import sqlite3
import csv
from typing import TextIO

def create_precipitation_table(db: str, data_file: TextIO) -> None:
    """Populate the database db with the contents of data_file
    as follows:
    Create a table called precipitation with four columns:
    city (text), snow (real), total (integer), days (integer).
    
    data_file (csv file): every line contatins one city, 
    snowfall amount, total precipitation amount, 
    and number of days per line
    """
    
    # Connect to database db
    con = sqlite3.connect(db)
    
    # Get the cursor
    cur = con.cursor()
    
    # Create precipitation table
    cur.execute(
        """CREATE TABLE precipitation (
        city TEXT,
        snow REAL,
        total INTEGER,
        days INTEGER)""")
    
    # Populate the precipitation table
    # Loop through each line in the csv file and insert data into the table
    reader = csv.reader(data_file)
    for line in reader:
        city = line[0]
        snow = line[1]
        total = line[2]
        days = line[3]
        
        # Now, we execute a 'INSERT' SQL query
        cur.execute("""INSERT INTO precipitation
        VALUES(?, ?, ?, ?)""", (city, snow, total, days))
  
    # commit changes
    con.commit()
    # Close the cursor
    cur.close()
    # Close the connection
    con.close()  
    
    
if __name__ == '__main__':
    db = 'weather.db'
    # create the database weather.db
    create_database = True
    
    if create_database:
        # set up the precipitation table
        precipitation_file = open('precipitation.csv')
        create_precipitation_table(db, precipitation_file)
        precipitation_file.close()