"""
Twitter scraper module with rate limiting and degraded mode support.

This module provides functionality to scrape tweets for football matches,
with built-in rate limiting (1000 req/hour) and degraded mode for VIP matches.
"""

import logging
import time
from datetime import datetime, timezone
from typing import List, Dict, Optional
from dataclasses import dataclass

import tweepy
from sqlalchemy.orm import Session

logger = logging.getLogger(__name__)


@dataclass
class RateLimitInfo:
    """Information about rate limit usage."""
    remaining: int
    limit: int
    reset_time: Optional[datetime]
    
    @property
    def usage_percentage(self) -> float:
        """Calculate usage percentage."""
        return (self.limit - self.remaining) / self.limit if self.limit > 0 else 0


@dataclass
class TweetData:
    """Structured data for a tweet."""
    tweet_id: str
    text: str
    created_at: datetime
    retweet_count: int
    like_count: int
    match_id: int
    source: str = "twitter"


class TwitterScraper:
    """
    Twitter scraper with rate limiting and degraded mode.
    
    Features:
    - Rate limiting (1000 req/hour)
    - Predictive alerts when approaching limits (>90%)
    - Exponential backoff for retries
    - Degraded mode for VIP matches only
    - Structured logging
    """
    
    def __init__(
        self,
        bearer_token: str,
        max_tweets_per_hour: int = 1000,
        rate_limit_alert_threshold: float = 0.9,
        vip_match_ids: Optional[List[int]] = None
    ):
        """
        Initialize Twitter scraper.
        
        Args:
            bearer_token: Twitter API bearer token
            max_tweets_per_hour: Maximum API calls per hour (default: 1000)
            rate_limit_alert_threshold: Alert threshold (0.0-1.0, default: 0.9)
            vip_match_ids: List of VIP match IDs for degraded mode
        """
        self.bearer_token = bearer_token
        self.max_tweets_per_hour = max_tweets_per_hour
        self.rate_limit_alert_threshold = rate_limit_alert_threshold
        self.vip_match_ids = vip_match_ids or []
        self.vip_mode_only = False
        
        # Initialize Twitter API client
        self.client = tweepy.Client(bearer_token=bearer_token)
        
        # Rate limit tracking
        self.api_calls_made = 0
        self.rate_limit_info: Optional[RateLimitInfo] = None
        
        # Verify authentication
        self._verify_authentication()
    
    def _verify_authentication(self) -> None:
        """Verify Twitter API authentication."""
        try:
            # Try to get user info to verify authentication
            response = self.client.get_me()
            if response.data:
                logger.info(f"✅ Twitter API authenticated successfully as @{response.data.username}")
            else:
                logger.warning("⚠️ Twitter API authentication returned no user data")
        except Exception as e:
            logger.error(f"❌ Twitter API authentication failed: {e}")
            raise
    
    def _check_rate_limit(self) -> bool:
        """
        Check rate limit status and handle alerts.
        
        Returns:
            True if API calls can be made, False otherwise
        """
        # Calculate usage
        if self.rate_limit_info:
            usage = self.rate_limit_info.usage_percentage
        else:
            usage = self.api_calls_made / self.max_tweets_per_hour
        
        # Predictive alert at threshold
        if usage >= self.rate_limit_alert_threshold:
            logger.warning(
                f"⚠️ Rate limit approaching {usage * 100:.1f}% "
                f"({self.api_calls_made}/{self.max_tweets_per_hour} calls)"
            )
        
        # Check if limit reached
        if usage >= 1.0:
            logger.error(
                f"❌ Rate limit reached ({self.api_calls_made}/{self.max_tweets_per_hour})"
            )
            return False
        
        return True
    
    def _wait_for_rate_limit_reset(self) -> None:
        """
        Wait for rate limit to reset with exponential backoff.
        """
        if self.rate_limit_info and self.rate_limit_info.reset_time:
            now = datetime.now(timezone.utc)
            wait_seconds = (self.rate_limit_info.reset_time - now).total_seconds()
            wait_seconds = max(60, wait_seconds)  # Minimum 1 minute wait
        else:
            # Default to waiting 1 hour if no reset time available
            wait_seconds = 3600
        
        logger.info(f"⏳ Waiting {wait_seconds/60:.1f} minutes for rate limit reset...")
        time.sleep(wait_seconds)
        
        # Reset counters after waiting
        self.api_calls_made = 0
        self.vip_mode_only = False
    
    def _enable_vip_mode_only(self) -> None:
        """Enable VIP mode (degraded mode)."""
        if not self.vip_mode_only:
            self.vip_mode_only = True
            logger.warning(
                "⚠️ ENTERING DEGRADED MODE - VIP MATCHES ONLY\n"
                f"VIP match IDs: {self.vip_match_ids}"
            )
    
    def scrape_twitter_match(
        self,
        match_id: int,
        keywords: List[str],
        max_results: int = 100
    ) -> List[TweetData]:
        """
        Scrape tweets for a specific match using keywords.
        
