import os
import argparse
import sys
import subprocess
import signal
import atexit
import time
from modules.logger_tool import initialise_logger
logger = initialise_logger(__name__, os.getenv("LOG_LEVEL"), os.getenv("LOG_PATH"), 'default', True)
from fastapi import FastAPI, HTTPException
import uvicorn
import requests
from typing import Dict, Any, Optional
from modules.database.tools.neo4j_driver_tools import get_driver

from run.setup import setup_cors
from run.routers import register_routes
from modules.task_processors import get_processor
from modules.queue_system import ServiceType

# FastAPI App Setup
app = FastAPI()
setup_cors(app)

# Health check endpoint
@app.get("/health")
async def health_check() -> Dict[str, Any]:
    """Health check endpoint that verifies all service dependencies"""
    health_status = {
        "status": "healthy",
        "services": {
            "neo4j": {"status": "healthy", "message": "Connected"},
            "supabase": {"status": "healthy", "message": "Connected"},
            "redis": {"status": "healthy", "message": "Connected"}
        }
    }
    
    try:
        # Check Neo4j
        driver = get_driver()
        if not driver:
            health_status["services"]["neo4j"] = {
                "status": "unhealthy",
                "message": "Failed to connect to Neo4j"
            }
            health_status["status"] = "unhealthy"
    except Exception as e:
        health_status["services"]["neo4j"] = {
            "status": "unhealthy",
            "message": f"Error checking Neo4j: {str(e)}"
        }
        health_status["status"] = "unhealthy"
    
    try:
        # Minimal check to confirm Supabase is responsive (e.g., pinging auth or storage endpoint)
        supabase_url = os.getenv("SUPABASE_URL")
        service_role_key = os.getenv("SERVICE_ROLE_KEY")
        response = requests.get(
            f"{supabase_url}/auth/v1/health",
            headers={"apikey": service_role_key},
            timeout=5
        )
        if response.status_code != 200:
            health_status["services"]["supabase"] = {
                "status": "unhealthy",
                "message": f"Supabase Auth API returned status {response.status_code}"
            }
            health_status["status"] = "unhealthy"
    except Exception as e:
        health_status["services"]["supabase"] = {
            "status": "unhealthy",
            "message": f"Error checking Supabase Auth API: {str(e)}"
        }
        health_status["status"] = "unhealthy"
    
    try:
        # Check Redis using new Redis manager
        from modules.redis_manager import get_redis_manager
        
        # Determine environment
        environment = 'dev' if os.getenv('BACKEND_DEV_MODE', 'true').lower() == 'true' else 'prod'
        redis_manager = get_redis_manager(environment)
        
        # Get comprehensive health check
        redis_health = redis_manager.health_check()
        
        health_status["services"]["redis"] = {
            "status": redis_health['status'],
            "message": redis_health.get('error', f"Connected to {environment} environment (db={redis_health['database']})"),
            "environment": redis_health['environment'],
            "database": redis_health['database'],
            "queue_stats": redis_health.get('queue_stats', {})
        }
        
        if redis_health['status'] != 'healthy':
            health_status["status"] = "unhealthy"
            
    except Exception as e:
        health_status["services"]["redis"] = {
            "status": "unhealthy",
            "message": f"Error checking Redis: {str(e)}"
        }
        health_status["status"] = "unhealthy"
    
    if health_status["status"] == "unhealthy":
        raise HTTPException(status_code=503, detail=health_status)
    
    return health_status

# Register routes
register_routes(app)

# Start workers in the application process to avoid uvicorn reload issues
@app.on_event("startup")
async def _start_workers_event():
    try:
        if os.getenv('AUTO_START_QUEUE_WORKERS', 'true').lower() != 'true':
            logger.info("AUTO_START_QUEUE_WORKERS=false, not starting in-process workers")
            return
        workers = int(os.getenv('QUEUE_WORKERS', '3'))
        services_csv = os.getenv('QUEUE_SERVICES', 'tika,docling,split_map,document_analysis,page_images')
        service_names = [s.strip().lower() for s in services_csv.split(',') if s.strip()]
        service_enums = []
        for name in service_names:
            try:
                service_enums.append(ServiceType(name))
            except Exception:
                pass
        if not service_enums:
            service_enums = list(ServiceType)
        processor = get_processor()
        started = []
        for i in range(workers):
            wid = processor.start_worker(worker_id=f"app-worker-{i+1}", services=service_enums)
            started.append(wid)
        logger.info(f"In-process queue workers started: {started} for services {[s.value for s in service_enums]}")
    except Exception as e:
        logger.error(f"Failed to start in-process workers: {e}")

