#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2013 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 HeuristicLab.DataImporter.Data.CommandBase;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;


namespace HeuristicLab.DataImporter.Data {
  [StorableClass]
  public class CommandChain : IEnumerable<ICommand> {
    private LinkedList<ICommand> commands;
    private LinkedListNode<ICommand> lastExecutedCommand;
    private LinkedListNode<ICommand> startMacroRecordingCommand;
    private bool isMacroRecording;

    [Storable]
    private List<ICommand> CommandStorable {
      get {
        LinkedListNode<ICommand> cmdNode = null;
        if (this.isMacroRecording && startMacroRecordingCommand != null)
          cmdNode = startMacroRecordingCommand.Next;
        else
          cmdNode = commands.First;

        List<ICommand> list = new List<ICommand>();
        while (cmdNode != lastExecutedCommand.Next) {
          list.Add(cmdNode.Value);
          cmdNode = cmdNode.Next;
        }
        return list;
      }
      set {
        foreach (ICommand command in value)
          commands.AddLast(command);
        this.lastExecutedCommand = commands.Last;
        this.FireChanged();
      }
    }

    [StorableConstructor]
    protected CommandChain(bool deserializing)
      : base() {
      this.commands = new LinkedList<ICommand>();
    }
    public CommandChain() {
      this.commands = new LinkedList<ICommand>();
    }

    public ICommand LastExecutedCommand {
      get { return lastExecutedCommand == null ? null : lastExecutedCommand.Value; }
    }

    public int CommandsCount {
      get { return this.commands.Count; }
    }

    public bool FirstCommandReached {
      get { return this.commands.Count == 0 || this.lastExecutedCommand == null; }
    }

    public bool LastCommandReached {
      get { return this.commands.Count == 0 || this.lastExecutedCommand == this.commands.Last; }
    }

    public bool IsMacroRecording {
      get { return isMacroRecording; }
    }

    public string NextCommandDescription {
      get {
        if (LastCommandReached)
          return "Redo";
        else if (lastExecutedCommand == null)
          return commands.First.Value.Description;
        else
          return lastExecutedCommand.Next.Value.Description;
      }
    }

    public string PreviousCommandDescription {
      get { return FirstCommandReached ? "Undo" : lastExecutedCommand.Value.Description; }
    }

    public event EventHandler Changed;
    protected virtual void OnChanged() {
      if (this.Changed != null)
        this.Changed(this, EventArgs.Empty);
    }
    public void FireChanged() {
      this.OnChanged();
    }

    public void Add(ICommand command) {
      this.Add(command, true);
    }

    public void Add(ICommand command, bool fireChangedEvent) {
      try {
        System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.WaitCursor;
        command.Execute();
        while (this.commands.Count != 0 && this.commands.Last != this.lastExecutedCommand)
          this.commands.RemoveLast();
        this.commands.AddLast(command);
        this.lastExecutedCommand = this.commands.Last;
        GC.Collect();
        if (fireChangedEvent)
          this.OnChanged();
      }
      finally {
        System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.Default;
      }
    }

    public void Clear() {
      this.commands.Clear();
      this.OnChanged();
    }

    public void Redo() {
      if (this.lastExecutedCommand != this.commands.Last) {
        System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.WaitCursor;
        if (this.lastExecutedCommand == null)
          this.lastExecutedCommand = this.commands.First;
        else
          this.lastExecutedCommand = this.lastExecutedCommand.Next;
        try {
          this.lastExecutedCommand.Value.Execute();
          this.OnChanged();
        }
        catch (CommandExecutionException) {
          this.lastExecutedCommand = this.lastExecutedCommand.Previous;
          throw;
        }
        finally {
          System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.Default;
        }
      }
    }

    public void Undo() {
      if (this.lastExecutedCommand != null) {
        System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.WaitCursor;
        try {
          this.lastExecutedCommand.Value.UndoExecute();
          if (this.lastExecutedCommand == this.startMacroRecordingCommand)
            isMacroRecording = false;
          this.lastExecutedCommand = this.lastExecutedCommand.Previous;
          this.OnChanged();
        }
        finally {
          System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.Default;
        }
      }
    }

    public void ToggleMacroRecording() {
      if (!isMacroRecording)
        this.startMacroRecordingCommand = lastExecutedCommand;
      isMacroRecording = !isMacroRecording;
      this.OnChanged();
    }

    #region IEnumerable<ICommand> Members
    public IEnumerator<ICommand> GetEnumerator() {
      return commands.GetEnumerator();
    }
    #endregion

    #region IEnumerable Members
    System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() {
      return commands.GetEnumerator();
    }
    #endregion
  }
}