package org.simantics.district.route;

import java.util.List;
import java.util.Objects;
import java.util.concurrent.CompletableFuture;

import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.jobs.Job;
import org.eclipse.osgi.util.NLS;
import org.simantics.ObjectIdentitySchedulingRule;
import org.simantics.db.Resource;
import org.simantics.district.route.internal.Activator;
import org.simantics.district.route.internal.RoutePersistence;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author Tuukka Lehtonen
 * @since 6.09
 */
public class RouteJob extends Job {

    private static final Logger LOGGER = LoggerFactory.getLogger(RouteJob.class);

    private RouterConfiguration config;
    private List<Resource> waypoints;
    private CompletableFuture<List<Resource>> callback;

    public RouteJob(RouterConfiguration config, Route route, CompletableFuture<List<Resource>> callback) {
        super("Compute route");
        Objects.requireNonNull(callback, "Callback must be non-null");
        setUser(true);
        setRule(new ObjectIdentitySchedulingRule(route));
        this.config = config;
        this.waypoints = RoutePersistence.toResources(route.waypoints());
        this.callback = callback;
    }

    @Override
    protected IStatus run(IProgressMonitor monitor) {
        List<Router> routers = Activator.getInstance().getRouteService().routers();
        for (Router router : routers) {
            try {
                List<Resource> path = router.findShortestPath(config, waypoints);
                if (!path.isEmpty()) {
                    callback.complete(path);
                    return Status.OK_STATUS;
                }
            } catch (RoutingException e) {
                LOGGER.error("Routing failed for waypoints {} and router '{}'", waypoints, router, e);
                callback.completeExceptionally(e);
                // This results in UI feedback of the error.
                // Perhaps later we get rid of this and let the UI code handle the notifications.
                return new Status(IStatus.ERROR, Activator.PLUGIN_ID, e.getMessage());
            }
        }
        LOGGER.info("No router could calculate route between waypoints {}. Available routers: {}", waypoints, routers);
        return new Status(IStatus.ERROR, Activator.PLUGIN_ID, NLS.bind("No router could calculate route between waypoints {0}. Available routers: {1}", waypoints, routers));
    }

}