decorator pattern

config/services.yaml

@@ -23,6 +23,6 @@ services:
   # add more service definitions when explicit configuration is needed
   # please note that last definitions always *replace* previous ones
 
-  App\Game:
-    calls:
-      - subscribe: [ '@App\Observer\XpEarnedObserver' ]
+#  App\Game:
+#    calls:
+#      - subscribe: [ '@App\Observer\XpEarnedObserver' ]

src/Command/GameCommand.php

@@ -8,6 +8,9 @@
 use App\Character\CharacterType;
 use App\Fight;
 use App\Game;
+use App\Observer\XpEarnedObserver;
+use App\Service\OutputtingXpCalculator;
+use App\Service\XpCalculator;
 use Symfony\Component\Console\Attribute\AsCommand;
 use Symfony\Component\Console\Command\Command;
 use Symfony\Component\Console\Input\InputInterface;
@@ -25,6 +28,10 @@ public function __construct(
 
     protected function execute(InputInterface $input, OutputInterface $output): int
     {
+        $xpCalculator = new XpCalculator();
+        $xpCalculator = new OutputtingXpCalculator($xpCalculator);
+        $this->game->subscribe(new XpEarnedObserver($xpCalculator));
+
         $io = new SymfonyStyle($input, $output);
 
         $io->text('Welcome to the game where warriors fight against each other for honor and glory... and 🍕!');

src/Observer/XpEarnedObserver.php

@@ -5,11 +5,11 @@
 namespace App\Observer;
 
 use App\Fight;
-use App\Service\XpCalculator;
+use App\Service\XpCalculatorInterface;
 
 readonly class XpEarnedObserver implements CanObserverFight
 {
-    public function __construct(private XpCalculator $xpCalculator)
+    public function __construct(private XpCalculatorInterface $xpCalculator)
     {
     }
 

src/Service/OutputtingXpCalculator.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service;
+
+use App\Character\Character;
+use Symfony\Component\Console\Output\ConsoleOutput;
+
+class OutputtingXpCalculator implements XpCalculatorInterface
+{
+    public function __construct(
+        private readonly XpCalculatorInterface $innerCalculator,
+    ) {
+    }
+
+    public function addXp(Character $winner, int $enemyLevel): void
+    {
+        $beforeLevel = $winner->getLevel();
+
+        $this->innerCalculator->addXp($winner, $enemyLevel);
+
+        $afterLevel = $winner->getLevel();
+
+        if ($beforeLevel !== $afterLevel) {
+            $output = new ConsoleOutput();
+
+            $output->writeln('--------------------------------');
+            $output->writeln('<bg=green;fg=white>Congratulations! You\'ve leveled up!</>');
+            $output->writeln(sprintf('You are now level "%d"', $winner->getLevel()));
+            $output->writeln('--------------------------------');
+        }
+    }
+}

src/Service/XpCalculator.php

@@ -6,7 +6,7 @@
 
 use App\Character\Character;
 
-class XpCalculator
+class XpCalculator implements XpCalculatorInterface
 {
     public function addXp(Character $winner, int $enemyLevel): void
     {

src/Service/XpCalculatorInterface.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service;
+
+use App\Character\Character;
+
+interface XpCalculatorInterface
+{
+    public function addXp(Character $winner, int $enemyLevel): void;
+}