Python script to find best prices for gas

best.py

# /// script
# requires-python = ">=3.12"
# dependencies = [
#     "requests",
# ]
# ///

import argparse
import csv
import shutil
from datetime import datetime, timedelta
from os.path import getmtime
from typing import Iterable

import requests


def _load_csv(url: str, filename: str) -> Iterable[list[str]]:
    download = True
    try:
        mtime = datetime.fromtimestamp(getmtime(filename))
        now = datetime.now()
        if timedelta(hours=24) > (now - mtime):
            download = False
    except FileNotFoundError:
        pass
    if download:
        with requests.get(url, stream=True) as r:
            r.raw.decode_content = True
            r.raise_for_status()
            with open(filename, "wb") as f:
                shutil.copyfileobj(r.raw, f)
    with open(filename, newline="") as csvfile:
        csvfile.read(26)  # Header
        prezzireader = csv.reader(csvfile, delimiter=";")
        return list(prezzireader)


def load_prices() -> Iterable[list[str]]:
    return _load_csv("https://www.mise.gov.it/images/exportCSV/prezzo_alle_8.csv", "prezzi.csv")


def load_stations() -> Iterable[list[str]]:
    return _load_csv(
        "https://www.mise.gov.it/images/exportCSV/anagrafica_impianti_attivi.csv", "impianti.csv"
    )


def main_cli() -> None:
    parser = argparse.ArgumentParser(
        description="Trova i migliori prezzi di carburante intorno a te."
    )
    parser.add_argument(
        "-c",
        "--carburante",
        type=str,
        dest="fuel_type",
        help="Tipo di carubrante (benzina, diesel, GPL, ...)",
        default="benzina",
    )
    parser.add_argument(
        "-r",
        "--raggio",
        type=float,
        dest="radius",
        help="Raggio di ricerca, in gradi decimali",
        default=0.015,
    )
    parser.add_argument(
        "-n",
        "--numero",
        type=int,
        dest="limit",
        help="Numero di risultati desiderati",
        default=5,
    )
    parser.add_argument("lat", type=float, metavar="latitudine", help="Un numero tra i 47 e i 35")
    parser.add_argument("long", type=float, metavar="longitudine", help="Un numero tra i 8 e i 18")
    args = parser.parse_args()
    return main(args)


def main(args: argparse.Namespace) -> None:
    pradius = pow(args.radius, 2)
    fuel_type = args.fuel_type.lower()

    def filter_stations(s):
        try:
            return (
                pow(abs(float(s[8]) - args.lat), 2) + pow(abs(float(s[9]) - args.long), 2) < pradius
            )
        except:
            # invalid rows
            return False

    stations = load_stations()
    stations = [s for s in stations if filter_stations(s)]
    id_stations = set([s[0] for s in stations])
    prices = load_prices()
    prices = [p for p in prices if p[0] in id_stations]
    prices = [p for p in prices if fuel_type in p[1].lower()]
    prices = sorted(prices, key=lambda p: float(p[2]))
    for price in prices[: args.limit]:
        station = [s for s in stations if s[0] == price[0]][0]
        print(station[1], station[5], station[6], price[2])


main_cli()