feature: implement payment gateway

- implement stripe checkout gateway
- add payment gateway factory and service

backend/app/Actions/ProcessOrderPaymentAction.php

@@ -0,0 +1,49 @@
+<?php
+
+namespace App\Actions;
+
+use App\Data\PaymentResponseDTO;
+use App\Enums\PaymentModes;
+use App\Enums\PaymentStatusEnum;
+use App\Models\Order;
+use App\Models\PaymentStatus;
+use App\Services\Payment\PaymentGatewayFactory;
+use DB;
+use Log;
+use Throwable;
+
+final readonly class ProcessOrderPaymentAction
+{
+    public function __construct(private PaymentGatewayFactory $paymentGatewayFactory) {}
+
+    /**
+     * Execute the action.
+     */
+    public function execute(Order $order, PaymentModes $mode): PaymentResponseDTO
+    {
+        $gateway = $this->paymentGatewayFactory->make($mode);
+        try {
+            DB::beginTransaction();
+            $response = $gateway->charge($order);
+
+            if ($response->isSuccess) {
+                $order->payments()->create(
+                    [
+                        'transaction_id' => $response->transactionId,
+                        'amount' => $response->amount,
+                        'currency' => $response->currency,
+                        'payment_method' => $response->method->value,
+                        'payment_status_id' => PaymentStatus::getIdByName(PaymentStatusEnum::Unpaid->value),
+                    ]
+                );
+            }
+            DB::commit();
+
+            return $response;
+        } catch (Throwable $e) {
+            DB::rollBack();
+            Log::error('Error occurred while processing the payment.', [$e->getMessage()]);
+            abort(500, 'Something went wrong. Please try again or contact us to get in touch with our support team. ');
+        }
+    }
+}

backend/app/Contracts/PaymentGateway.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace App\Contracts;
+
+use App\Data\PaymentResponseDTO;
+use App\Models\Order;
+
+interface PaymentGateway
+{
+    public function charge(Order $order): PaymentResponseDTO;
+}

backend/app/Data/PaymentResponseDTO.php

@@ -0,0 +1,63 @@
+<?php
+
+namespace App\Data;
+
+use App\Contracts\OutputDataTransferObject;
+use App\Enums\PaymentModes;
+
+final readonly class PaymentResponseDTO implements OutputDataTransferObject
+{
+    public function __construct(
+        public bool $isSuccess,
+        public int $amount,
+        public string $currency,
+        public PaymentModes $method,
+        public ?string $transactionId = null,
+        public ?string $errorMessage = null,
+        public ?string $redirectUrl = null,
+    ) {}
+
+    public static function success(
+        string $transactionId,
+        int $amount,
+        string $currency,
+        PaymentModes $method,
+        ?string $redirectUrl = null
+    ): self {
+        return new self(
+            isSuccess: true,
+            amount: $amount,
+            currency: $currency,
+            method: $method,
+            transactionId: $transactionId,
+            redirectUrl: $redirectUrl,
+        );
+    }
+
+    public static function failure(int $amount, string $currency, PaymentModes $method, string $errorMessage): self
+    {
+        return new self(
+            isSuccess: false,
+            amount: $amount,
+            currency: $currency,
+            method: $method,
+            errorMessage: $errorMessage,
+        );
+    }
+
+    /**
+     * @return array<string, mixed>
+     */
+    public function toArray(): array
+    {
+        return [
+            'isSuccess' => $this->isSuccess,
+            'transactionId' => $this->transactionId,
+            'amount' => $this->amount,
+            'currency' => $this->currency,
+            'method' => $this->method,
+            'redirectUrl' => $this->redirectUrl,
+            'errorMessage' => $this->errorMessage,
+        ];
+    }
+}

backend/app/Enums/PaymentModes.php

@@ -0,0 +1,9 @@
+<?php
+
+namespace App\Enums;
+
+enum PaymentModes: string
+{
+    case StripeCheckout = 'stripeCheckout';
+    case CashOnDelivery = 'cashOnDelivery';
+}

backend/app/Enums/PaymentStatusEnum.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace App\Enums;
+
+enum PaymentStatusEnum: string
+{
+    case Unpaid = 'unpaid';
+    case Paid = 'paid';
+    case Refunded = 'refunded';
+    case Failed = 'failed';
+}

