Gun class

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

public class Gun : MonoBehaviour {

    // Dependiences
    public GameObject bulletHolePrefab;
    public ParticleSystem muzzleFlash;
    public Transform muzzle;
    public Transform weaponModel;
    private Camera weaponCamera;

    // Properties of the gun
    public float damage;
    public int rateOfFire;
    public float maxVerticalRecoil;
    public float verticalRecoilStep;
    public float maxHorizontalRecoil;
    public float horizontalRecoilStep;
    public int magCapacity;
    public int maxAmmo;
    public float reloadingTime;
    public AudioClip shootAudio;
    public Vector3 hipPos;
    public Vector3 sightedPos;

    private Transform playerCamera;
    private float fireCooldown;
    private float fireInterval;
    private List<GameObject> bulletHolesList;

    [HideInInspector]
    public int ammoInMag;
    [HideInInspector]
    public int ammoLeft;

    public float verticalRecoil;
    public float horizontalRecoil;
    private float recoilCooldown;
    private bool isReloading = false;

    void Awake()
    {
        // set the right camera and move the weapon to hip pos
        weaponCamera = transform.parent.GetComponent<Camera>();
        weaponModel.localPosition = hipPos;

        playerCamera = transform.parent;

        //calculate the interval between shots to match the rate of fire
        if (rateOfFire > 1)
            fireInterval = 1f / (rateOfFire / 60);
        else
            fireInterval = 0.1f;

        // update the UI and set all the ammo to right values
        UIUpdate();
        ammoInMag = magCapacity;
        ammoLeft = 0;

        // zero out the recoil and cooldowns
        fireCooldown = 0;
        recoilCooldown = 0;
    }

    void Update () {

        //right click = zoom and sighted position, otherwise hip pos
        if(Input.GetKey(KeyCode.Mouse1))
            SightAim();
        else
            HipAim();

        //lmb = tries to fire, if weapon is automatic then fires automaticaly
        if (Input.GetButton("Fire1") && rateOfFire > 1)
        {
            TryToFire();
        }
        else if(Input.GetButtonDown("Fire1"))
        {
            TryToFire();
        }

        //r = reloads
        if(Input.GetKeyDown(KeyCode.R))
        {
            StartCoroutine(Reload());
        }

        //descreases fire cooldown as time passes, manages the right rate of fire
        if(fireCooldown > 0)
        {
            fireCooldown -= Time.deltaTime;
        }

        //calculates the recoil descrease
        RecoilChecks();


    }

    void RecoilChecks()
    {
        //the recoil value always decreases
        if (recoilCooldown > 0)
            recoilCooldown -= Time.deltaTime;

        //in case of recoil being lower than 0 it goes to zero
        if (recoilCooldown < 0)
            recoilCooldown = 0;

        //if you haven't shot in a while and there is vrecoil, decrease it
        if (verticalRecoil > 0 && recoilCooldown == 0)
            verticalRecoil -= (Time.deltaTime / 10f);

        //in case of recoil being lower than 0 it goes to zero
        if (verticalRecoil < 0)
            verticalRecoil = 0;

        //if you haven't shot in a while and there is hrecoil, decrease it
        if (horizontalRecoil != 0 && recoilCooldown == 0)
        {
            if(horizontalRecoil > 0)
                horizontalRecoil -= (Time.deltaTime / 10f);
            else
                horizontalRecoil += (Time.deltaTime / 10f);
        }

        //if the hrecoil is very close to 0, set it to 0
        if (Mathf.Abs(horizontalRecoil) < 0.001f)
            horizontalRecoil = 0;

        //try to bring the weapon to 0,0,0 (remove the visual recoil)
        if (transform.localRotation != Quaternion.Euler(Vector3.zero))
            transform.localRotation = Quaternion.Slerp(transform.localRotation, Quaternion.Euler(Vector3.zero), Time.deltaTime * 2);

    }
    void TryToFire()
    {
        //if the weapon is semi automatic or the fire cooldown is zero AND there is any ammo, fire
        if ((fireCooldown <= 0 || rateOfFire == 1) && ammoInMag > 0 && !isReloading)
        {
            //fire, decrease ammo in mag, add fire cooldown and update the UI
            Fire();
            ammoInMag--;
            fireCooldown += fireInterval;

            UIUpdate();
        }

    }

    void Fire()
    {
        //calculate the shot direction including the recoil
        Vector3 dir = playerCamera.forward + new Vector3(0, verticalRecoil, 0) + (playerCamera.right * horizontalRecoil);

        //the direction of the shot is the forward vector modified by the recoil
        Ray ray = new Ray(playerCamera.position, dir);
        RaycastHit hit;

