_url="/docs",  # Swagger UI documentation
    redoc_url="/redoc"  # ReDoc documentation
)

# Configure CORS middleware
# Allow all origins for Hugging Face Spaces deployment
cors_origins = [CORS_ORIGIN] if CORS_ORIGIN != "*" else ["*"]

app.add_middleware(
    CORSMiddleware,
    allow_origins=cors_origins,
    allow_credentials=True,
    allow_methods=["GET", "POST", "PUT", "DELETE", "OPTIONS"],
    allow_headers=["*"],
)

# MongoDB connection setup
client = None
db = None

async def connect_to_mongodb():
    """
    Establish connection to MongoDB Atlas
    
    This function creates an async connection to MongoDB using the Motor driver.
    It handles connection errors gracefully and logs the status.
    """
    global client, db
    try:
        client = motor.motor_asyncio.AsyncIOMotorClient(MONGODB_URI)
        db = client.audit_checklist
        
        # Test the connection
        await client.admin.command('ping')
        logger.info("Successfully connected to MongoDB Atlas")
        
        # Create indexes for better performance
        await create_database_indexes()
        
    except Exception as e:
        logger.error(f"Failed to connect to MongoDB: {e}")
        raise e

async def create_database_indexes():
    """
    Create database indexes for optimal query performance
    
    This function creates indexes on frequently queried fields to improve
    database performance and query speed.
    """
    try:
        # Index on userId for faster user-specific queries
        await db.checklists.create_index("userId", unique=False)
        
        # Index on createdAt for time-based queries
        await db.checklists.create_index("createdAt", unique=False)
        
        logger.info("Database indexes created successfully")
        
    except Exception as e:
        logger.warning(f"Could not create indexes: {e}")

async def close_mongodb_connection():
    """Close MongoDB connection gracefully"""
    global client
    if client:
        client.close()
        logger.info("MongoDB connection closed")

# =============================================================================
# PYDANTIC MODELS FOR DATA VALIDATION
# =============================================================================

class ChecklistItem(BaseModel):
    """
    Model for individual checklist items
    
    Attributes:
        id: Unique identifier for the item
        requirement: Description of the requirement to be checked
        compliance: Compliance status (N/A, Compliant, Non-Compliant)
        deviation: Description of any deviation found
        action: Action taken to address the issue
        checkedAt: Timestamp when the item was checked
        checkedBy: Name of the person who checked the item
    """
    id: str = Field(..., description="Unique identifier for the checklist item")
    requirement: str = Field(..., description="Description of the requirement")
    compliance: str = Field(default="N/A", description="Compliance status: N/A, Compliant, or Non-Compliant")
    deviation: str = Field(default="", description="Description of any deviation found")
    action: str = Field(default="", description="Action taken to address the issue")
    checkedAt: Optional[datetime] = Field(default=None, description="Timestamp when item was checked")
    checkedBy: str = Field(default="", description="Name of the person who checked the item")

class ChecklistSection(BaseModel):
    """
    Model for checklist sections containing multiple items
    
    Attributes:
        id: Unique identifier for the section
        title: Display title of the section
        icon: Icon identifier for UI display
        items: List of checklist items in this section
    """
    id: str = Field(..., description="Unique identifier for the section")
    title: str = Field(..., description="Display title of the section")
    icon: str = Field(..., description="Icon identifier for UI display")
    items: List[ChecklistItem] = Field(default=[], description="List of checklist items")

class Metadata(BaseModel):
    """
    Metadata model for checklist information
    """
    userName: Optional[str] = Field(default=None, description="Name of the user who saved the checklist")
    savedAt: Optional[str] = Field(default=None, description="ISO timestamp when saved")
    savedAtFormatted: Optional[str] = Field(default=None, description="Formatted timestamp when saved")
    userId: Optional[str] = Field(default=None, description="User ID")
    version: Optional[str] = Field(default="1.0", description="Version of the checklist")

class ChecklistData(BaseModel):
    """
    Complete checklist data model
    
    Attributes:
        userId: Unique identifier for the user
        title: Title of the checklist
        sections: List of sections in the checklist
        totalItems: Total number of items across all sections
        completedItems: Number of completed items
        nonCompliantItems: Number of non-compliant items
        complianceScore: Calculated compliance percentage
        verificationDate: Date when the checklist was verified
        createdAt: Timestamp when the checklist was created
        updatedAt: Timestamp when the checklist was last updated
        imageData: Base64 encoded image data (stored when compliance < 100%)
        imageType: MIME type of the image (e.g., image/jpeg, image/png)
    """
    userId: str = Field(..., description="Unique identifier for the user")
    title: str = Field(..., description="Title of the checklist")
    sections: List[ChecklistSection] = Field(default=[], description="List of checklist sections")
    totalItems: Optional[int] = Field(default=0, description="Total number of items")
    completedItems: Optional[int] = Field(default=0, description="Number of completed items")
    nonCompliantItems: Optional[int] = Field(default=0, description="Number of non-compliant items")
    complianceScore: Optional[float] = Field(default=0.0, description="Compliance percentage score")
    verificationDate: Optional[datetime] = Field(default=None, description="Date of verification")
    createdAt: Optional[datetime] = Field(default=None, description="Creation timestamp")
    updatedAt: Optional[datetime] = Field(default=None, description="Last update timestamp")
    metadata: Optional[Metadata] = Field(default=None, description="Additional metadata including user information")
    imageData: Optional[str] = Field(default=None, description="Base64 encoded image data for non-compliant checklists")
    imageType: Optional[str] = Field(default=None, description="MIME type of the image")
    
    class Config:
        # Allow extra fields that might be sent from frontend
        extra = "allow"

class ChecklistResponse(BaseModel):
    """
    Standard API response model for checklist operations
    
    Attributes:
        success: Boolean indicating if the operation was successful
        data: The checklist data (if successful)
        message: Optional message describing the result
        error: Error message (if unsuccessful)
    """
    success: bool = Field(..., description="Whether the operation was successful")
    data: Optional[Union[ChecklistData, Dict[str, Any]]] = Field(default=None, description="Checklist data")
    message: Optional[str] = Field(default=None, description="Success message")
    error: Optional[str] = Field(default=None, description="Error message")

class HealthResponse(BaseModel):
    """Health check response model"""
    status: str = Field(..., description="Health status")
    timestamp: datetime = Field(..., description="Current timestamp")
    database: str = Field(..., description="Database connection status")
    version: str = Field(default="1.0.0", description="API version")

# =============================================================================
# UTILITY FUNCTIONS
# =============================================================================

def calculate_checklist_metrics(checklist_data: Dict[str, Any]) -> Dict[str, Any]:
    """
    Calculate compliance metrics for a checklist
    
