import threading
import time
from datetime import datetime, timedelta
from typing import Callable, Optional


class DailyRefresh:
    """Simple daily auto-refresh mechanism."""
    
    def __init__(self, refresh_callback: Callable, refresh_hour: int = 2):
        """
        Initialize daily refresh.
        
        Args:
            refresh_callback: Function to call for refresh
            refresh_hour: Hour of day to refresh (0-23), default 2 AM
        """
        self.refresh_callback = refresh_callback
        self.refresh_hour = refresh_hour
        self.timer: Optional[threading.Timer] = None
        self.running = False
    
    def _calculate_next_refresh(self) -> float:
        """Calculate seconds until next refresh time."""
        now = datetime.now()
        
        # Calculate next refresh time (today or tomorrow at refresh_hour)
        next_refresh = now.replace(hour=self.refresh_hour, minute=0, second=0, microsecond=0)
        
        # If we've passed today's refresh time, schedule for tomorrow
        if now >= next_refresh:
            next_refresh += timedelta(days=1)
        
        return (next_refresh - now).total_seconds()
    
    def _refresh_and_reschedule(self):
        """Execute refresh and schedule the next one."""
        if not self.running:
            return
            
        print(f"[{datetime.now()}] Auto-refreshing leaderboard...")
        
        # Execute refresh
        try:
            self.refresh_callback()
            print("✅ Auto-refresh completed successfully")
        except Exception as e:
            print(f"❌ Auto-refresh failed: {e}")
        
        # Schedule next refresh
        if self.running:
            self._schedule_next()
    
    def _schedule_next(self):
        """Schedule the next refresh."""
        seconds_until_next = self._calculate_next_refresh()
        print(f"Next auto-refresh scheduled in {seconds_until_next/3600:.1f} hours")
        
        self.timer = threading.Timer(seconds_until_next, self._refresh_and_reschedule)
        self.timer.daemon = True  # Don't prevent app shutdown
        self.timer.start()
    
    def start(self):
        """Start the daily auto-refresh."""
        if self.running:
            return
            
        self.running = True
        print(f"🔄 Daily auto-refresh enabled (refresh time: {self.refresh_hour:02d}:00)")
        self._schedule_next()
    
    def stop(self):
        """Stop the auto-refresh."""
        self.running = False
        if self.timer:
            self.timer.cancel()
            print("🛑 Daily auto-refresh stopped")