backend/app/Http/Controllers/PaymentController.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace App\Http\Controllers;
+
+use App\Actions\ProcessOrderPaymentAction;
+use App\Enums\PaymentModes;
+use App\Http\Requests\PaymentRequest;
+use App\Http\Resources\PaymentResource;
+use App\Models\Order;
+use App\Models\Payment;
+
+class PaymentController extends Controller
+{
+    public function index()
+    {
+        return PaymentResource::collection(Payment::all());
+    }
+
+    public function store(PaymentRequest $request, Order $order, ProcessOrderPaymentAction $action)
+    {
+        $response = $action->execute($order, PaymentModes::tryFrom($request->mode));
+
+        return new PaymentResource($response);
+    }
+
+    public function show(Payment $payment)
+    {
+        return new PaymentResource($payment);
+    }
+
+    public function update(PaymentRequest $request, Payment $payment)
+    {
+        $payment->update($request->validated());
+
+        return new PaymentResource($payment);
+    }
+
+    public function destroy(Payment $payment)
+    {
+        $payment->delete();
+
+        return response()->json();
+    }
+}

backend/app/Http/Requests/PaymentRequest.php

@@ -0,0 +1,22 @@
+<?php
+
+namespace App\Http\Requests;
+
+use App\Enums\PaymentModes;
+use Illuminate\Foundation\Http\FormRequest;
+use Illuminate\Validation\Rule;
+
+class PaymentRequest extends FormRequest
+{
+    public function rules(): array
+    {
+        return [
+            'mode' => ['required', Rule::enum(PaymentModes::class)],
+        ];
+    }
+
+    public function authorize(): bool
+    {
+        return true;
+    }
+}

backend/app/Http/Resources/PaymentResource.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace App\Http\Resources;
+
+use App\Data\PaymentResponseDTO;
+use App\Models\Payment;
+use Illuminate\Http\Request;
+use Illuminate\Http\Resources\Json\JsonResource;
+
+/**
+ * @mixin Payment
+ *
+ * @property PaymentResponseDTO $resource
+ */
+class PaymentResource extends JsonResource
+{
+    public static $wrap = null;
+
+    public function toArray(Request $request): array
+    {
+        return [
+            'success' => $this->resource->isSuccess,
+            'amount' => $this->resource->amount,
+            'currency' => $this->resource->currency,
+            'method' => $this->resource->method,
+            'redirectUrl' => $this->resource->redirectUrl,
+            'errorMessage' => $this->resource->errorMessage,
+        ];
+    }
+}

backend/app/Models/Payment.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Casts\Attribute;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+/**
+ * @mixin IdeHelperPayment
+ */
+class Payment extends Model
+{
+    protected $fillable = [
+        'order_id',
+        'transaction_id',
+        'amount',
+        'currency',
+        'payment_method',
+        'payment_status_id',
+        'error_message',
+    ];
+
+    protected $with = ['paymentStatus'];
+
+    public function order(): BelongsTo
+    {
+        return $this->belongsTo(Order::class);
+    }
+
+    public function paymentStatus(): BelongsTo
+    {
+        return $this->belongsTo(PaymentStatus::class);
+    }
+
+    protected function status(): Attribute
+    {
+        return Attribute::make(fn () => $this->paymentStatus?->name);
+    }
+}

backend/app/Models/PaymentStatus.php

@@ -0,0 +1,22 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+
+/**
+ * @mixin IdeHelperPaymentStatus
+ */
+class PaymentStatus extends Model
+{
+    public $timestamps = false;
+
+    protected $fillable = [
+        'name',
+    ];
+
+    public static function getIdByName(string $name): ?int
+    {
+        return static::where('name', $name)->value('id');
+    }
+}

backend/app/Services/Payment/CodPaymentGateway.php

@@ -0,0 +1,14 @@
+<?php
+
+namespace App\Services\Payment;
+
+use App\Contracts\PaymentGateway;
+use App\Models\Order;
+
+class CodPaymentGateway implements PaymentGateway
+{
+    public function charge(Order $order)
+    {
+        // TODO: Implement charge() method
+    }
+}

backend/app/Services/Payment/PaymentGatewayFactory.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace App\Services\Payment;
+
+use App\Enums\PaymentModes;
+
+class PaymentGatewayFactory
+{
+    public function make(PaymentModes $mode)
+    {
+        return match ($mode) {
+            PaymentModes::CashOnDelivery => new CodPaymentGateway,
+            PaymentModes::StripeCheckout => new StripePaymentGateway,
+        };
+    }
+}