    Args:
        checklist_data: Dictionary containing checklist data
        
    Returns:
        Dictionary with calculated metrics (totalItems, completedItems, nonCompliantItems, complianceScore)
    """
    total_items = 0
    completed_items = 0
    non_compliant_items = 0
    
    # Iterate through all sections and items
    for section in checklist_data.get('sections', []):
        for item in section.get('items', []):
            total_items += 1
            
            # Count completed items (those that are not N/A)
            if item.get('compliance') != 'N/A':
                completed_items += 1
                
                # Count non-compliant items
                if item.get('compliance') == 'Non-Compliant':
                    non_compliant_items += 1
    
    # Calculate compliance score
    compliance_score = (completed_items / total_items * 100) if total_items > 0 else 0
    
    return {
        'totalItems': total_items,
        'completedItems': completed_items,
        'nonCompliantItems': non_compliant_items,
        'complianceScore': round(compliance_score, 2)
    }

def serialize_checklist(checklist_doc: Dict[str, Any]) -> Dict[str, Any]:
    """
    Serialize MongoDB document to JSON-serializable format
    
    Args:
        checklist_doc: MongoDB document
        
    Returns:
        Dictionary with ObjectId converted to string
    """
    if checklist_doc and '_id' in checklist_doc:
        checklist_doc['_id'] = str(checklist_doc['_id'])
    
    # Convert datetime objects to ISO strings
    for field in ['createdAt', 'updatedAt', 'verificationDate']:
        if field in checklist_doc and checklist_doc[field]:
            # Only convert if it's a datetime object, not a string
            if hasattr(checklist_doc[field], 'isoformat'):
                checklist_doc[field] = checklist_doc[field].isoformat()
    
    # Convert datetime objects in items
    for section in checklist_doc.get('sections', []):
        for item in section.get('items', []):
            if 'checkedAt' in item and item['checkedAt']:
                # Only convert if it's a datetime object, not a string
                if hasattr(item['checkedAt'], 'isoformat'):
                    item['checkedAt'] = item['checkedAt'].isoformat()
    
    return checklist_doc

# =============================================================================
# API ENDPOINTS
# =============================================================================

@app.on_event("startup")
async def startup_event():
    """
    Application startup event handler
    
    This function is called when the FastAPI application starts up.
    It initializes the MongoDB connection and sets up the database.
    """
    logger.info("Starting Audit Checklist API server...")
    await connect_to_mongodb()
    logger.info(f"Server ready on port {PORT}")

@app.on_event("shutdown")
async def shutdown_event():
    """
    Application shutdown event handler
    
    This function is called when the FastAPI application shuts down.
    It gracefully closes the MongoDB connection.
    """
    logger.info("Shutting down Audit Checklist API server...")
    await close_mongodb_connection()

@app.get("/", response_model=Dict[str, str])
async def root():
    """
    Root endpoint providing basic API information
    
    Returns:
        Dictionary with API name and version
    """
    return {
        "message": "Audit Checklist API",
        "version": "1.0.0",
        "docs": "/docs",
        "health": "/health"
    }

@app.get("/health", response_model=HealthResponse)
async def health_check():
    """
    Health check endpoint for monitoring and load balancers
    
    This endpoint checks the status of the API server and database connection.
    It's useful for health monitoring, load balancers, and DevOps automation.
    
    Returns:
        HealthResponse with current status information
    """
    try:
        # Test database connection
        await client.admin.command('ping')
        db_status = "connected"
    except Exception as e:
        logger.error(f"Database health check failed: {e}")
        db_status = "disconnected"
    
    return HealthResponse(
        status="healthy" if db_status == "connected" else "unhealthy",
        timestamp=datetime.utcnow(),
        database=db_status,
        version="1.0.0"
    )

@app.get("/api/checklist/{user_id}", response_model=ChecklistResponse)
async def get_checklist(user_id: str):
    """
    Retrieve checklist data for a specific user
    
    This endpoint fetches the checklist data for a given user ID. If no checklist
    exists for the user, it creates a new one with the default structure.
    
    Args:
        user_id: Unique identifier for the user
        
    Returns:
        ChecklistResponse containing the checklist data
        
    Raises:
        HTTPException: If database operation fails
    """
    try:
        logger.info(f"Fetching checklist for user: {user_id}")
        
        # Query the database for the user's checklist
        # Find the most recent checklist for the user
        checklist_doc = await db.checklists.find_one(
            {"userId": user_id},
            sort=[("createdAt", -1)]  # Get the most recent one
        )
        
        if not checklist_doc:
            # Create new checklist if none exists
            logger.info(f"No checklist found for user {user_id}, creating new one")
            
