gather-and-defend/Assets/Scripts/Detection.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Detection : MonoBehaviour
{
    private Vector2 detectionRange;
    private BoxCollider2D _collider;
    public Rect DetectionRectangle
    {
        get
        {
            if (!_collider) _collider = GetComponent<BoxCollider2D>();
            var bounds = _collider.bounds;
            return new Rect(bounds.min - transform.position, bounds.size);
        }
    }
    [SerializeField]
    private Entity _entityLinked;
    protected virtual void Start()
    {
        _collider = GetComponent<BoxCollider2D>();
        detectionRange = _collider.size;
    }
    void ResizeCollider()
    {
        var range = GlobalConfig.Instance.Current.enemyBaseRange;

        var size = _collider.size;
        size.x = detectionRange.x * range.x;
        size.y = detectionRange.y * range.y;
        _collider.size = size;

        var offset = _collider.offset;
        if (offset == Vector2.zero) return;

        offset.x = size.x / 2;
        _collider.offset = offset;
    }
    //If it's a projectile damage > 0
    private int _projectileDamage = 0;
    private float _distanceMin = 100f;

    protected virtual void Update()
    {
        ResizeCollider();
    }

    void OnTriggerEnter2D(Collider2D other)
    {
        //Projectiles detection + damage deal
        if(_entityLinked != null) {
            if(_projectileDamage > 0 && other.gameObject.GetComponent<Entity>() == _entityLinked) {

                _entityLinked.Hit(_projectileDamage);
                //Kill if no hp
                if(other.gameObject.GetComponent<Entity>().Hp <= 0) {
                    other.gameObject.GetComponent<Entity>().Death();
                }

                _entityLinked = null;

            }
        }
        
    }

    void OnTriggerStay2D(Collider2D other) 
    {
        if(_entityLinked != null && _projectileDamage == 0) {

                //Detect the enemy and inform the Ally
                if (other.gameObject.tag == "Opponent" && _entityLinked.gameObject.tag == "Ally") {
                    if(other.gameObject.transform.position.x <= _distanceMin) {
                        _distanceMin = other.gameObject.transform.position.x;
                        _entityLinked.IsEnemyDetected = true;
                        _entityLinked.Enemy = other.gameObject.GetComponent<Entity>();
                    }
                }

                //Detect the enemy and inform the Opponent
                if (other.gameObject.tag == "Ally" &&  _entityLinked.gameObject.tag == "Opponent" ) {
                    if(other.gameObject.transform.position.x <= _distanceMin) {
                        _distanceMin = other.gameObject.transform.position.x;
                        _entityLinked.IsEnemyDetected = true;
                        _entityLinked.Enemy = other.gameObject.GetComponent<Entity>();
                    }
                }  
                
                if(_entityLinked.Enemy == null && _distanceMin != 100f) {
                    _distanceMin = 100f;
                }       
        }

        
                    
    }

    void OnTriggerExit2D(Collider2D other)
    {
        if(_entityLinked != null) {
            if(_projectileDamage == 0) {
                if ((other.gameObject.tag == "Opponent" && _entityLinked is Ally) || (other.gameObject.tag == "Ally" && _entityLinked is Opponent)) {
                    _entityLinked.IsEnemyDetected = false;
                }
            }
        }
        
    }


    //Getter and Setter
    public Entity EntityLinked
    {
        get { return _entityLinked; }
        set { _entityLinked = value; }
    }

    public int ProjectileDamage
    {
        get { return _projectileDamage; }
        set { _projectileDamage = value; }
    }
    
}