import requests
import logging
from datetime import datetime, timezone
from django.conf import settings

logger = logging.getLogger(__name__)


class CoinGeckoFetcher:
    """Fetches Bitcoin data from CoinGecko API."""
    
    def __init__(self):
        self.base_url = "https://api.coingecko.com/api/v3"
        self.session = requests.Session()
        self.session.headers.update({
            'User-Agent': 'BitcoinMonitor/1.0',
            'Accept': 'application/json',
        })
        
        # Optional API key for higher rate limits
        api_key = settings.BITCOIN_MONITOR.get('COINGECKO_API_KEY')
        if api_key:
            self.session.headers['x-cg-pro-api-key'] = api_key
    
    def fetch_current_price(self):
        """Fetch current Bitcoin price."""
        try:
            url = f"{self.base_url}/simple/price"
            params = {
                'ids': 'bitcoin',
                'vs_currencies': 'usd',
                'include_market_cap': 'true',
                'include_24hr_vol': 'true',
                'include_last_updated_at': 'true',
            }
            
            logger.debug(f"Fetching current price from {url}")
            response = self.session.get(url, params=params, timeout=10)
            response.raise_for_status()
            
            data = response.json()
            
            if 'bitcoin' not in data:
                logger.error("Bitcoin data not found in response")
                return None
            
            btc_data = data['bitcoin']
            
            return {
                'timestamp': datetime.fromtimestamp(
                    btc_data.get('last_updated_at', datetime.now(timezone.utc).timestamp()),
                    timezone.utc
                ),
                'price_usd': btc_data['usd'],
                'market_cap': btc_data.get('usd_market_cap'),
                'volume': btc_data.get('usd_24h_vol'),
            }
            
        except requests.exceptions.RequestException as e:
            logger.error(f"Request error fetching current price: {e}")
            return None
        except Exception as e:
            logger.error(f"Error fetching current price: {e}")
            return None
    
    def fetch_price_history(self, days=30):
        """Fetch historical price data (for future use)."""
        try:
            url = f"{self.base_url}/coins/bitcoin/market_chart"
            params = {
                'vs_currency': 'usd',
                'days': days,
                'interval': 'daily',
            }
            
            logger.debug(f"Fetching {days} days of price history")
            response = self.session.get(url, params=params, timeout=30)
            response.raise_for_status()
            
            data = response.json()
            
            prices = []
            for point in data.get('prices', []):
                prices.append({
                    'timestamp': datetime.fromtimestamp(point[0] / 1000, timezone.utc),
                    'price': point[1],
                })
            
            return {
                'prices': prices,
                'total_points': len(prices),
            }
            
        except requests.exceptions.RequestException as e:
            logger.error(f"Request error fetching price history: {e}")
            return None
        except Exception as e:
            logger.error(f"Error fetching price history: {e}")
            return None