# notification_service.py
import logging
import json
import time
import uuid
import pytz
from datetime import datetime, timedelta
from enum import Enum
from collections import deque
from typing import List, Dict, Any, Optional, Union
from config import get_timezone

# Constants to replace magic values
ONE_DAY_SECONDS = 86400
DEFAULT_TARGET_HOUR = 12
SIGNIFICANT_HASHRATE_CHANGE_PERCENT = 25
NOTIFICATION_WINDOW_MINUTES = 5

class NotificationLevel(Enum):
    INFO = "info"
    SUCCESS = "success"
    WARNING = "warning"
    ERROR = "error"

class NotificationCategory(Enum):
    HASHRATE = "hashrate"
    BLOCK = "block"
    WORKER = "worker"
    EARNINGS = "earnings"
    SYSTEM = "system"

class NotificationService:
    """Service for managing mining dashboard notifications."""
    
    def __init__(self, state_manager):
        """Initialize with state manager for persistence."""
        self.state_manager = state_manager
        self.notifications = []
        self.daily_stats_time = "00:00:00"  # When to post daily stats (midnight)
        self.last_daily_stats = None
        self.max_notifications = 100  # Maximum number to store
        self.last_block_height = None  # Track the last seen block height
        self.last_payout_notification_time = None  # Track the last payout notification time
        self.last_estimated_payout_time = None  # Track the last estimated payout time
        
        # Load existing notifications from state
        self._load_notifications()
        
        # Load last block height from state
        self._load_last_block_height()

    def _get_current_time(self) -> datetime:
        """Get current datetime with the configured timezone."""
        try:
            tz = pytz.timezone(get_timezone())
            return datetime.now(tz)
        except Exception as e:
            logging.error(f"[NotificationService] Error getting timezone: {e}")
            # Fallback to naive datetime if timezone fails
            return datetime.now()
    
    def _parse_timestamp(self, timestamp_str: str) -> datetime:
        """Parse an ISO format timestamp string into a timezone-aware datetime."""
        try:
            # Parse the naive datetime from the string
            dt = datetime.fromisoformat(timestamp_str)
            
            # If it's already timezone-aware, return it
            if dt.tzinfo is not None:
                return dt
                
            # Otherwise, make it timezone-aware
            tz = pytz.timezone(get_timezone())
            return tz.localize(dt)
        except Exception as e:
            logging.error(f"[NotificationService] Error parsing timestamp: {e}")
            # Return current time as fallback
            return self._get_current_time()
    
    def _get_redis_value(self, key: str, default: Any = None) -> Any:
        """Generic method to retrieve values from Redis."""
        try:
            if hasattr(self.state_manager, 'redis_client') and self.state_manager.redis_client:
                value = self.state_manager.redis_client.get(key)
                if value:
                    return value.decode('utf-8')
            return default
        except Exception as e:
            logging.error(f"[NotificationService] Error retrieving {key} from Redis: {e}")
            return default

    def _set_redis_value(self, key: str, value: Any) -> bool:
        """Generic method to set values in Redis."""
        try:
            if hasattr(self.state_manager, 'redis_client') and self.state_manager.redis_client:
                self.state_manager.redis_client.set(key, str(value))
                logging.info(f"[NotificationService] Saved {key} to Redis: {value}")
                return True
            return False
        except Exception as e:
            logging.error(f"[NotificationService] Error saving {key} to Redis: {e}")
            return False
    
    def _load_notifications(self) -> None:
        """Load notifications with enhanced error handling."""
        try:
            stored_notifications = self.state_manager.get_notifications()
            if stored_notifications:
                self.notifications = stored_notifications
                logging.info(f"[NotificationService] Loaded {len(self.notifications)} notifications from storage")
            else:
                self.notifications = []
                logging.info("[NotificationService] No notifications found in storage, starting with empty list")
        except Exception as e:
            logging.error(f"[NotificationService] Error loading notifications: {e}")
            self.notifications = []  # Ensure we have a valid list
    