            # Default checklist structure - Complete 38-item audit checklist
            default_checklist = {
                "userId": user_id,
                "title": "Checklist di Audit Operativo (38 Controlli)",
                "sections": [
                    {
                        "id": "S1",
                        "title": "1. PERSONALE E IGIENE (6 Controlli)",
                        "icon": "Users",
                        "items": [
                            {"id": "I1.1", "requirement": "Indumenti da lavoro puliti (divisa, grembiule).", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I1.2", "requirement": "Scarpe antinfortunistiche / Calzature pulite.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I1.3", "requirement": "Cuffie e/o Retine per capelli indossate correttamente.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I1.4", "requirement": "Assenza di gioielli, piercing visibili, unghie lunghe.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I1.5", "requirement": "Lavaggio mani documentato all'ingresso/reingresso.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I1.6", "requirement": "Assenza di cibo/bevande non autorizzate nelle aree produttive.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""}
                        ]
                    },
                    {
                        "id": "S2",
                        "title": "2. STRUTTURE E IMPIANTI (6 Controlli)",
                        "icon": "Building",
                        "items": [
                            {"id": "I2.1", "requirement": "Illuminazione adeguata e funzionante in tutte le aree.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I2.2", "requirement": "Porte esterne/interne in buone condizioni e chiuse correttamente (sigillatura).", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I2.3", "requirement": "Integrità di pavimenti, pareti e soffitti (assenza di crepe/danni).", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I2.4", "requirement": "Controllo vetri / lampade protette o anti-frantumazione.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I2.5", "requirement": "Condizioni igieniche dei servizi igienici e spogliatoi (pulizia e dotazioni).", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I2.6", "requirement": "Ventilazione e aspirazione funzionanti, pulite e non ostruite.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""}
                        ]
                    },
                    {
                        "id": "S3",
                        "title": "3. GESTIONE E IGIENE AMBIENTALE (4 Controlli)",
                        "icon": "Package",
                        "items": [
                            {"id": "I3.1", "requirement": "Contenitori dei rifiuti puliti, chiusi e identificati.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I3.2", "requirement": "Separazione corretta dei rifiuti (es. umido, secco, plastica).", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I3.3", "requirement": "Area di stoccaggio rifiuti (interna ed esterna) ordinata e sanificata.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I3.4", "requirement": "Frequenza di rimozione dei rifiuti adeguata a prevenire accumuli.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""}
                        ]
                    },
                    {
                        "id": "S4",
                        "title": "4. CONTROLLO PROCESSO E QUALITÀ (6 Controlli)",
                        "icon": "Settings",
                        "items": [
                            {"id": "I4.1", "requirement": "Monitoraggio e registrazione dei Punti Critici di Controllo (CCP).", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I4.2", "requirement": "Procedure di Buona Fabbricazione (GMP) rispettate (es. pulizia prima dell'avvio).", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I4.3", "requirement": "Verifica e calibrazione del Metal Detector eseguita e registrata.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I4.4", "requirement": "Corretta identificazione dei lotti di materie prime e semilavorati.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I4.5", "requirement": "Rispettate le temperature di stoccaggio dei prodotti finiti e intermedi.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I4.6", "requirement": "Corretta gestione, etichettatura e isolamento dei prodotti non conformi.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""}
                        ]
                    },
                    {
                        "id": "S5",
                        "title": "5. CONTROLLO INFESTANTI (5 Controlli)",
                        "icon": "Shield",
                        "items": [
                            {"id": "I5.1", "requirement": "Assenza di tracce visibili di roditori, insetti o uccelli.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I5.2", "requirement": "Stazioni di monitoraggio/trappole numerate, integre e registrate.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I5.3", "requirement": "Mappe e registri delle trappole aggiornati e disponibili.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I5.4", "requirement": "Barriere fisiche (es. reti, spazzole) anti-intrusione in buone condizioni.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I5.5", "requirement": "Prodotti chimici di controllo infestanti stoccati in modo sicuro e separato.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""}
                        ]
                    },
                    {
                        "id": "S6",
                        "title": "6. MANUTENZIONE E VETRI (6 Controlli)",
                        "icon": "Settings",
                        "items": [
                            {"id": "I6.1", "requirement": "Piano di manutenzione preventiva e correttiva rispettato e registrato.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I6.2", "requirement": "Lubrificanti e oli utilizzati autorizzati per uso alimentare (se richiesto).", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I6.3", "requirement": "Registri di calibrazione/verifica degli strumenti di misura critici aggiornati.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I6.4", "requirement": "Gestione dei vetri rotti (registri rotture) aggiornata e conforme alla procedura.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I6.5", "requirement": "Assenza di perdite, gocciolamenti o cavi scoperti da impianti/macchinari.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I6.6", "requirement": "Area di deposito utensili e pezzi di ricambio ordinata e pulita.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""}
                        ]
                    },
                    {
                        "id": "S7",
                        "title": "7. DOCUMENTAZIONE E FORMAZIONE (5 Controlli)",
                        "icon": "FileText",
                        "items": [
                            {"id": "I7.1", "requirement": "Documentazione di processo (procedure, istruzioni) aggiornata e disponibile.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I7.2", "requirement": "Registri di formazione del personale aggiornati e verificabili.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I7.3", "requirement": "Certificazioni e attestati del personale validi e aggiornati.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I7.4", "requirement": "Controllo documenti (versioni, distribuzione, obsolescenza) conforme.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""},
                            {"id": "I7.5", "requirement": "Archiviazione e conservazione documenti secondo i requisiti normativi.", "compliance": "N/A", "deviation": "", "action": "", "checkedAt": None, "checkedBy": ""}
                        ]
                    }
                ],
                "totalItems": 38,
                "completedItems": 0,
                "nonCompliantItems": 0,
                "complianceScore": 0.0,
                "verificationDate": None,
                "createdAt": datetime.utcnow(),
                "updatedAt": datetime.utcnow()
            }
            
            # Insert the new checklist
            result = await db.checklists.insert_one(default_checklist)
            checklist_doc = await db.checklists.find_one({"_id": result.inserted_id})
            logger.info(f"Created new checklist for user {user_id}")
        
        # Serialize the document
        serialized_checklist = serialize_checklist(checklist_doc)
        
        return ChecklistResponse(
            success=True,
            data=ChecklistData(**serialized_checklist),
            message="Checklist retrieved successfully"
        )
        
    except Exception as e:
        logger.error(f"Error retrieving checklist for user {user_id}: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to retrieve checklist: {str(e)}"
        )

@app.put("/api/checklist/{user_id}", response_model=ChecklistResponse)
async def save_checklist(user_id: str, checklist_data: dict):
    """
    Save or update checklist data for a specific user
    
    This endpoint saves the checklist data to the database. It calculates
    compliance metrics and updates the timestamp.
    
    Args:
        user_id: Unique identifier for the user
        checklist_data: The checklist data to save
        
    Returns:
        ChecklistResponse confirming the save operation
        
    Raises:
        HTTPException: If database operation fails
    """
    try:
        logger.info(f"Saving checklist for user: {user_id}")
        
        # Use the dictionary directly (already converted from JSON)
        checklist_dict = checklist_data.copy()
        
        # Calculate compliance metrics
        metrics = calculate_checklist_metrics(checklist_dict)
        checklist_dict.update(metrics)
        
        # Handle image data for non-compliant checklists
        compliance_score = metrics.get('complianceScore', 0.0)
        if compliance_score < 100.0 and 'collectedImages' in checklist_dict and checklist_dict['collectedImages']:
            # Process collected images from individual items
            collected_images = checklist_dict['collectedImages']
            logger.info(f"Storing {len(collected_images)} images for non-compliant checklist (score: {compliance_score}%)")
            
            # Store the collected images in the checklist data
            checklist_dict['imageData'] = collected_images
            checklist_dict['imageType'] = 'multiple_items'
        elif compliance_score < 100.0:
            logger.info(f"No image data provided for non-compliant checklist (score: {compliance_score}%)")
        
        # Update timestamps
        checklist_dict['updatedAt'] = datetime.utcnow()
        
        # Check if this is an update to existing checklist or new save
        existing_checklist = await db.checklists.find_one({"userId": user_id})
        
        if existing_checklist:
            # Update existing checklist
            checklist_dict['createdAt'] = existing_checklist.get('createdAt', datetime.utcnow())
            
            # Remove _id if it exists to prevent immutable field error
            if '_id' in checklist_dict:
                del checklist_dict['_id']
            
            result = await db.checklists.update_one(
                {"userId": user_id},
                {"$set": checklist_dict}
            )
            
            if result.modified_count > 0:
                logger.info(f"Updated existing checklist for user {user_id}")
                message = "Checklist updated successfully"
            else:
                logger.error(f"Failed to update checklist for user {user_id}")
                raise HTTPException(
                    status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
                    detail="Failed to update checklist"
                )
        else:
            # Create new checklist
            checklist_dict['createdAt'] = datetime.utcnow()
            
