Add Pricing Engine to fresh Laravel installation

app/Enums/DiscountType.php

@@ -0,0 +1,9 @@
+<?php
+
+namespace App\Enums;
+
+enum DiscountType : string
+{
+    case Percentage = 'percentage';
+    case FixedValue = 'fixed';
+}

app/Enums/UserRole.php

@@ -0,0 +1,9 @@
+<?php
+
+namespace App\Enums;
+
+enum UserRole : string
+{
+    case Customer = 'customer';
+    case WholesaleCustomer = 'wholesale_customer';
+}

app/Http/Controllers/Auth/LoginController.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace App\Http\Controllers\Auth;
+
+use App\Http\Controllers\Controller;
+use Illuminate\Http\Request;
+
+class LoginController extends Controller
+{
+    public function showLogin()
+    {
+        return view('auth.login');
+    }
+
+    public function authenticate(Request $request)
+    {
+        $request->validate([
+            'email' => ['required', 'email'],
+            'password' => ['required']
+        ]);
+
+        if (auth()->attempt($request->only('email', 'password'))) {
+            return redirect()->route('products.index');
+        }
+
+        return back()->withErrors(['message' => 'Invalid credentials']);
+    }
+}

app/Http/Controllers/Auth/LogoutController.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace App\Http\Controllers\Auth;
+
+use App\Http\Controllers\Controller;
+use Illuminate\Http\Request;
+
+class LogoutController extends Controller
+{
+    public function logout()
+    {
+        auth()->logout();
+
+        return redirect()->route('auth.login');
+    }
+}

app/Http/Controllers/ProductsController.php

@@ -0,0 +1,46 @@
+<?php
+
+namespace App\Http\Controllers;
+
+use App\Models\Product;
+use App\Models\ProductCategory;
+use App\PricingEngine\Data\CalculatedProduct;
+use App\PricingEngine\Services\CalculatorService;
+use Illuminate\Http\Request;
+
+class ProductsController extends Controller
+{
+    public function index(CalculatorService $calculatorService)
+    {
+        $products = Product::query()
+            ->with('productCategory')
+            ->get();
+
+        $calculatedProducts = $calculatorService->calculateForProducts(
+            products: $products,
+            user: auth()->user(),
+        );
+
+        $calculatedProductsByCategories = $calculatedProducts->mapToGroups(
+            fn(CalculatedProduct $calculatedProduct) => [
+                $calculatedProduct->getProduct()->productCategory->title => $calculatedProduct,
+            ]
+        );
+
+        return view('products.index', [
+            'calculatedProductsByCategories' => $calculatedProductsByCategories,
+        ]);
+    }
+
+    public function view(CalculatorService $calculatorService, Product $product)
+    {
+        $calculatedProduct = $calculatorService->calculateForProduct(
+            product: $product,
+            user: auth()->user(),
+        );
+
+        return view('products.view', [
+            'calculatedProduct' => $calculatedProduct
+        ]);
+    }
+}

app/Models/Product.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class Product extends Model
+{
+    use HasFactory;
+
+    protected $fillable = [
+        'title',
+        'description',
+        'price',
+    ];
+
+    public function productCategory(): BelongsTo
+    {
+        return $this->belongsTo(ProductCategory::class);
+    }
+}

app/Models/ProductCategory.php

@@ -0,0 +1,58 @@
+<?php
+
+namespace App\Models;
+
+use App\Enums\DiscountType;
+use Brick\Money\Money;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+
+class ProductCategory extends Model
+{
+    use HasFactory;
+
+    protected $fillable = [
+        'title',
+        'discount_type',
+        'discount_value',
+    ];
+
+    protected $appends = [
+        'formatted_discount'
+    ];
+
+    protected function casts(): array
+    {
+        return [
+            'discount_type' => DiscountType::class,
+        ];
+    }
+
+    public function products() : HasMany
+    {
+        return $this->hasMany(Product::class);
+    }
+
+    public function getFormattedDiscountAttribute(): string
+    {
+        return match ($this->discount_type) {
+            DiscountType::Percentage => "{$this->discount_value}%",
+            DiscountType::FixedValue => Money::ofMinor($this->discount_value, 'GBP')->formatTo('en_GB'),
+            default => 'No discount'
+        };
+    }
+
+    public function hasValidDiscount(): bool
+    {
+        if (empty($this->discount_type) || empty($this->discount_value)) {
+            return false;
+        }
+
+        if ($this->discount_value === 0 || $this->discount_value < 0) {
+            return false;
+        }
+
+        return true;
+    }
+}

app/Models/User.php

@@ -3,6 +3,7 @@
 namespace App\Models;
 
