namespace HeuristicLab.Problems.ProgramSynthesis.Push.Expressions {
  using System;

  using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
  using HeuristicLab.Problems.ProgramSynthesis.Push.Attributes;
  using HeuristicLab.Problems.ProgramSynthesis.Push.Stack;

  using Interpreter;

  /// <summary>
  /// Pushes the sum of the top two items.
  /// </summary>
  [PushExpression(
    StackTypes.Integer,
    "INTEGER.+",
    "Pushes the sum of the top two items.")]
  [StorableClass]
  public class IntegerAddExpression : StatelessExpression {
    public IntegerAddExpression() { }
    [StorableConstructor]
    protected IntegerAddExpression(bool deserializing) : base(deserializing) { }

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

    public override void Eval(IInternalPushInterpreter interpreter) {
      var first = interpreter.IntegerStack.Pop();
      var second = interpreter.IntegerStack.Top;
      var result = unchecked(second + first);

      interpreter.IntegerStack.Top = result;
    }
  }

  /// <summary>
  /// Pushes the difference of the top two items; that is, the second item minus the top item.
  /// </summary>
  [PushExpression(
    StackTypes.Integer,
    "INTEGER.-",
    "Pushes the difference of the top two items; that is, the second item minus the top item.")]
  [StorableClass]
  public class IntegerSubtractExpression : StatelessExpression {
    public IntegerSubtractExpression() { }
    [StorableConstructor]
    protected IntegerSubtractExpression(bool deserializing) : base(deserializing) { }

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

    public override void Eval(IInternalPushInterpreter interpreter) {
      var first = interpreter.IntegerStack.Pop();
      var second = interpreter.IntegerStack.Top;
      var result = unchecked(second - first);

      interpreter.IntegerStack.Top = result;
    }
  }

  /// <summary>
  /// Pushes the product of the top two items.
  /// </summary>
  [PushExpression(
    StackTypes.Integer,
    "INTEGER.*",
    "Pushes the product of the top two items.")]
  [StorableClass]
  public class IntegerMultiplyExpression : StatelessExpression {
    public IntegerMultiplyExpression() { }
    [StorableConstructor]
    protected IntegerMultiplyExpression(bool deserializing) : base(deserializing) { }

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

    public override void Eval(IInternalPushInterpreter interpreter) {
      var first = interpreter.IntegerStack.Pop();
      var second = interpreter.IntegerStack.Top;
      var result = unchecked(second * first);

      interpreter.IntegerStack.Top = result;
    }
  }

  /// <summary>
  /// Pushes the quotient of the top two items; that is, the second item divided by the top item.
  /// If the top item is zero this acts as a NOOP.
  /// </summary>
  [PushExpression(
    StackTypes.Integer,
    "INTEGER./",
    "Pushes the quotient of the top two items; that is, the second item divided by the top item. If the top item is zero this acts as a NOOP.")]
  [StorableClass]
  public class IntegerDivideExpression : StatelessExpression {
    public IntegerDivideExpression() { }
    [StorableConstructor]
    protected IntegerDivideExpression(bool deserializing) : base(deserializing) { }

    public override bool IsNoop(IInternalPushInterpreter interpreter) {
      return interpreter.IntegerStack.Count < 2 ||
             interpreter.IntegerStack.Top == 0 ||
             (interpreter.IntegerStack.Top == -1 && interpreter.IntegerStack[1] == long.MinValue);
    }

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

      interpreter.IntegerStack.Top = result;
    }
  }

  /// <summary>
  /// Pushes the second stack item modulo the top stack item. If the top item is zero this acts as a NOOP.
  /// </summary>
  [PushExpression(
    StackTypes.Integer,
    "INTEGER.%",
    "Pushes the second stack item modulo the top stack item. If the top item is zero this acts as a NOOP.")]
  [StorableClass]
  public class IntegerModuloExpression : StatelessExpression {
    public IntegerModuloExpression() { }
    [StorableConstructor]
    protected IntegerModuloExpression(bool deserializing) : base(deserializing) { }

    public override bool IsNoop(IInternalPushInterpreter interpreter) {
      return interpreter.IntegerStack.Count < 2 ||
             interpreter.IntegerStack.Top == 0 ||
             (interpreter.IntegerStack.Top == -1 && interpreter.IntegerStack[1] == long.MinValue);
    }

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

      interpreter.IntegerStack.Top = result;
    }
  }

  /// <summary>
  /// Pushes the minimum of the top two items.
  /// </summary>
  [PushExpression(
    StackTypes.Integer,
    "INTEGER.MIN",
    "Pushes the minimum of the top two items.")]
  [StorableClass]
  public class IntegerMinExpression : StatelessExpression {
    public IntegerMinExpression() { }
    [StorableConstructor]
    protected IntegerMinExpression(bool deserializing) : base(deserializing) { }

