how to make enemy damage player?

im trying to make a script so that when the enemy is close enough to the player (since its a melee attack) it takes a point of damage off the player every amount of time. Enemy Script: using System.Collections; using System.Collections.Generic; using UnityEngine;

 public class Enemy : MonoBehaviour {
 
     public int health;
     public float speed;
 
     public GameObject BloodEffect;
 
     public bool FindPlayer;
 
     public Animator enemyAnim;
 
     // Use this for initialization
     void Start () {
         
     }
     
     // Update is called once per frame
     void Update () {
 
         if(health <= 0)
         {
             Destroy(gameObject);
         }
         transform.Translate(Vector2.left * speed * Time.deltaTime);
     }
 
     public void TakeDamage(int damage)
     {
         Instantiate(BloodEffect, transform.position, Quaternion.identity);
         health -= damage;
         Debug.Log("Damage Taken");
     }
 
     void GiveDamage()
     {
         if (FindPlayer)
         {
             if (GameObject.FindGameObjectWithTag("Player"))
             {
                 GetComponent<HealthSystem>().Damaged();
             }
         }
     }
 
     private void OnTriggerEnter2D(Collider2D collision)
     {
         FindPlayer = true;  
     }
 }

Player Health Script: using System.Collections; using System.Collections.Generic; using UnityEngine; using UnityEngine.UI;

 public class HealthSystem : MonoBehaviour
 {
 
     public int health;
     public int numOfHearts;
 
     public Image[] hearts;
     public Sprite fullHeart;
     public Sprite emptyHeart;
 
     void Update()
     {
         if (health > numOfHearts)
         {
             health = numOfHearts;
         }
 
         for (int i = 0; i < hearts.Length; i++)
         {
             if (i < health)
             {
                 hearts[i].sprite = fullHeart;
             }
             else
             {
                 hearts[i].sprite = emptyHeart;
             }
 
             if (i < numOfHearts)
             {
                 hearts[i].enabled = true;
             }
             else
             {
                 hearts[i].enabled = false;
             }
 
             //if (health > 0)
             //{
             //   Destroy(gameObject);
             // }
         }
     }
 
     public void Damaged()
     {
         health -= 1;
         if (health < numOfHearts)
         {
             numOfHearts = health;
         }
 
     }
 }

any help would be great thanks =)