        //play the fire sound and instantiate the particle system
        GetComponent<AudioSource>().PlayOneShot(shootAudio, 0.5f);
        Instantiate(muzzleFlash, muzzle.position, muzzle.rotation, muzzle);

        //[DEBUG] draw the ray in the preview
        Debug.DrawRay(playerCamera.position, playerCamera.forward * 100, Color.cyan);

        //if the raycast hit anything
        if (Physics.Raycast(ray, out hit, 100f))
        {
            //[DEBUG] draw a line between the player and hit point
            Debug.DrawLine(playerCamera.position, hit.point, Color.red);
            //instantiate a bullet hole and inflict weapon's damage on the hit target
            Instantiate(bulletHolePrefab, hit.point, Quaternion.FromToRotation(Vector3.up, hit.normal), hit.transform);
            DealDamage(hit);
        }

        //recoil using the firing direction
        Recoil(dir);
    }

    void DealDamage(RaycastHit hit)
    {
        //if we hit the enemy, damage it
        if(hit.transform.CompareTag("Enemy"))
        {
            hit.transform.SendMessage("TakeDamage", damage, SendMessageOptions.DontRequireReceiver);
        }
    }

    IEnumerator Reload()
    {
        //cant do few reloads at the same time
        if (isReloading || ammoInMag == magCapacity)
            yield break;

        //calculate the ammo needed to fill the mag

        int ammoNeeded = magCapacity - ammoInMag;

        //reloading takes a while
        isReloading = true;
        StartCoroutine(UIManager.instance.Reloading(reloadingTime));
        yield return new WaitForSeconds(reloadingTime);
        isReloading = false;

        //if we have more ammo than needed fill the mag and subtract ammo needed
        if(ammoLeft >= ammoNeeded)
        {
            ammoInMag = magCapacity;
            ammoLeft -= ammoNeeded;
        }
        else
        {
            // otherwise add all the ammo to the mag and zero the leftover ammo
            ammoInMag += ammoLeft;
            ammoLeft = 0;
        }

        //update the UI
        UIUpdate();
    }

    //in case reload is stopped by switching slots
    public void CancelReload()
    {
        StopCoroutine(Reload());
        isReloading = false;
    }

    void Recoil(Vector3 dir)
    {
        //recoil won't decrease until player hasn't shot for the next interval
        recoilCooldown += fireInterval;

        //if the vrecoil is below maximum, add more
        if(verticalRecoil <= maxVerticalRecoil)
        {
            verticalRecoil += verticalRecoilStep;
        }
        else
        {
            //otherwise set it to maximum
            verticalRecoil = maxVerticalRecoil;
        }

        //if the hrecoil is below maximum, add more
        if (Mathf.Abs(horizontalRecoil) <= maxHorizontalRecoil)
        {
            //the hrecoil is random, but in the range of the step
            float randomRecoil = Random.Range(-horizontalRecoilStep, horizontalRecoilStep);
            horizontalRecoil += randomRecoil;
        }
        else
        {
            //otherwise set it to maximum
            horizontalRecoil = maxHorizontalRecoil;
        }

        //play the firing animation and make the model look in the firing direction
        GetComponent<Animator>().SetTrigger("Fire");
        transform.rotation = Quaternion.LookRotation(dir, Vector3.up);
    }

    public void UIUpdate()
    {
        //update the ammo UI
        UIManager.instance.UpdateAmmoUI(ammoInMag, ammoLeft);
    }

    public void RefillAmmo(int amount)
    {
        //if you want to refill more ammo than you can carry, max it out, otherwise just add it
        if (ammoLeft + amount <= maxAmmo)
            ammoLeft += amount;
        else
            ammoLeft = maxAmmo;

        //update the ammo UI
        UIUpdate();
    }

    //aim through the sights
    void SightAim()
    {
        //decrease the fov for better visibility
        weaponCamera.fieldOfView = 20;

        //smoothly transform to sightpos
        if (Vector3.Distance(weaponModel.localPosition, sightedPos) <= 0.001f)
            weaponModel.localPosition = sightedPos;
        else
            weaponModel.localPosition = Vector3.Lerp(weaponModel.localPosition, sightedPos, Time.deltaTime * 10);
    }

    void HipAim()
    {
        //inscrease the fov for normal view
        weaponCamera.fieldOfView = 50;

        //smoothly transform to hippos
        if (Vector3.Distance(weaponModel.localPosition, hipPos) <= 0.001f)
            weaponModel.localPosition = hipPos;
        else
            weaponModel.localPosition = Vector3.Lerp(weaponModel.localPosition, hipPos, Time.deltaTime * 10);
    }
}