#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.Optimization;
using HeuristicLab.Analysis;

namespace HeuristicLab.PDPSimulation {
  [Item("PickupDeliverySimulation", "A pickup and delivery simulation.")]
  [Creatable("Simulations")]
  [StorableClass]
  public sealed class PickupDeliverySimulation: Simulation {
    #region parameters
    public OptionalValueParameter<PickupDeliveryOptimization> OptimizationParameter {
      get { return (OptionalValueParameter<PickupDeliveryOptimization>)Parameters["PickupDeliveryOptimization"]; }
    }

    public OptionalValueParameter<WaitingStrategy> WaitingStrategyParameter {
      get { return (OptionalValueParameter<WaitingStrategy>)Parameters["WaitingStrategy"]; }
    }

    public OptionalValueParameter<PickupDeliveryAnalyzer> AnalyzerParameter {
      get { return (OptionalValueParameter<PickupDeliveryAnalyzer>)Parameters["Analyzer"]; }
    }

    public ValueParameter<DoubleValue> TimeStepParameter {
      get { return (ValueParameter<DoubleValue>)Parameters["TimeStep"]; }
    }

    public ValueParameter<DoubleValue> ResultCollectionIntervalParameter {
      get { return (ValueParameter<DoubleValue>)Parameters["ResultCollectionInterval"]; }
    }


    public ValueParameter<BoolValue> SynchronizedParameter {
      get { return (ValueParameter<BoolValue>)Parameters["Synchronized"]; }
    }
    public ValueParameter<IntValue> DelayParameter {
      get { return (ValueParameter<IntValue>)Parameters["Delay"]; }
    }
    public ValueParameter<IntValue> InitialDelayParameter {
      get { return (ValueParameter<IntValue>)Parameters["InitialDelay"]; }
    }

    private ValueParameter<IntValue> SeedParameter {
      get { return (ValueParameter<IntValue>)Parameters["Seed"]; }
    }
    private ValueParameter<BoolValue> SetSeedRandomlyParameter {
      get { return (ValueParameter<BoolValue>)Parameters["SetSeedRandomly"]; }
    }
    #endregion

    #region properties
    public double SimulationTime {
      get {
        return simulationTime;
      }

      private set {
        simulationTime = value;
      }
    }

    public double TimeStep {
      get {
        return TimeStepParameter.Value.Value;
      }
    }

    private double ResultCollectionInterval {
      get {
        return ResultCollectionIntervalParameter.Value.Value;
      }
    }

    private bool Synchronized {
      get {
        return SynchronizedParameter.Value.Value;
      }
    }

    private int Delay {
      get {
        return DelayParameter.Value.Value;
      }
    }

    public override Type ProblemType {
      get { return typeof(PickupDeliveryScenario); }
    }

    private PickupDeliveryScenario Scenario {
      get {
        return Problem as PickupDeliveryScenario;
      }
    }

    private PickupDeliveryOptimization Optimization {
      get { return OptimizationParameter.Value;  }
    }

    private WaitingStrategy WaitingStrategy {
      get { return WaitingStrategyParameter.Value; }
    }

    private PickupDeliveryAnalyzer Analyzer {
      get { return AnalyzerParameter.Value; }
    }
    #endregion

    #region constructors
    public PickupDeliverySimulation()
      : base() {
      Parameters.Add(new OptionalValueParameter<PickupDeliveryOptimization>("PickupDeliveryOptimization", new BestInsertion()));
      Parameters.Add(new OptionalValueParameter<WaitingStrategy>("WaitingStrategy", new DriveFirstWaitingStrategy()));
      Parameters.Add(new OptionalValueParameter<PickupDeliveryAnalyzer>("Analyzer", new PickupDeliveryAnalyzer()));
      Parameters.Add(new ValueParameter<DoubleValue>("TimeStep", "The time progress after every tick", new DoubleValue(1)));
      Parameters.Add(new ValueParameter<DoubleValue>("ResultCollectionInterval", "The result collection interval", new DoubleValue(1)));
      Parameters.Add(new ValueParameter<BoolValue>("Synchronized", "Indicates if the simulation and optimization should be synchronized", new BoolValue(true)));
      Parameters.Add(new ValueParameter<IntValue>("Delay", "The delay after each tick", new IntValue(0)));
      Parameters.Add(new ValueParameter<IntValue>("InitialDelay", "The initial delay", new IntValue(0)));
      Parameters.Add(new ValueParameter<IntValue>("Seed", "The random seed used to initialize the new pseudo random number generator.", new IntValue(0)));
      Parameters.Add(new ValueParameter<BoolValue>("SetSeedRandomly", "True if the random seed should be set to a random value, otherwise false.", new BoolValue(true)));

