private void ScheduleTrip(Patron patron)
{
Trip last;
/* Backfill the schedule until the Patron's request can be fulfilled,
* if at all possible given known set of constraints. */
while ((last = _scheduledTrips
.Where(t => t.IsNorthbound == patron.IsNorthbound)
.OrderBy(t => t.DepartureTimeMinutes).LastOrDefault())
.CannotBeScheduled(patron, GetStopIntervalsMinutes))
{
TripConstraint constraint;
var nextDepartureTimeMinutes = GetNextDepartureTimeMinutes(last, patron, out constraint);
// It is not possible to fulfill the Patron's itinerary given the allowable constraints.
if (nextDepartureTimeMinutes == null) break;
var trip = new Trip(constraint, nextDepartureTimeMinutes.Value);
_scheduledTrips.Add(trip);
}
// Because Patron may have jumped into the queue midstream.
patron.Itinerary = _scheduledTrips.First(
t => t.CanBeScheduled(patron, GetStopIntervalsMinutes));
}
// ReSharper disable SuggestBaseTypeForParameter
/// <summary>
///
/// </summary>
/// <param name="trip"></param>
/// <param name="patron"></param>
/// <param name="constraint"></param>
/// <returns></returns>
/// <remarks>This was another impacted area where not only calculating the desired
/// departure time, but also knowing about the associated constraint, was desirable.</remarks>
private int? GetNextDepartureTimeMinutes(Trip trip, Patron patron, out TripConstraint constraint)
{
// Should work for both Northbound (true/false), inverse of which is Southbound.
constraint = Constraints.Single(t => t.IsNorthbound == patron.IsNorthbound);
if (trip == null)
return constraint.FirstDepartureTimeMinutes;
var dtm = trip.DepartureTimeMinutes;
// Which closing the loop the refactor should be relatively painless after all.
var result = dtm + constraint.Frequencies.GetWaitTimeMinutes(dtm);
return result > constraint.MaxAllowableDepartureTimeMinutes
? (int?) null
: result;
}