using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Problems.DataAnalysis.Evaluators;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
using HeuristicLab.Parameters;

namespace HeuristicLab.Problems.DataAnalysis.MultiVariate.Evaluators {
  public class OnlineMultiVariateEvaluator<T> : IMultiVariateOnlineEvaluator where T : IOnlineEvaluator, new() {
    private List<T> evaluators;

    public OnlineMultiVariateEvaluator() {

      Reset();
    }

    #region IMultiVariateOnlineEvaluator Members
    public double Value {
      get { return evaluators.Sum(e => e.Value); }
    }

    public void Add(IEnumerable<double> original, IEnumerable<double> estimated) {
      var originalEnumerator = original.GetEnumerator();
      var estimatedEnumerator = estimated.GetEnumerator();
      // first call of Add() => initialize evaluators list
      if (evaluators == null) {
        evaluators = new List<T>();
        while (originalEnumerator.MoveNext() & estimatedEnumerator.MoveNext()) {
          T evaluator = new T();
          evaluator.Add(originalEnumerator.Current, estimatedEnumerator.Current);
          evaluators.Add(evaluator);
        }
      } else {
        // subsequent call of Add(): for each evaluator a value must be added
        int i = 0;
        while (originalEnumerator.MoveNext() & estimatedEnumerator.MoveNext() && i < evaluators.Count) {
          evaluators[i++].Add(originalEnumerator.Current, estimatedEnumerator.Current);
        }
        if (i < evaluators.Count) {
          throw new ArgumentException("Number of elements in original and estimated does not match the number of elements in previously added vectors.");
        }
      }
      if (originalEnumerator.MoveNext() | estimatedEnumerator.MoveNext()) {
        throw new ArgumentException("Number of elements in original and estimated does not match.");
      }
    }

    public void Reset() {
      if (evaluators != null) {
        foreach (var evaluator in evaluators)
          evaluator.Reset();
      }
    }

    #endregion
  }
}