add new car commands and make tanken aware of cars

Cars are names associated to a service charge. They are stored in the
state file in a dict called "cars". Each car has its own balance
from which money can be pulled or pushed. Because of this cars and users
can't share a name.

Service charges are calculated per drive and split among all drivers
similar to fuel cost. If a driver is not known by geldschieberbot the
recipient of the "tanken" cmd is held accountable and has to collect
the service charge manually just like fuel cost.

NOTE: This change breaks geldschieberbot if the state file does not contain the field "cars" !!!
      You have to add it manually !!!

1 files changed, 14 insertions, 5 deletions

diff --git a/tanken.py b/tanken.py
index 2ca80bd..b7064cd 100644
--- a/tanken.py
+++ b/tanken.py
@@ -1,8 +1,9 @@
 #!/bin/env python3
 
 # cost should be given in cents
-def tanken(drives, cost):
+def tanken(drives, cost, service_charge=0):
     passengers = {}
+    service_charges = {}
     distance = 0.
     drives = [d.split(' ') for d in drives]
 
@@ -18,19 +19,27 @@ def tanken(drives, cost):
         # collect distances per passenger
         for p in d[1:]:
             if p not in passengers:
-                passengers[p] = [d[0],0]
+                passengers[p] = {"distance": d[0],
+                                 "cost": 0,
+                                 "service_charge": 0}
             else:
-                passengers[p][0] += d[0]
+                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 through passengers
+        # calculate cost per drive split among passengers
         c_d = int(c * d[0] / (len(d) - 1))
         for p in d[1:]:
-            passengers[p][1] += c_d
+            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