using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using HeuristicLab.Services.Optimization.ControllerService.Model;

namespace HeuristicLab.Services.Optimization.ControllerService.Parameters {
  public interface IParameterHandler<I> {
    Type HandledType { get; }
    Parameter Map(I item);
  };

  public class ParameterMappingException : Exception {
    public ParameterMappingException(string message) : base(message) {
    }
  }

  public class ParameterMapper<I> {
    Dictionary<Type, IParameterHandler<I>> handlers = new Dictionary<Type,IParameterHandler<I>>();

    public ParameterMapper() {
    }

    public void Register(IParameterHandler<I> handler) {
      handlers[handler.HandledType] = handler;
    }

    public bool IsHandlerAvailable(I element) {
      return handlers.ContainsKey(element.GetType());
    }

    public Parameter Map(string name, I element) {
      if (element == null)
        throw new ArgumentNullException("Element parameter may not be null");
      IParameterHandler<I> handler;
      if (handlers.TryGetValue(element.GetType(), out handler)) {
        var param = handler.Map(element);
        if (param == null)
          throw new ParameterMappingException("Handler '" + handler.GetType().FullName + "' returned null parameter for type " + element.GetType().FullName);
        param.Value.Name = name;
        return param;
      }
      throw new ParameterMappingException("No handler for type " + element.GetType().FullName);
    }
  }
}