I have a project where I have implemented coupon system. Problem is, one user can use a coupon multiple times until the coupon expires. I would lke: Limiting coupon usage based on max usage defined in coupon table;

I have also looked for various sites in google. Which includes stackoverflow along with others.

id
code
type
value
cart_value
expiry_date
timestamps
max

Max- maximum time a coupon can be used.

Pivot table: user_coupons

id
coupon_id
user_id
code

The code column here stores how many times a specific coupon has been used.

Apply Coupon Method.

public function applyCouponCode()
{
    $promo = Coupon::where('code', $this->couponCode)
        ->where('expiry_date', '>=', Carbon::today())
        ->where('cart_value', '<=', Cart::instance('cart')->subtotal())
        ->first();
    $coupon = Coupon::with('userCoupon')
        ->where('expiry_date', '>=', Carbon::today())
        ->where('code', '!=', 'user_coupons.code')
        ->where('cart_value', '<=', Cart::instance('cart')->subtotal())
        ->first();

    if ($coupon->userCoupon()->code === $this->couponCode) {
        $this->alert('error', 'Code already used!');
        return;
        // dd($coupon->code);
    } else if (!$promo) {
        $this->alert('error', 'Invalid code!');
        return;
    } else if ($coupon) {
        
        $this->alert('success', 'Code ok!');
        return;
    }
    
    //this part never appears. Even though coupon is valid
    $this->alert('success', 'Coupon is applied');
}

Issues:

1.codes previously used are recognised.

2. invalid codes are recognised. But valid codes also says Invalid code.

What am I missing? I am using Laravel 8 with livewire. I have tried many methods. Nothing seems to work. I have tried query builder. At some point I was able to get the codes used by the user by joining coupons using inner join with the user_coupons table. I have also tried using model relationship however it says collection does not exist.

CodePudding user response：

I do implementing coupon system on my project. And I think we have the same term for this. You might try my way:

1. This is my vouchers table attributes. I declared it as fillable attributes in Voucher model.

protected $fillable = [
   'service_id',
   'code',
   'name',
   'description',
   'percentage', // percentage of discount
   'maximum_value', // maximum value of discount
   'maximum_usage', // maximum usage per user. If it's 1, it means user only can use it once.
   'user_terms', // additional terms
   'amount', // amount of voucher. If it's 1, it means the voucher is only can be redeemed once.
   'expired_at',
   'is_active', // for exception if we want to deactivate the voucher (although voucher is valid)
];

2. This is my voucher_redemptions table, this table is used when the user redeem the voucher. I declared it in VoucherRedemption model.

protected $fillable = [
   'redeemer_id', // user id who redeems the voucher
   'voucher_id', // voucher
   'item_id', // product item
];

3. This is my function to redeem voucher

/**
 * Apply voucher to an item
 * @param int $redeemerId user id
 * @param string $voucherCode voucher code
 * @param int $itemId project batch package id
 * @return VoucherRedemption $redemption
 */
public static function apply($redeemerId, $voucherCode, $itemId)
{
    $voucher = Voucher::where('code', $voucherCode)->first();

    // Make sure item is exist and the batch has not been checked out
    $item = ProjectBatchPackage::where('id', $itemId)->first();
    if (!$item) {
        return;
    } else if ($item->batch->status != null) {
        return;
    }

    // Make sure voucher exist
    if (!$voucher) {
        return;
    }

    // Make sure is voucher active, not expired and available.
    if ($voucher->is_active == false || $voucher->isExpired() || !$voucher->isAvailable()) {
        return;
    }

    // Make sure voucher usage for user
    if ($voucher->maximum_usage != null) {
        $user_usages = VoucherRedemption::where('redeemer_id', $redeemerId)
            ->where('voucher_id', $voucher->id)
            ->get()
            ->count();
        if ($user_usages >= $voucher->maximum_usage) {
            return;
        }
    }

    // Apply voucher to project batch package (item)
    $redemption = VoucherRedemption::create([
        'redeemer_id' => $redeemerId,
        'voucher_id' => $voucher->id,
        'item_id' => $itemId
    ]);

    return $redemption;
}

Thank you.