Tomix1 · Tomix1 · Oct 1, 2025
diff --git a/app/Dto/Parameters/OfferParameters.php b/app/Dto/Parameters/OfferParameters.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace App\Dto\Parameters;
+
+class OfferParameters
+{
+    public function __construct(
+        public int $id,
+        public int $count,
+        public int $price,
+        public int $pack,
+    ){
+    }
+}
diff --git a/app/Dto/Parameters/OptimalProcurementParameters.php b/app/Dto/Parameters/OptimalProcurementParameters.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace App\Dto\Parameters;
+
+use App\Http\Api\V1\Requests\OptimalProcurementRequest;
+use Illuminate\Support\Collection;
+
+class OptimalProcurementParameters
+{
+    /**
+     * @param Collection<OfferParameters> $offers
+     */
+    public function __construct(
+        public int        $need,
+        public Collection $offers,
+    ) {
+    }
+
+    public static function fromRequest(OptimalProcurementRequest $request): static
+    {
+        $data = $request->validated();
+
+        return new static(
+            need:   $data['need'],
+            offers: collect($data['offers'])->map(
+                        static fn($offer) => new OfferParameters(
+                            id:    $offer['id'],
+                            count: $offer['count'],
+                            price: $offer['price'],
+                            pack:  $offer['pack'],
+                        )
+                    )
+        );
+    }
+}
diff --git a/app/Dto/Results/OptimalProcurementDto.php b/app/Dto/Results/OptimalProcurementDto.php
@@ -0,0 +1,12 @@
+<?php
+
+namespace App\Dto\Results;
+
+class OptimalProcurementDto
+{
+    public function __construct(
+        public int $id,
+        public int $qty,
+    ) {
+    }
+}
diff --git a/app/Http/Api/V1/Controllers/ProcurementController.php b/app/Http/Api/V1/Controllers/ProcurementController.php
@@ -0,0 +1,24 @@
+<?php
+
+namespace App\Http\Api\V1\Controllers;
+
+use App\Dto\Parameters\OptimalProcurementParameters;
+use App\Http\Api\V1\Requests\OptimalProcurementRequest;
+use App\Http\Api\V1\Resources\OptimalProcurementResource;
+use App\Http\Controllers\Controller;
+use App\Services\ProcurementService;
+use Illuminate\Http\Resources\Json\AnonymousResourceCollection;
+
+class ProcurementController extends Controller
+{
+    public function optimal(OptimalProcurementRequest $request): AnonymousResourceCollection
+    {
+        $procurementService = app(ProcurementService::class);
+
+        $parameters = OptimalProcurementParameters::fromRequest($request);
+
+        $optimalProcurement = $procurementService->calculateOptimal($parameters);
+
+        return OptimalProcurementResource::collection($optimalProcurement);
+    }
+}
diff --git a/app/Http/Api/V1/Requests/OptimalProcurementRequest.php b/app/Http/Api/V1/Requests/OptimalProcurementRequest.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace App\Http\Api\V1\Requests;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class OptimalProcurementRequest extends FormRequest
+{
+    public function rules(): array
+    {
+        return [
+            'need'           => ['required', 'integer', 'min:1'],
+            'offers'         => ['required', 'array'],
+            'offers.*.id'    => ['required', 'integer'],
+            'offers.*.count' => ['required', 'integer', 'min:1'],
+            'offers.*.price' => ['required', 'integer', 'min:1'],
+            'offers.*.pack'  => ['required', 'integer', 'min:1'],
+        ];
+    }
+}
diff --git a/app/Http/Api/V1/Resources/OptimalProcurementResource.php b/app/Http/Api/V1/Resources/OptimalProcurementResource.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace App\Http\Api\V1\Resources;
+
+use App\Dto\Results\OptimalProcurementDto;
+use Illuminate\Http\Request;
+use Illuminate\Http\Resources\Json\JsonResource;
+
+class OptimalProcurementResource extends JsonResource
+{
+    public function __construct(OptimalProcurementDto $dto)
+    {
+        parent::__construct($dto);
+    }
+