      OptimizationParameter.GetsCollected = false;

      orders = new List<Order>();
      vehicles = new List<Vehicle>();

      AttachEventHandlers();
      SetOptimizationSimulation();
      SetOptimizationScenario();
      SetWaitingStrategy();
      SetWaitingStrategyScenario();
    }
    [StorableConstructor]
    private PickupDeliverySimulation(bool deserializing) : base(deserializing) {
    }

    [StorableHook(HookType.AfterDeserialization)]
    private void AfterDeserialization() {
      AttachEventHandlers();
    }

    private PickupDeliverySimulation(PickupDeliverySimulation original, Cloner cloner)
      : base(original, cloner) {
      orders = new List<Order>();
      foreach (Order order in original.orders) {
        orders.Add(cloner.Clone<Order>(order));
      }

      vehicles = new List<Vehicle>();
      foreach (Vehicle vehicle in original.vehicles) {
        vehicles.Add(cloner.Clone<Vehicle>(vehicle));
      }

      simulationTime = original.simulationTime;
      newSimulationTime = original.newSimulationTime;
      lastResultCollection = original.lastResultCollection;
      simulationObject = cloner.Clone<SimulationObject>(original.simulationObject);

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

    [StorableHook(HookType.AfterDeserialization)]
    private void AttachEventHandlers() {
      OptimizationParameter.ValueChanged += new EventHandler(OptimizationParameter_ValueChanged);
      WaitingStrategyParameter.ValueChanged += new EventHandler(WaitingStrategyParameter_ValueChanged);

      if(Scenario != null)
        Scenario.ScenarioChanged += new EventHandler(Scenario_ScenarioChanged);
    }

    void Scenario_ScenarioChanged(object sender, EventArgs e) {
      SetOptimizationScenario();
      SetWaitingStrategy();
      SetWaitingStrategyScenario();

      Prepare();
    }

    void WaitingStrategyParameter_ValueChanged(object sender, EventArgs e) {
      SetWaitingStrategy();
      SetWaitingStrategyScenario();
    }

    void OptimizationParameter_ValueChanged(object sender, EventArgs e) {
      SetOptimizationSimulation();
      SetOptimizationScenario();
      SetWaitingStrategy();
    }

    protected override void OnProblemChanged() {
      base.OnProblemChanged();

      SetOptimizationScenario();
      SetWaitingStrategy();
      SetWaitingStrategyScenario();

      if (Scenario != null)
        Scenario.ScenarioChanged += new EventHandler(Scenario_ScenarioChanged);
    }
    #endregion

    #region state
    [Storable]
    private List<Order> orders;

    public List<Order> Orders {
      get {
        lock (orders) {
          return new List<Order>(orders);
        }
      }
    }

    public Order GetOrder(Guid orderId) {
      lock (orders) {
        return orders.FirstOrDefault(o => o.Id == orderId);
      }
    }

    public double OrderRangeX {
      get { return Scenario.OrderRangeX(); }
    }

    public double OrderRangeY {
      get { return Scenario.OrderRangeY(); }
    }

    private bool AllOrdersDelivered() {
      bool delivered = true;

      foreach(Order order in orders) {
        if (order.OrderState != OrderState.Delivered) {
          delivered = false;
          break;
        }
      }

      return delivered;
    }

    [Storable]
    private List<Vehicle> vehicles;

    public List<Vehicle> Vehicles {
      get {
        return new List<Vehicle>(vehicles);
      }
    }

    public Vehicle GetVehicle(Guid vehicleId) {
      return vehicles.FirstOrDefault(v => v.Id == vehicleId);
    }

    private bool AllVehiclesAtDepot() {
      bool atDepot = true;

      foreach (Vehicle vehicle in vehicles) {
        if ((vehicle.VehicleState != VehicleState.Parked && vehicle.VehicleState != VehicleState.Waiting) ||
          vehicle.PositionX != vehicle.DepotX ||
          vehicle.PositionY != vehicle.DepotY) {
          atDepot = false;
          break;
        }
      }

      return atDepot;
    }

    public PDAction GetAction(Vehicle vehicle) {
      if (Optimization != null)
        return Optimization.GetAction(vehicle);
      else
        return null;
    }