@app.on_event("shutdown")
async def _shutdown_workers_event():
    try:
        processor = get_processor()
        processor.shutdown(timeout=30)
    except Exception as e:
        logger.warning(f"Error during workers shutdown: {e}")

# Global subprocess handles (only for workers now)
workers_process: Optional[subprocess.Popen] = None

# Global Redis manager for cleanup
redis_manager = None

def start_queue_workers():
    """Start queue workers as a subprocess (tied to API lifecycle)."""
    global workers_process
    if os.getenv('AUTO_START_QUEUE_WORKERS', 'true').lower() != 'true':
        logger.info("AUTO_START_QUEUE_WORKERS=false, not starting workers")
        return

    # If already started, skip
    if workers_process is not None and workers_process.poll() is None:
        logger.info("Queue workers already running")
        return

    services = os.getenv(
        'QUEUE_SERVICES',
        'tika,docling,split_map,document_analysis,page_images'
    )
    workers = int(os.getenv('QUEUE_WORKERS', '3'))
    check_interval = os.getenv('QUEUE_CHECK_INTERVAL', '15')

    cmd = [
        sys.executable,
        'start_queue_workers.py',
        '--workers', str(workers),
        '--services', services,
        '--check-interval', check_interval,
    ]
    # Workers will auto-detect environment and use appropriate Redis database

    log_path = os.getenv('QUEUE_WORKERS_LOG', './queue_workers.log')
    try:
        log_file = open(log_path, 'a')
        logger.info(f"Starting queue workers ({workers}) for services [{services}] → {log_path}")
        workers_process = subprocess.Popen(
            cmd,
            stdout=log_file,
            stderr=log_file,
            preexec_fn=os.setsid if os.name != 'nt' else None
        )
    except Exception as e:
        logger.error(f"Failed to start queue workers: {e}")

def stop_queue_workers():
    """Stop queue workers subprocess."""
    global workers_process
    if workers_process is not None:
        try:
            logger.info("Stopping queue workers...")
            if os.name != 'nt':
                os.killpg(os.getpgid(workers_process.pid), signal.SIGTERM)
            else:
                workers_process.terminate()
            try:
                workers_process.wait(timeout=10)
                logger.info("Queue workers stopped gracefully")
            except subprocess.TimeoutExpired:
                logger.warning("Queue workers did not stop gracefully, forcing shutdown...")
                if os.name != 'nt':
                    os.killpg(os.getpgid(workers_process.pid), signal.SIGKILL)
                else:
                    workers_process.kill()
                workers_process.wait()
                logger.info("Queue workers force stopped")
        except Exception as e:
            logger.error(f"Error stopping queue workers: {e}")
        finally:
            workers_process = None

def _install_signal_handlers():
    def signal_handler(signum, frame):
        logger.info(f"Received signal {signum}, shutting down...")
        stop_queue_workers()
        # Gracefully shutdown Redis manager if it exists
        global redis_manager
        if redis_manager:
            redis_manager.shutdown()
        sys.exit(0)
    signal.signal(signal.SIGINT, signal_handler)
    signal.signal(signal.SIGTERM, signal_handler)

def run_infrastructure_mode():
    """Run infrastructure setup: Neo4j schema, calendar, and Supabase buckets"""
    logger.info("Running in infrastructure mode")
    logger.info("Starting infrastructure setup...")
    
    try:
        from run.initialization import initialize_infrastructure_mode
        initialize_infrastructure_mode()
        logger.info("Infrastructure setup completed successfully")
        return True
    except Exception as e:
        logger.error(f"Infrastructure setup failed: {str(e)}")
        return False

def run_demo_school_mode():
    """Run demo school creation"""
    logger.info("Running in demo school mode")
    logger.info("Starting demo school creation...")
    
    try:
        from run.initialization import initialize_demo_school_mode
        initialize_demo_school_mode()
        logger.info("Demo school creation completed successfully")
        return True
    except Exception as e:
        logger.error(f"Demo school creation failed: {str(e)}")
        return False

def run_demo_users_mode():
    """Run demo users creation"""
    logger.info("Running in demo users mode")
    logger.info("Starting demo users creation...")
    
    try:
        from run.initialization import initialize_demo_users_mode
        initialize_demo_users_mode()
        logger.info("Demo users creation completed successfully")
        return True
    except Exception as e:
        logger.error(f"Demo users creation failed: {str(e)}")
        return False

def run_gais_data_mode():
    """Run GAIS data import"""
    logger.info("Running in GAIS data import mode")
    logger.info("Starting GAIS data import...")
    