    def _load_last_block_height(self) -> None:
        """Load last block height from persistent storage."""
        try:
            self.last_block_height = self._get_redis_value("last_block_height")
            if self.last_block_height:
                logging.info(f"[NotificationService] Loaded last block height from storage: {self.last_block_height}")
            else:
                logging.info("[NotificationService] No last block height found, starting with None")
        except Exception as e:
            logging.error(f"[NotificationService] Error loading last block height: {e}")
    
    def _save_last_block_height(self) -> None:
        """Save last block height to persistent storage."""
        if self.last_block_height:
            self._set_redis_value("last_block_height", self.last_block_height)
    
    def _save_notifications(self) -> None:
        """Save notifications with improved pruning."""
        try:
            # Sort by timestamp before pruning to ensure we keep the most recent
            if len(self.notifications) > self.max_notifications:
                self.notifications.sort(key=lambda n: n.get("timestamp", ""), reverse=True)
                self.notifications = self.notifications[:self.max_notifications]
                
            self.state_manager.save_notifications(self.notifications)
            logging.info(f"[NotificationService] Saved {len(self.notifications)} notifications")
        except Exception as e:
            logging.error(f"[NotificationService] Error saving notifications: {e}")
    
    def add_notification(self, 
                        message: str, 
                        level: NotificationLevel = NotificationLevel.INFO, 
                        category: NotificationCategory = NotificationCategory.SYSTEM, 
                        data: Optional[Dict[str, Any]] = None) -> Dict[str, Any]:
        """
        Add a new notification.
        
        Args:
            message (str): Notification message text
            level (NotificationLevel): Severity level
            category (NotificationCategory): Classification category
            data (dict, optional): Additional data for the notification
            
        Returns:
            dict: The created notification
        """
        notification = {
            "id": str(uuid.uuid4()),
            "timestamp": self._get_current_time().isoformat(),
            "message": message,
            "level": level.value,
            "category": category.value,
            "read": False
        }
        
        if data:
            notification["data"] = data
        
        self.notifications.append(notification)
        self._save_notifications()
        
        logging.info(f"[NotificationService] Added notification: {message}")
        return notification
    
    def get_notifications(self, 
                         limit: int = 50, 
                         offset: int = 0, 
                         unread_only: bool = False, 
                         category: Optional[str] = None, 
                         level: Optional[str] = None) -> List[Dict[str, Any]]:
        """
        Get filtered notifications with optimized filtering.
        
        Args:
            limit (int): Maximum number to return
            offset (int): Starting offset for pagination
            unread_only (bool): Only return unread notifications
            category (str): Filter by category
            level (str): Filter by level
            
        Returns:
            list: Filtered notifications
        """
        # Apply all filters in a single pass
        filtered = [
            n for n in self.notifications
            if (not unread_only or not n.get("read", False)) and
               (not category or n.get("category") == category) and
               (not level or n.get("level") == level)
        ]
        
        # Sort by timestamp (newest first)
        filtered = sorted(filtered, key=lambda n: n.get("timestamp", ""), reverse=True)
        
        # Apply pagination
        return filtered[offset:offset + limit]
    
    def get_unread_count(self) -> int:
        """Get count of unread notifications."""
        return sum(1 for n in self.notifications if not n.get("read", False))
    
    def mark_as_read(self, notification_id: Optional[str] = None) -> bool:
        """
        Mark notification(s) as read.
        
        Args:
            notification_id (str, optional): ID of specific notification to mark read,
                                            or None to mark all as read
        
        Returns:
            bool: True if successful
        """
        if notification_id:
            # Mark specific notification as read
            for n in self.notifications:
                if n.get("id") == notification_id:
                    n["read"] = True
                    logging.info(f"[NotificationService] Marked notification {notification_id} as read")
                    break
        else:
            # Mark all as read
            for n in self.notifications:
                n["read"] = True
            logging.info(f"[NotificationService] Marked all {len(self.notifications)} notifications as read")
        
        self._save_notifications()
        return True
    
    def delete_notification(self, notification_id: str) -> bool:
        """
        Delete a specific notification.
        
