feat: Add user level and experience attributes, and implement reward, task, and quest models with corresponding controllers and migrations

backend/app/Http/Controllers/QuestController.php

@@ -0,0 +1,70 @@
+<?php
+
+namespace App\Http\Controllers;
+
+use App\Models\Quest;
+use App\Models\Task;
+use Illuminate\Http\Request;
+
+class QuestController extends Controller
+{
+    public function index(Request $request)
+    {
+        $quests = Quest::where('user_id', $request->user()->id)->where('is_completed', false)->get();
+        return response()->json($quests);
+    }
+
+    public function generate(Request $request)
+    {
+        // Vereinfachte Logik: Nimmt die letzten 5 offenen Tasks und macht daraus Quests
+        $tasks = Task::where('user_id', $request->user()->id)->limit(5)->get();
+
+        $quests = [];
+        foreach ($tasks as $task) {
+            $quests[] = Quest::create([
+                'user_id' => $request->user()->id,
+                'task_id' => $task->id,
+                'title' => $task->title,
+                'category' => $task->category,
+                'due_date' => $task->due_date,
+                'xp_reward' => 50,
+                'is_completed' => false
+            ]);
+        }
+
+        return response()->json($quests, 201);
+    }
+
+    public function complete(Request $request, $id)
+    {
+        $quest = Quest::where('user_id', $request->user()->id)->findOrFail($id);
+
+        if ($quest->is_completed) {
+            return response()->json(['message' => 'Quest already completed'], 400);
+        }
+
+        // Mark as completed
+        $quest->update(['is_completed' => true]);
+
+        $user = $request->user();
+        $user->xp += $quest->xp_reward;
+
+        // Level-Up Check (vereinfachte Logik)
+        $xpForNextLevel = $user->level * 100;
+        $levelUp = false;
+        while ($user->xp >= $xpForNextLevel) {
+            $user->level += 1;
+            $user->xp = $user->xp - $xpForNextLevel;
+            $xpForNextLevel = $user->level * 100;
+            $levelUp = true;
+        }
+        $user->save();
+
+        return response()->json([
+            'quest' => $quest,
+            'xp_gained' => $quest->xp_reward,
+            'new_level' => $user->level,
+            'level_up' => $levelUp
+        ]);
+    }
+}