using UniRx;
using UnityEngine;
using UnityEngine.UI;

// Presenter for scene(canvas) root.
public class ReactivePresenter : MonoBehaviour
{
    // Presenter is aware of its View (binded in the inspector)
    public Button MyButton;
    public Toggle MyToggle;
    public Text MyText;

    Enemy enemy = new Enemy(1000);

    // Start is called before the first frame update
    void Start()
    {
        // Rx supplies user events from Views and Models in a reactive manner 
        MyButton.OnClickAsObservable().Subscribe(_ => enemy.CurrentHp.Value -= 99);
        MyToggle.OnValueChangedAsObservable().SubscribeToInteractable(MyButton);

        // Models notify Presenters via Rx, and Presenters update their views
        enemy.CurrentHp.SubscribeToText(MyText);
        enemy.IsDead.Where(isDead => isDead == true)
            .Subscribe(_ =>
            {
                MyToggle.interactable = MyButton.interactable = false;
            });
    }
}

// The Model. All property notify when their values change
public class Enemy
{
    public ReactiveProperty<long> CurrentHp { get; private set; }
    public IReadOnlyReactiveProperty<bool> IsDead { get; private set; }

    public Enemy(int initialHp)
    {
        // Declarative Property
        CurrentHp = new ReactiveProperty<long>(initialHp);
        IsDead = CurrentHp.Select(x => x <= 0).ToReactiveProperty();
    }
}