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

public class EnemyMove : MonoBehaviour
{
    //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;
    //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;
    // number of bullets enemy shoots (in a fan like a shotgun)
    public int numBullets = 1;
    //Original offset between each bullet
    public float bulletOffset = 0.1f;
    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, run the if statement
        if(timer > shootDelay )
        {
            // Shoot the bullet
            ShootBullet();
            //reset the timer
            timer = 0f;
        }   
    }
    void FixedUpdate()
    {
        //set the direction that the enemy will move towards
        Vector2 moveTo = Vector2.MoveTowards(transform.position, player.transform.position, moveSpeed * Time.fixedDeltaTime);
        //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
        Vector3 dir =  player.transform.position - transform.position;
        //normalize the values so they do not jump 
        dir.Normalize();
        //setting the spread in the x direction for each bullet
        dir.x -= bulletOffset * numBullets /2;
        //setting the spread in the y direction for each bullet
        dir.y -= bulletOffset * numBullets /2;
        //For loop creates the number of bullets set by designer
        for(int i = 0; i < numBullets; i++)
        {
            //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
            rb.AddForce(dir * bulletSpeed);
            //add to x offset for bullet fan
            dir.x += bulletOffset;
            //add to y offset for bullet fan
            dir.y += bulletOffset;
        }
    }
}