        Args:
            notification_id (str): ID of notification to delete
            
        Returns:
            bool: True if successful
        """
        original_count = len(self.notifications)
        self.notifications = [n for n in self.notifications if n.get("id") != notification_id]
        deleted = original_count - len(self.notifications)
        
        if deleted > 0:
            logging.info(f"[NotificationService] Deleted notification {notification_id}")
            self._save_notifications()
        
        return deleted > 0
    
    def clear_notifications(self, category: Optional[str] = None, older_than_days: Optional[int] = None) -> int:
        """
        Clear notifications with optimized filtering.
        
        Args:
            category (str, optional): Only clear specific category
            older_than_days (int, optional): Only clear notifications older than this
            
        Returns:
            int: Number of notifications cleared
        """
        original_count = len(self.notifications)
        
        cutoff_date = None
        if older_than_days:
            cutoff_date = self._get_current_time() - timedelta(days=older_than_days)
            
        # Apply filters in a single pass
        self.notifications = [
            n for n in self.notifications
            if (not category or n.get("category") != category) and
               (not cutoff_date or self._parse_timestamp(n.get("timestamp", self._get_current_time().isoformat())) >= cutoff_date)
        ]
        
        cleared_count = original_count - len(self.notifications)
        if cleared_count > 0:
            logging.info(f"[NotificationService] Cleared {cleared_count} notifications")
            self._save_notifications()
        
        return cleared_count
    
    def check_and_generate_notifications(self, current_metrics: Dict[str, Any], previous_metrics: Optional[Dict[str, Any]]) -> List[Dict[str, Any]]:
        """
        Check metrics and generate notifications for significant events.
        
        Args:
            current_metrics: Current system metrics
            previous_metrics: Previous system metrics for comparison
            
        Returns:
            list: Newly created notifications
        """
        new_notifications = []
    
        try:
            # Skip if no metrics
            if not current_metrics:
                logging.warning("[NotificationService] No current metrics available, skipping notification checks")
                return new_notifications
        
            # Check for block updates (using persistent storage)
            last_block_height = current_metrics.get("last_block_height")
            if last_block_height and last_block_height != "N/A":
                if self.last_block_height is not None and self.last_block_height != last_block_height:
                    logging.info(f"[NotificationService] Block change detected: {self.last_block_height} -> {last_block_height}")
                    block_notification = self._generate_block_notification(current_metrics)
                    if block_notification:
                        new_notifications.append(block_notification)
            
                # Always update the stored last block height when it changes
                if self.last_block_height != last_block_height:
                    self.last_block_height = last_block_height
                    self._save_last_block_height()
        
            # Regular comparison with previous metrics
            if previous_metrics:
                # Check for daily stats
                if self._should_post_daily_stats():
                    stats_notification = self._generate_daily_stats(current_metrics)
                    if stats_notification:
                        new_notifications.append(stats_notification)
            
                # Check for significant hashrate drop
                hashrate_notification = self._check_hashrate_change(current_metrics, previous_metrics)
                if hashrate_notification:
                    new_notifications.append(hashrate_notification)
            
                # Check for earnings and payout progress
                earnings_notification = self._check_earnings_progress(current_metrics, previous_metrics)
                if earnings_notification:
                    new_notifications.append(earnings_notification)
        
            return new_notifications
            
        except Exception as e:
            logging.error(f"[NotificationService] Error generating notifications: {e}")
            error_notification = self.add_notification(
                f"Error generating notifications: {str(e)}",
                level=NotificationLevel.ERROR,
                category=NotificationCategory.SYSTEM
            )
            return [error_notification]
    
    def _should_post_daily_stats(self) -> bool:
        """Check if it's time to post daily stats with improved clarity."""
        now = self._get_current_time()
        
        # Only proceed if we're in the target hour and within first 5 minutes
        if now.hour != DEFAULT_TARGET_HOUR or now.minute >= NOTIFICATION_WINDOW_MINUTES:
            return False
            
