#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2011 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * HeuristicLab is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using HeuristicLab.Core;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
using HeuristicLab.PDPSimulation.SimulationCore;
using HeuristicLab.Parameters;
using HeuristicLab.Data;
using System.Threading;
using HeuristicLab.Common;
using HeuristicLab.PDPSimulation.DomainModel;
using HeuristicLab.PDPSimulation.DistanceMeasures;
using HeuristicLab.Optimization;

namespace HeuristicLab.PDPSimulation {
  [Item("PickupDeliveryOptimization", "A pickup and delivery optimization.")]
  [StorableClass]
  public abstract class PickupDeliveryOptimization: ParameterizedNamedItem {
    #region constructors
    public PickupDeliveryOptimization() : base() {
      objectChanges = new Dictionary<BaseObject, List<PDChange>>();
      actions = new Dictionary<Guid, PDAction>();
    }
    [StorableConstructor]
    protected PickupDeliveryOptimization(bool deserializing) : base(deserializing) { }
    protected PickupDeliveryOptimization(PickupDeliveryOptimization original, Cloner cloner)
      : base(original, cloner) {
      lock (original.objectChanges) {
        lock (original.actionLocker) {
          simulation = cloner.Clone<PickupDeliverySimulation>(original.simulation);
          if (simulation != null) {
            simulation.SimulationStateChanged +=
              new PickupDeliverySimulation.SimulationStateChangedHandler(simulation_SimulationStateChanged);
          }

          objectChanges = new Dictionary<BaseObject, List<PDChange>>();
          foreach (BaseObject obj in original.objectChanges.Keys) {
            BaseObject objClone = cloner.Clone<BaseObject>(obj);

            objectChanges.Add(objClone, new List<PDChange>());
            foreach (PDChange change in original.objectChanges[obj])
              objectChanges[objClone].Add(cloner.Clone<PDChange>(change));
          }

          actions = new Dictionary<Guid, PDAction>();
          foreach (Guid objId in original.actions.Keys) {
            actions.Add(objId, cloner.Clone<PDAction>(original.actions[objId]));
          }
        }
      }

      this.scenario = cloner.Clone<PickupDeliveryScenario>(original.scenario);
      this.waitingStrategy = cloner.Clone<WaitingStrategy>(original.waitingStrategy);
    }
    #endregion

    [StorableHook(HookType.AfterDeserialization)]
    private void AfterDeserialization() {
      if (this.simulation != null) {
        this.simulation.SimulationStateChanged +=
         new PickupDeliverySimulation.SimulationStateChangedHandler(simulation_SimulationStateChanged);
      }
    }

    [Storable]
    protected PickupDeliveryScenario scenario;

    [Storable]
    protected WaitingStrategy waitingStrategy;

    [Storable]
    private PickupDeliverySimulation simulation;

    protected double GetSimulationTime() {
      return simulation.SimulationTime;
    }

    protected double GetTimeStep() {
      return simulation.TimeStep;
    }

    protected List<Order> GetOrders() {
      return simulation.Orders;
    }

    protected Order GetOrder(Guid orderId) {
      return simulation.GetOrder(orderId);
    }

    protected Vehicle GetVehicle(Guid vehicleId) {
      return simulation.GetVehicle(vehicleId);
    }

    protected List<Vehicle> GetVehicles() {
      return simulation.Vehicles;
    }

    protected ResultCollection GetResults() {
      return simulation.Results;
    }

    [Storable]
    private Dictionary<BaseObject, List<PDChange>> objectChanges;

    private void RemoveObsoleteChanges(PDChange change) {
      List<PDChange> toBeRemoved = new List<PDChange>();

      foreach (PDChange existingChange in objectChanges[change.BaseObject]) {
        if (existingChange.ChangeType == change.ChangeType) {
          toBeRemoved.Add(existingChange);
        }
      }

      foreach (PDChange removed in toBeRemoved) {
        objectChanges[change.BaseObject].Remove(removed);
      }
    }

    protected void AddChange(PDChange change) {
      lock (objectChanges) {
        if (!objectChanges.ContainsKey(change.BaseObject))
          objectChanges.Add(change.BaseObject, new List<PDChange>());

        RemoveObsoleteChanges(change);

        objectChanges[change.BaseObject].Add(change);
      }
    }

    protected List<PDChange> GetChanges(bool clear) {
      lock (objectChanges) {
        List<PDChange> result = new List<PDChange>();
        foreach (List<PDChange> objChanges in objectChanges.Values)
          result.AddRange(objChanges);

        if(clear)
          objectChanges.Clear();

        return result;
      }
    }

    protected struct ChangeInformation {
      public List<Vehicle> CreatedVehicles { get; set; }
      public List<Order> CreatedOrders { get; set; }
      public List<Vehicle> ChangedVehicles { get; set; }
      public List<Order> ChangedOrders { get; set; }
      public bool InvalidActions { get; set; }
      public bool SimulationFinished { get; set; }
    }

    protected ChangeInformation GetChangeInformation(List<PDChange> changes) {
      ChangeInformation changeInformation = new ChangeInformation();

      changeInformation.CreatedVehicles = new List<Vehicle>();
      changeInformation.CreatedOrders = new List<Order>();
      changeInformation.ChangedVehicles = new List<Vehicle>();
      changeInformation.ChangedOrders = new List<Order>();
      changeInformation.InvalidActions = false;
      changeInformation.SimulationFinished = false;

