import logging
import os
from datetime import datetime
from zoneinfo import ZoneInfo
from apscheduler.schedulers.background import BackgroundScheduler
from apscheduler.triggers.cron import CronTrigger
from apscheduler.executors.pool import ThreadPoolExecutor
from apscheduler.jobstores.memory import MemoryJobStore

from app_core.services.daily_report import main as run_daily_report

# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

class SchedulerService:
    def __init__(self):
        self.scheduler = None
        self.ist = ZoneInfo("Asia/Kolkata")
        
    def start_scheduler(self):
        """Start the background scheduler for daily email reports."""
        if self.scheduler and self.scheduler.running:
            logger.info("Scheduler is already running")
            return
            
        # Configure job stores and executors
        jobstores = {
            'default': MemoryJobStore()
        }
        executors = {
            'default': ThreadPoolExecutor(20)
        }
        job_defaults = {
            'coalesce': False,
            'max_instances': 1
        }
        
        self.scheduler = BackgroundScheduler(
            jobstores=jobstores,
            executors=executors,
            job_defaults=job_defaults,
            timezone=self.ist
        )
        
        # Schedule daily email at 8:00 PM IST (20:00)
        self.scheduler.add_job(
            func=self._send_daily_report,
            trigger=CronTrigger(hour=20, minute=0, timezone=self.ist),
            id='daily_email_report',
            name='Daily Email Report',
            replace_existing=True
        )
        
        # Start the scheduler
        self.scheduler.start()
        logger.info("Daily email scheduler started - will send reports at 8:00 PM IST")
        
    def stop_scheduler(self):
        """Stop the background scheduler."""
        if self.scheduler and self.scheduler.running:
            self.scheduler.shutdown()
            logger.info("Daily email scheduler stopped")
            
    def _send_daily_report(self):
        """Internal method to send daily report."""
        try:
            logger.info(f"Starting daily report at {datetime.now(self.ist)}")
            result = run_daily_report()
            if result == 0:
                logger.info("Daily report sent successfully")
            else:
                logger.warning(f"Daily report failed with exit code: {result}")
        except Exception as e:
            logger.error(f"Error sending daily report: {str(e)}")
            
    def get_next_run_time(self):
        """Get the next scheduled run time for the daily report."""
        if not self.scheduler or not self.scheduler.running:
            return None
            
        job = self.scheduler.get_job('daily_email_report')
        if job:
            return job.next_run_time
        return None
        
    def is_running(self):
        """Check if scheduler is running."""
        return self.scheduler is not None and self.scheduler.running