using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Encodings.RealVectorEncoding;
using HeuristicLab.Parameters;
using HeuristicLab.PDPSimulation.DomainModel;
using HeuristicLab.PDPSimulation.Operators;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;

namespace HeuristicLab.PDPSimulation {
  [Item("PriorityDispatching", "")]
  [StorableClass]
  public sealed class PriorityDispatching : DynamicPDPOptimization {

    private bool IsIdle(Vehicle v) {
      return v.CurrentOrder == Guid.Empty;
    }

    protected override bool OptimizationRequired(ChangeInformation changeInformation) {
      // either there are vehicles waiting and there are orders to dispatch
      // or there are new orders and waiting vehicles
      return (GetVehicles().Any(x => IsIdle(x))
        && GetOrders().Any(x => x.AssignedVehicle == Guid.Empty || GetVehicles().Any(y => IsIdle(y) && x.AssignedVehicle == y.Id)));
    }

    public IValueLookupParameter<RealVector> WeightsParameter {
      get { return (IValueLookupParameter<RealVector>)Parameters["Weights"]; }
    }

    [StorableConstructor]
    private PriorityDispatching(bool deserializing) : base(deserializing) { }
    private PriorityDispatching(PriorityDispatching original, Cloner cloner) : base(original, cloner) { }
    public PriorityDispatching() {
      Parameters.Add(new ValueLookupParameter<RealVector>("Weights", "The weights for the individual priorities."));
      WeightsParameter.Value = new RealVector(new double[] {
         100.000, 100.000,  22.349,  74.573,  18.424,  28.913,   0.331,  91.323,  36.969,  44.992,  64.892,  30.736,  23.113,  36.458,   6.178,  99.065, 100.0, 100.0
      });
    }

    public override IDeepCloneable Clone(Cloner cloner) {
      return new PriorityDispatching(this, cloner);
    }

    protected override bool PerformOptimization(DynamicPDProblemInstance instance, ChangeInformation changeInformation) {
      var waitingVehicles = GetVehicles().Where(x => IsIdle(x)).ToList();
      var waitingOrders = GetOrders().Where(x => x.AssignedVehicle == Guid.Empty).ToList();

      while (waitingVehicles.Any() && (waitingOrders.Any()
        || GetOrders().Any(x => x.OrderState == OrderState.PickedUp && waitingVehicles.Any(y => y.Id == x.AssignedVehicle)))) {
        var tmp = new Dictionary<Vehicle, Tuple<Order, double>>();
        foreach (var vehicle in waitingVehicles) {
          var pickedupOrders = GetOrders().Where(x => x.OrderState == OrderState.PickedUp && x.AssignedVehicle == vehicle.Id);
          var orders = waitingOrders.Concat(pickedupOrders);
          if (orders.Any()) {
            Order selectedOrder;
            double priority;
            GetHighestPriorityOrder((DynPDPProblemInstance)instance.StaticInstance, vehicle, orders, out selectedOrder, out priority);
            tmp[vehicle] = Tuple.Create(selectedOrder, priority);
          }
        }
        var assignment = tmp.GroupBy(x => x.Value.Item1, x => new { Vehicle = x.Key, Priority = x.Value.Item2 });
        foreach (var a in assignment) {
          var bestVehicle = a.MaxItems(x => x.Priority).Select(x => x.Vehicle).First();
          var order = a.Key;

          bool first = true;

