import asyncio
import logging
from database import SessionLocal
from models import VitalReading, TransmissionLog
from schemas import NormalizedVitals
from api_client import forward_vitals_to_api
from config import settings

logger = logging.getLogger(__name__)

async def retry_failed_transmissions():
    """
    Background task that periodically checks for untransmitted vital readings
    and attempts to forward them to the API.
    """
    logger.info("Starting background task for retrying failed transmissions...")
    
    while True:
        try:
            db = SessionLocal()
            try:
                # Get readings that haven't been transmitted
                failed_readings = db.query(VitalReading).filter(VitalReading.transmitted == False).limit(50).all()
                
                for reading in failed_readings:
                    vitals = NormalizedVitals(
                        device_id=reading.device_id,
                        patient_id=reading.patient_id,
                        timestamp=reading.timestamp,
                        heart_rate=reading.heart_rate,
                        spo2=reading.spo2,
                        systolic_bp=reading.systolic_bp,
                        diastolic_bp=reading.diastolic_bp,
                        map_bp=reading.map_bp,
                        respiratory_rate=reading.respiratory_rate,
                        temperature=reading.temperature
                    )
                    
                    success = await forward_vitals_to_api(vitals)
                    
                    if success:
                        reading.transmitted = True
                        log_entry = TransmissionLog(
                            reading_id=reading.id,
                            status="success",
                            response_code=200
                        )
                        db.add(log_entry)
                        logger.info(f"Successfully re-transmitted reading {reading.id}")
                    else:
                        # Log the failure but don't mark as transmitted
                        log_entry = TransmissionLog(
                            reading_id=reading.id,
                            status="failed",
                            error_message="Retry failed"
                        )
                        db.add(log_entry)
                        
                if failed_readings:
                    db.commit()
            finally:
                db.close()
                
        except Exception as e:
            logger.error(f"Error in retry background task: {e}")
            
        await asyncio.sleep(settings.retry_interval_seconds)