83 - Promoting Charges to Objects

app/Billing/Charge.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace App\Billing;
+
+class Charge
+{
+    private $data;
+
+    public function __construct($data)
+    {
+        $this->data = $data;
+    }
+
+    public function amount()
+    {
+        return $this->data['amount'];
+    }
+
+    public function cardLastFour()
+    {
+        return $this->data['card_last_four'];
+    }
+}

app/Billing/FakePaymentGateway.php

@@ -5,16 +5,20 @@ namespace App\Billing;
 class FakePaymentGateway implements PaymentGateway
 {
     private $charges;
+    private $tokens;
     private $beforeFirstChargeCallback;
 
     public function __construct()
     {
         $this->charges = collect();
+        $this->tokens = collect();
     }
 
-    public function getValidTestToken()
+    public function getValidTestToken($cardNumber = '4242424242424242')
     {
-        return "valid-token";
+        $token = 'fake-tok_'.str_random(24);
+        $this->tokens[$token] = $cardNumber;
+        return $token;
     }
 
     public function charge($amount, $token)
@@ -25,10 +29,14 @@ class FakePaymentGateway implements PaymentGateway
             $callback($this);
         }
 
-        if ($token !== $this->getValidTestToken()) {
+        if (! $this->tokens->has($token)) {
             throw new PaymentFailedException;
         }
-        $this->charges[] = $amount;
+
+        return $this->charges[] = new Charge([
+            'amount' => $amount,
+            'card_last_four' => substr($this->tokens[$token], -4),
+        ]);
     }
 
     public function newChargesDuring($callback)
@@ -40,7 +48,7 @@ class FakePaymentGateway implements PaymentGateway
 
     public function totalCharges()
     {
-        return $this->charges->sum();
+        return $this->charges->map->amount()->sum();
     }
 
     public function beforeFirstCharge($callback)