    [Storable]
    private double newSimulationTime;

    [Storable]
    private double simulationTime;

    [Storable]
    private double lastResultCollection;

    [Storable]
    private SimulationObject simulationObject;
    #endregion

    #region events

    public delegate void SimulationStateChangedHandler(BaseObject obj, SimulationStateChange change);
    public event SimulationStateChangedHandler SimulationStateChanged;

    private void OnSimulationStateChanged(BaseObject obj, SimulationStateChange change) {
      SimulationStateChangedHandler handler = SimulationStateChanged;
      if (handler != null)
        handler(obj, change);
    }
    #endregion

    #region synchronization
    private EventWaitHandle wh;
    private void InitWaitHandle() {
      if(wh != null)
        wh.Dispose();

      wh = null;
      if (Synchronized)
        wh = new EventWaitHandle(false, EventResetMode.AutoReset);
    }
    private void SignalWaitHandle() {
      if (wh != null)
        wh.Set();
    }
    public void WaitForSimulation() {
      if (wh != null)
        wh.WaitOne();
    }
    private void WaitForOptimization() {
      if (Optimization != null)
        Optimization.WaitForOptimization();
    }
    #endregion

    #region simulation logic
    private void UpdateVisualization() {
      if (Analyzer != null)
        Analyzer.UpdateVisualization(this, Scenario, Results);
    }

    private void UpdateSimulationState() {
      if (Optimization != null) {
        foreach (PDAction action in Optimization.GetActions()) {
          BaseObject obj = vehicles.FirstOrDefault(v => v.Id == action.BaseObjectId);
          if(obj == null)
            obj = orders.FirstOrDefault(o => o.Id == action.BaseObjectId);

          List<PDChange> changes = action.Perform(obj, SimulationTime, TimeStep);

          foreach (PDChange change in changes)
            OnSimulationStateChanged(change.BaseObject, change.ChangeType);
        }
      }
    }

    private void UpdateResults(bool stopped) {
      if (stopped || SimulationTime == 0 ||
         (SimulationTime - lastResultCollection) >= ResultCollectionInterval) {
        UpdateVisualization();   
        if (Analyzer != null) {
          Analyzer.Analyze(this, Scenario, Results);
        }

        lastResultCollection = SimulationTime;
      }
      if (Analyzer != null) {
        Analyzer.Tick(this, Scenario, Results);
      }
    }

    private void UpdateOrders() {
      lock (orders) {
        IEnumerable<Order> newOrders = Scenario.GetOrders(SimulationTime, newSimulationTime);
        foreach (Order order in newOrders) {
          orders.Add(order);
          OnSimulationStateChanged(order, SimulationStateChange.OrderCreated);
        }

        if (!Scenario.MoreOrders(newSimulationTime))
          OnSimulationStateChanged(simulationObject, SimulationStateChange.NoMoreOrders);
      }
    }

    private void CreateSimulation() {
      vehicles.Clear();
      orders.Clear();

      simulationObject = new SimulationObject();
      lastResultCollection = 0;
      simulationTime = 0;
      newSimulationTime = 0;

      //create vehicles
      for (int i = 0; i < Scenario.VehicleCapacitiesParameter.Value.Length; i++) {
        Vehicle v = new Vehicle();
        v.VehicleState = VehicleState.Parked;
        v.Availibility = 1;
        v.DepotX = v.PositionX = v.TargetPositionX = Scenario.DepotCoordinatesParameter.Value[i, 0];
        v.DepotY = v.PositionY = v.TargetPositionY = Scenario.DepotCoordinatesParameter.Value[i, 1];
        v.Capacity = v.TotalCapacity = Scenario.VehicleCapacitiesParameter.Value[i];
        v.ReadyTime = Scenario.VehicleReadyTimesParameter.Value[i];
        v.DueTime = Scenario.VehicleDueTimesParameter.Value[i];

        vehicles.Add(v);
        OnSimulationStateChanged(v, SimulationStateChange.VehicleCreated);
      }

