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

namespace HeuristicLab.Problems.Robocode {
  [StorableClass]
  public class NumericalOperation : CodeNode {
    public override int MinimumArity { get { return 3; } }
    public override int MaximumArity { get { return 3; } }

    [Storable]
    public override string Prefix { get; set; }

    [Storable]
    public override string Suffix { get; set; }

    [StorableConstructor]
    private NumericalOperation(bool deserializing) : base(deserializing) { }
    private NumericalOperation(NumericalOperation original, Cloner cloner)
      : base(original, cloner) {
    }

    public NumericalOperation()
      : base("NumericalOperation", "An expression consisting of two numbers and an operator.") {
      this.Prefix = "(";
      this.Suffix = ")";
    }

    public override IDeepCloneable Clone(Cloner cloner) {
      return new NumericalOperation(this, cloner);
    }

    public override string Interpret(ISymbolicExpressionTreeNode node, System.Collections.Generic.IEnumerable<ISymbolicExpressionTreeNode> children) {
      ISymbolicExpressionTreeNode condition = null, lhs = null, rhs = null;
      var enumerator = children.GetEnumerator();
      int childCount = 0;
      while (enumerator.MoveNext()) {
        childCount++;
        switch (childCount) {
          case 1: condition = enumerator.Current; break;
          case 2: lhs = enumerator.Current; break;
          case 3: rhs = enumerator.Current; break;
          default: throw new System.Exception("Unexpected number of children. Expected 3 children.");
        }
      }
      if (childCount < 3) throw new System.Exception("Unexpected number of children. Expected 3 children.");

      if (!(condition.Symbol is Addition || condition.Symbol is Division ||
          condition.Symbol is Modulus || condition.Symbol is Multiplication || condition.Symbol is Subtraction))
        throw new System.Exception("Unexpected first child for NumericalOperation of type: " +
            condition.GetType().ToString() + ". Expected " + typeof(Addition).ToString() +
            " or " + typeof(Division).ToString() +
            " or " + typeof(Modulus).ToString() +
            " or " + typeof(Multiplication).ToString() +
            " or " + typeof(Subtraction).ToString() + ".");

      // TODO Check children 2 & 3 for correct types

      string[] result = new string[]
            {
                ((CodeNode)condition.Symbol).Interpret(condition, condition.Subtrees),
                ((CodeNode)lhs.Symbol).Interpret(lhs, lhs.Subtrees),
                ((CodeNode)rhs.Symbol).Interpret(rhs, rhs.Subtrees)
            };

      return this.Prefix + " " + result[1] + " " + result[0] + " " + result[2] + " " + this.Suffix;
    }
  }
}