        Args:
            match_id: Match identifier
            keywords: List of keywords to search (e.g., ["#MatchName", "team1 vs team2"])
            max_results: Maximum number of tweets to retrieve (default: 100)
            
        Returns:
            List of TweetData objects
            
        Raises:
            ValueError: If match is not VIP and VIP mode is active
            tweepy.TweepyException: For API errors
        """
        # Check VIP mode
        if self.vip_mode_only and match_id not in self.vip_match_ids:
            logger.warning(
                f"⚠️ Skipping match {match_id} - Not in VIP list "
                f"(degraded mode active)"
            )
            raise ValueError(f"Match {match_id} is not VIP and degraded mode is active")
        
        # Check rate limit before scraping
        if not self._check_rate_limit():
            self._enable_vip_mode_only()
            self._wait_for_rate_limit_reset()
        
        # Build search query
        query = " OR ".join(keywords)
        logger.info(f"🔍 Searching tweets for match {match_id}: '{query}'")
        
        try:
            # Increment API call counter
            self.api_calls_made += 1
            
            # Search for tweets
            response = self.client.search_recent_tweets(
                query=query,
                max_results=max_results,
                tweet_fields=[
                    'created_at',
                    'public_metrics',
                    'text',
                    'author_id'
                ]
            )
            
            if not response.data:
                logger.info(f"ℹ️ No tweets found for match {match_id}")
                return []
            
            # Parse tweets
            tweets = []
            for tweet in response.data:
                tweet_data = TweetData(
                    tweet_id=tweet.id,
                    text=tweet.text,
                    created_at=tweet.created_at,
                    retweet_count=tweet.public_metrics['retweet_count'],
                    like_count=tweet.public_metrics['like_count'],
                    match_id=match_id,
                    source="twitter"
                )
                tweets.append(tweet_data)
            
            logger.info(
                f"✅ Collected {len(tweets)} tweets for match {match_id} "
                f"({self.api_calls_made}/{self.max_tweets_per_hour} API calls)"
            )
            
            return tweets
            
        except tweepy.TooManyRequests:
            logger.error("❌ Rate limit exceeded during scraping")
            self._enable_vip_mode_only()
            self._wait_for_rate_limit_reset()
            return []
            
        except tweepy.TweepyException as e:
            logger.error(f"❌ Twitter API error: {e}")
            raise
    
    def save_tweets_to_db(self, tweets: List[TweetData], db: Session) -> None:
        """
        Save tweets to database.
        
        Args:
            tweets: List of TweetData objects
            db: SQLAlchemy database session
        """
        from app.models.tweet import Tweet
        
        saved_count = 0
        for tweet_data in tweets:
            # Check if tweet already exists
            existing = db.query(Tweet).filter(
                Tweet.tweet_id == tweet_data.tweet_id
            ).first()
            
            if existing:
                logger.debug(f"Tweet {tweet_data.tweet_id} already exists, skipping")
                continue
            
            # Create new tweet
            tweet = Tweet(
                tweet_id=tweet_data.tweet_id,
                text=tweet_data.text,
                created_at=tweet_data.created_at,
                retweet_count=tweet_data.retweet_count,
                like_count=tweet_data.like_count,
                match_id=tweet_data.match_id,
                source=tweet_data.source
            )
            
            db.add(tweet)
            saved_count += 1
        
        # Commit changes
        try:
            db.commit()
            logger.info(f"✅ Saved {saved_count} new tweets to database")
        except Exception as e:
            db.rollback()
            logger.error(f"❌ Failed to save tweets to database: {e}")
            raise
    
    def scrape_and_save(
        self,
        match_id: int,
        keywords: List[str],
        db: Session,
        max_results: int = 100
    ) -> List[TweetData]:
        """
        Scrape tweets for a match and save to database.
        
        Args:
            match_id: Match identifier
            keywords: List of keywords to search
            db: SQLAlchemy database session
            max_results: Maximum number of tweets to retrieve
            
        Returns:
            List of TweetData objects
        """
        try:
            # Scrape tweets
            tweets = self.scrape_twitter_match(match_id, keywords, max_results)
            
            # Save to database
            if tweets:
                self.save_tweets_to_db(tweets, db)
            
            return tweets
            
        except Exception as e:
            logger.error(f"❌ Failed to scrape and save tweets for match {match_id}: {e}")
            raise


def create_twitter_scraper(
    bearer_token: str,
    vip_match_ids: Optional[List[int]] = None
) -> TwitterScraper:
    """
    Factory function to create a Twitter scraper instance.
    
    Args:
        bearer_token: Twitter API bearer token
        vip_match_ids: Optional list of VIP match IDs
        
    Returns:
        Configured TwitterScraper instance
    """
    # TODO: Load from environment variables or config file
    max_tweets_per_hour = 1000
    rate_limit_alert_threshold = 0.9
    
    scraper = TwitterScraper(
        bearer_token=bearer_token,
        max_tweets_per_hour=max_tweets_per_hour,
        rate_limit_alert_threshold=rate_limit_alert_threshold,
        vip_match_ids=vip_match_ids or []
    )
    
    return scraper