#!/bin/env python3

# cost should be given in cents
def tanken(drives, cost, service_charge=0):
    passengers = {}
    service_charges = {}
    distance = 0.
    drives = [d.split(' ') for d in drives]

    for d in drives:
        try:
            d[0] = int(d[0])
        except:
            return None, "Lines have to start with the driven distance!"

        # calculate overall distance
        distance += d[0]

        # collect distances per passenger
        for p in d[1:]:
            if p not in passengers:
                passengers[p] = {"distance": d[0],
                                 "cost": 0,
                                 "service_charge": 0}
            else:
                passengers[p]["distance"] += d[0]
   
    # calculate cost per kilometer
    if distance <= 0:
        return None, "Driven distance must be greater than 0!"

    c = cost/distance

    for d in drives:
        # calculate cost per drive split among passengers
        c_d = int(c * d[0] / (len(d) - 1))
        for p in d[1:]:
            passengers[p]["cost"] += c_d

        # calculate service charge per drive split among passengers
        sc_d = int(service_charge * d[0] / (len(d) - 1))
        for p in d[1:]:
            passengers[p]["service_charge"] += sc_d

    return passengers, None