#!/usr/bin/env python3
"""
Queue Workers Startup Script

This script starts document processing queue workers.
Run this alongside your main FastAPI application to process queued tasks.

Usage:
    python start_queue_workers.py --workers 4 --services tika,docling
    python start_queue_workers.py --help
"""

import argparse
import signal
import sys
import time
import os
import redis
from typing import List

# Add the current directory to Python path so we can import modules
sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))

from modules.task_processors import get_processor
from modules.queue_system import ServiceType
from modules.logger_tool import initialise_logger

logger = initialise_logger(__name__, os.getenv("LOG_LEVEL", "INFO"), os.getenv("LOG_PATH", "./data/logs/"), 'default', True)

def parse_services(services_str: str) -> List[ServiceType]:
    """Parse comma-separated service names into ServiceType enums."""
    if not services_str:
        return list(ServiceType)
    
    services = []
    for service_name in services_str.split(','):
        service_name = service_name.strip().lower()
        try:
            services.append(ServiceType(service_name))
        except ValueError:
            logger.error(f"Invalid service name: {service_name}")
            logger.error(f"Valid services: {[s.value for s in ServiceType]}")
            sys.exit(1)
    
    return services

def main():
    parser = argparse.ArgumentParser(description='Start document processing queue workers')
    parser.add_argument(
        '--workers', '-w',
        type=int,
        default=2,
        help='Number of worker threads to start (default: 2)'
    )
    parser.add_argument(
        '--services', '-s',
        type=str,
        default='',
        help='Comma-separated list of services to handle (default: all). Options: tika,docling,llm,split_map'
    )
    # No longer accept REDIS_URL; rely on REDIS_HOST/REDIS_PORT envs
    parser.add_argument(
        '--check-interval',
        type=int,
        default=30,
        help='Health check interval in seconds (default: 30)'
    )
    
    args = parser.parse_args()
    
    # Parse services
    services = parse_services(args.services)
    
    logger.info(f"Starting {args.workers} queue workers")
    logger.info(f"Services: {[s.value for s in services]}")
    logger.info(f"Redis: {os.getenv('REDIS_HOST', '127.0.0.1')}:{os.getenv('REDIS_PORT', '6379')}")
    
    # Get processor instance
    processor = get_processor()
    
    # Processor reads REDIS_HOST/REDIS_PORT in its constructor
    
    # Start workers
    worker_ids = []
    for i in range(args.workers):
        worker_id = processor.start_worker(
            worker_id=f"cli-worker-{i+1}",
            services=services
        )
        worker_ids.append(worker_id)
    
    logger.info(f"Started workers: {worker_ids}")
    
    # Set up signal handlers for graceful shutdown
    def signal_handler(signum, frame):
        logger.info(f"Received signal {signum}, shutting down workers...")
        processor.shutdown(timeout=30)
        logger.info("Workers shut down. Exiting.")
        sys.exit(0)
    
    signal.signal(signal.SIGINT, signal_handler)
    signal.signal(signal.SIGTERM, signal_handler)
    
    # Main loop - monitor workers and queue health
    try:
        while True:
            time.sleep(args.check_interval)
            
            # Check queue stats
            try:
                stats = processor.get_queue_stats()
                total_queued = sum(stats['queues'].values())
                total_processing = stats['total_processing']
                dead_letter = stats['dead_letter_count']
                
                logger.info(f"Queue status - Queued: {total_queued}, Processing: {total_processing}, Dead: {dead_letter}")
                
                # Log service-specific stats
                for service in ServiceType:
                    processing_count = stats['processing'].get(service.value, 0)
                    limit = processor.service_limits[service]
                    if processing_count > 0:
                        logger.debug(f"{service.value}: {processing_count}/{limit} processing")
                
                # Warn about dead letters
                if dead_letter > 10:
                    logger.warning(f"High number of dead letter tasks: {dead_letter}")
                
            except Exception as e:
                logger.error(f"Error checking queue stats: {e}")
    
    except KeyboardInterrupt:
        logger.info("Keyboard interrupt received, shutting down...")
        processor.shutdown(timeout=30)
        logger.info("Workers shut down. Exiting.")

if __name__ == "__main__":
    main()