using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using HeuristicLab.Core;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
using HeuristicLab.Common;
using HeuristicLab.PDPSimulation.Operators;
using HeuristicLab.Problems.VehicleRouting;
using HeuristicLab.Problems.VehicleRouting.Interfaces;
using HeuristicLab.Parameters;
using HeuristicLab.Data;

namespace HeuristicLab.PDPSimulation {
  [Item("WaitFirstWaitingStrategy", "A pickup and delivery waiting strategy.")]
  [StorableClass]
  public class WaitFirstWaitingStrategy : WaitingStrategy {
    protected ValueParameter<BoolValue> OnlyFirstStopParameter {
      get { return (ValueParameter<BoolValue>)Parameters["OnlyFirstStop"]; }
    }

    public WaitFirstWaitingStrategy()
      : base() {
        Parameters.Add(new ValueParameter<BoolValue>("OnlyFirstStop", "Indicates, if waiting should only occur at the first stop.", new BoolValue(false)));
    }
    [StorableConstructor]
    protected WaitFirstWaitingStrategy(bool deserializing) : base(deserializing) { }
    protected WaitFirstWaitingStrategy(WaitFirstWaitingStrategy original, Cloner cloner)
      : base(original, cloner) {
    }
    public override IDeepCloneable Clone(Cloner cloner) {
      return new WaitFirstWaitingStrategy(this, cloner);
    }

    public static double GetSlack(double time, DynPDPProblemInstance instance, IVRPEncoding solution, Tour tour, int stop) {
      double slack = 0;
      double minBuffer = double.MaxValue;
      int count = tour.Stops.Count;
      if (!(instance as DynPDPProblemInstance).RelocateBackToDepot)
        count -= 1;
      for (int i = stop; i <= count; i++) {
        int customer = 0;
        if (i < tour.Stops.Count)
          customer = tour.Stops[i];
        int prev = 0;
        if (i > 0)
          prev = tour.Stops[i - 1];

        int depots = instance.Depots.Value;
        double distance = instance.GetDistance(prev, customer, solution);
        time += distance;

        double arrivalTime = time;
        double deadline = 0;
        if (customer > 0) {
          double readyTime = instance.ReadyTime[customer + depots - 1];
          if (time < readyTime) {
            slack += readyTime - time;
            time = readyTime;
            arrivalTime = time;
          }

          double serviceTime = instance.ServiceTime[customer - 1];
          time += serviceTime;

          deadline = instance.DueTime[customer + depots - 1];
        } else {
          int depot = instance.GetDepot(prev, solution);
          deadline = instance.DueTime[depot];
        }

        double buffer = Math.Max(0, Math.Max(slack, deadline - arrivalTime + slack));
        if (buffer < minBuffer)
          minBuffer = buffer;
      }

      return Math.Floor(minBuffer * 100) / 100;
    }

    public override double GetWaitingTime(double time, DynPDPProblemInstance instance, IVRPEncoding solution, Tour tour, int stop) {
      bool onlyFirstStop = OnlyFirstStopParameter.Value.Value;
      
      int vehicle = solution.GetVehicleAssignment(solution.GetTourIndex(tour));
      bool moving = instance.VehicleStates[vehicle] == DomainModel.VehicleState.Moving;

      if (onlyFirstStop) {
        if ((!moving && stop != 0) || (moving && stop != 1))
          return 0;
      } else {
        if (moving && stop == 0)
          return 0;
      }

      return GetSlack(time, instance, solution, tour, stop);
    }
  }
}