+    public function toArray(Request $request): array
+    {
+        /** @var OptimalProcurementDto $dto */
+        $dto = $this->resource;
+
+        return [
+            'id'  => $dto->id,
+            'qty' => $dto->qty,
+        ];
+    }
+}
diff --git a/app/Services/ProcurementService.php b/app/Services/ProcurementService.php
@@ -0,0 +1,46 @@
+<?php
+
+namespace App\Services;
+
+use App\Dto\Parameters\OptimalProcurementParameters;
+use App\Dto\Results\OptimalProcurementDto;
+use Illuminate\Support\Collection;
+
+class ProcurementService
+{
+    /**
+     * @return Collection<OptimalProcurementDto>
+     */
+    public function calculateOptimal(OptimalProcurementParameters $parameters): Collection
+    {
+        $offers = $parameters->offers->sortBy('price');
+
+        $result = collect();
+        $need   = $parameters->need;
+
+        foreach ($offers as $offer) {
+            if ($need <= 0) {
+                break;
+            }
+
+            $maxNeedFromOffer = min($offer->count, $need);
+
+            $maxByPack = (int)(floor($maxNeedFromOffer / $offer->pack) * $offer->pack);
+
+            if ($maxByPack > 0) {
+                $result[] = new OptimalProcurementDto(
+                    id:  $offer->id,
+                    qty: $maxByPack,
+                );
+
+                $need -= $maxByPack;
+            }
+        }
+
+        if ($need > 0) {
+            return collect();
+        }
+
+        return $result->sortBy('id');
+    }
+}
diff --git a/bootstrap/app.php b/bootstrap/app.php
@@ -9,6 +9,7 @@
         web: __DIR__.'/../routes/web.php',
         commands: __DIR__.'/../routes/console.php',
         health: '/up',
+        api: __DIR__ . '/../routes/api.php'
     )
     ->withMiddleware(function (Middleware $middleware): void {
         //

diff --git a/routes/api.php b/routes/api.php
@@ -0,0 +1,9 @@
+<?php
+
+use App\Http\Api\V1\Controllers\ProcurementController;
+
+Route::prefix('v1')->group(function () {
+    Route::get('procurement/optimal', [ProcurementController::class, 'optimal'])
+         ->name('api.procurement.optimal');
+});
+
diff --git a/tests/Feature/ProcurementControllerTest.php b/tests/Feature/ProcurementControllerTest.php
@@ -0,0 +1,69 @@
+<?php
+
+namespace Tests\Feature;
+
+use Tests\TestCase;
+
+class ProcurementControllerTest extends TestCase
+{
+    public function test_successful_procurement_optimal()
+    {
+        $data = [
+            'need'   => 76,
+            'offers' => [
+                ['id' => 111, 'count' => 42, 'price' => 13, 'pack' => 1],
+                ['id' => 222, 'count' => 77, 'price' => 11, 'pack' => 10],
+                ['id' => 333, 'count' => 103, 'price' => 10, 'pack' => 50],
+                ['id' => 444, 'count' => 65, 'price' => 12, 'pack' => 5],
+            ],
+        ];
+
+        $response = $this->getJson(route('api.procurement.optimal', $data));
+
+        $response->assertStatus(200)
+                 ->assertJson(
+                     [
+                         'data' => [
+                             ['id' => 111, 'qty' => 1],
+                             ['id' => 222, 'qty' => 20],
+                             ['id' => 333, 'qty' => 50],
+                             ['id' => 444, 'qty' => 5],
+                         ],
+                     ]
+                 );
+    }
+
+    public function test_invalid_count_procurement_optimal()
+    {
+        $data = [
+            'need'   => 300,
+            'offers' => [
+                ['id' => 111, 'count' => 42, 'price' => 13, 'pack' => 1],
+                ['id' => 222, 'count' => 77, 'price' => 11, 'pack' => 10],
+                ['id' => 333, 'count' => 103, 'price' => 10, 'pack' => 50],
+                ['id' => 444, 'count' => 65, 'price' => 12, 'pack' => 5],
+            ],
+        ];
+
+        $response = $this->getJson(route('api.procurement.optimal', $data));
+
+        $response->assertStatus(200)
+                 ->assertJson([]);
+    }
+
+    public function test_inappropriate_pack_multiplicity()
+    {
