using System;
using HeuristicLab.Common;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;

namespace HeuristicLab.Problems.ProgramSynthesis {

  /// <summary>
  ///     Pushes the logical AND of the top two BOOLEANs.
  /// </summary>
  [PushExpression(StackTypes.Boolean, "BOOLEAN.AND", "Pushes the logical AND of the top two BOOLEANs.")]
  [StorableClass]
  public class BooleanAndExpression : StatelessExpression {
    public BooleanAndExpression() { }
    [StorableConstructor]
    public BooleanAndExpression(bool deserializing) : base(deserializing) { }

    public override bool IsNoop(IInternalPushInterpreter interpreter) {
      return interpreter.BooleanStack.Count < 2;
    }

    public override void Eval(IInternalPushInterpreter interpreter) {
      var first = interpreter.BooleanStack.Pop();
      var second = interpreter.BooleanStack.Top;
      var result = second && first;

      interpreter.BooleanStack.Top = result;
    }
  }

  /// <summary>
  ///     Pushes the logical OR of the top two BOOLEANs.
  /// </summary>
  [PushExpression(StackTypes.Boolean, "BOOLEAN.OR", "Pushes the logical OR of the top two BOOLEANs.")]
  [StorableClass]
  public class BooleanOrExpression : StatelessExpression {
    public BooleanOrExpression() { }
    [StorableConstructor]
    public BooleanOrExpression(bool deserializing) : base(deserializing) { }

    public override bool IsNoop(IInternalPushInterpreter interpreter) {
      return interpreter.BooleanStack.Count < 2;
    }

    public override void Eval(IInternalPushInterpreter interpreter) {
      var first = interpreter.BooleanStack.Pop();
      var second = interpreter.BooleanStack.Top;
      var result = second || first;

      interpreter.BooleanStack.Top = result;
    }
  }

  /// <summary>
  ///     Pushes the logical NOT of the top BOOLEAN.
  /// </summary>
  [PushExpression(StackTypes.Boolean, "BOOLEAN.NOT", "Pushes the logical NOT of the top BOOLEAN.")]
  [StorableClass]
  public class BooleanNotExpression : StatelessExpression {
    public BooleanNotExpression() { }
    [StorableConstructor]
    public BooleanNotExpression(bool deserializing) : base(deserializing) { }

    public override bool IsNoop(IInternalPushInterpreter interpreter) {
      return interpreter.BooleanStack.IsEmpty;
    }

    public override void Eval(IInternalPushInterpreter interpreter) {
      interpreter.BooleanStack.Top = !interpreter.BooleanStack.Top;
    }
  }

  /// <summary>
  ///     Pushes FALSE if the top FLOAT is 0.0, or TRUE otherwise.
  /// </summary>
  [PushExpression(StackTypes.Boolean, "BOOLEAN.FROMFLOAT", "Pushes FALSE if the top FLOAT is 0.0, or TRUE otherwise.", StackTypes.Float)]
  [StorableClass]
  public class BooleanFromFloatExpression : StatelessExpression {
    public BooleanFromFloatExpression() { }
    [StorableConstructor]
    public BooleanFromFloatExpression(bool deserializing) : base(deserializing) { }

    public override bool IsNoop(IInternalPushInterpreter interpreter) {
      return interpreter.FloatStack.Count == 0;
    }

    public override void Eval(IInternalPushInterpreter interpreter) {
      var value = !Math.Abs(interpreter.FloatStack.Pop()).IsAlmost(0);
      interpreter.BooleanStack.Push(value);
    }
  }

  /// <summary>
  ///     Pushes FALSE if the top INTEGER is 0, or TRUE otherwise.
  /// </summary>
  [PushExpression(StackTypes.Boolean, "BOOLEAN.FROMINTEGER", "Pushes FALSE if the top INTEGER is 0, or TRUE otherwise.", StackTypes.Integer)]
  [StorableClass]
  public class BooleanFromIntegerExpression : StatelessExpression {
    public BooleanFromIntegerExpression() { }
    [StorableConstructor]
    public BooleanFromIntegerExpression(bool deserializing) : base(deserializing) { }

    public override bool IsNoop(IInternalPushInterpreter interpreter) {
      return interpreter.IntegerStack.Count == 0;
    }

    public override void Eval(IInternalPushInterpreter interpreter) {
      var value = interpreter.IntegerStack.Pop() != 0;
      interpreter.BooleanStack.Push(value);
    }
  }

  /// <summary>
  ///     Pushes the logical AND of the top two BOOLEANs, whereby the first value is inverted first.
  /// </summary>
  [PushExpression(StackTypes.Boolean, "BOOLEAN.INVERT_FIRST_THEN_AND", "Pushes the logical AND of the top two BOOLEANs, whereby the first value is inverted first.")]
  [StorableClass]
  public class BooleanInvertFirstThenAnd : StatelessExpression {
    public BooleanInvertFirstThenAnd() { }
    [StorableConstructor]
    public BooleanInvertFirstThenAnd(bool deserializing) : base(deserializing) { }

    public override bool IsNoop(IInternalPushInterpreter interpreter) {
      return interpreter.BooleanStack.Count < 2;
    }

    public override void Eval(IInternalPushInterpreter interpreter) {
      var first = interpreter.BooleanStack.Pop();
      var second = interpreter.BooleanStack.Top;
      var result = second && !first;

      interpreter.BooleanStack.Top = result;
    }
  }

  /// <summary>
  ///     Pushes the logical AND of the top two BOOLEANs, whereby the second value is inverted first.
  /// </summary>
  [PushExpression(StackTypes.Boolean, "BOOLEAN.INVERT_SECOND_THEN_AND", "Pushes the logical AND of the top two BOOLEANs, whereby the second value is inverted first.")]
  [StorableClass]
  public class BooleanInvertSecondThenAnd : StatelessExpression {
    public BooleanInvertSecondThenAnd() { }
    [StorableConstructor]
    public BooleanInvertSecondThenAnd(bool deserializing) : base(deserializing) { }

    public override bool IsNoop(IInternalPushInterpreter interpreter) {
      return interpreter.BooleanStack.Count < 2;
    }

    public override void Eval(IInternalPushInterpreter interpreter) {
      var first = interpreter.BooleanStack.Pop();
      var second = interpreter.BooleanStack.Top;
      var result = !second && first;

      interpreter.BooleanStack.Top = result;
    }
  }


  /// <summary>
  ///     Pushes the xor of the top tow BOOLEANs
  /// </summary>
  [PushExpression(StackTypes.Boolean, "BOOLEAN.XOR", "Pushes the xor of the top tow BOOLEANs.")]
  [StorableClass]
  public class BooleanXorExpression : StatelessExpression {
    public BooleanXorExpression() { }
    [StorableConstructor]
    public BooleanXorExpression(bool deserializing) : base(deserializing) { }

    public override bool IsNoop(IInternalPushInterpreter interpreter) {
      return interpreter.BooleanStack.Count < 2;
    }

    public override void Eval(IInternalPushInterpreter interpreter) {
      var first = interpreter.BooleanStack.Pop();
      var second = interpreter.BooleanStack.Top;
      var result = second ^ first;

      interpreter.BooleanStack.Top = result;
    }
  }
}