            # Remove _id if it exists to let MongoDB generate a new one
            if '_id' in checklist_dict:
                del checklist_dict['_id']
            
            result = await db.checklists.insert_one(checklist_dict)
            
            if result.inserted_id:
                logger.info(f"Created new checklist for user {user_id}")
                message = "Checklist created successfully"
            else:
                logger.error(f"Failed to create checklist for user {user_id}")
                raise HTTPException(
                    status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
                    detail="Failed to save checklist"
                )
        
        # Retrieve the updated/created checklist
        if existing_checklist:
            # For updates, get the updated document
            updated_checklist = await db.checklists.find_one({"userId": user_id})
            serialized_checklist = serialize_checklist(updated_checklist)
        else:
            # For new checklists, get the newly created document
            created_checklist = await db.checklists.find_one({"_id": result.inserted_id})
            serialized_checklist = serialize_checklist(created_checklist)
        
        return ChecklistResponse(
            success=True,
            data=serialized_checklist,  # Return as dict instead of Pydantic model
            message=message
        )
        
    except Exception as e:
        logger.error(f"Error saving checklist for user {user_id}: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to save checklist: {str(e)}"
        )

@app.get("/api/checklists/by-user/{user_name}", response_model=Dict[str, Any])
async def get_checklists_by_user_name(user_name: str):
    """
    Retrieve all checklists for a specific user name
    
    Args:
        user_name: The name of the user to retrieve checklists for
        
    Returns:
        Dictionary containing list of checklists for the user
        
    Raises:
        HTTPException: If database operation fails
    """
    try:
        logger.info(f"Retrieving checklists for user: {user_name}")
        
        # Find all checklists where metadata.userName matches
        cursor = db.checklists.find({"metadata.userName": user_name})
        checklists = []
        
        async for checklist_doc in cursor:
            serialized_checklist = serialize_checklist(checklist_doc)
            checklists.append(serialized_checklist)
        
        return {
            "success": True,
            "data": checklists,
            "count": len(checklists),
            "user_name": user_name
        }
        
    except Exception as e:
        logger.error(f"Error retrieving checklists for user {user_name}: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to retrieve checklists for user: {str(e)}"
        )

@app.post("/api/checklist/{user_id}/image")
async def upload_checklist_image(user_id: str, image: UploadFile = File(...)):
    """
    Upload an image for a checklist (for non-compliant cases)
    
    Args:
        user_id: Unique identifier for the user
        image: The image file to upload
        
    Returns:
        Dictionary containing the base64 encoded image data and metadata
    """
    try:
        logger.info(f"Uploading image for user: {user_id}")
        
        # Validate image file type
        allowed_types = ["image/jpeg", "image/jpg", "image/png", "image/gif", "image/webp"]
        if image.content_type not in allowed_types:
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail=f"Invalid image type. Allowed types: {', '.join(allowed_types)}"
            )
        
        # Read image data
        image_data = await image.read()
        
        # Encode to base64
        base64_data = base64.b64encode(image_data).decode('utf-8')
        
        # Create data URL
        data_url = f"data:{image.content_type};base64,{base64_data}"
        
        logger.info(f"Image uploaded successfully for user {user_id}, size: {len(image_data)} bytes")
        
        return {
            "success": True,
            "data": {
                "imageData": base64_data,
                "imageType": image.content_type,
                "dataUrl": data_url,
                "size": len(image_data),
                "filename": image.filename
            },
            "message": "Image uploaded successfully"
        }
        
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error uploading image for user {user_id}: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to upload image: {str(e)}"
        )

async def ensure_default_template_exists():
    """
    Ensure the default template exists in the database.
    Creates it if it doesn't exist.
    """
    try:
        logger.info("Checking if default template exists...")
        # Check if template exists (check both old and new IDs)
        template = await db.checklist_templates.find_one({
            "$or": [
                {"templateId": "default"},
                {"templateId": "default-audit-checklist"}
            ]
        })
        
        if not template:
            logger.info("Default template not found, creating it now...")
            
