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

namespace MetaheuristicsPCL
{
    public class ParticleSwarmOptimizationForKnapsack : ParticleSwarmOptimizationAlgorithm
    {
        int nbIterations = 1;
        private const int MAX_ITERATIONS = 200;

        protected override void UpdateSolutions()
        {
            List<Box> possibleBoxes = ((KnapsackProblem)pb).Boxes();

            foreach (ISolution genericSolution in currentSolutions)
            {
                KnapsackSolution solution = (KnapsackSolution)genericSolution;

                if (!solution.Equals(bestSoFarSolution))
                {
                    int index = KnapsackProblem.randomGenerator.Next(0, ((KnapsackSolution)bestActualSolution).LoadedContent.Count);
                    Box element = ((KnapsackSolution)bestActualSolution).LoadedContent.ElementAt(index);
                    if (!solution.LoadedContent.Contains(element))
                    {
                        solution.LoadedContent.Add(element);
                    }

                    index = KnapsackProblem.randomGenerator.Next(0, ((KnapsackSolution)bestSoFarSolution).LoadedContent.Count);
                    element = ((KnapsackSolution)bestSoFarSolution).LoadedContent.ElementAt(index);
                    if (!solution.LoadedContent.Contains(element))
                    {
                        solution.LoadedContent.Add(element);
                    }

                    while (solution.Weight > ((KnapsackProblem)pb).MaxWeight)
                    {
                        index = KnapsackProblem.randomGenerator.Next(0, solution.LoadedContent.Count);
                        solution.LoadedContent.RemoveAt(index);
                    }

                    double enableSpace = ((KnapsackProblem)pb).MaxWeight - solution.Weight;
                    List<Box> availableBoxes = possibleBoxes.Except(solution.LoadedContent).Where(x => (x.Weight <= enableSpace)).ToList();

                    while (enableSpace > 0 && availableBoxes.Count != 0)
                    {
                        index = KnapsackProblem.randomGenerator.Next(0, availableBoxes.Count);
                        solution.LoadedContent.Add(availableBoxes.ElementAt(index));
                        enableSpace = ((KnapsackProblem)pb).MaxWeight - solution.Weight;
                        availableBoxes = possibleBoxes.Except(solution.LoadedContent).Where(x => (x.Weight <= enableSpace)).ToList();
                    }
                }
            }
        }

        protected override void UpdateGeneralVariables()
        {
            bestActualSolution = currentSolutions.OrderByDescending(x => x.Value).FirstOrDefault();
            if (bestActualSolution.Value > bestSoFarSolution.Value)
            {
                bestSoFarSolution = bestActualSolution;
            }
        }

        protected override bool Done()
        {
            return nbIterations >= MAX_ITERATIONS;
        }

        protected override void Increment()
        {
            nbIterations++;
        }

        protected override void SendResult()
        {
            ihm.PrintMessage(bestSoFarSolution.ToString());
        }
    }
}