#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2010 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 HeuristicLab.Collections;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Optimization;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
using HeuristicLab.Problems.DataAnalysis;

namespace HeuristicLab.Algorithms.DataAnalysis {
  [Item("Cross Validation", "Cross Validation wrapper for data analysis algorithms.")]
  [Creatable("Data Analysis")]
  [StorableClass]
  public sealed class CrossValidation : NamedItem, IOptimizer {
    //TODO cloning, persistence, creation of clonedAlgs, execution logic, ...
    public CrossValidation()
      : base() {
      name = ItemName;
      description = ItemDescription;

      executionState = ExecutionState.Stopped;
      executionTime = TimeSpan.Zero;
      Runs = new RunCollection();

      algorithmTemplate = null;
      clonedAlgorithms = new ItemCollection<IAlgorithm>();
      RegisterClonedAlgorithmEvents();
      readOnlyClonedAlgorithms = null;

      folds = new IntValue(1);
      samplesStart = new IntValue(0);
      samplesEnd = new IntValue(0);
      numberOfWorkers = new IntValue(1);
    }

    #region properties
    private IAlgorithm algorithmTemplate;
    public IAlgorithm AlgorithmTemplate {
      get { return algorithmTemplate; }
      set {
        if (algorithmTemplate != value) {
          if (value != null && value.Problem != null && !(value.Problem is IDataAnalysisProblem))
            throw new ArgumentException("Only algorithms with a DataAnalysisProblem could be used for the cross validation.");
          if (algorithmTemplate != null) DeregisterAlgorithmTemplateEvents();
          algorithmTemplate = value;
          if (algorithmTemplate != null) RegisterAlgorithmTemplateEvents();
          OnAlgorithmTemplateChanged();
        }
      }
    }
    public IDataAnalysisProblem Problem {
      get {
        if (algorithmTemplate == null)
          return null;
        return (IDataAnalysisProblem)algorithmTemplate.Problem;
      }
    }
    private ItemCollection<IAlgorithm> clonedAlgorithms;
    private ReadOnlyItemCollection<IAlgorithm> readOnlyClonedAlgorithms;
    public IItemCollection<IAlgorithm> ClonedAlgorithms {
      get {
        if (readOnlyClonedAlgorithms == null) readOnlyClonedAlgorithms = clonedAlgorithms.AsReadOnly();
        return readOnlyClonedAlgorithms;
      }
    }

    private IntValue folds;
    public IntValue Folds {
      get { return folds; }
    }
    private IntValue samplesStart;
    public IntValue SamplesStart {
      get { return SamplesStart; }
    }
    private IntValue samplesEnd;
    public IntValue SamplesEnd {
      get { return SamplesEnd; }
    }
    private IntValue numberOfWorkers;
    public IntValue NumberOfWorkers {
      get { return numberOfWorkers; }
    }

    private RunCollection runs;
    public RunCollection Runs {
      get { return runs; }
      private set {
        if (value == null) throw new ArgumentNullException();
        if (runs != value) {
          if (runs != null) DeregisterRunsEvents();
          runs = value;
          if (runs != null) RegisterRunsEvents();
        }
      }
    }
    private ExecutionState executionState;
    public ExecutionState ExecutionState {
      get { return executionState; }
      private set {
        if (executionState != value) {
          executionState = value;
          OnExecutionStateChanged();
          OnItemImageChanged();
        }
      }
    }
    private TimeSpan executionTime;
    public TimeSpan ExecutionTime {
      get { return executionTime; }
      private set {
        executionTime = value;
        OnExecutionTimeChanged();
      }
    }
    #endregion

    public void Prepare() {
      OnPrepared();
    }
    public void Prepare(bool clearRuns) {
      if (clearRuns) runs.Clear();
      Prepare();
    }
    public void Start() {
      OnStarted();
    }
    public void Pause() {
      OnPaused();
    }
    public void Stop() {
      OnStopped();
    }

    #region events
    public event EventHandler AlgorithmTemplateChanged;
    private void OnAlgorithmTemplateChanged() {
      Prepare();
      EventHandler handler = AlgorithmTemplateChanged;
      if (handler != null) handler(this, EventArgs.Empty);
    }
    private void RegisterAlgorithmTemplateEvents() {
      algorithmTemplate.ProblemChanged += new EventHandler(algorithmTemplate_ProblemChanged);
    }
    private void DeregisterAlgorithmTemplateEvents() {
      algorithmTemplate.ProblemChanged -= new EventHandler(algorithmTemplate_ProblemChanged);
    }
    private void algorithmTemplate_ProblemChanged(object sender, EventArgs e) {
      SamplesStart.Value = 0;
      SamplesEnd.Value = Problem.DataAnalysisProblemData.Dataset.Rows;
    }