            # Create the default template
            default_template = {
                "templateId": "default",
                "title": "Checklist di Audit Operativo",
                "sections": [
                    {
                        "id": "S1",
                        "title": "1. PERSONALE E IGIENE",
                        "icon": "Users",
                        "items": [
                            {"id": "I1.1", "requirement": "Indumenti da lavoro puliti (divisa, grembiule)."},
                            {"id": "I1.2", "requirement": "Scarpe antinfortunistiche / Calzature pulite."},
                            {"id": "I1.3", "requirement": "Cuffie e/o Retine per capelli indossate correttamente."},
                            {"id": "I1.4", "requirement": "Assenza di gioielli, piercing visibili, unghie lunghe."},
                            {"id": "I1.5", "requirement": "Lavaggio mani documentato all'ingresso/reingresso."},
                            {"id": "I1.6", "requirement": "Assenza di cibo/bevande non autorizzate nelle aree produttive."},
                        ],
                    },
                    {
                        "id": "S2",
                        "title": "2. STRUTTURE E IMPIANTI",
                        "icon": "Building",
                        "items": [
                            {"id": "I2.1", "requirement": "Illuminazione adeguata e funzionante in tutte le aree."},
                            {"id": "I2.2", "requirement": "Porte esterne/interne in buone condizioni e chiuse correttamente (sigillatura)."},
                            {"id": "I2.3", "requirement": "Integrità di pavimenti, pareti e soffitti (assenza di crepe/danni)."},
                            {"id": "I2.4", "requirement": "Controllo vetri / lampade protette o anti-frantumazione."},
                            {"id": "I2.5", "requirement": "Condizioni igieniche dei servizi igienici e spogliatoi (pulizia e dotazioni)."},
                            {"id": "I2.6", "requirement": "Ventilazione e aspirazione funzionanti, pulite e non ostruite."},
                        ],
                    },
                    {
                        "id": "S3",
                        "title": "3. GESTIONE E IGIENE AMBIENTALE",
                        "icon": "Package",
                        "items": [
                            {"id": "I3.1", "requirement": "Contenitori dei rifiuti puliti, chiusi e identificati."},
                            {"id": "I3.2", "requirement": "Separazione corretta dei rifiuti (es. umido, secco, plastica)."},
                            {"id": "I3.3", "requirement": "Area di stoccaggio rifiuti (interna ed esterna) ordinata e sanificata."},
                            {"id": "I3.4", "requirement": "Frequenza di rimozione dei rifiuti adeguata a prevenire accumuli."},
                        ],
                    },
                    {
                        "id": "S4",
                        "title": "4. CONTROLLO PROCESSO E QUALITÀ",
                        "icon": "Settings",
                        "items": [
                            {"id": "I4.1", "requirement": "Monitoraggio e registrazione dei Punti Critici di Controllo (CCP)."},
                            {"id": "I4.2", "requirement": "Procedure di Buona Fabbricazione (GMP) rispettate (es. pulizia prima dell'avvio)."},
                            {"id": "I4.3", "requirement": "Verifica e calibrazione del Metal Detector eseguita e registrata."},
                            {"id": "I4.4", "requirement": "Corretta identificazione dei lotti di materie prime e semilavorati."},
                            {"id": "I4.5", "requirement": "Rispettate le temperature di stoccaggio dei prodotti finiti e intermedi."},
                            {"id": "I4.6", "requirement": "Corretta gestione, etichettatura e isolamento dei prodotti non conformi."},
                        ],
                    },
                    {
                        "id": "S5",
                        "title": "5. CONTROLLO INFESTANTI",
                        "icon": "Shield",
                        "items": [
                            {"id": "I5.1", "requirement": "Assenza di tracce visibili di roditori, insetti o uccelli."},
                            {"id": "I5.2", "requirement": "Stazioni di monitoraggio/trappole numerate, integre e registrate."},
                            {"id": "I5.3", "requirement": "Mappe e registri delle trappole aggiornati e disponibili."},
                            {"id": "I5.4", "requirement": "Barriere fisiche (es. reti, spazzole) anti-intrusione in buone condizioni."},
                            {"id": "I5.5", "requirement": "Prodotti chimici di controllo infestanti stoccati in modo sicuro e separato."},
                        ],
                    },
                    {
                        "id": "S6",
                        "title": "6. MANUTENZIONE E VETRI",
                        "icon": "Settings",
                        "items": [
                            {"id": "I6.1", "requirement": "Piano di manutenzione preventiva e correttiva rispettato e registrato."},
                            {"id": "I6.2", "requirement": "Lubrificanti e oli utilizzati autorizzati per uso alimentare (se richiesto)."},
                            {"id": "I6.3", "requirement": "Registri di calibrazione/verifica degli strumenti di misura critici aggiornati."},
                            {"id": "I6.4", "requirement": "Gestione dei vetri rotti (registri rotture) aggiornata e conforme alla procedura."},
                            {"id": "I6.5", "requirement": "Assenza di perdite, gocciolamenti o cavi scoperti da impianti/macchinari."},
                            {"id": "I6.6", "requirement": "Area di deposito utensili e pezzi di ricambio ordinata e pulita."},
                        ],
                    },
                    {
                        "id": "S7",
                        "title": "7. DOCUMENTAZIONE E FORMAZIONE",
                        "icon": "FileText",
                        "items": [
                            {"id": "I7.1", "requirement": "Documentazione di processo (procedure, istruzioni) aggiornata e disponibile."},
                            {"id": "I7.2", "requirement": "Registri di formazione del personale aggiornati e verificabili."},
                            {"id": "I7.3", "requirement": "Certificazioni e attestati del personale validi e aggiornati."},
                            {"id": "I7.4", "requirement": "Controllo documenti (versioni, distribuzione, obsolescenza) conforme."},
                            {"id": "I7.5", "requirement": "Archiviazione e conservazione documenti secondo i requisiti normativi."},
                        ],
                    },
                ],
                "metadata": {
                    "createdAt": datetime.utcnow().isoformat(),
                    "updatedAt": datetime.utcnow().isoformat(),
                }
            }
            
            result = await db.checklist_templates.insert_one(default_template)
            logger.info(f"✅ Successfully created default template with ID: {result.inserted_id}")
            # Fetch the newly created template to return with _id
            template = await db.checklist_templates.find_one({"templateId": "default"})
            return template
        else:
            logger.info("✅ Default template already exists in database")
            return template
            
    except Exception as e:
        logger.error(f"❌ Error ensuring default template exists: {e}", exc_info=True)
        return None

@app.get("/api/checklist-template/default", response_model=Dict[str, Any])
async def get_default_checklist_template():
    """
    Get the default checklist template
    
    Returns:
        Dictionary containing the default checklist template structure
        
    Raises:
        HTTPException: If template not found or database operation fails
    """
    try:
        logger.info("📋 GET /api/checklist-template/default - Retrieving default checklist template")
        
        # Ensure template exists (creates if not found)
        template_doc = await ensure_default_template_exists()
        logger.info(f"Template check result: {'Found' if template_doc else 'Not Found'}")
        
        if not template_doc:
            # Fallback to looking for old template ID
            logger.info("Checking for old template ID: default-audit-checklist")
            template_doc = await db.checklist_templates.find_one({"templateId": "default-audit-checklist"})
        
        if not template_doc:
            # If template doesn't exist, create it from the hardcoded structure
            logger.info("Default template not found, creating from hardcoded structure")
            