        # If we have a last_daily_stats timestamp, check if it's a different day
        if self.last_daily_stats and now.date() <= self.last_daily_stats.date():
            return False
            
        # All conditions met, update timestamp and return True
        logging.info(f"[NotificationService] Posting daily stats at {now.hour}:{now.minute}")
        self.last_daily_stats = now
        return True
    
    def _generate_daily_stats(self, metrics: Dict[str, Any]) -> Optional[Dict[str, Any]]:
        """Generate daily stats notification."""
        try:
            if not metrics:
                logging.warning("[NotificationService] No metrics available for daily stats")
                return None
                
            # Format hashrate with appropriate unit
            hashrate_24hr = metrics.get("hashrate_24hr", 0)
            hashrate_unit = metrics.get("hashrate_24hr_unit", "TH/s")
            
            # Format daily earnings
            daily_mined_sats = metrics.get("daily_mined_sats", 0)
            daily_profit_usd = metrics.get("daily_profit_usd", 0)
            
            # Build message
            message = f"Daily Mining Summary: {hashrate_24hr} {hashrate_unit} average hashrate, {daily_mined_sats} SATS mined (${daily_profit_usd:.2f})"
            
            # Add notification
            logging.info(f"[NotificationService] Generating daily stats notification: {message}")
            return self.add_notification(
                message,
                level=NotificationLevel.INFO,
                category=NotificationCategory.HASHRATE,
                data={
                    "hashrate": hashrate_24hr,
                    "unit": hashrate_unit,
                    "daily_sats": daily_mined_sats,
                    "daily_profit": daily_profit_usd
                }
            )
        except Exception as e:
            logging.error(f"[NotificationService] Error generating daily stats notification: {e}")
            return None
    
    def _generate_block_notification(self, metrics: Dict[str, Any]) -> Optional[Dict[str, Any]]:
        """Generate notification for a new block found."""
        try:
            last_block_height = metrics.get("last_block_height", "Unknown")
            last_block_earnings = metrics.get("last_block_earnings", "0")
            
            logging.info(f"[NotificationService] Generating block notification: height={last_block_height}, earnings={last_block_earnings}")
            
            message = f"New block found by the pool! Block #{last_block_height}, earnings: {last_block_earnings} SATS"
            
            return self.add_notification(
                message,
                level=NotificationLevel.SUCCESS,
                category=NotificationCategory.BLOCK,
                data={
                    "block_height": last_block_height,
                    "earnings": last_block_earnings
                }
            )
        except Exception as e:
            logging.error(f"[NotificationService] Error generating block notification: {e}")
            return None
    
    def _parse_numeric_value(self, value_str: Any) -> float:
        """Parse numeric values from strings that may include units."""
        if isinstance(value_str, (int, float)):
            return float(value_str)
            
        if isinstance(value_str, str):
            # Extract just the numeric part
            parts = value_str.split()
            try:
                return float(parts[0])
            except (ValueError, IndexError):
                pass
        
        return 0.0
    
    def _check_hashrate_change(self, current: Dict[str, Any], previous: Dict[str, Any]) -> Optional[Dict[str, Any]]:
        """Check for significant hashrate changes using 10-minute average."""
        try:
            # Get 10min hashrate values
            current_10min = current.get("hashrate_10min", 0)
            previous_10min = previous.get("hashrate_10min", 0)
    
            # Log what we're comparing
            logging.debug(f"[NotificationService] Comparing 10min hashrates - current: {current_10min}, previous: {previous_10min}")
    
            # Skip if values are missing
            if not current_10min or not previous_10min:
                logging.debug("[NotificationService] Skipping hashrate check - missing values")
                return None
    
            # Parse values consistently
            current_value = self._parse_numeric_value(current_10min)
            previous_value = self._parse_numeric_value(previous_10min)
            
            logging.debug(f"[NotificationService] Converted 10min hashrates - current: {current_value}, previous: {previous_value}")
    
            # Skip if previous was zero (prevents division by zero)
            if previous_value == 0:
                logging.debug("[NotificationService] Skipping hashrate check - previous was zero")
                return None
        
