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

public class EnemyMove : MonoBehaviour
{
    /*Add the following elements to the inspector:
     * Rigidbody 2d: freeze rotation in the z axis
     * Boxcollider 2d: Make the size of the enemy
     * Second Boxcollider 2d: make very thin at the bottom of the Enemy and set isTrigger
     * add this Enemy Move Script
     * Set all values in the script, make sure that you add the player from the level, and the bullet from the prefabs
     */

    //Set the following values in the inspector!
    
    //public variable for the player object(use the player object on the scene NOT the prefab)
    public GameObject player;
    //Variable for Enemy Health
    public int EnemyHealth = 5;
    //public variable for the bullet(use the prefab)
    public GameObject bulletPrefab;
    //Speed of bullet
    public int bulletSpeed = 200;
    //speed of enemy object
    public float moveSpeed = 5f;
    //variable for the rigidbody of the enemy and the bullet
    Rigidbody2D rb;
    //global variable for the rotation of the enemy object
    Quaternion rotation;
    //boolean to see if player is in range of enemy
    bool inRange = false;
    //float for the distance the player is away from
    //the enemy objects, set in inspector
    public float enemyRange = 5;
    //timer for shoot delay.
    float timer = 0f;
    //Amount of delay before enemy repeats its shots.
    public float shootDelay = 1;
    //boolean to see if the enemy has walked off of a platform.
    bool onPlatform = true;
    void Start()
    {
        //locate the player object on the first frame of the scene
        player = GameObject.FindGameObjectWithTag("Player");
        //get the rigidbody of the enemy on the first frame of the scene
        rb = GetComponent<Rigidbody2D>();
    }
    // Update is called once per frame
    void Update()
    {
        //set the rotation value for turning the enemy to the player object
        //rotation = Quaternion.LookRotation(player.transform.position - transform.position, transform.TransformDirection(Vector3.up));
        //Turn the enemy to look towards the player
        gameObject.transform.LookAt(player.transform.position);
        //rotate the object, but lock the rotation in the x and y axes
        transform.rotation = new Quaternion(0, 0, rotation.z, rotation.w);
        //adding time to the timer for the shoot delay
        timer += Time.fixedDeltaTime;
        //if the timer has counted higher than the shoot delay and player is within range, run the if statement
        if (timer > shootDelay && Vector3.Distance(transform.position, player.transform.position) < enemyRange)
        {
            // Shoot the bullet
            ShootBullet();
            //reset the timer
            timer = 0f;
        }
    }
    void FixedUpdate()
    {
        //this if statement enables movement when on a platform, but allows the enemy to drop when not on a platform
        if(onPlatform)
        {
            //Local variable that gets Enemy y position
            float y = transform.position.y;
            //set the direction that the enemy will move towards
            Vector2 moveTo = Vector2.MoveTowards(transform.position, player.transform.position, moveSpeed * Time.fixedDeltaTime);
            //Sets the enemy movement to move only horizontally
            moveTo.y = y;
            //if statement that will only enable the move command if the player is within range
            //distance method measures the distance from the enemy object to the player
            //if the distance is less than the enemy range setting, then the enemy will move.
            if (Vector3.Distance(transform.position, player.transform.position) < enemyRange)
            {
                //move the enemy to the player
                rb.MovePosition(moveTo);
            }
        }
        
        
    }
    void ShootBullet()
    {
        
        //Get the direction from the enemy to the player in the x axis
        float x = player.transform.position.x - transform.position.x;
      
       
        //Create bullet with correct 3d rotation
        GameObject bullet = Instantiate(bulletPrefab, transform.position, Quaternion.Euler(0f, 0f, 1.6f));
        // Make sure the bullet does not hit the player
        // You may have to change the two collider types depending
        // on what you are using
        Physics2D.IgnoreCollision(bullet.GetComponent<Collider2D>(),
                        GetComponent<Collider2D>());
        //get the rigidbody component of the bullet object
        Rigidbody2D rb = bullet.GetComponent<Rigidbody2D>();
        // Add force to the bullet so it flies off
        if(x >0)
        {
            //If Player is to the right of the enemy, shoot right
            rb.AddForce(new Vector2(1,0)*bulletSpeed);
        }
        else
        {
            //If player is to the left of the enemy, shoot left
            rb.AddForce(new Vector2(-1, 0) * bulletSpeed);
        }
            
            
        
    }
    private void OnTriggerExit2D(Collider2D collision)
    {
        if(collision.tag == "Ground")
        {
            //bool set to false when the enemy walks off of a platform
            onPlatform = false;
        }
    }
    private void OnTriggerEnter2D(Collider2D collision)
    {
        if (collision.tag == "Ground")
        {
            //bool set to true when the enemy lands on a platform
            onPlatform = true;
        }
        if(collision.tag == "PlayerBullet")
        {
            //Enemy takes damage here, if you would like a different damage you can use the -= statement to remove more.
            EnemyHealth--;
            if(EnemyHealth <= 0)
            {
                //When the enemy health drops below 1, enemy is destroyed.
                Destroy(gameObject);
            }
        }
    }
}