using System;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;

namespace HeuristicLab.Problems.MetaOptimization {
  [StorableClass]
  public class ConstrainedValue : Item {
    [Storable]
    protected Type valueDataType;
    public Type ValueDataType {
      get { return this.valueDataType; }
      protected set { this.valueDataType = value; }
    }

    [Storable]
    protected IItem value;
    public IItem Value {
      get { return value; }
      set {
        if (this.value != value) {
          if(this.value != null) DeregisterEvents();
          this.value = value;
          if(this.value != null) RegisterEvents();
          OnToStringChanged();
        }
      }
    }

    [Storable]
    protected IItemSet<IItem> validValues;
    public IItemSet<IItem> ValidValues {
      get { return validValues; }
      protected set {
        if (this.validValues != value) {
          this.validValues = value;
        }
      }
    }

    [Storable]
    protected bool isNullable;
    public bool IsNullable {
      get { return isNullable; }
      protected set {
        if (this.isNullable != value) {
          this.isNullable = value;
        }
      }
    }

    private void RegisterEvents() {
      this.value.ToStringChanged += new EventHandler(value_ToStringChanged);
      if (this.value is Symbol) {
        ((Symbol)this.value).Changed += new EventHandler(ConstrainedValue_Changed);
      }
    }

    private void DeregisterEvents() {
      this.value.ToStringChanged -= new EventHandler(value_ToStringChanged);
      if (this.value is Symbol) {
        ((Symbol)this.value).Changed -= new EventHandler(ConstrainedValue_Changed);
      }
    }

    #region constructors and cloning
    public ConstrainedValue() { }
    [StorableConstructor]
    protected ConstrainedValue(bool deserializing) : base(deserializing) { }
    public ConstrainedValue(IItem value, Type valueDataType, IItemSet<IItem> validValues, bool isNullable) {
      this.Value = value;
      this.ValueDataType = valueDataType;
      this.ValidValues = validValues;
      this.isNullable = isNullable;
    }
    protected ConstrainedValue(ConstrainedValue original, Cloner cloner) : base(original, cloner) {
      this.valueDataType = original.valueDataType;
      this.Value = cloner.Clone(original.value);
      if(original.ValidValues != null) this.ValidValues = cloner.Clone(original.ValidValues);
      this.isNullable = original.isNullable;
    }
    public override IDeepCloneable Clone(Cloner cloner) {
      return new ConstrainedValue(this, cloner);
    }
    [StorableHook(HookType.AfterDeserialization)]
    private void AfterDeserialization() {
      if (this.value != null) RegisterEvents();
    }
    #endregion

    private void value_ToStringChanged(object sender, EventArgs e) {
      OnToStringChanged();
    }

    private void ConstrainedValue_Changed(object sender, EventArgs e) {
      OnToStringChanged();
    }

    public override string ToString() {
      if (this.value is Symbol) {
        return string.Format("{0}: {1}", this.value, ((Symbol)this.value).InitialFrequency);
      }
      return value != null ? value.ToString() : base.ToString();
    }
  }
}