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

    public override void Eval(IInternalPushInterpreter interpreter) {
      var first = interpreter.IntegerStack.Pop();
      var second = interpreter.IntegerStack.Top;
      var result = Math.Min(second, first);

      interpreter.IntegerStack.Top = result;
    }
  }

  /// <summary>
  /// Pushes the maximum of the top two items.
  /// </summary>
  [PushExpression(
    StackTypes.Integer,
    "INTEGER.MAX",
    "Pushes the maximum of the top two items.")]
  [StorableClass]
  public class IntegerMaxExpression : StatelessExpression {
    public IntegerMaxExpression() { }
    [StorableConstructor]
    protected IntegerMaxExpression(bool deserializing) : base(deserializing) { }

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

    public override void Eval(IInternalPushInterpreter interpreter) {
      var first = interpreter.IntegerStack.Pop();
      var second = interpreter.IntegerStack.Top;
      var result = Math.Max(second, first);

      interpreter.IntegerStack.Top = result;
    }
  }

  /// <summary>
  /// Pushes TRUE onto the BOOLEAN stack if the second item is less than the top item, or FALSE otherwise.
  /// </summary>
  [PushExpression(
    StackTypes.Integer,
    "INTEGER.<",
    "Pushes TRUE onto the BOOLEAN stack if the second item is less than the top item, or FALSE otherwise.",
    StackTypes.Boolean)]
  [StorableClass]
  public class IntegerSmallerThanExpression : StatelessExpression {
    public IntegerSmallerThanExpression() { }
    [StorableConstructor]
    protected IntegerSmallerThanExpression(bool deserializing) : base(deserializing) { }

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

    public override void Eval(IInternalPushInterpreter interpreter) {
      var first = interpreter.IntegerStack.Top;
      var second = interpreter.IntegerStack[1];
      interpreter.IntegerStack.Remove(2);

      var result = second < first;
      interpreter.BooleanStack.Push(result);
    }
  }

  /// <summary>
  /// Pushes TRUE onto the BOOLEAN stack if the second item is less than or equal to the top item, or FALSE otherwise.
  /// </summary>
  [PushExpression(
    StackTypes.Integer,
    "INTEGER.<=",
    "Pushes TRUE onto the BOOLEAN stack if the second item is less than or equal to the top item, or FALSE otherwise.",
    StackTypes.Boolean)]
  [StorableClass]
  public class IntegerSmallerOrEqualToExpression : StatelessExpression {
    public IntegerSmallerOrEqualToExpression() { }
    [StorableConstructor]
    protected IntegerSmallerOrEqualToExpression(bool deserializing) : base(deserializing) { }

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

    public override void Eval(IInternalPushInterpreter interpreter) {
      var first = interpreter.IntegerStack.Top;
      var second = interpreter.IntegerStack[1];
      interpreter.IntegerStack.Remove(2);

      var result = second <= first;
      interpreter.BooleanStack.Push(result);
    }
  }

  /// <summary>
  /// Pushes TRUE onto the BOOLEAN stack if the second item is greater than the top item, or FALSE otherwise.
  /// </summary>
  [PushExpression(
    StackTypes.Integer,
    "INTEGER.>",
    "Pushes TRUE onto the BOOLEAN stack if the second item is greater than the top item, or FALSE otherwise.",
    StackTypes.Boolean)]
  [StorableClass]
  public class IntegerGreaterThanExpression : StatelessExpression {
    public IntegerGreaterThanExpression() { }
    [StorableConstructor]
    protected IntegerGreaterThanExpression(bool deserializing) : base(deserializing) { }

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

    public override void Eval(IInternalPushInterpreter interpreter) {
      var first = interpreter.IntegerStack.Top;
      var second = interpreter.IntegerStack[1];
      interpreter.IntegerStack.Remove(2);

      var result = second > first;
      interpreter.BooleanStack.Push(result);
    }
  }


  /// <summary>
  /// Pushes TRUE onto the BOOLEAN stack if the second item is greater than or equal to the top item, or FALSE otherwise.
  /// </summary>
  [PushExpression(
    StackTypes.Integer,
    "INTEGER.>=",
    "Pushes TRUE onto the BOOLEAN stack if the second item is greater than or equal to the top item, or FALSE otherwise.",
    StackTypes.Boolean)]
  [StorableClass]
  public class IntegerGreaterOrEqualToExpression : StatelessExpression {
    public IntegerGreaterOrEqualToExpression() { }
    [StorableConstructor]
    protected IntegerGreaterOrEqualToExpression(bool deserializing) : base(deserializing) { }