            # Calculate percentage change
            percent_change = ((current_value - previous_value) / previous_value) * 100
            logging.debug(f"[NotificationService] 10min hashrate change: {percent_change:.1f}%")
    
            # Significant decrease
            if percent_change <= -SIGNIFICANT_HASHRATE_CHANGE_PERCENT:
                message = f"Significant 10min hashrate drop detected: {abs(percent_change):.1f}% decrease"
                logging.info(f"[NotificationService] Generating hashrate notification: {message}")
                return self.add_notification(
                    message,
                    level=NotificationLevel.WARNING,
                    category=NotificationCategory.HASHRATE,
                    data={
                        "previous": previous_value,
                        "current": current_value,
                        "change": percent_change,
                        "timeframe": "10min"
                    }
                )
    
            # Significant increase
            elif percent_change >= SIGNIFICANT_HASHRATE_CHANGE_PERCENT:
                message = f"10min hashrate increase detected: {percent_change:.1f}% increase"
                logging.info(f"[NotificationService] Generating hashrate notification: {message}")
                return self.add_notification(
                    message,
                    level=NotificationLevel.SUCCESS,
                    category=NotificationCategory.HASHRATE,
                    data={
                        "previous": previous_value,
                        "current": current_value,
                        "change": percent_change,
                        "timeframe": "10min"
                    }
                )
    
            return None
        except Exception as e:
            logging.error(f"[NotificationService] Error checking hashrate change: {e}")
            return None
    
    def _check_earnings_progress(self, current: Dict[str, Any], previous: Dict[str, Any]) -> Optional[Dict[str, Any]]:
        """Check for significant earnings progress or payout approach."""
        try:
            current_unpaid = self._parse_numeric_value(current.get("unpaid_earnings", "0"))
            
            # Check if approaching payout
            if current.get("est_time_to_payout"):
                est_time = current.get("est_time_to_payout")
                
                # If estimated time is a number of days
                if est_time.isdigit() or (est_time[0] == '-' and est_time[1:].isdigit()):
                    days = int(est_time)
                    if 0 < days <= 1:
                        if self._should_send_payout_notification():
                            message = f"Payout approaching! Estimated within 1 day"
                            self.last_payout_notification_time = self._get_current_time()
                            return self.add_notification(
                                message,
                                level=NotificationLevel.SUCCESS,
                                category=NotificationCategory.EARNINGS,
                                data={"days_to_payout": days}
                            )
                # If it says "next block"
                elif "next block" in est_time.lower():
                    if self._should_send_payout_notification():
                        message = f"Payout expected with next block!"
                        self.last_payout_notification_time = self._get_current_time()
                        return self.add_notification(
                            message,
                            level=NotificationLevel.SUCCESS,
                            category=NotificationCategory.EARNINGS,
                            data={"payout_imminent": True}
                        )
            
            # Check for payout (unpaid balance reset)
            if previous.get("unpaid_earnings"):
                previous_unpaid = self._parse_numeric_value(previous.get("unpaid_earnings", "0"))
                
                # If balance significantly decreased, likely a payout occurred
                if previous_unpaid > 0 and current_unpaid < previous_unpaid * 0.5:
                    message = f"Payout received! Unpaid balance reset from {previous_unpaid} to {current_unpaid} BTC"
                    return self.add_notification(
                        message,
                        level=NotificationLevel.SUCCESS,
                        category=NotificationCategory.EARNINGS,
                        data={
                            "previous_balance": previous_unpaid,
                            "current_balance": current_unpaid,
                            "payout_amount": previous_unpaid - current_unpaid
                        }
                    )
            
            return None
        except Exception as e:
            logging.error(f"[NotificationService] Error checking earnings progress: {e}")
            return None

    def _should_send_payout_notification(self) -> bool:
        """Check if enough time has passed since the last payout notification."""
        if self.last_payout_notification_time is None:
            return True
        time_since_last_notification = self._get_current_time() - self.last_payout_notification_time
        return time_since_last_notification.total_seconds() > ONE_DAY_SECONDS