using System;
using System.Collections.Generic;
using System.Linq;

namespace Client.Engine
{
    /// <summary>
    /// Класс описывает модель решения
    /// </summary>
    [Serializable]
    class Combination : IEquatable<Combination>, IComparable
    {
        public SortedSet<Variable> Variables { get; set; }
        public double MeanError { get; private set; }
        public double[] A { get; private set; }

        public Combination()
        {
            Variables = new SortedSet<Variable>();
            MeanError = double.NaN;
        }

        /// <summary>
        /// Подсчет среднеквадратической ошибки
        /// </summary>
        /// <param name="x">Выборочные значения X</param>
        /// <param name="y">Значения Y</param>
        /// <param name="a">Тестовые значения A, начиная с a0</param>
        /// <returns>Успешность выполнения функции</returns>
        public bool Test(double[][] x, double[] y, double[] a)
        {
            if (a.Length != (Variables.Count + 1) || x.Length != y.Length)
                return false;
            A = a;
            MeanError = 0;
            for (var k0 = 0; k0 < x.Length; k0++)
            {
                var ty = a[0];
                for (var k1 = 1; k1 < a.Length; k1++)
                {
                    ty += x[k0][k1 - 1]*a[k1];
                }
                MeanError += Math.Pow(y[k0] - ty, 2.0);
            }
            return true;
        }

        public override bool Equals(object obj)
        {
            return Equals(obj as Combination);
        }

        bool IEquatable<Combination>.Equals(Combination other)
        {
            return Equals(other);
        }

        public bool Equals(Combination other)
        {
            if (Variables.Count != other.Variables.Count)
                return false;
            for (var i = 0; i < Variables.Count; i++)
            {
                if (!Variables.ElementAt(i).Equals(other.Variables.ElementAt(i)))
                    return false;
            }
            return true;
        }

        public int CompareTo(object obj)
        {
            return CompareTo(obj as Combination);
        }

        public int CompareTo(Combination obj)
        {
            if (Equals(obj))
                return 0;
            return Variables.Count < obj.Variables.Count ? -1 : 1;
        }
    }
}