          XY target;
          MoveVehicleAction action;
          if (order.OrderState == OrderState.Waiting) {
            target = new XY(order.PickupXCoord, order.PickupYCoord);
            action = new MoveVehicleAction(bestVehicle.Id, order.PickupXCoord, order.PickupYCoord, VehicleAction.Pickup, order, scenario.AllowDiversion, scenario.DistanceMeasure);
          } else {
            target = new XY(order.DeliveryXCoord, order.DeliveryYCoord);
            action = new MoveVehicleAction(bestVehicle.Id, order.DeliveryXCoord, order.DeliveryYCoord, VehicleAction.Deliver, order, scenario.AllowDiversion, scenario.DistanceMeasure);
          }
          var pickedupOrders = GetOrders().Where(x => x.OrderState == OrderState.PickedUp && x.AssignedVehicle == bestVehicle.Id);
          var pickedupOrdersAtDestination = pickedupOrders.Where(o => o.DeliveryXCoord == target.X && o.DeliveryYCoord == target.Y);
          List<MoveVehicleAction> deliveryActions = new List<MoveVehicleAction>();
          foreach (var pickedupOrder in pickedupOrdersAtDestination) {
            if (pickedupOrder != order) {
              MoveVehicleAction deliveryAction = new MoveVehicleAction(bestVehicle.Id, pickedupOrder.DeliveryXCoord, pickedupOrder.DeliveryYCoord, VehicleAction.Deliver, pickedupOrder, scenario.AllowDiversion, scenario.DistanceMeasure);
              if (first) {
                SetAction(deliveryAction);
                first = false;
              } else {
                AppendAction(deliveryAction);
              }
            }
          }

          if (first) {
            SetAction(action);
            first = false;
          } else {
            AppendAction(action);
          }
          waitingVehicles.Remove(bestVehicle);
          waitingOrders.Remove(order);

          foreach (var assignedOrder in GetOrders().Where(o => o.AssignedVehicle == bestVehicle.Id && o.OrderState == OrderState.Waiting))
            assignedOrder.AssignedVehicle = Guid.Empty;

          order.AssignedVehicle = bestVehicle.Id;
        }
      }
      return true;
    }

    private void GetHighestPriorityOrder(DynPDPProblemInstance instance, Vehicle vehicle, IEnumerable<Order> orders, out Order order, out double priority) {
      var weights = WeightsParameter.Value;
      Order best = null;
      double bestPriority = double.MinValue;
      var pickupOrdersByLocation = (from o in orders
                                   where IsPickup(o, instance)
                                   group o by new { X = o.PickupXCoord, Y = o.PickupYCoord })
                                   .ToDictionary(x => new XY(x.Key.X, x.Key.Y), y => y.ToArray(), new XYEqComparer());
      var deliveryOrdersByLocation = (from o in orders
                                      where !IsPickup(o, instance) && o.Vehicle == vehicle.Id
                                      group o by new { X = o.DeliveryXCoord, Y = o.DeliveryYCoord })
                                      .ToDictionary(x => new XY(x.Key.X, x.Key.Y), y => y.ToArray(), new XYEqComparer());
      var destinations = deliveryOrdersByLocation.Keys.ToArray();
      foreach (var o in orders) {
        if (IsPickup(o, instance) && o.Demand > vehicle.Capacity) continue;
        
         double prio;
         if (!IsPickup(o, instance) && vehicle.TargetPositionX == o.DeliveryXCoord && vehicle.TargetPositionY == o.DeliveryYCoord) {
           prio = double.MaxValue;
         } else {
           var target = new XY(o.PickupXCoord, o.PickupYCoord);
           if (!IsPickup(o, instance)) target = new XY(o.DeliveryXCoord, o.DeliveryYCoord);

           var destinationDifference = destinations.Select(x => scenario.DistanceMeasure.GetDistance(o.DeliveryXCoord, o.DeliveryYCoord, x.X, x.Y)).ToArray();
           var courierDifference = GetVehicles().Where(x => x != vehicle).Select(x => new XY(x.TargetPositionX, x.TargetPositionY))
             .Select(x => scenario.DistanceMeasure.GetDistance(target.X, target.Y, x.X, x.Y)).ToArray();

           var commonDestinations = orders.Where(x => !IsPickup(x, instance) && x.Vehicle == vehicle.Id &&
                                    x.DeliveryXCoord == o.PickupXCoord &&
                                    x.DeliveryYCoord == o.PickupYCoord);