 // use Illuminate\Contracts\Auth\MustVerifyEmail;
+use App\Enums\UserRole;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Foundation\Auth\User as Authenticatable;
 use Illuminate\Notifications\Notifiable;
@@ -43,6 +44,7 @@ protected function casts(): array
         return [
             'email_verified_at' => 'datetime',
             'password' => 'hashed',
+            'role' => UserRole::class,
         ];
     }
 }

app/PricingEngine/Calculators/ProductCategoryCalculator.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace App\PricingEngine\Calculators;
+
+use App\Models\Product;
+use App\Models\ProductCategory;
+use App\Models\User;
+use App\PricingEngine\Contracts\DiscountCalculatorInterface;
+use App\PricingEngine\Data\PricingEngineResult;
+use App\PricingEngine\Resolvers\DiscountTypeResolver;
+
+class ProductCategoryCalculator implements DiscountCalculatorInterface
+{
+    public function __construct(
+        private DiscountTypeResolver $discountTypeResolver
+    ) {
+    }
+
+    public function apply(int $currentPrice, Product $product, ?User $user = null): int
+    {
+        /** @var ProductCategory $productCategory */
+        $productCategory = $product->productCategory;
+
+        if ($productCategory->hasValidDiscount() === false) {
+            return $currentPrice;
+        }
+
+        $discountType = $this->discountTypeResolver->resolve($productCategory->discount_type);
+
+        return $discountType->modify(
+            currentPrice: $currentPrice,
+            discountValue: $productCategory->discount_value
+        );
+    }
+}

app/PricingEngine/Calculators/UserCalculator.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace App\PricingEngine\Calculators;
+
+use App\Enums\UserRole;
+use App\Models\Product;
+use App\Models\User;
+use App\PricingEngine\Contracts\DiscountCalculatorInterface;
+use App\PricingEngine\Repositories\UserDiscountPercentageRepository;
+
+class UserCalculator implements DiscountCalculatorInterface
+{
+    public function __construct(
+        protected UserDiscountPercentageRepository $userDiscountPercentageRepository
+    ) {
+    }
+
+    public function apply(int $currentPrice, Product $product, ?User $user = null): int
+    {
+        $userDiscount = $this->userDiscountPercentageRepository->getDiscountPercentage($user);
+
+        if ( ! $userDiscount) {
+            return $currentPrice;
+        }
+
+        return max(
+            0,
+            $currentPrice - ($currentPrice * ($userDiscount / 100))
+        );
+    }
+}

app/PricingEngine/Contracts/DiscountCalculatorInterface.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace App\PricingEngine\Contracts;
+
+use App\Models\Product;
+use App\Models\User;
+
+interface DiscountCalculatorInterface
+{
+    public function apply(int $currentPrice, Product $product, ?User $user = null): int;
+}

app/PricingEngine/Contracts/DiscountTypeInterface.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace App\PricingEngine\Contracts;
+
+interface DiscountTypeInterface
+{
+    public function modify(int $currentPrice, int $discountValue): int;
+}

app/PricingEngine/Data/CalculatedProduct.php

@@ -0,0 +1,53 @@
+<?php
+
+namespace App\PricingEngine\Data;
+
+use App\Models\Product;
+use Brick\Money\Money;
+
+readonly class CalculatedProduct
+{
+    public function __construct(
+        public Product $product,
+        public int $calculatedPrice,
+        public int $calculatedDiscount,
+    ) {
+    }
+
+    public function getProduct(): Product
+    {
+        return $this->product;
+    }
+
+    public function getCalculatedPrice(): int
+    {
+        return $this->calculatedPrice;
+    }
+
+    public function getCalculatedDiscount(): int
+    {
+        return $this->calculatedDiscount;
+    }
+
+    public function getDiscountPercentage(): int
+    {
+        return $this->product->price > 0
+            ? (int)round(($this->calculatedDiscount / $this->product->price) * 100)
+            : 0;
+    }
+
+    public function getFormattedBasePrice(): string
+    {
+        return Money::ofMinor($this->product->price, 'GBP')->formatTo('en_GB');
+    }
+
+    public function getFormattedCalculatedPrice(): string
+    {
+        return Money::ofMinor($this->calculatedPrice, 'GBP')->formatTo('en_GB');
+    }
+
+    public function getFormattedDiscountPrice(): string
+    {
+        return Money::ofMinor($this->calculatedDiscount, 'GBP')->formatTo('en_GB');
+    }
+}

app/PricingEngine/DiscountTypes/FixedDiscountType.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace App\PricingEngine\DiscountTypes;
+
+use App\PricingEngine\Contracts\DiscountTypeInterface;
+
+class FixedDiscountType implements DiscountTypeInterface
+{
+    public function modify(int $currentPrice, int $discountValue): int
+    {
+        return max(
+            0,
+            $currentPrice - $discountValue
+        );
+    }
+}

app/PricingEngine/DiscountTypes/PercentageDiscountType.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace App\PricingEngine\DiscountTypes;
+
+use App\PricingEngine\Contracts\DiscountTypeInterface;
+use Brick\Money\Money;
+
+class PercentageDiscountType implements DiscountTypeInterface
+{
+    public function modify(int $currentPrice, int $discountValue): int
+    {
+        return max(
+            0,
+            round($currentPrice - ($currentPrice * ($discountValue / 100)))
+        );
+    }
+}