+        $data = [
+            'need'   => 12,
+            'offers' => [
+                ['id' => 111, 'count' => 20, 'price' => 10, 'pack' => 5],
+                ['id' => 222, 'count' => 10, 'price' => 12, 'pack' => 3],
+            ],
+        ];
+
+        $response = $this->getJson(route('api.procurement.optimal', $data));
+
+        $response->assertStatus(200)
+                 ->assertJson([]);
+    }
+}
diff --git a/tests/Unit/ProcurementServiceTest.php b/tests/Unit/ProcurementServiceTest.php
@@ -0,0 +1,100 @@
+<?php
+
+namespace Tests\Unit;
+
+use App\Dto\Parameters\OfferParameters;
+use App\Dto\Parameters\OptimalProcurementParameters;
+use App\Dto\Results\OptimalProcurementDto;
+use App\Services\ProcurementService;
+use Illuminate\Support\Collection;
+use Tests\TestCase;
+
+class ProcurementServiceTest extends TestCase
+{
+    private ProcurementService $service;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $this->service = app(ProcurementService::class);
+    }
+
+    public function test_calculate_optimal_procurement()
+    {
+        $need   = 76;
+        $offers = [
+            ['id' => 111, 'count' => 42, 'price' => 13, 'pack' => 1],
+            ['id' => 222, 'count' => 77, 'price' => 11, 'pack' => 10],
+            ['id' => 333, 'count' => 103, 'price' => 10, 'pack' => 50],
+            ['id' => 444, 'count' => 65, 'price' => 12, 'pack' => 5],
+        ];
+
+        $params = $this->createOptimalProcurementParameters($need, $offers);
+
+        $result = $this->service->calculateOptimal($params);
+
+        $this->assertInstanceOf(Collection::class, $result);
+        $this->assertCount(4, $result);
+
+        $this->assertContainsOnlyInstancesOf(OptimalProcurementDto::class, $result);
+
+        $expectedOrder = [111, 222, 333, 444];
+        $actualOrder   = $result->pluck('id')->toArray();
+        $this->assertEquals($expectedOrder, $actualOrder);
+
+        $this->assertEquals(1, $result->first(fn($dto) => $dto->id === 111)->qty);
+        $this->assertEquals(20, $result->first(fn($dto) => $dto->id === 222)->qty);
+        $this->assertEquals(50, $result->first(fn($dto) => $dto->id === 333)->qty);
+        $this->assertEquals(5, $result->first(fn($dto) => $dto->id === 444)->qty);
+    }
+
+    public function test_invalid_count_procurement_optimal()
+    {
+        $need   = 300;
+        $offers = [
+            ['id' => 111, 'count' => 42, 'price' => 13, 'pack' => 1],
+            ['id' => 222, 'count' => 77, 'price' => 11, 'pack' => 10],
+            ['id' => 333, 'count' => 103, 'price' => 10, 'pack' => 50],
+            ['id' => 444, 'count' => 65, 'price' => 12, 'pack' => 5],
+        ];
+
+        $params = $this->createOptimalProcurementParameters($need, $offers);
+
+        $result = $this->service->calculateOptimal($params);
+
+        $this->assertInstanceOf(Collection::class, $result);
+        $this->assertTrue($result->isEmpty());
+    }
+
+    public function test_inappropriate_pack_multiplicity()
+    {
+        $need   = 12;
+        $offers = [
+            ['id' => 111, 'count' => 20, 'price' => 10, 'pack' => 5],
+            ['id' => 222, 'count' => 10, 'price' => 12, 'pack' => 3],
+        ];
+
+        $params = $this->createOptimalProcurementParameters($need, $offers);
+
+        $result = $this->service->calculateOptimal($params);
+
+        $this->assertInstanceOf(Collection::class, $result);
+        $this->assertTrue($result->isEmpty());
+    }
+
+    private function createOptimalProcurementParameters(int $need, array $offers): OptimalProcurementParameters
+    {
+        return new OptimalProcurementParameters(
+            need:   $need,
+            offers: collect($offers)->map(
+                        static fn($offer) => new OfferParameters(
+                            id:    $offer['id'],
+                            count: $offer['count'],
+                            price: $offer['price'],
+                            pack:  $offer['pack'],
+                        )
+                    )
+        );
+    }
+}