Discount Service: Pricing & Promotions Engine

The DiscountService (App\Services\DiscountService) is the central pricing engine for Site Store Pro. It governs every price adjustment a customer sees — from category-wide markdowns and quantity breaks to BOGO promotions and stacking order coupons. Understanding how it works lets you build integrations, custom rules, and reporting tools that align with the platform’s pricing logic.

Public Methods

These two methods are your primary entry points when working with discounted pricing programmatically.

applyDiscountsToCart

Runs the full 3-phase discount pipeline against a set of cart line items for a given user. Use this when you need the complete, order-ready price breakdown.

getDiscountedPriceForVariant

Calculates the discounted price for a single variant given user context and quantity. Use this for catalog displays and buy-box pricing.

`applyDiscountsToCart`

applyDiscountsToCart($items, $user): array

Pass the array of cart line items and the authenticated (or guest) user. Both parameters are intentionally untyped — $items accepts any iterable collection of cart line objects, and $user accepts either an authenticated User model or a guest user representation. The method runs all three discount phases in sequence and returns a structured array:

Key	Type	Description
`items`	`array`	Line items with per-item adjusted prices
`subtotal`	`float`	Raw subtotal before order-level discounts
`discounts`	`array`	List of applied discount objects with metadata
`total_discount`	`float`	Total currency amount discounted
`adjusted_subtotal`	`float`	Final subtotal after all discounts

Example:

use App\Services\DiscountService;

$discountService = app(DiscountService::class);

$result = $discountService->applyDiscountsToCart($cart->items, auth()->user());

$adjustedSubtotal = $result['adjusted_subtotal'];
$appliedDiscounts = $result['discounts'];
$totalSaved       = $result['total_discount'];

`getDiscountedPriceForVariant`

getDiscountedPriceForVariant($variant, $user, $qty): float

Use this single-variant helper when you need a discounted price outside of the full cart context — for example, on a product listing page or in a custom buy-box component. $variant accepts a ProductVariant model instance, $user accepts an authenticated user or guest, and $qty is the requested quantity as an integer or numeric string. Example:

$price = $discountService->getDiscountedPriceForVariant(
    $variant,
    auth()->user(),
    $requestedQty
);

The 3-Phase Discount Pipeline

When applyDiscountsToCart runs, it evaluates discounts in three sequential phases. Each phase builds on the previous one. Later phases cannot override item-level pricing settled in Phase 1 — they add to or further reduce the running total.

Phase 1 — Item-Level Evaluation

For each line item in the cart, the service walks through up to five discount rules in ascending priority order. The last applicable rule wins — meaning a higher-priority rule will replace a lower-priority one if both match.

Because the last applicable rule wins, a more specific discount (like an item-specific price) will always take precedence over a broader one (like a category discount) as long as it is evaluated later in the sequence. Design your discount rules with this ordering in mind to avoid unintended overrides.

The evaluation order per line item is:

Priority	Rule	Discount Type
1 (lowest)	Category & Brand Discount	Type 5
2	Item-Specific Discount	Type 6
3	On-Sale Special Price	`variant->sale_price`
4	Quantity Break Tier	`variant->quantityDiscounts`
5 (highest)	Wholesale Price	`variant->wholesale_price`

After this phase, every line item has its final per-unit adjusted price.

Phase 2 — BOGO Evaluation

After item-level pricing is settled, the service evaluates any active Buy X Get Y (BOGO) promotions.

Trigger check: Validates that the trigger product X is present in the cart at or above the required free_range1 quantity threshold.
Target discount: Applies the configured product_y_percent discount to the target product Y in the cart.
Slide cart lock: Marks the BOGO target item’s quantity as locked in the slide cart to prevent the customer from editing it to exploit the promotion.

Phase 3 — Order-Level Discounts

With item and BOGO pricing settled, the service evaluates discounts that apply to the order as a whole. These are processed in the following priority order (highest priority applied first):

Priority	Type	Slug
1	Coupon / Gift Certificate	`code`
2	General Order Value	`order_value`
3	Preferred Customer	`preferred`
4	New Customer	`new_customer`

Each candidate discount is validated against:

Minimum and maximum order spend
Minimum order quantity
Minimum order weight
Customer role eligibility

If the allow_multiple_order_discounts config flag is enabled, valid discounts at this phase can stack. Otherwise, only the highest-priority applicable discount is applied.

Discount Type Reference

Use these type identifiers and slugs when querying the discounts table or building custom tooling around the discount system.

Type	Slug	Scope	Description
1	`code`	Order	Coupon code or gift certificate entered at checkout
2	`preferred`	Order	Automatic discount targeted at specific user accounts
3	`order_value`	Order	Automatic discount triggered by order subtotal threshold
4	`new_customer`	Order	Automatic discount applied to a customer’s first order
5	`category_brand`	Item	Discount applied to all products in a category or brand
6	`item_specific`	Item	Discount applied to a single specific product
7	`bogo`	Item	Buy X Get Y promotion

CurrencyService Integration

App\Services\CurrencyService works alongside DiscountService to ensure that every price returned is formatted correctly for the active storefront language. The service calls LanguageService::currencyOverride() to check whether the current language has a currency override configured. Based on the result, it dynamically formats:

Symbol — e.g. $, €, £
Symbol placement — prefix or suffix
Decimal and thousands separators — locale-aware formatting

You do not need to call CurrencyService directly when using applyDiscountsToCart or getDiscountedPriceForVariant — prices are returned as raw floats. Apply CurrencyService formatting at the display layer when rendering prices to the storefront.

use App\Services\CurrencyService;

$currencyService = app(CurrencyService::class);

$formattedPrice = $currencyService->format($result['adjusted_subtotal']);
// e.g. "€ 49,95" for a Dutch locale

Installation

Extending the Platform

Core Services

Discount Service: Pricing & Promotions Engine

Public Methods

applyDiscountsToCart

getDiscountedPriceForVariant

`applyDiscountsToCart`

`getDiscountedPriceForVariant`

The 3-Phase Discount Pipeline

Discount Type Reference

CurrencyService Integration

​Public Methods

applyDiscountsToCart

getDiscountedPriceForVariant

​applyDiscountsToCart

​getDiscountedPriceForVariant

​The 3-Phase Discount Pipeline

​Discount Type Reference

​CurrencyService Integration

Public Methods

`applyDiscountsToCart`

`getDiscountedPriceForVariant`

The 3-Phase Discount Pipeline

Discount Type Reference

CurrencyService Integration