#!/usr/bin/env python3
"""
Migration script to fix missing fields in warehouse documents.

This script adds missing required fields to existing warehouse documents:
- created_at: Default timestamp for warehouses missing this field
- created_by: Default to "system" for warehouses missing this field
- updated_at: Set to None for warehouses missing this field
- updated_by: Set to None for warehouses missing this field
- capabilities: Default capabilities for warehouses missing this field

Usage:
    python migration_fix_warehouse_fields.py
"""

import asyncio
import os
import sys
from datetime import datetime, timezone
from typing import Dict, Any

# Add the app directory to Python path
sys.path.append(os.path.join(os.path.dirname(__file__), '.'))

from app.nosql import get_database, connect_to_mongo, close_mongo_connection
from app.warehouses.constants import SCM_WAREHOUSES_COLLECTION


async def get_default_capabilities() -> Dict[str, Any]:
    """Get default capabilities structure."""
    return {
        "can_receive": True,
        "can_fulfil": True,
        "can_sell": False,
        "can_adjust": True,
        "can_stock_take": True
    }


async def fix_warehouse_fields():
    """Fix missing fields in warehouse documents."""
    
    print("🔧 Starting warehouse fields migration...")
    
    try:
        db = get_database()
        collection = db[SCM_WAREHOUSES_COLLECTION]
        
        # Find all warehouses
        warehouses = await collection.find({}).to_list(length=None)
        print(f"📦 Found {len(warehouses)} warehouse documents")
        
        if not warehouses:
            print("✅ No warehouses found. Migration complete.")
            return
        
        # Default values
        default_timestamp = "2025-01-01T00:00:00Z"
        default_capabilities = await get_default_capabilities()
        
        updated_count = 0
        
        for warehouse in warehouses:
            warehouse_id = warehouse.get("warehouse_id", "unknown")
            updates = {}
            
            # Check and fix missing fields
            if warehouse.get("created_at") is None:
                updates["created_at"] = default_timestamp
                print(f"  📅 Adding created_at to {warehouse_id}")
            
            if warehouse.get("created_by") is None:
                updates["created_by"] = "system"
                print(f"  👤 Adding created_by to {warehouse_id}")
            
            if warehouse.get("updated_at") is None:
                updates["updated_at"] = None
                print(f"  📅 Setting updated_at to null for {warehouse_id}")
            
            if warehouse.get("updated_by") is None:
                updates["updated_by"] = None
                print(f"  👤 Setting updated_by to null for {warehouse_id}")
            
            if warehouse.get("capabilities") is None:
                updates["capabilities"] = default_capabilities
                print(f"  ⚙️  Adding default capabilities to {warehouse_id}")
            
            # Apply updates if any
            if updates:
                result = await collection.update_one(
                    {"warehouse_id": warehouse_id},
                    {"$set": updates}
                )
                
                if result.modified_count > 0:
                    updated_count += 1
                    print(f"  ✅ Updated {warehouse_id}")
                else:
                    print(f"  ⚠️  Failed to update {warehouse_id}")
            else:
                print(f"  ✨ {warehouse_id} already has all required fields")
        
        print(f"\n🎉 Migration complete!")
        print(f"📊 Total warehouses processed: {len(warehouses)}")
        print(f"📊 Warehouses updated: {updated_count}")
        print(f"📊 Warehouses already complete: {len(warehouses) - updated_count}")
        
    except Exception as e:
        print(f"❌ Migration failed: {e}")
        import traceback
        traceback.print_exc()
        sys.exit(1)


async def verify_migration():
    """Verify that all warehouses now have required fields."""
    
    print("\n🔍 Verifying migration results...")
    
    try:
        db = get_database()
        collection = db[SCM_WAREHOUSES_COLLECTION]
        
        # Check for warehouses missing required fields
        missing_fields_queries = [
            {"created_at": {"$exists": False}},
            {"created_at": None},
            {"created_by": {"$exists": False}},
            {"created_by": None},
            {"capabilities": {"$exists": False}},
            {"capabilities": None}
        ]
        
        issues_found = False
        
        for query in missing_fields_queries:
            count = await collection.count_documents(query)
            if count > 0:
                field_name = list(query.keys())[0]
                print(f"  ⚠️  Found {count} warehouses still missing {field_name}")
                issues_found = True
        
        if not issues_found:
            print("  ✅ All warehouses have required fields!")
            
            # Show sample of updated warehouses
            sample = await collection.find({}).limit(3).to_list(length=3)
            print("\n📋 Sample warehouse documents:")
            for warehouse in sample:
                print(f"  - {warehouse.get('warehouse_id')}: "
                      f"created_at={warehouse.get('created_at')}, "
                      f"created_by={warehouse.get('created_by')}, "
                      f"capabilities={'present' if warehouse.get('capabilities') else 'missing'}")
        
    except Exception as e:
        print(f"❌ Verification failed: {e}")


async def main():
    """Main migration function."""
    print("🚀 Warehouse Fields Migration Script")
    print("=" * 50)
    
    try:
        # Connect to database
        print("🔌 Connecting to MongoDB...")
        await connect_to_mongo()
        print("✅ Connected to MongoDB")
        
        # Run migration
        await fix_warehouse_fields()
        
        # Verify results
        await verify_migration()
        
        print("\n✨ Migration script completed!")
        
    except Exception as e:
        print(f"❌ Migration script failed: {e}")
        import traceback
        traceback.print_exc()
    finally:
        # Close database connection
        print("🔌 Closing MongoDB connection...")
        await close_mongo_connection()
        print("✅ MongoDB connection closed")


if __name__ == "__main__":
    asyncio.run(main())