using UnityEngine;
using TMPro;

public class ProjectileGun : MonoBehaviour
{
    // audio
    public AudioSource Audio;
    public AudioClip GunShotSFX;
    public AudioClip ReloadSFX;

    // bullet
    public GameObject bullet;

    // bullet force
    public float shootForce, upwardForce;

    // Gun stats
    public float timeBetweenShooting, spread, reloadTime, timeBetweenShots;
    public int magazineSize, bulletsPerTap;
    public bool allowButtonHold;

    int bulletsLeft, bulletsShot;

    // recoil
    public Rigidbody playerRb;
    public float recoilForce;

    // bools
    bool shooting, readyToShoot, reloading;

    // Reference
    public Camera fpsCam;
    public Transform attackPoint;

    // graphics
    public TextMeshProUGUI ammunitionDisplay;

    // bug fixing 
    public bool allowInvoke = true;

    private void Awake()
    {
        // make sure magazine is full
        bulletsLeft = magazineSize;
        readyToShoot = true;
    }

    private void Update()
    {
        MyInputs();

        // set ammo display, if it exists
        if (ammunitionDisplay != null)
        {
            ammunitionDisplay.text = "Ammo: " + (bulletsLeft / bulletsPerTap + " / " + magazineSize / bulletsPerTap);
        }
    }

    private void MyInputs()
    {
        // check if allowed to hold down button and take corresponding input
        if (allowButtonHold) shooting = Input.GetKey(KeyCode.Mouse0);
        else shooting = Input.GetKeyDown(KeyCode.Mouse0);

        // reloading 
        if (Input.GetKeyDown(KeyCode.R) && bulletsLeft < magazineSize && !reloading)
        {
            Reload();
        }
        // reload automatically when trying to shoot without ammo
        if (readyToShoot && shooting && !reloading && bulletsLeft <= 0)
        {
            Reload();
        }

        // shooting 
        if (readyToShoot && shooting && !reloading && bulletsLeft > 0)
        {
            // set bullets shot to 0 
            bulletsShot = 0;

            Shoot();
            Audio.PlayOneShot(GunShotSFX);
        }
    }

    public void Shoot()
    {
        readyToShoot = false;

        // find the exact hit position using a raycast
        Ray ray = fpsCam.ViewportPointToRay(new Vector3(0.5f, 0.5f, 0));
        RaycastHit hit;

        // check if ray hits something 
        Vector3 targetPoint;
        if (Physics.Raycast(ray, out hit))
        {
            targetPoint = hit.point;
        }
        else
        {
            targetPoint = ray.GetPoint(75); // just a point far away from the player
        }

        // calculate direction from attackPoint to targetPoint
        Vector3 directionWithoutSpread = targetPoint - attackPoint.position;

        // calculate spread
        float x = Random.Range(-spread, spread);
        float y = Random.Range(-spread, spread);

        // calculate new direction with spread
        Vector3 directionWithSpread = directionWithoutSpread + new Vector3(x, y, 0); // just add spread to last direction

        // instantiate bullet/projectile
        GameObject currentBullet = Instantiate(bullet, attackPoint.position, Quaternion.identity);
      
        // rotate bullet to shoot direction 
        currentBullet.transform.forward = directionWithSpread.normalized;

        // add force to bullet
        currentBullet.GetComponent<Rigidbody>().AddForce(directionWithSpread.normalized * shootForce, ForceMode.Impulse);
        currentBullet.GetComponent<Rigidbody>().AddForce(fpsCam.transform.up * upwardForce, ForceMode.Impulse);

        bulletsLeft--;
        bulletsShot++;

        // invoke resetShot function (if not already invoked)
        if (allowInvoke)
        {
            Invoke("ResetShot", timeBetweenShooting);
            allowInvoke = false;

            // add recoil to player 
            playerRb.AddForce(-directionWithSpread.normalized * recoilForce, ForceMode.Impulse);
        }

        // if more than one bulletPerTap make sure to repeat shoot function
        if (bulletsShot < bulletsPerTap && bulletsLeft > 0)
        {
            Invoke("Shoot", timeBetweenShots);
        }
    }

    private void ResetShot()
    {
        readyToShoot = true;
        allowInvoke = true;
    }

    private void Reload()
    {
        reloading = true;
        Invoke("ReloadFinished", reloadTime);
        Audio.PlayOneShot(ReloadSFX);
    }

    private void ReloadFinished()
    {
        bulletsLeft = magazineSize;
        reloading = false;
    }
}