            # Use the same structure as in get_checklist but mark as template
            default_template = {
                "templateId": "default-audit-checklist",
                "title": "Checklist di Audit Operativo (38 Controlli)",
                "description": "Template per audit operativo in ambiente di produzione alimentare",
                "version": "1.0",
                "isTemplate": True,
                "createdAt": datetime.utcnow(),
                "updatedAt": datetime.utcnow(),
                "sections": [
                    {
                        "id": "S1",
                        "title": "1. PERSONALE E IGIENE",
                        "icon": "Users",
                        "items": [
                            {"id": "I1.1", "requirement": "Indumenti da lavoro puliti (divisa, grembiule).", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I1.2", "requirement": "Scarpe antinfortunistiche / Calzature pulite.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I1.3", "requirement": "Cuffie e/o Retine per capelli indossate correttamente.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I1.4", "requirement": "Assenza di gioielli, piercing visibili, unghie lunghe.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I1.5", "requirement": "Lavaggio mani documentato all'ingresso/reingresso.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I1.6", "requirement": "Assenza di cibo/bevande non autorizzate nelle aree produttive.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None}
                        ]
                    },
                    {
                        "id": "S2",
                        "title": "2. STRUTTURE E IMPIANTI",
                        "icon": "Building",
                        "items": [
                            {"id": "I2.1", "requirement": "Illuminazione adeguata e funzionante in tutte le aree.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I2.2", "requirement": "Porte esterne/interne in buone condizioni e chiuse correttamente (sigillatura).", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I2.3", "requirement": "Integrità di pavimenti, pareti e soffitti (assenza di crepe/danni).", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I2.4", "requirement": "Controllo vetri / lampade protette o anti-frantumazione.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I2.5", "requirement": "Condizioni igieniche dei servizi igienici e spogliatoi (pulizia e dotazioni).", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I2.6", "requirement": "Ventilazione e aspirazione funzionanti, pulite e non ostruite.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None}
                        ]
                    },
                    {
                        "id": "S3",
                        "title": "3. GESTIONE E IGIENE AMBIENTALE",
                        "icon": "Package",
                        "items": [
                            {"id": "I3.1", "requirement": "Contenitori dei rifiuti puliti, chiusi e identificati.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I3.2", "requirement": "Separazione corretta dei rifiuti (es. umido, secco, plastica).", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I3.3", "requirement": "Area di stoccaggio rifiuti (interna ed esterna) ordinata e sanificata.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I3.4", "requirement": "Frequenza di rimozione dei rifiuti adeguata a prevenire accumuli.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None}
                        ]
                    },
                    {
                        "id": "S4",
                        "title": "4. CONTROLLO PROCESSO E QUALITÀ",
                        "icon": "Settings",
                        "items": [
                            {"id": "I4.1", "requirement": "Monitoraggio e registrazione dei Punti Critici di Controllo (CCP).", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I4.2", "requirement": "Procedure di Buona Fabbricazione (GMP) rispettate (es. pulizia prima dell'avvio).", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I4.3", "requirement": "Verifica e calibrazione del Metal Detector eseguita e registrata.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I4.4", "requirement": "Corretta identificazione dei lotti di materie prime e semilavorati.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I4.5", "requirement": "Rispettate le temperature di stoccaggio dei prodotti finiti e intermedi.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I4.6", "requirement": "Corretta gestione, etichettatura e isolamento dei prodotti non conformi.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None}
                        ]
                    },
                    {
                        "id": "S5",
                        "title": "5. CONTROLLO INFESTANTI",
                        "icon": "Shield",
                        "items": [
                            {"id": "I5.1", "requirement": "Assenza di tracce visibili di roditori, insetti o uccelli.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I5.2", "requirement": "Stazioni di monitoraggio/trappole numerate, integre e registrate.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I5.3", "requirement": "Mappe e registri delle trappole aggiornati e disponibili.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I5.4", "requirement": "Barriere fisiche (es. reti, spazzole) anti-intrusione in buone condizioni.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I5.5", "requirement": "Prodotti chimici di controllo infestanti stoccati in modo sicuro e separato.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None}
                        ]
                    },
                    {
                        "id": "S6",
                        "title": "6. MANUTENZIONE E VETRI",
                        "icon": "Settings",
                        "items": [
                            {"id": "I6.1", "requirement": "Piano di manutenzione preventiva e correttiva rispettato e registrato.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I6.2", "requirement": "Lubrificanti e oli utilizzati autorizzati per uso alimentare (se richiesto).", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I6.3", "requirement": "Registri di calibrazione/verifica degli strumenti di misura critici aggiornati.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I6.4", "requirement": "Gestione dei vetri rotti (registri rotture) aggiornata e conforme alla procedura.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I6.5", "requirement": "Assenza di perdite, gocciolamenti o cavi scoperti da impianti/macchinari.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I6.6", "requirement": "Area di deposito utensili e pezzi di ricambio ordinata e pulita.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None}
                        ]
                    },
                    {
                        "id": "S7",
                        "title": "7. DOCUMENTAZIONE E FORMAZIONE",
                        "icon": "FileText",
                        "items": [
                            {"id": "I7.1", "requirement": "Documentazione di processo (procedure, istruzioni) aggiornata e disponibile.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I7.2", "requirement": "Registri di formazione del personale aggiornati e verificabili.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I7.3", "requirement": "Certificazioni e attestati del personale validi e aggiornati.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I7.4", "requirement": "Controllo documenti (versioni, distribuzione, obsolescenza) conforme.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None},
                            {"id": "I7.5", "requirement": "Archiviazione e conservazione documenti secondo i requisiti normativi.", "compliance": "N/A", "deviation": "", "action": "", "imageData": None}
                        ]
                    }
                ],
                "totalItems": 38,
                "completedItems": 0,
                "nonCompliantItems": 0,
                "complianceScore": 0.0
            }
            
            # Insert the template
            await db.checklist_templates.insert_one(default_template)
            template_doc = default_template
        
        # Serialize the document
        serialized_template = serialize_checklist(template_doc)
        
        return {
            "success": True,
            "data": serialized_template,
            "message": "Default checklist template retrieved successfully"
        }
        
    except Exception as e:
        logger.error(f"Error retrieving default checklist template: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to retrieve checklist template: {str(e)}"
        )

@app.post("/api/checklist-template/item", response_model=Dict[str, Any])
async def add_template_item(item_data: dict):
    """
    Add a new item to the shared checklist template
    
    Args:
        item_data: Dictionary containing item information (sectionId, requirement, etc.)
        
    Returns:
        Dictionary confirming the item was added
        
    Raises:
        HTTPException: If database operation fails
    """
    try:
        logger.info(f"Adding new item to shared template")
        
        # Ensure template exists first and get it
        template = await ensure_default_template_exists()
        
        if not template:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail="Template not found"
            )
        
        template_id = template.get("templateId", "default")
        
        # Find the section and add the new item
        section_id = item_data.get('sectionId')
        section_index = next((i for i, s in enumerate(template['sections']) if s['id'] == section_id), None)
        
        if section_index is None:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"Section {section_id} not found"
            )
        
        new_item = {
            "id": item_data.get('id', f"I{section_id[-1]}.{len(template['sections'][section_index]['items'])+1}"),
            "requirement": item_data.get('requirement', ''),
        }
        
        # Update the template
        result = await db.checklist_templates.update_one(
            {"templateId": template_id, "sections.id": section_id},
            {"$push": {"sections.$.items": new_item}}
        )
        
        if result.modified_count > 0:
            logger.info(f"Successfully added item to template")
            return {
                "success": True,
                "message": "Item added successfully",
                "data": new_item
            }
        else:
            raise HTTPException(
                status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
                detail="Failed to add item"
            )
        
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error adding item to template: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to add item: {str(e)}"
        )

@app.put("/api/checklist-template/item/{item_id}", response_model=Dict[str, Any])
async def update_template_item(item_id: str, item_data: dict):
    """
    Update an existing item in the shared checklist template
    
    Args:
        item_id: ID of the item to update
        item_data: Dictionary containing updated item information
        
    Returns:
        Dictionary confirming the item was updated
        
    Raises:
        HTTPException: If database operation fails
    """
    try:
        logger.info(f"Updating item {item_id} in shared template")
        
        # Ensure template exists first and get it
        template = await ensure_default_template_exists()
        template_id = template.get("templateId") if template else "default"
        
