pflaenz.li/pflaenzli/pflaenzli/utils/distance.py

from geopy.distance import distance
import os
from pflaenzli.models import Plz


def calculate_distance(plz_1: Plz, plz_2: Plz):
    if plz_1 == plz_2:
        return 0

    try:
        dist = round(distance((plz_1.lat, plz_1.lon), (plz_2.lat, plz_2.lon)).kilometers)
    except AttributeError:
        return None

    return None if dist > 400 else dist


def filter_by_distance(qs, filter_zipcode, max_dist):
    filtered_offers = []

    try:
        filter_plz = Plz.objects.get(plz=filter_zipcode)
    except Plz.MultipleObjectsReturned:
        filter_plz = Plz.objects.filter(plz=filter_zipcode)[0]
    except Plz.DoesNotExist:
        return filtered_offers

    for offer in qs:
        try:
            offer_plz = Plz.objects.get(plz=offer.zipcode)
        except Plz.MultipleObjectsReturned:
            offer_plz = Plz.objects.filter(plz=offer.zipcode)[0]
        except Plz.DoesNotExist:
            offer_plz = None

        d = calculate_distance(offer_plz, filter_plz)
        if d is not None and d <= max_dist:
            filtered_offers.append(offer)
    return filtered_offers