    private void RegisterClonedAlgorithmEvents() {
      clonedAlgorithms.ItemsAdded += new CollectionItemsChangedEventHandler<IAlgorithm>(ClonedAlgorithms_ItemsAdded);
      clonedAlgorithms.ItemsRemoved += new CollectionItemsChangedEventHandler<IAlgorithm>(ClonedAlgorithms_ItemsRemoved);
      clonedAlgorithms.CollectionReset += new CollectionItemsChangedEventHandler<IAlgorithm>(ClonedAlgorithms_CollectionReset);
    }
    private void ClonedAlgorithms_ItemsAdded(object sender, CollectionItemsChangedEventArgs<IAlgorithm> e) {
      foreach (IAlgorithm algorithm in e.Items)
        RegisterClonedAlgorithmEvents(algorithm);
    }
    private void ClonedAlgorithms_ItemsRemoved(object sender, CollectionItemsChangedEventArgs<IAlgorithm> e) {
      foreach (IAlgorithm algorithm in e.Items)
        DeregisterClonedAlgorithmEvents(algorithm);
    }
    private void ClonedAlgorithms_CollectionReset(object sender, CollectionItemsChangedEventArgs<IAlgorithm> e) {
      foreach (IAlgorithm algorithm in e.Items)
        RegisterClonedAlgorithmEvents(algorithm);
      foreach (IAlgorithm algorithm in e.OldItems)
        DeregisterClonedAlgorithmEvents(algorithm);
    }
    private void RegisterClonedAlgorithmEvents(IAlgorithm algorithm) {
      algorithm.Runs.ItemsAdded += new CollectionItemsChangedEventHandler<IRun>(Algorithm_Runs_Added);
      algorithm.Paused += new EventHandler(Algorithm_Paused);
      algorithm.Stopped += new EventHandler(Algorithm_Stopped);
    }
    private void DeregisterClonedAlgorithmEvents(IAlgorithm algorithm) {
      algorithm.Runs.ItemsAdded -= new CollectionItemsChangedEventHandler<IRun>(Algorithm_Runs_Added);
      algorithm.Paused -= new EventHandler(Algorithm_Paused);
      algorithm.Stopped -= new EventHandler(Algorithm_Stopped);
    }
    private void Algorithm_Runs_Added(object sender, CollectionItemsChangedEventArgs<IRun> e) {
      throw new NotImplementedException("TODO added finished run to actual results if the cross validation is running");
    }
    private void Algorithm_Paused(object sender, EventArgs e) {
      throw new NotImplementedException("TODO pause the cross validation if an algorithm no algorithm is running.");
    }
    private void Algorithm_Stopped(object sender, EventArgs e) {
      throw new NotImplementedException("TODO stop the cross validation if all algorithms are stopped. and start remaining prepared algs");
    }
    public event EventHandler ExecutionStateChanged;
    private void OnExecutionStateChanged() {
      EventHandler handler = ExecutionStateChanged;
      if (handler != null) handler(this, EventArgs.Empty);
    }
    public event EventHandler ExecutionTimeChanged;
    private void OnExecutionTimeChanged() {
      EventHandler handler = ExecutionTimeChanged;
      if (handler != null) handler(this, EventArgs.Empty);
    }
    public event EventHandler Prepared;
    private void OnPrepared() {
      ExecutionState = ExecutionState.Prepared;
      EventHandler handler = Prepared;
      if (handler != null) handler(this, EventArgs.Empty);
    }
    public event EventHandler Started;
    private void OnStarted() {
      ExecutionState = ExecutionState.Started;
      EventHandler handler = Started;
      if (handler != null) handler(this, EventArgs.Empty);
    }
    public event EventHandler Paused;
    private void OnPaused() {
      ExecutionState = ExecutionState.Paused;
      EventHandler handler = Paused;
      if (handler != null) handler(this, EventArgs.Empty);
    }
    public event EventHandler Stopped;
    private void OnStopped() {
      ExecutionState = ExecutionState.Stopped;
      EventHandler handler = Stopped;
      if (handler != null) handler(this, EventArgs.Empty);
    }
    public event EventHandler<EventArgs<Exception>> ExceptionOccurred;
    private void OnExceptionOccurred(Exception exception) {
      EventHandler<EventArgs<Exception>> handler = ExceptionOccurred;
      if (handler != null) handler(this, new EventArgs<Exception>(exception));
    }

    private void RegisterRunsEvents() {
      runs.CollectionReset += new CollectionItemsChangedEventHandler<IRun>(Runs_CollectionReset);
      runs.ItemsAdded += new CollectionItemsChangedEventHandler<IRun>(Runs_ItemsAdded);
      runs.ItemsRemoved += new CollectionItemsChangedEventHandler<IRun>(Runs_ItemsRemoved);
    }
    private void DeregisterRunsEvents() {
      runs.CollectionReset -= new CollectionItemsChangedEventHandler<IRun>(Runs_CollectionReset);
      runs.ItemsAdded -= new CollectionItemsChangedEventHandler<IRun>(Runs_ItemsAdded);
      runs.ItemsRemoved -= new CollectionItemsChangedEventHandler<IRun>(Runs_ItemsRemoved);
    }
    private void Runs_CollectionReset(object sender, CollectionItemsChangedEventArgs<IRun> e) {
      foreach (IRun run in e.OldItems) {
        IItem item;
        run.Results.TryGetValue("Execution Time", out item);
        TimeSpanValue executionTime = item as TimeSpanValue;
        if (executionTime != null) ExecutionTime -= executionTime.Value;
      }
      foreach (IRun run in e.Items) {
        IItem item;
        run.Results.TryGetValue("Execution Time", out item);
        TimeSpanValue executionTime = item as TimeSpanValue;
        if (executionTime != null) ExecutionTime += executionTime.Value;
      }
    }
    private void Runs_ItemsAdded(object sender, CollectionItemsChangedEventArgs<IRun> e) {
      foreach (IRun run in e.Items) {
        IItem item;
        run.Results.TryGetValue("Execution Time", out item);
        TimeSpanValue executionTime = item as TimeSpanValue;
        if (executionTime != null) ExecutionTime += executionTime.Value;
      }
    }
    private void Runs_ItemsRemoved(object sender, CollectionItemsChangedEventArgs<IRun> e) {
      foreach (IRun run in e.Items) {
        IItem item;
        run.Results.TryGetValue("Execution Time", out item);
        TimeSpanValue executionTime = item as TimeSpanValue;
        if (executionTime != null) ExecutionTime -= executionTime.Value;
      }
    }
    #endregion
  }
}