using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using System.Text;
using System.Threading.Tasks;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;

namespace HeuristicLab.Algorithms.IteratedSymbolicExpressionConstruction {
  [StorableClass]
  [Item("SymbolicExpressionTermsStateFunction", "")]
  public class SymbolicExpressionTermsStateFunction : Item, IStateFunction {
    public SymbolicExpressionTermsStateFunction()
      : base() {
    }

    public object CreateState(ISymbolicExpressionTreeNode root, List<ISymbol> actions, ISymbolicExpressionTreeNode parentNode, int childIdx) {
      var terms = new List<Tuple<string, double>>();
      var formatter = new HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.SymbolicExpressionTreeStringFormatter();
      var t = new SymbolicExpressionTree();
      terms.Add(Tuple.Create("const", 1.0));
      foreach (var n in root.IterateNodesPrefix()) {
        if (n.Symbol is StartSymbol && n.SubtreeCount > 0) {
          t.Root = n;
          terms.Add(Tuple.Create("start-" + n.GetSubtree(0).Symbol.Name, 1.0));
        } else if (n.Symbol.Name == "+" || n.Symbol.Name == "-") {
          foreach (var child in n.Subtrees.OrderBy(c => c.Symbol.Name)) {
            if (child.Symbol.Name == "+" || n.Symbol.Name == "-") continue; // skip (+ (+ ...) ...), only non-decomposable terms are relevant for us
            t.Root = child;
            terms.Add(Tuple.Create(formatter.Format(t), 1.0));
          }
        }
      }
      return terms;
    }

    #region item
    [StorableConstructor]
    protected SymbolicExpressionTermsStateFunction(bool deserializing) : base(deserializing) { }
    protected SymbolicExpressionTermsStateFunction(SymbolicExpressionTermsStateFunction original, Cloner cloner)
      : base(original, cloner) {
    }
    public override IDeepCloneable Clone(Cloner cloner) {
      return new SymbolicExpressionTermsStateFunction(this, cloner);
    }
    #endregion
  }
}