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)
        {
            this.Prefix = "(";
            this.Suffix = ")";
        }

        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;
        }
    }
}