import math

RADIUS = 3956.6

def give_intro():
    pass

def find(file, target_zip):
    for line in file:
        zip, lat, lng, city = line.rstrip().split(" : ")
        if zip == target_zip:
            print(zip + ":", city)
            return float(lat), float(lng)
    return 0, 0

def show_matches(file, lat1, lng1, miles):
    pass

def distance(lat1, lng1, lat2, lng2):
    lat1 = math.radians(lat1)
    lng1 = math.radians(lng1)
    lat2 = math.radians(lat2)
    lng2 = math.radians(lng2)
    the_cos = math.sin(lat1) * math.sin(lat2) \
        + math.cos(lat1)  * math.cos(lat2) * math.cos(lng1 - lng2)
    arc_length = math.acos(the_cos)
    return arc_length * RADIUS

def main():
    give_intro()
    zip = input("What zip code are you interested in? ")
    miles = float(input("And what proximity (in miles)? "))
    print()
    with open("zipcode.txt") as file:
        lat, lng = find(file, zip)
        file.seek(0)
        show_matches(file, lat, lng, miles)

main()