           var variables = new Dictionary<string, double>();
           variables.Add("Distance", scenario.DistanceMeasure.GetDistance(vehicle.TargetPositionX, vehicle.TargetPositionY, target.X, target.Y));
           variables.Add("EarliestTimeOfArrival", vehicle.ReadyTime + variables["Distance"]);
           variables.Add("DueDate", o.DeliveryDueTime - GetSimulationTime());
           variables.Add("StartDate", IsPickup(o, instance) ? o.PickupReadyTime - GetSimulationTime() : 0);
           variables.Add("PickupOrdersAtTarget", pickupOrdersByLocation.ContainsKey(target) ? pickupOrdersByLocation[target].Count() : 0);
           variables.Add("PickupOrderItemsAtTarget", pickupOrdersByLocation.ContainsKey(target) ? pickupOrdersByLocation[target].Sum(x => x.Demand) : 0);
           variables.Add("DeliveryOrdersAtTarget", deliveryOrdersByLocation.ContainsKey(target) ? deliveryOrdersByLocation[target].Count() : 0);
           variables.Add("DeliveryOrderItemsAtTarget", deliveryOrdersByLocation.ContainsKey(target) ? deliveryOrdersByLocation[target].Sum(x => x.Demand) : 0);
           variables.Add("AverageDistanceToDestinations", destinationDifference.Any() ? destinationDifference.Average() : 0);
           variables.Add("MinimumDistanceToDestinations", destinationDifference.Any() ? destinationDifference.Min() : 0);
           variables.Add("MaximumDistanceToDestinations", destinationDifference.Any() ? destinationDifference.Max() : 0);
           variables.Add("NumberOfOtherCouriersToTarget", GetVehicles().Count > 2 ? GetVehicles().Where(x => x != vehicle).Count(x => target.X == x.TargetPositionX && target.Y == x.TargetPositionY) : 0);
           variables.Add("AverageDistanceToOtherCouriers", courierDifference.Any() ? courierDifference.Average() : 0);
           variables.Add("MinimumDistanceToOtherCouriers", courierDifference.Any() ? courierDifference.Min() : 0);
           variables.Add("MaximumDistanceToOtherCouriers", courierDifference.Any() ? courierDifference.Max() : 0);
           variables.Add("DemandSize", o.Demand);
           variables.Add("Slack", o.DeliveryDueTime - GetSimulationTime()
             - (vehicle.ReadyTime + variables["Distance"] +
                (IsPickup(o, instance) ? (o.PickupServiceTime + scenario.DistanceMeasure.GetDistance(o.PickupXCoord, o.PickupYCoord, o.DeliveryXCoord, o.DeliveryYCoord)) : 0)));
           variables.Add("EDD", commonDestinations.Any() ? commonDestinations.Min(d => d.DeliveryDueTime - GetSimulationTime()) : 0);

           prio =
               weights[0] * variables["DueDate"]
             + weights[1] * variables["StartDate"]
             + weights[2] * variables["PickupOrdersAtTarget"]
             + weights[3] * variables["Distance"]
             + weights[4] * variables["AverageDistanceToDestinations"]
             + weights[5] * variables["MinimumDistanceToDestinations"]
             + weights[6] * variables["MaximumDistanceToDestinations"]
             + weights[7] * variables["NumberOfOtherCouriersToTarget"]
             + weights[8] * variables["AverageDistanceToOtherCouriers"]
             + weights[9] * variables["EarliestTimeOfArrival"]
             + weights[10] * variables["DeliveryOrdersAtTarget"]
             + weights[11] * variables["PickupOrderItemsAtTarget"]
             + weights[12] * variables["DeliveryOrderItemsAtTarget"]
             + weights[13] * variables["MinimumDistanceToOtherCouriers"]
             + weights[14] * variables["MaximumDistanceToOtherCouriers"]
             + weights[15] * variables["DemandSize"]
             + weights[16] * variables["Slack"]
             + weights[17] * variables["EDD"];
         }

        if (prio > bestPriority) {
          bestPriority = prio;
          best = o;
        }
      }

      order = best != null ? best : orders.First();
      priority = bestPriority;
    }

    private bool IsPickup(Order o, DynPDPProblemInstance instance) {
      return instance.Demand[Instance.GetStops(o.Id).First()] > 0;
    }

    private struct XY {
      public double X { get; private set; }
      public double Y { get; private set; }

      public XY(double x, double y) : this() {
        X = x;
        Y = y;
      }
    }

    private class XYEqComparer : EqualityComparer<XY> {

      public override bool Equals(XY x, XY y) {
        return x.X == y.X && x.Y == y.Y;
      }

      public override int GetHashCode(XY obj) {
        return obj.X.GetHashCode() ^ obj.Y.GetHashCode();
      }
    }
  }
}