from datetime import date
import requests
from decimal import Decimal

# Import your database model and the session from your database configuration
from app.models.auto import Auto_Temp
from database import session

def Average(lst):
    """Calculates the average of a list of numbers."""
    return sum(lst) / len(lst)

def fetch_and_store_daily_temp() -> bool:
    """
    Fetches the current day's weather for Worcester, MA, calculates the
    Heating Degree Day (HDD), and stores it in the database if it doesn't already exist.

    Returns:
        bool: True if the temperature is successfully fetched and stored (or already exists),
              False if an error occurs.
    """
    # 1. Check if the temperature for today already exists in the database
    today = date.today()
    if session.query(Auto_Temp).filter(Auto_Temp.todays_date == today).first():
        print(f"Temperature for {today} already exists in the database. Skipping fetch.")
        return True

    # 2. If it doesn't exist, fetch it from the API
    print(f"Fetching temperature for {today} from OpenWeatherMap...")
    try:
        # API key and location
        api_key = '21648d8c8d1a4ae495ace0b7810b4d36'
        location = 'Worcester,US'

        # Make request to OpenWeatherMap Current Weather API with imperial units for Fahrenheit
        url = f"http://api.openweathermap.org/data/2.5/weather?q={location}&appid={api_key}&units=imperial"
        response = requests.get(url)
        response.raise_for_status()  # Raise an error for bad status codes

        data = response.json()

        # Extract temperatures in Fahrenheit
        main = data.get('main', {})
        current_temp = Decimal(main.get('temp', 0))
        low_temp = Decimal(main.get('temp_min', 0))
        high_temp = Decimal(main.get('temp_max', 0))

        # Calculate average temperature and Heating Degree Days (HDD)
        avg_temp = (low_temp + high_temp) / 2
        
        # HDD is based on a baseline of 65°F. It cannot be negative for heating calculations.
        degree_day = max(Decimal(0), 65 - avg_temp)

        # 3. Create a new database object
        add_new_temp = Auto_Temp(
            temp=current_temp,
            temp_max=high_temp,
            temp_min=low_temp,
            temp_avg=round(avg_temp, 2),
            degree_day=round(degree_day),
            todays_date=today
        )
        
        # 4. Add the new record to the session (it will be committed by the calling function)
        session.add(add_new_temp)
        print(f"Successfully fetched and staged temperature for {today}.")
        return True

    except Exception as e:
        print(f"An error occurred while fetching weather data: {e}")
        # Make sure to rollback the session in case of a partial failure
        session.rollback()
        return False