"""Scheduler service for managing background tasks with APScheduler."""

import logging
from typing import Optional

from apscheduler.schedulers.background import BackgroundScheduler
from apscheduler.triggers.cron import CronTrigger

from app.services.credit_service import CreditService

logger = logging.getLogger(__name__)


class SchedulerService:
    """Service for managing scheduled background tasks."""

    def __init__(self) -> None:
        """Initialize the scheduler service."""
        self.scheduler: Optional[BackgroundScheduler] = None

    def start(self) -> None:
        """Start the scheduler and add all scheduled jobs."""
        if self.scheduler is not None:
            logger.warning("Scheduler is already running")
            return

        self.scheduler = BackgroundScheduler()
        
        # Add daily credit refill job
        self._add_daily_credit_refill_job()
        
        # Start the scheduler
        self.scheduler.start()
        logger.info("Scheduler started successfully")

    def stop(self) -> None:
        """Stop the scheduler."""
        if self.scheduler is not None:
            self.scheduler.shutdown()
            self.scheduler = None
            logger.info("Scheduler stopped")

    def _add_daily_credit_refill_job(self) -> None:
        """Add the daily credit refill job."""
        if self.scheduler is None:
            raise RuntimeError("Scheduler not initialized")

        # Schedule daily at 00:00 UTC
        trigger = CronTrigger(hour=0, minute=0)
        
        self.scheduler.add_job(
            func=self._run_daily_credit_refill,
            trigger=trigger,
            id="daily_credit_refill",
            name="Daily Credit Refill",
            replace_existing=True,
        )
        
        logger.info("Daily credit refill job scheduled for 00:00 UTC")

    def _run_daily_credit_refill(self) -> None:
        """Execute the daily credit refill task."""
        logger.info("Starting daily credit refill task")
        
        try:
            result = CreditService.refill_all_users_credits()
            
            if result["success"]:
                logger.info(
                    f"Daily credit refill completed successfully: "
                    f"{result['users_processed']} users processed, "
                    f"{result['credits_added']} credits added"
                )
            else:
                logger.error(f"Daily credit refill failed: {result['message']}")
                
        except Exception as e:
            logger.exception(f"Error during daily credit refill: {e}")

    def trigger_credit_refill_now(self) -> dict:
        """Manually trigger credit refill for testing purposes."""
        logger.info("Manually triggering credit refill")
        return CreditService.refill_all_users_credits()

    def get_scheduler_status(self) -> dict:
        """Get the current status of the scheduler."""
        if self.scheduler is None:
            return {"running": False, "jobs": []}

        jobs = []
        for job in self.scheduler.get_jobs():
            jobs.append({
                "id": job.id,
                "name": job.name,
                "next_run": job.next_run_time.isoformat() 
                          if job.next_run_time else None,
                "trigger": str(job.trigger),
            })

        return {
            "running": self.scheduler.running,
            "jobs": jobs,
        }


# Global scheduler instance
scheduler_service = SchedulerService()