scripts/backend/app/generate_bundles.py

import argparse
import asyncio
import logging
from core.config import get_settings
from core.database import AsyncSessionLocal
from core.redis_client import create_cache
from services.emergency_locator import EmergencyLocatorService, OFFLINE_CITY_CENTERS
from services.overpass_service import OverpassService

logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s [%(levelname)s] %(message)s",
)
logger = logging.getLogger(__name__)

async def generate_bundles(cities_filter: list[str] | None = None) -> None:
    settings = get_settings()
    
    # Ensure nested output directories exist
    settings.offline_bundle_dir.mkdir(parents=True, exist_ok=True)
    
    cache = create_cache(settings.redis_url)
    overpass = OverpassService(settings)
    locator = EmergencyLocatorService(
        settings=settings,
        cache=cache,
        overpass_service=overpass,
    )

    cities_to_process = list(OFFLINE_CITY_CENTERS.keys())
    if cities_filter:
        cities_to_process = [c for c in cities_to_process if c in cities_filter]

    if not cities_to_process:
        logger.warning("No cities matched your filter. Check spelling.")
        return

    logger.info(f"Generating offline bundles for {len(cities_to_process)} cities...")
    
    success_count = 0
    for idx, city in enumerate(cities_to_process, 1):
        try:
            logger.info(f"[{idx}/{len(cities_to_process)}] Processing {city}...")
            async with AsyncSessionLocal() as db:
                bundle = await locator.build_city_bundle(db=db, city=city)
                
            service_count = len(bundle.get("services", []))
            source = bundle.get("source", "unknown")
            output_file = settings.offline_bundle_dir / f"{city.lower()}.json"
            
            logger.info(
                f"  -> SUCCESS ({city}): Fetched {service_count} services "
                f"from '{source}'. Saved to {output_file.name}"
            )
            success_count += 1
            
            # Be gentle with Overpass rate limits if processing many cities
            if idx < len(cities_to_process):
                await asyncio.sleep(2.0)
                
        except Exception as e:
            logger.error(f"  -> ERROR ({city}): {str(e)}", exc_info=True)

    await cache.close()
    if hasattr(overpass, 'close'):
        await overpass.close()

    logger.info(f"Build complete. Successfully processed {success_count}/{len(cities_to_process)} cities.")

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Generate offline PWA city JSON bundles")
    parser.add_argument(
        "--cities", 
        type=str, 
        help="Comma-separated list of cities to generate (e.g., chennai,delhi,mumbai)"
    )
    args = parser.parse_args()
    
    filter_list = None
    if args.cities:
        filter_list = [c.strip().lower() for c in args.cities.split(",") if c.strip()]
        
    asyncio.run(generate_bundles(cities_filter=filter_list))