using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using static ProjectKnapsack.classes.KnapsackParameters;

namespace ProjectKnapsack.classes;

public class KnapsackSolver
{
    private List<Item> items;
    private int capacity;
    private double currentWeight;
    private double currentValue;
    private int currentIndex;

    public KnapsackSolver(KnapsackParameters parameters)
    {
        items = parameters.Items.OrderByDescending(i => i.Value / i.Weight).ToList();
        capacity = parameters.Capacity;
        currentWeight = 0;
        currentValue = 0;
        currentIndex = 0;
    }

    public KnapsackState SaveState()
    {
        return new KnapsackState(items, currentWeight, currentValue, currentIndex,capacity);
    }

    public void RestoreState(KnapsackState state)
    {
        items = new List<Item>(state.Items);
        currentWeight = state.CurrentWeight;
        currentValue = state.CurrentValue;
        currentIndex = state.CurrentIndex;
    }

    public bool Step()
    {
        if (currentIndex >= items.Count)
            return false;

        Item item = items[currentIndex];
        if (currentWeight + item.Weight <= capacity)
        {
            currentWeight += item.Weight;
            currentValue += item.Value;
        }
        currentIndex++;
        return true;
    }
}