from constants import DB_NAME, DB_PW, DB_USER
from pandas import DataFrame, read_csv
from sqlalchemy import create_engine, engine


def create_connection() -> engine:
    host = "localhost:3306"
    connection_uri = "mysql+pymysql://{user}:{pw}@{url}/{db}".format(
        user=DB_USER, pw=DB_PW, url=host, db=DB_NAME
    )
    engine = create_engine(connection_uri)
    return engine


def create_dataframes() -> DataFrame:
    files = {
        "glacier": "../data/glacier.csv",
        "annual__data": "../data/annual_data.csv",
        "annual__change": "../data/annual_change.csv",
        "users": "../data/users.csv",
    }
    df_list = {}
    for csv in files.keys():
        df_list[csv] = read_csv(files[csv])
    return df_list


def insert_data(df_list, conn):
    for key, value in df_list.items():
        value.to_sql(key, con=conn, index=False, if_exists="append", chunksize=1)


def main():
    conn = create_connection()
    df_list = create_dataframes()
    insert_data(df_list, conn)


if __name__ == "__main__":
    main()