source: 2014/30/MitjaK/Attack to Agora/Attack to Agora/Attack to Agora/Attack to Agora/ChromaCase.cs @ 10337

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Jypeli;

public class ChromaCase
{
    public GameObject OpeningScreenFront;
    private int CurrentItem = 0;
    public int Items;

    private List<GameObject> PossibleItems = new List<GameObject>();
    private List<GameObject> ShownItems = new List<GameObject>();

    private GameObject FinalItem;

    public Vector Position = Vector.Zero;
    public Vector ItemRelativePosition;

    public const double START_SPEED = 0.02;
    public const double STOP_SPEED = 1.0;
    private Timer changeTimer = new Timer();

    private int layer;

    public delegate void CaseHandler(GameObject item);
    public event CaseHandler ItemReceived;

    /// <summary>
    /// Luo ChromaCase-olion. Lisää olio ruudulle Add-metodilla.
    /// Todennäköisyydet ovat esineiden tageissa object-taulukossa[0] doublena mielivaltaisella välillä,
    /// esim 0.0 - 100.0
    /// </summary>
    /// <param name="possibleItems"></param>
    /// <param name="finalItem"></param>
    public ChromaCase(List<GameObject> possibleItems, GameObject front, GameObject finalItem, int items)
    {
        this.PossibleItems.AddRange(possibleItems);
        if (finalItem != null)
            FinalItem = finalItem;

        this.OpeningScreenFront = front;
        this.Items = items;
    }

    public void Add(Vector position, int layer = 0)
    {
        Game.Instance.Add(OpeningScreenFront, layer);

        this.Position = position;
        OpeningScreenFront.Position = this.Position;
        this.layer = layer;
    }

    public void Destroy()
    {
        OpeningScreenFront.Destroy();
        for (int i = 0; i < ShownItems.Count; i++)
        {
            ShownItems[i].Destroy();
        }
    }

    public void Start()
    {
        GenerateItemList(Items);

        if (ShownItems.Count == 0)
            return;
        // y == startSpeed
        // x == speedIncrease
        // n == shownItems.Count
        // z == stopSpeed
        //  y*x^n=z x:n suhteen =>       x = (z / y) ^ (1 / n)
        double speedIncrease = Math.Pow((STOP_SPEED / START_SPEED), (1.0 / ShownItems.Count));

        changeTimer.Interval = START_SPEED;
        changeTimer.Timeout += delegate
        {
            changeTimer.Interval *= speedIncrease;
            if (CurrentItem == ShownItems.Count - 1)
            {
                changeTimer.Timeout += delegate
                {
                    StopTimer();
                    GiveItem();
                    Destroy();
                };
            }
            else ChangeItem(); 
        };
        changeTimer.Start();

        // eka esine näkyville
        ChangeItem(false);
    }

    private void ChangeItem(bool destroyOld = true)
    {
        if (CurrentItem >= ShownItems.Count - 1)
            return;

        if (destroyOld)
        {
            Game.Instance.Remove(ShownItems[CurrentItem]);
            CurrentItem++;
        }

        ShownItems[CurrentItem].Position = this.Position + ItemRelativePosition;
        if (layer > -3)
            Game.Instance.Add(ShownItems[CurrentItem], layer - 1);
        else
            Game.Instance.Add(ShownItems[CurrentItem], layer);
    }

    private void StopTimer()
    {
        changeTimer.Stop();
    }

    private void GiveItem()
    {
        if (ItemReceived != null)
            ItemReceived(ShownItems[ShownItems.Count - 1]);
    }

    private void GenerateItemList(int itemAmount)
    {
        for (int i = 0; i < itemAmount; i++)
        {
            if (i == itemAmount - 1 && FinalItem != null)
            {
                ShownItems.Add(FinalItem);
                break;
            }

            AddItemWithProbabilities();
        }
    }

    /// <summary>
    /// Lisää ShownItems-listaan esineen PossibleItems-listasta.
    /// Todennäköisyydet ovat esineiden tageissa doublena mielivaltaisella välillä,
    /// esim 0.0 - 100.0
    /// </summary>
    private void AddItemWithProbabilities()
    {
        double total = 0;
        List<double> limits = new List<double>();
        limits.Add(0.0);

        for (int i = 0; i < PossibleItems.Count; i++)
        {
            double current = (double)(((object[])PossibleItems[i].Tag)[0]);
            total += current;

            limits.Add(total);
        }

        double rNumber = RandomGen.NextDouble(0, total);

        for (int i = 0; i < limits.Count - 1; i++)
        {
            if (rNumber >= limits[i] && rNumber < limits[i + 1])
            {
                PossibleItems[i].Position = ItemRelativePosition;
                ShownItems.Add(PossibleItems[i]);
            }
        }
    }
}