backend/app/Services/Payment/StripePaymentGateway.php

@@ -0,0 +1,83 @@
+<?php
+
+namespace App\Services\Payment;
+
+use App\Contracts\PaymentGateway;
+use App\Data\PaymentResponseDTO;
+use App\Data\StripeLineItemDTO;
+use App\Data\StripeSessionDataDTO;
+use App\Enums\PaymentModes;
+use App\Enums\StripeCurrency;
+use App\Enums\StripePaymentMode;
+use App\Models\Order;
+use Exception;
+use Illuminate\Support\Facades\Log;
+use Stripe\Checkout\Session;
+use Stripe\Stripe;
+
+class StripePaymentGateway implements PaymentGateway
+{
+    public function __construct()
+    {
+        Stripe::setApiKey(config('services.stripe.secret'));
+    }
+
+    public function charge(Order $order): PaymentResponseDTO
+    {
+        $cart = $order->cart()->withProducts()->first();
+
+        $totalAmount = 0;
+        $lineItems = [];
+
+        foreach ($cart->products as $product) {
+            $priceInCents = (int) ($product->pivot->price * 100);
+
+            $totalAmount += ($priceInCents * $product->pivot->quantity);
+
+            $lineItems[] = new StripeLineItemDTO(
+                currency: StripeCurrency::INR,
+                price: $priceInCents,
+                productName: $product->title,
+                productDescription: $product->description,
+                quantity: $product->pivot->quantity,
+            );
+        }
+
+        $currency = StripeCurrency::INR->value;
+
+        try {
+            $data = new StripeSessionDataDTO(
+                lineItems: $lineItems,
+                mode: StripePaymentMode::Payment,
+                successUrl: config('app.frontend_url').'/order/payment/success?session_id={CHECKOUT_SESSION_ID}"',
+                cancelUrl: config('app.frontend_url').'/order/payment/cancel',
+            );
+            $session = Session::create($data->toArray());
+
+            // add stripe session to order
+            $order->stripeSession()->create(
+                [
+                    'session_id' => $session->id,
+                ]
+            );
+
+            return PaymentResponseDTO::success(
+                transactionId: $session->id,
+                amount: $totalAmount,
+                currency: $currency,
+                method: PaymentModes::StripeCheckout,
+                redirectUrl: $session->url,
+            );
+
+        } catch (Exception $e) {
+            Log::error('Stripe Checkout session cannot be created.', ['error' => $e->getMessage()]);
+
+            return PaymentResponseDTO::failure(
+                amount: $totalAmount,
+                currency: $currency,
+                method: PaymentModes::StripeCheckout,
+                errorMessage: 'Payment gateway unavailable. Please try again.'
+            );
+        }
+    }
+}

backend/database/migrations/2026_03_22_134921_create_payments_table.php

@@ -0,0 +1,29 @@
+<?php
+
+use App\Models\PaymentStatus;
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Schema::create('payments', function (Blueprint $table) {
+            $table->id();
+            $table->foreignId('order_id');
+            $table->string('transaction_id');
+            $table->integer('amount');
+            $table->string('currency');
+            $table->string('payment_method');
+            $table->foreignIdFor(PaymentStatus::class);
+            $table->timestamps();
+            $table->unique(['transaction_id']);
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::dropIfExists('payments');
+    }
+};

backend/database/migrations/2026_03_23_044430_create_payment_statuses_table.php

@@ -0,0 +1,21 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Schema::create('payment_statuses', function (Blueprint $table) {
+            $table->id();
+            $table->string('name');
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::dropIfExists('payment_statuses');
+    }
+};

backend/database/seeders/PaymentStatusSeeder.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace Database\Seeders;
+
+use App\Enums\PaymentStatusEnum;
+use App\Models\PaymentStatus;
+use Illuminate\Database\Seeder;
+
+class PaymentStatusSeeder extends Seeder
+{
+    public function run(): void
+    {
+        $data = array_map(function (PaymentStatusEnum $status) {
+            return [
+                'name' => $status->value,
+            ];
+        }, PaymentStatusEnum::cases());
+        PaymentStatus::insertOrIgnore($data);
+    }
+}

backend/routes/api.php

@@ -4,6 +4,7 @@
 use App\Http\Controllers\CartController;
 use App\Http\Controllers\FavouriteProductController;
 use App\Http\Controllers\OrderController;
+use App\Http\Controllers\PaymentController;
 use App\Http\Controllers\ProductCategoryController;
 use App\Http\Controllers\ProductController;
 use App\Http\Controllers\ProductImagesController;
@@ -29,6 +30,7 @@
 
     Route::apiResource('user.addresses', UserAddressController::class)->shallow();
     Route::apiResource('users.orders', OrderController::class)->shallow();
+    Route::post('orders/{order}/payments', [PaymentController::class, 'store']);
 });
 Route::get('/categories', [ProductCategoryController::class, 'index']);
 Route::apiResource('products', ProductController::class);