using System.Collections.Generic;

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

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

  /// <summary>
  /// Takes the reverse of the top item on the type stack.
  /// </summary>
  /// <param name="vectorStack"></param>
  /// <returns></returns>
  [StorableClass]
  public abstract class VectorReverseExpression<T> : StatelessExpression {
    protected VectorReverseExpression() { }
    [StorableConstructor]
    protected VectorReverseExpression(bool deserializing) : base(deserializing) { }

    protected bool IsNoop(IPushStack<IReadOnlyList<T>> vectorStack) {
      return vectorStack.IsEmpty || vectorStack.Top.Count < 2;
    }

    protected void Eval(IPushStack<IReadOnlyList<T>> vectorStack) {
      vectorStack.Top = vectorStack.Top.Reverse().ToList();
    }
  }

  [StorableClass]
  [PushExpression(
    StackTypes.IntegerVector,
    "INTEGER[].REVERSE",
    "Reverses the top INTEGER[].")]
  public class IntegerVectorReverseExpression : VectorReverseExpression<long> {
    public IntegerVectorReverseExpression() { }
    [StorableConstructor]
    protected IntegerVectorReverseExpression(bool deserializing) : base(deserializing) { }

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

    public override void Eval(IInternalPushInterpreter interpreter) {
      Eval(interpreter.IntegerVectorStack);
    }
  }

  [StorableClass]
  [PushExpression(
    StackTypes.FloatVector,
    "FLOAT[].REVERSE",
    "Reverses the top FLOAT[].")]
  public class FloatVectorReverseExpression : VectorReverseExpression<double> {
    public FloatVectorReverseExpression() { }
    [StorableConstructor]
    protected FloatVectorReverseExpression(bool deserializing) : base(deserializing) { }

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

    public override void Eval(IInternalPushInterpreter interpreter) {
      Eval(interpreter.FloatVectorStack);
    }
  }

  [StorableClass]
  [PushExpression(
    StackTypes.BooleanVector,
    "BOOLEAN[].REVERSE",
    "Reverses the top BOOLEAN[].")]
  public class BooleanVectorReverseExpression : VectorReverseExpression<bool> {
    public BooleanVectorReverseExpression() { }
    [StorableConstructor]
    protected BooleanVectorReverseExpression(bool deserializing) : base(deserializing) { }

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

    public override void Eval(IInternalPushInterpreter interpreter) {
      Eval(interpreter.BooleanVectorStack);
    }
  }

  [StorableClass]
  [PushExpression(
    StackTypes.StringVector,
    "STRING[].REVERSE",
    "Reverses the top STRING[].")]
  public class StringVectorReverseExpression : VectorReverseExpression<string> {
    public StringVectorReverseExpression() { }
    [StorableConstructor]
    protected StringVectorReverseExpression(bool deserializing) : base(deserializing) { }

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

    public override void Eval(IInternalPushInterpreter interpreter) {
      Eval(interpreter.StringVectorStack);
    }
  }
}