Unity Atoms v4 is out! - EnemyHealthBarManager.cs

EnemyHealthBarManager.cs

using System;
using UnityAtoms;
using UnityAtoms.BaseAtoms;
using UnityEngine;

public class EnemyHealthBarManager : MonoBehaviour
{
    [SerializeField]
    private AtomList _enemies;

    [SerializeField]
    private GameObject _healthBarPrefab;

    [SerializeField]
    private RectTransform _canvasRectTransform;

    public void SetupHealthBar(AtomBaseVariable enemyData)
    {
        var enemyDataCollection = (AtomCollection)enemyData;
        var healthBar = Instantiate(_healthBarPrefab).GetComponent<HealthBar>();
        healthBar.transform.SetParent(transform);

        IntVariable health = default;
        Vector3Variable position = default;
        Action<Vector3> positionChangedHandler = default;
        Action<AtomBaseVariable> varAddedHandler = (AtomBaseVariable baseVar) =>
        {
            switch (baseVar.Id)
            {
                case "Health":
                    var healthVar = (IntVariable)baseVar;
                    health = healthVar;
                    healthBar.InitialHealth.Value = healthVar.InitialValue;
                    healthVar.Changed.Register(healthBar.HealthChanged);
                    break;
                case "Position":
                    var positionVar = (Vector3Variable)baseVar;
                    position = positionVar;
                    positionChangedHandler = (pos) =>
                    {
                        Vector2 viewportPos = Camera.main.WorldToViewportPoint(pos);
                        Vector2 healthBarPos = new Vector2(
                            (viewportPos.x * _canvasRectTransform.sizeDelta.x) - (_canvasRectTransform.sizeDelta.x * 0.5f),
                            (viewportPos.y * _canvasRectTransform.sizeDelta.y) - (_canvasRectTransform.sizeDelta.y * 0.5f) + 38f
                        );
                        healthBar.GetComponent<RectTransform>().anchoredPosition = healthBarPos;
                    };
                    positionVar.Changed.Register(positionChangedHandler);
                    break;
            }
        };

        Action<AtomBaseVariable> varRemovedHandler = (AtomBaseVariable baseVar) =>
        {
            switch (baseVar.Id)
            {
                case "Health":
                    var healthVar = (IntVariable)baseVar;
                    healthVar.Changed.Unregister(healthBar.HealthChanged);
                    break;
                case "Position":
                    var positionVar = (Vector3Variable)baseVar;
                    positionVar.Changed.Unregister(positionChangedHandler);
                    break;
            }
        };

        enemyDataCollection.Added.Register(varAddedHandler);
        enemyDataCollection.Removed.Register(varRemovedHandler);

        Action<AtomBaseVariable> enemyDataRemovedHandler = default;
        enemyDataRemovedHandler = (enemyDataToBeRemoved) =>
        {
            if (enemyDataToBeRemoved == enemyData)
            {
                enemyDataCollection.Added.Unregister(varAddedHandler);
                enemyDataCollection.Removed.Unregister(varRemovedHandler);
                _enemies.Removed.Unregister(enemyDataRemovedHandler);

                if (healthBar != null && healthBar.gameObject != null)
                {
                    if (health != null)
                    {
                        health.Changed.Unregister(healthBar.HealthChanged);
                    }
                    else if (position != null)
                    {
                        position.Changed.Unregister(positionChangedHandler);
                    }

                    Destroy(healthBar.gameObject);
                }

            }
        };
        _enemies.Removed.Register(enemyDataRemovedHandler);
    }
}