      //create initial orders
      UpdateOrders();
      UpdateResults(false);

      UpdateVisualization();
    }

    protected override void OnPrepared() {
      base.OnPrepared();
      PrepareOptimization();
      simulationTime = 0;
      newSimulationTime = 0;
    }

    private void InitSimulation() {
      pausePending = false;
      stopPending = false;
      InitWaitHandle();

      if (simulationTime == 0) {
        PrepareOptimization();
        CreateSimulation();

        SignalWaitHandle();
        if (OptimizationRequired()) {
          StartOptimization();
          Thread.Sleep(InitialDelayParameter.Value.Value);
          WaitForOptimization();
        } else {
          Thread.Sleep(InitialDelayParameter.Value.Value);
        }

        Step();
      }
    }

    private void StartOptimization() {
      if (Optimization != null) {
        Optimization.Start(Synchronized);
      }
    }

    private void StopOptimization() {
      if (Optimization != null)
        Optimization.Stop();
    }

    private void PrepareOptimization() {
      if (Optimization != null)
        Optimization.Prepare();
    }

    private void SetOptimizationScenario() {
      if (Optimization != null)
        Optimization.SetScenario(Scenario);
    }

    private void SetOptimizationSimulation() {
      if (Optimization != null)
        Optimization.SetSimulation(this);
    }

    private void SetWaitingStrategyScenario() {
      if (WaitingStrategy != null)
        WaitingStrategy.SetScenario(Scenario);
    }

    private void SetWaitingStrategy() {
      if (Optimization != null)
        Optimization.SetWaitingStrategy(WaitingStrategyParameter.Value);
    }

    private bool OptimizationRunning() {
      bool running = false;

      if (Optimization != null)
        running = Optimization.Running();

      return running;
    }

    private void RelocateVehicles() {
      if (Optimization != null)
        Optimization.RelocateVehicles();
    }

    private bool OptimizationRequired() {
      bool required = false;

      if (Optimization != null)
        required = Optimization.OptimizationRequired();

      return required;
    }

    private void WaitForOptimizationExit() {
      if (Optimization != null) {
        while (Optimization.Running()) {
          Thread.Sleep(100);
          SignalWaitHandle();
        }
        Optimization.Exit();
      }
    }

    private void StopSimulation() {
      SignalWaitHandle();
      StopOptimization();
    }

    private bool pausePending;
    public override void Pause() {
      base.Pause();
      pausePending = true;
    }

    private bool stopPending;
    public override void Stop() {
      base.Stop();
      stopPending = true;
    }

    private void Step() {
      //next step
      SimulationTime = newSimulationTime;
      newSimulationTime = SimulationTime + TimeStep;
    }

    protected override void Run(CancellationToken cancellationToken) {
      InitSimulation();

      while (!AllOrdersDelivered() || Scenario.MoreOrders(SimulationTime) || (Scenario.RelocateBackToDepot && !AllVehiclesAtDepot())) {
        //perform actions
        UpdateSimulationState();
        UpdateOrders();
        UpdateResults(false);

        Step();

        if (OptimizationRequired()) {
          SignalWaitHandle();

          if (!OptimizationRunning() && !(pausePending || stopPending)) {
            SignalWaitHandle();
            StartOptimization();
          }

          WaitForOptimization();
        } else {
          RelocateVehicles();
        }

        if (pausePending || stopPending) {
          if (!OptimizationRunning()) {
            cancellationToken.ThrowIfCancellationRequested();
          } else
            StopOptimization();
        }

        Thread.Sleep(Delay);
      }

      if (Optimization != null)
        Optimization.RemoveCompletedActions();
      UpdateResults(true);

      Results.Add(new Result("Finished", new BoolValue(true)));

      Thread.Sleep(500);
      StopSimulation();
      WaitForOptimizationExit();
    }
  }
  #endregion
}