        # Prepare update fields
        update_fields = {}
        if 'requirement' in item_data:
            update_fields["sections.$[].items.$[item].requirement"] = item_data['requirement']
        
        if not update_fields:
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail="No valid fields to update"
            )
        
        # Update the item in template (use the template ID we found)
        result = await db.checklist_templates.update_one(
            {"templateId": template_id},
            {"$set": update_fields},
            array_filters=[{"item.id": item_id}]
        )
        
        if result.modified_count > 0:
            logger.info(f"Successfully updated item {item_id} in template")
            return {
                "success": True,
                "message": "Item updated successfully",
                "data": item_data
            }
        else:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail="Item not found or no changes made"
            )
        
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error updating item {item_id} in template: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to update item: {str(e)}"
        )

@app.delete("/api/checklist-template/item/{item_id}", response_model=Dict[str, Any])
async def delete_template_item(item_id: str):
    """
    Delete an item from the shared checklist template
    
    Args:
        item_id: ID of the item to delete
        
    Returns:
        Dictionary confirming the item was deleted
        
    Raises:
        HTTPException: If database operation fails
    """
    try:
        logger.info(f"Deleting item {item_id} from shared template")
        
        # Ensure template exists first and get it
        template = await ensure_default_template_exists()
        template_id = template.get("templateId") if template else "default"
        
        # Remove the item from the template
        result = await db.checklist_templates.update_one(
            {"templateId": template_id},
            {"$pull": {"sections.$[].items": {"id": item_id}}}
        )
        
        if result.modified_count > 0:
            logger.info(f"Successfully deleted item {item_id} from template")
            return {
                "success": True,
                "message": "Item deleted successfully"
            }
        else:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail="Item not found"
            )
        
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error deleting item {item_id} from template: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to delete item: {str(e)}"
        )

@app.post("/api/checklist-template/section", response_model=Dict[str, Any])
async def add_template_section(section_data: dict):
    """
    Add a new section to the shared checklist template
    
    Args:
        section_data: Dictionary containing section information
        
    Returns:
        Dictionary confirming the section was added
        
    Raises:
        HTTPException: If database operation fails
    """
    try:
        logger.info(f"Adding new section to shared template")
        
        # Ensure template exists first and get it
        template = await ensure_default_template_exists()
        
        if not template:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail="Template not found"
            )
        
        template_id = template.get("templateId", "default")
        
        # Create new section
        new_section = {
            "id": section_data.get('id', f"S{len(template['sections'])+1}"),
            "title": section_data.get('title', 'New Section'),
            "icon": section_data.get('icon', 'Settings'),
            "items": []
        }
        
        # Add the new section
        result = await db.checklist_templates.update_one(
            {"templateId": template_id},
            {"$push": {"sections": new_section}}
        )
        
        if result.modified_count > 0:
            logger.info(f"Successfully added section to template")
            return {
                "success": True,
                "message": "Section added successfully",
                "data": new_section
            }
        else:
            raise HTTPException(
                status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
                detail="Failed to add section"
            )
        
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error adding section to template: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to add section: {str(e)}"
        )

@app.delete("/api/checklist-template/section/{section_id}", response_model=Dict[str, Any])
async def delete_template_section(section_id: str):
    """
    Delete a section from the shared checklist template
    
    Args:
        section_id: ID of the section to delete
        
    Returns:
        Dictionary confirming the section was deleted
        
    Raises:
        HTTPException: If database operation fails
    """
    try:
        logger.info(f"Deleting section {section_id} from shared template")
        
        # Ensure template exists first and get it
        template = await ensure_default_template_exists()
        template_id = template.get("templateId") if template else "default"
        
        # Remove the section from the template
        result = await db.checklist_templates.update_one(
            {"templateId": template_id},
            {"$pull": {"sections": {"id": section_id}}}
        )
        
        if result.modified_count > 0:
            logger.info(f"Successfully deleted section {section_id} from template")
            return {
                "success": True,
                "message": "Section deleted successfully"
            }
        else:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail="Section not found"
            )
        
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error deleting section {section_id} from template: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to delete section: {str(e)}"
        )

@app.post("/api/checklist/{user_id}/item", response_model=Dict[str, Any])
async def add_checklist_item(user_id: str, item_data: dict):
    """
    Add a new item to a checklist
    
    Args:
        user_id: Unique identifier for the user
        item_data: Dictionary containing item information (sectionId, requirement, etc.)
        
    Returns:
        Dictionary confirming the item was added
        
    Raises:
        HTTPException: If database operation fails
    """
    try:
        logger.info(f"Adding new item to checklist for user: {user_id}")
        
        # Get the user's checklist
        checklist_doc = await db.checklists.find_one({"userId": user_id})
        
        if not checklist_doc:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail="Checklist not found for user"
            )
        
        # Find the section and add the new item
        section_id = item_data.get('sectionId')
        new_item = {
            "id": item_data.get('id', f"I{section_id}.{len(checklist_doc['sections'][int(section_id[-1])-1]['items'])+1}"),
            "requirement": item_data.get('requirement', ''),
            "compliance": "N/A",
            "deviation": "",
            "action": "",
            "imageData": None,
            "checkedAt": None,
            "checkedBy": ""
        }
        
        # Update the checklist
        result = await db.checklists.update_one(
            {"userId": user_id, "sections.id": section_id},
            {"$push": {f"sections.$.items": new_item}}
        )
        
        if result.modified_count > 0:
            logger.info(f"Successfully added item to checklist for user {user_id}")
            return {
                "success": True,
                "message": "Item added successfully",
                "data": new_item
            }
        else:
            raise HTTPException(
                status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
                detail="Failed to add item"
            )
        
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error adding item for user {user_id}: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to add item: {str(e)}"
        )

@app.put("/api/checklist/{user_id}/item/{item_id}", response_model=Dict[str, Any])
async def update_checklist_item(user_id: str, item_id: str, item_data: dict):
    """
    Update an existing checklist item
    
    Args:
        user_id: Unique identifier for the user
        item_id: ID of the item to update
        item_data: Dictionary containing updated item information
        
    Returns:
        Dictionary confirming the item was updated
        
    Raises:
        HTTPException: If database operation fails
    """
    try:
        logger.info(f"Updating item {item_id} for user: {user_id}")
        
        # Check if checklist exists
        checklist = await db.checklists.find_one({"userId": user_id})
        if not checklist:
            logger.warning(f"No checklist found for user {user_id}")
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"Checklist not found for user {user_id}. Please create a checklist first."
            )
        
        # Prepare update fields
        update_fields = {}
        for field in ['requirement', 'compliance', 'deviation', 'action']:
            if field in item_data:
                update_fields[f"sections.$[].items.$[item].{field}"] = item_data[field]
        
        if not update_fields:
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail="No valid fields to update"
            )
        
