add json plan repository

app/Plan/JsonPlanRepository.php

@@ -0,0 +1,93 @@
+<?php
+
+namespace App\Plan;
+
+use App\User\User;
+use App\User\UserRepository;
+use App\ValueObjects\EmailAddress;
+
+class JsonPlanRepository implements PlanRepository
+{
+    private string $filePath;
+
+    public function __construct(
+        private UserRepository $userRepository,
+    ) {
+        $this->filePath = __DIR__ . '/../../data/plans.json';
+    }
+
+    public function create(CreatePlanDto $dto): Plan
+    {
+        $plans = $this->readPlans();
+        $id = $this->getNextId($plans);
+
+        $plans[] = [
+            'id' => $id,
+            'name' => $dto->name,
+            'userId' => $dto->user->getId(),
+        ];
+        $this->writePlans($plans);
+
+        return new Plan(
+            id: $id,
+            name: $dto->name,
+            user: $dto->user,
+        );
+    }
+
+    public function find(int $id): ?Plan
+    {
+        $plans = $this->readPlans();
+
+        foreach ($plans as $data) {
+            if ($data['id'] === $id) {
+                $user = $this->userRepository->find($data['userId']);
+                if ($user === null) {
+                    return null;
+                }
+                return new Plan(
+                    id: $data['id'],
+                    name: $data['name'],
+                    user: $user,
+                );
+            }
+        }
+
+        return null;
+    }
+
+    private function readPlans(): array
+    {
+        if (!file_exists($this->filePath)) {
+            return [];
+        }
+
+        $content = file_get_contents($this->filePath);
+
+        return json_decode($content, true) ?? [];
+    }
+
+    private function writePlans(array $plans): void
+    {
+        file_put_contents(
+            $this->filePath,
+            json_encode($plans, JSON_PRETTY_PRINT)
+        );
+    }
+
+    private function getNextId(array $plans): int
+    {
+        if (empty($plans)) {
+            return 0;
+        }
+
+        $maxId = -1;
+        foreach ($plans as $plan) {
+            if ($plan['id'] > $maxId) {
+                $maxId = $plan['id'];
+            }
+        }
+
+        return $maxId + 1;
+    }
+}