SimpleHealthController.cs

/* HealthController.cs */
using System.Collections;
using UnityEngine;
using UnityEngine.UI;

public class HealthController : MonoBehaviour
{
    [SerializeField]
    private GameObject healthPanel;

    [SerializeField]
    private RectTransform healthBar;

    [SerializeField]
    private Text healthText;

    private float healthBarStartWidth;

    private float currentHealth;

    [SerializeField]
    private float maxHealth;

    [SerializeField]
    private float respawnTime;

    private MeshRenderer meshRenderer;

    private bool isDead;

    // Start is called before the first frame update
    void Start()
    {
        healthBarStartWidth = healthBar.sizeDelta.x;
        meshRenderer = GetComponent<MeshRenderer>();
        ResetHealth();
        UpdateHealthUI();
    }

    public void ApplyDamage(float damage)
    {
        if (isDead) return;

        currentHealth -= damage;

        if (currentHealth <= 0)
        {
            currentHealth = 0;
            isDead = true;
            meshRenderer.enabled = false;
            healthPanel.SetActive(false);
            StartCoroutine(RespawnAfterTime());
        }

        UpdateHealthUI();
    }

    IEnumerator RespawnAfterTime()
    {
        yield return new WaitForSeconds(respawnTime);
        ResetHealth();
    }

    private void ResetHealth()
    {
        isDead = false;
        currentHealth = maxHealth;
        meshRenderer.enabled = true;
        healthPanel.SetActive(true);
        UpdateHealthUI();
    }

    private void UpdateHealthUI()
    {        
        float percentOutOf = (currentHealth / maxHealth) * 100;
        float newWidth = (percentOutOf/ 100f) * healthBarStartWidth;

        healthBar.sizeDelta = new Vector2(newWidth, healthBar.sizeDelta.y);
        healthText.text = currentHealth + "/" + maxHealth;
    }
}

/* WeaponController.cs */
using UnityEngine;

public class WeaponController : MonoBehaviour
{
    [SerializeField]
    private Weapon weapon;

    [SerializeField]
    private string enemyTag;

    private bool fire;

    void Update()
    {
        if (Input.GetMouseButtonDown(0))
        {
            fire = true;
        }   
        
        if (Input.GetMouseButtonUp(0))
        {
            fire = false;
        }

        if (fire)
        {
            weapon.Fire(enemyTag);

            if (weapon.UseTap())
            {
                fire = false;
            }
        }
    }
}


/* Weapon.cs */
using System.Collections;
using UnityEngine;

public class Weapon : MonoBehaviour
{
    [SerializeField]
    private float damage;

    [SerializeField]
    private float fireRate;

    [SerializeField]
    private float fireDistance = 10;

    [SerializeField]
    private Transform bulletPoint;

    private RaycastHit hit;

    private bool cooldown;

    public void Fire(string enemyTag)
    {
        if (cooldown) return;

        Ray ray = new Ray();
        ray.origin = bulletPoint.position;
        ray.direction = bulletPoint.TransformDirection(Vector3.forward);

        Debug.DrawRay(ray.origin, ray.direction*fireDistance, Color.green);

        if (Physics.Raycast(ray, out hit, fireDistance))
        {
            if (hit.collider.CompareTag(enemyTag))
            {
                var healthCtrl = hit.collider.GetComponent<HealthController>();
                healthCtrl.ApplyDamage(damage);
            }
        }

        cooldown = true;
        StartCoroutine(StopCooldownAfterTime());
    }

    private IEnumerator StopCooldownAfterTime()
    {
        yield return new WaitForSeconds(fireRate);
        cooldown = false;
    }

    public bool UseTap()
    {
        return fireRate == 0;
    }
}

/* Movement.cs */
using UnityEngine;

public class Movement : MonoBehaviour
{
    private Rigidbody rigidbody;

    private float speed = 10;

    void Start ()
    {
        rigidbody = GetComponent<Rigidbody>();
    }

    void Update()
    {
        float h = Input.GetAxis("Horizontal");
        float v = Input.GetAxis("Vertical");
        Vector3 velocity = (new Vector3(h, 0, v) * speed)-rigidbody.velocity;
        rigidbody.AddForce(velocity);
    }
}