        # Update the item
        result = await db.checklists.update_one(
            {"userId": user_id},
            {"$set": update_fields},
            array_filters=[{"item.id": item_id}]
        )
        
        if result.modified_count > 0:
            logger.info(f"Successfully updated item {item_id} for user {user_id}")
            return {
                "success": True,
                "message": "Item updated successfully",
                "data": item_data
            }
        else:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail="Item not found or no changes made"
            )
        
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error updating item {item_id} for user {user_id}: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to update item: {str(e)}"
        )

@app.delete("/api/checklist/{user_id}/item/{item_id}", response_model=Dict[str, Any])
async def delete_checklist_item(user_id: str, item_id: str):
    """
    Delete a checklist item
    
    Args:
        user_id: Unique identifier for the user
        item_id: ID of the item to delete
        
    Returns:
        Dictionary confirming the item was deleted
        
    Raises:
        HTTPException: If database operation fails
    """
    try:
        logger.info(f"Deleting item {item_id} for user: {user_id}")
        
        # Check if checklist exists
        checklist = await db.checklists.find_one({"userId": user_id})
        if not checklist:
            logger.warning(f"No checklist found for user {user_id}")
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"Checklist not found for user {user_id}. Please create a checklist first."
            )
        
        # Remove the item from the checklist
        result = await db.checklists.update_one(
            {"userId": user_id},
            {"$pull": {"sections.$[].items": {"id": item_id}}}
        )
        
        if result.modified_count > 0:
            logger.info(f"Successfully deleted item {item_id} for user {user_id}")
            return {
                "success": True,
                "message": "Item deleted successfully"
            }
        else:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail="Item not found"
            )
        
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error deleting item {item_id} for user {user_id}: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to delete item: {str(e)}"
        )

@app.post("/api/checklist/{user_id}/section", response_model=Dict[str, Any])
async def add_checklist_section(user_id: str, section_data: dict):
    """
    Add a new section to a checklist
    
    Args:
        user_id: Unique identifier for the user
        section_data: Dictionary containing section information
        
    Returns:
        Dictionary confirming the section was added
        
    Raises:
        HTTPException: If database operation fails
    """
    try:
        logger.info(f"Adding new section to checklist for user: {user_id}")
        
        # Get the user's checklist
        checklist_doc = await db.checklists.find_one({"userId": user_id})
        
        if not checklist_doc:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail="Checklist not found for user"
            )
        
        # Create new section
        new_section = {
            "id": section_data.get('id', f"S{len(checklist_doc['sections'])+1}"),
            "title": section_data.get('title', 'New Section'),
            "icon": section_data.get('icon', 'Settings'),
            "items": []
        }
        
        # Add the new section
        result = await db.checklists.update_one(
            {"userId": user_id},
            {"$push": {"sections": new_section}}
        )
        
        if result.modified_count > 0:
            logger.info(f"Successfully added section to checklist for user {user_id}")
            return {
                "success": True,
                "message": "Section added successfully",
                "data": new_section
            }
        else:
            raise HTTPException(
                status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
                detail="Failed to add section"
            )
        
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error adding section for user {user_id}: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to add section: {str(e)}"
        )

@app.delete("/api/checklist/{user_id}/section/{section_id}", response_model=Dict[str, Any])
async def delete_checklist_section(user_id: str, section_id: str):
    """
    Delete a checklist section and all its items
    
    Args:
        user_id: Unique identifier for the user
        section_id: ID of the section to delete
        
    Returns:
        Dictionary confirming the section was deleted
        
    Raises:
        HTTPException: If database operation fails
    """
    try:
        logger.info(f"Deleting section {section_id} for user: {user_id}")
        
        # Check if checklist exists
        checklist = await db.checklists.find_one({"userId": user_id})
        if not checklist:
            logger.warning(f"No checklist found for user {user_id}")
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"Checklist not found for user {user_id}. Please create a checklist first."
            )
        
        # Remove the section from the checklist
        result = await db.checklists.update_one(
            {"userId": user_id},
            {"$pull": {"sections": {"id": section_id}}}
        )
        
        if result.modified_count > 0:
            logger.info(f"Successfully deleted section {section_id} for user {user_id}")
            return {
                "success": True,
                "message": "Section deleted successfully"
            }
        else:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail="Section not found"
            )
        
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error deleting section {section_id} for user {user_id}: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to delete section: {str(e)}"
        )

@app.get("/api/checklists", response_model=Dict[str, Any])
async def get_all_checklists():
    """
    Retrieve all checklists (admin endpoint)
    
    This endpoint returns all checklists in the database. It's intended for
    administrative purposes and should be protected with proper authentication
    in a production environment.
    
    Returns:
        Dictionary containing list of all checklists
        
    Raises:
        HTTPException: If database operation fails
    """
    try:
        logger.info("Retrieving all checklists")
        
        # Find all checklists
        cursor = db.checklists.find({})
        checklists = []
        
        async for checklist_doc in cursor:
            serialized_checklist = serialize_checklist(checklist_doc)
            checklists.append(serialized_checklist)
        
        return {
            "success": True,
            "data": checklists,
            "count": len(checklists),
            "message": f"Retrieved {len(checklists)} checklists"
        }
        
    except Exception as e:
        logger.error(f"Error retrieving all checklists: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to retrieve checklists: {str(e)}"
        )

# =============================================================================
# ERROR HANDLERS
# =============================================================================

@app.exception_handler(HTTPException)
async def http_exception_handler(request, exc):
    """Handle HTTP exceptions with consistent error format"""
    logger.error(f"HTTP Exception: {exc.detail}")
    return JSONResponse(
        status_code=exc.status_code,
        content={
            "success": False,
            "error": exc.detail,
            "status_code": exc.status_code
        }
    )

@app.exception_handler(Exception)
async def general_exception_handler(request, exc):
    """Handle general exceptions with logging"""
    logger.error(f"Unhandled exception: {exc}", exc_info=True)
    return JSONResponse(
        status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
        content={
            "success": False,
            "error": "Internal server error",
            "detail": str(exc) if os.getenv("DEBUG", "false").lower() == "true" else "An unexpected error occurred"
        }
    )

# =============================================================================
# MAIN EXECUTION
# =============================================================================

if __name__ == "__main__":
    """
    Main execution block for running the server
    
    This block is executed when the script is run directly (not imported).
    It starts the Uvicorn ASGI server with the configured settings.
    """
    import uvicorn
    
    logger.info("Starting FastAPI server...")
    
    # Run the server
    uvicorn.run(
        "main:app",
        host="0.0.0.0",
        port=PORT,
        reload=True,  # Enable auto-reload for development
        log_level="info"
    )