      foreach (PDChange change in changes) {
        if (change.ChangeType == SimulationStateChange.VehicleCreated) {
          Vehicle vehicle = change.BaseObject as Vehicle;
          changeInformation.CreatedVehicles.Add(vehicle);
        } else if (change.ChangeType == SimulationStateChange.VehicleMoved ||
           change.ChangeType == SimulationStateChange.VehicleState) {
          Vehicle vehicle = change.BaseObject as Vehicle;
          changeInformation.ChangedVehicles.Add(vehicle);

          if (change.ChangeType == SimulationStateChange.VehicleState &&
            vehicle.VehicleState == VehicleState.InvalidAction)
            changeInformation.InvalidActions = true;
        } else if (change.ChangeType == SimulationStateChange.OrderCreated) {
          Order order = change.BaseObject as Order;
          changeInformation.CreatedOrders.Add(order);
        } else if (change.ChangeType == SimulationStateChange.OrderState) {
          Order order = change.BaseObject as Order;
          changeInformation.ChangedOrders.Add(order);
        } else if (change.ChangeType == SimulationStateChange.NoMoreOrders) {
          changeInformation.SimulationFinished = true;
        } else if (change.ChangeType == SimulationStateChange.OrderFailed) {
          changeInformation.InvalidActions = true;
        }
      }

      changeInformation.InvalidActions = changeInformation.InvalidActions ||
        GetVehicles().Where(v => v.VehicleState == VehicleState.InvalidAction).Count() > 0;

      return changeInformation;
    }

    protected object actionLocker = new object();

    [Storable]
    private Dictionary<Guid, PDAction> actions;

    public PDAction GetAction(BaseObject obj) {
      lock (actionLocker) {
        if (actions.ContainsKey(obj.Id))
          return actions[obj.Id];
        else
          return null;
      }
    }

    protected void SetAction(PDAction action) {
      lock (actionLocker) {
        if (actions.ContainsKey(action.BaseObjectId)) {
          lock (actions[action.BaseObjectId]) {
            if (!actions[action.BaseObjectId].Interruptable())
              actions[action.BaseObjectId].AppendAction(action, false);
            else
              actions[action.BaseObjectId] = action;
          }
        } else {
          actions[action.BaseObjectId] = action;
        }
      }
    }

    protected void AppendAction(PDAction action) {
      lock (actionLocker) {
        if (actions.ContainsKey(action.BaseObjectId)) {
          actions[action.BaseObjectId].AppendAction(action, true);
        } else {
          actions[action.BaseObjectId] = action;
        } 
      }
    }

    public void RemoveCompletedActions() {
      lock (actionLocker) {
        List<Guid> toBeRemoved = new List<Guid>();
        foreach (Guid objId in actions.Keys) {
          if (actions[objId].IsCompleted)
            toBeRemoved.Add(objId);
        }
        foreach (Guid objId in toBeRemoved)
          actions.Remove(objId);
      }
    }

    public List<PDAction> GetActions() {
      lock (actionLocker) {
        RemoveCompletedActions();

        return actions.Values.ToList();
      }
    }

    public virtual void SetScenario(PickupDeliveryScenario scenario) {
      if (scenario != null) {
        this.scenario = scenario;
      }
    }

    public virtual void SetWaitingStrategy(WaitingStrategy waitingStrategy) {
      this.waitingStrategy = waitingStrategy;      
    }

    public virtual void Prepare() {
      //clear state
      objectChanges.Clear();
      actions.Clear();
    }

    public virtual void SetSimulation(PickupDeliverySimulation simulation) {
      if (this.simulation != simulation) {
        if (this.simulation != null) {
          this.simulation.SimulationStateChanged -=
            new PickupDeliverySimulation.SimulationStateChangedHandler(simulation_SimulationStateChanged);
        }

        this.simulation = simulation;

        this.simulation.SimulationStateChanged +=
           new PickupDeliverySimulation.SimulationStateChangedHandler(simulation_SimulationStateChanged);
      }
    }

    private EventWaitHandle wh;
    private void InitWaitHandle(bool synchronized) {
      if(wh != null)
        wh.Dispose();
      wh = null;

      if(synchronized)
        wh = new EventWaitHandle(false, EventResetMode.AutoReset);
    }
    protected void SignalWaitHandle() {
      if(wh != null)
        wh.Set();
    }
    public void WaitForOptimization() {
      if (wh != null) {
        bool signal = false;

        while (!signal && Running())
          signal = wh.WaitOne(100);
      }
    }
    protected void WaitForSimulation() {
      simulation.WaitForSimulation();
    }

    protected abstract void Optimize(CancellationToken token);
    Thread optThread;
    CancellationTokenSource cts;

    protected bool running;

    public void Start(bool synchronized) {
      running = true;
      InitWaitHandle(synchronized);

      using (EventWaitHandle wh = new EventWaitHandle(false, EventResetMode.ManualReset)) {
        cts = new CancellationTokenSource();
        optThread = new Thread(delegate() {
          wh.Set();
          Optimize(cts.Token);
        });
        optThread.IsBackground = true;
        optThread.Start();

        wh.WaitOne();
      }
    }

    public abstract bool OptimizationRequired();

    public virtual void RelocateVehicles() {

    }

    public void Stop() {
      if(cts != null)
       cts.Cancel();
    }

    public bool Running() {
      return optThread != null && optThread.IsAlive && running;
    }

    public void Exit() {
      optThread = null;
    }

    void simulation_SimulationStateChanged(BaseObject obj, SimulationStateChange changeType) {
      PDChange change = new PDChange() { BaseObject = obj.Clone() as BaseObject, ChangeType = changeType };
      AddChange(change);
    }
  }
}