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

    public override void Eval(IInternalPushInterpreter interpreter) {
      var first = interpreter.IntegerStack.Top;
      var second = interpreter.IntegerStack[1];
      interpreter.IntegerStack.Remove(2);

      var result = second >= first;
      interpreter.BooleanStack.Push(result);
    }
  }

  /// <summary>
  /// Pushes 1 if the top BOOLEAN is TRUE, or 0 if the top BOOLEAN is FALSE.
  /// </summary>
  [PushExpression(
    StackTypes.Integer,
    "INTEGER.FROMBOOLEAN",
    "Pushes 1 if the top BOOLEAN is TRUE, or 0 if the top BOOLEAN is FALSE.",
    StackTypes.Boolean)]
  [StorableClass]
  public class IntegerFromBooleanExpression : StatelessExpression {
    public IntegerFromBooleanExpression() { }
    [StorableConstructor]
    protected IntegerFromBooleanExpression(bool deserializing) : base(deserializing) { }

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

    public override void Eval(IInternalPushInterpreter interpreter) {
      var condition = interpreter.BooleanStack.Pop();
      var value = condition ? 1 : 0;
      interpreter.IntegerStack.Push(value);
    }
  }

  /// <summary>
  /// Pushes the result of truncating the top FLOAT.
  /// </summary>
  [PushExpression(
    StackTypes.Integer,
    "INTEGER.FROMFLOAT",
    "Pushes the result of truncating the top FLOAT.",
    StackTypes.Float)]
  [StorableClass]
  public class IntegerFromFloatExpression : StatelessExpression {
    public IntegerFromFloatExpression() { }
    [StorableConstructor]
    protected IntegerFromFloatExpression(bool deserializing) : base(deserializing) { }

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

    public override void Eval(IInternalPushInterpreter interpreter) {
      var value = unchecked((long)interpreter.FloatStack.Pop());
      interpreter.IntegerStack.Push(value);
    }
  }

  /// <summary>
  /// Pushes the result of truncating the top CHAR.
  /// </summary>
  [PushExpression(
    StackTypes.Integer,
    "INTEGER.FROMCHAR",
    "Pushes the result of truncating the top CHAR.",
    StackTypes.Char)]
  [StorableClass]
  public class IntegerFromCharExpression : StatelessExpression {
    public IntegerFromCharExpression() { }
    [StorableConstructor]
    protected IntegerFromCharExpression(bool deserializing) : base(deserializing) { }

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

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

  /// <summary>
  /// Pushes the result of parsing the top STRING.
  /// </summary>
  [PushExpression(
    StackTypes.Integer,
    "INTEGER.FROMSTRING",
    "Pushes the result of parsing the top STRING.",
    StackTypes.String)]
  [StorableClass]
  public class IntegerFromStringExpression : StatelessExpression {
    public IntegerFromStringExpression() { }
    [StorableConstructor]
    protected IntegerFromStringExpression(bool deserializing) : base(deserializing) { }

    public override bool IsNoop(IInternalPushInterpreter interpreter) {
      long tmp;

      return interpreter.StringStack.IsEmpty ||
             interpreter.StringStack.Top.Length == 0 ||
             !long.TryParse(interpreter.StringStack.Top, out tmp);
    }

    public override void Eval(IInternalPushInterpreter interpreter) {
      var str = interpreter.StringStack.Pop();
      var value = long.Parse(str);
      interpreter.IntegerStack.Push(value);
    }
  }

  /// <summary>
  /// Pushes the result of increasing the top INTEGER by 1.
  /// </summary>
  [PushExpression(
    StackTypes.Integer,
    "INTEGER.INC",
    "Pushes the result of increasing the top INTEGER by 1.")]
  [StorableClass]
  public class IntegerIncExpression : StatelessExpression {
    public IntegerIncExpression() { }
    [StorableConstructor]
    protected IntegerIncExpression(bool deserializing) : base(deserializing) { }

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

    public override void Eval(IInternalPushInterpreter interpreter) {
      var result = unchecked(interpreter.IntegerStack.Top + 1);
      interpreter.IntegerStack.Top = result;
    }
  }

  /// <summary>
  /// Pushes the result of decreasing the top INTEGER by 1.
  /// </summary>
  [PushExpression(
    StackTypes.Integer,
    "INTEGER.DEC",
    "Pushes the result of decreasing the top INTEGER by 1.")]
  [StorableClass]
  public class IntegerDecExpression : StatelessExpression {
    public IntegerDecExpression() { }
    [StorableConstructor]
    protected IntegerDecExpression(bool deserializing) : base(deserializing) { }

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

    public override void Eval(IInternalPushInterpreter interpreter) {
      var result = unchecked(interpreter.IntegerStack.Top - 1);
      interpreter.IntegerStack.Top = result;
    }
  }
}