    try:
        from run.initialization import initialize_gais_data_mode
        initialize_gais_data_mode()
        logger.info("GAIS data import completed successfully")
        return True
    except Exception as e:
        logger.error(f"GAIS data import failed: {str(e)}")
        return False

# Old clear_dev_redis_queue function removed - now handled by Redis Manager

def run_development_mode():
    """Run the server in development mode with auto-reload"""
    logger.info("Running in development mode")
    
    # Initialize Redis manager for development (auto-clears data)
    global redis_manager
    from modules.redis_manager import get_redis_manager
    redis_manager = get_redis_manager('dev')
    
    if not redis_manager.initialize_environment():
        logger.error("Failed to initialize Redis for development")
        return False
    
    # Workers are started in app startup event

    logger.info("Starting uvicorn server with auto-reload...")
    
    # Install signal handlers for graceful shutdown
    _install_signal_handlers()
    
    try:
        uvicorn.run(
            "main:app",
            host="0.0.0.0",
            port=int(os.getenv('UVICORN_PORT', 8000)),
            log_level=os.getenv('LOG_LEVEL', 'info'),
            proxy_headers=True,
            timeout_keep_alive=10,
            reload=True
        )
    finally:
        stop_queue_workers()
        if redis_manager:
            redis_manager.shutdown()

def run_production_mode():
    """Run the server in production mode"""
    logger.info("Running in production mode")
    
    # Initialize Redis manager for production (preserves data, recovers tasks)
    global redis_manager
    from modules.redis_manager import get_redis_manager
    redis_manager = get_redis_manager('prod')
    
    if not redis_manager.initialize_environment():
        logger.error("Failed to initialize Redis for production")
        return False
    
    # Workers are started in app startup event

    logger.info("Starting uvicorn server in production mode...")
    
    # Install signal handlers for graceful shutdown
    _install_signal_handlers()
    
    try:
        uvicorn.run(
            "main:app",
            host="0.0.0.0",
            port=int(os.getenv('UVICORN_PORT', 8000)),
            log_level=os.getenv('LOG_LEVEL', 'info'),
            proxy_headers=True,
            timeout_keep_alive=10,
            workers=int(os.getenv('UVICORN_WORKERS', '1'))
        )
    finally:
        stop_queue_workers()
        if redis_manager:
            redis_manager.shutdown()

def parse_arguments():
    """Parse command line arguments"""
    parser = argparse.ArgumentParser(
        description="ClassroomCopilot API Server",
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog="""
Startup modes:
  infra                    - Setup infrastructure (Neo4j schema, calendar, Supabase buckets)
  demo-school             - Create demo school (KevlarAI)
  demo-users              - Create demo users
  gais-data               - Import GAIS data (Edubase, etc.)
  dev                     - Run development server with auto-reload
  prod                    - Run production server (for Docker/containerized deployment)
        """
    )
    
    parser.add_argument(
        '--mode', '-m',
        choices=['infra', 'demo-school', 'demo-users', 'gais-data', 'dev', 'prod'],
        default='dev',
        help='Startup mode (default: dev)'
    )
    
    return parser.parse_args()

if __name__ == "__main__":
    args = parse_arguments()
    
    # Set environment variable for backward compatibility
    if args.mode == 'dev':
        os.environ['BACKEND_DEV_MODE'] = 'true'
    else:
        os.environ['BACKEND_DEV_MODE'] = 'false'
    
    logger.info(f"Starting ClassroomCopilot API in {args.mode} mode")
    
    if args.mode == 'infra':
        # Run infrastructure setup
        success = run_infrastructure_mode()
        sys.exit(0 if success else 1)
    
    elif args.mode == 'demo-school':
        # Run demo school creation
        success = run_demo_school_mode()
        sys.exit(0 if success else 1)
    
    elif args.mode == 'demo-users':
        # Run demo users creation
        success = run_demo_users_mode()
        sys.exit(0 if success else 1)
    
    elif args.mode == 'gais-data':
        # Run GAIS data import
        success = run_gais_data_mode()
        sys.exit(0 if success else 1)
    
    elif args.mode == 'dev':
        # Run development server
        run_development_mode()
    
    elif args.mode == 'prod':
        # Run production server
        run_production_mode()
    
    else:
        logger.error(f"Invalid mode: {args.mode}")
        sys.exit(1)