public async Task <IActionResult> RouteRequest(string startNode, string endNode, string routeType, TimeSpan startingTime)
{
try
{
// Get all student routes.
AllStudentRoutes = await CongestionHelper.GenerateAllStudentRoutes(DissDatabaseContext, Pathfinder, MemoryCache, AppSettings.Accommodations);
RouteRequestResponse response = new RouteRequestResponse();
// If start and end are the same, return empty response.
if (startNode == endNode)
{
return(Ok(response));
}
// Get a list of possible start and end nodes that fulfil this request.
List <string> starts = await RoutingHelper.GetMatchingIds(DissDatabaseContext, startNode, routeType[0].ToString());
List <string> ends = await RoutingHelper.GetMatchingIds(DissDatabaseContext, endNode, routeType.Last().ToString());
// Check we have a start location.
if (starts.Count == 0)
{
return(BadRequest("Could not find start points."));
}
// Check we have an end location.
if (ends.Count == 0)
{
return(BadRequest("Could not find end points"));
}
// Calculate all possible routes between all starts and all ends.
// There is more than one start or end point - probably more efficient to calculate in parallel.
if (starts.Count > 1 || ends.Count > 1)
{
ConcurrentBag <Route> possibleRoutes = new ConcurrentBag <Route>();
ConcurrentBag <Route> possibleAdjustedRoutes = new ConcurrentBag <Route>();
Parallel.ForEach(starts, startPoint =>
{
Parallel.ForEach(ends, destination =>
{
// Calculate route and add to possible.
possibleRoutes.Add(Pathfinder.BuildAStar(startPoint, destination));
possibleAdjustedRoutes.Add(Pathfinder.BuildAStar(startPoint, destination, AllStudentRoutes, startingTime));
});
});
// Find the shortest route from the possible routes.
response.NormalRoute = RoutingHelper.FindTheBestRouteFromPossibleRoutes(possibleRoutes.ToList());
response.AdjustedRoute = RoutingHelper.FindTheBestRouteFromPossibleRoutes(possibleAdjustedRoutes.ToList());
}
else
{
// Only one start and end point - only need to do this once, so avoid parallel overheads.
response.NormalRoute = Pathfinder.BuildAStar(starts[0], ends[0]);
response.AdjustedRoute = Pathfinder.BuildAStar(starts[0], ends[0], AllStudentRoutes, startingTime);
}
// Adjust walking times based on congestion values.
response.NormalRoute.CalculateAdjustedWalkingTime(AllStudentRoutes, startingTime);
response.AdjustedRoute.CalculateAdjustedWalkingTime(AllStudentRoutes, startingTime);
if (response.AdjustedRoute.WalkingTimeSeconds == response.NormalRoute.WalkingTimeSeconds)
{
// Both routes are the same, remove the adjusted route - there was likely no congestion.
response.AdjustedRoute = new Route();
}
return(Ok(response));
}
catch (Exception exception)
{
return(StatusCode(500, exception.Message));
}
}
