Rebased and fixed issue nabeelio#1275

app/Http/Controllers/Admin/RankController.php

@@ -7,6 +7,7 @@
 use App\Http\Requests\UpdateRankRequest;
 use App\Repositories\RankRepository;
 use App\Repositories\SubfleetRepository;
+use App\Repositories\UserRepository;
 use App\Services\FleetService;
 use Cache;
 use Illuminate\Http\Request;
@@ -18,22 +19,26 @@ class RankController extends Controller
     private FleetService $fleetSvc;
     private RankRepository $rankRepository;
     private SubfleetRepository $subfleetRepo;
+    private UserRepository $userRepo;
 
     /**
      * RankController constructor.
      *
      * @param FleetService       $fleetSvc
      * @param RankRepository     $rankingRepo
      * @param SubfleetRepository $subfleetRepo
+     * @param UserRepository     $userRepo
      */
     public function __construct(
         FleetService $fleetSvc,
         RankRepository $rankingRepo,
-        SubfleetRepository $subfleetRepo
+        SubfleetRepository $subfleetRepo,
+        UserRepository $userRepo
     ) {
         $this->fleetSvc = $fleetSvc;
         $this->rankRepository = $rankingRepo;
         $this->subfleetRepo = $subfleetRepo;
+        $this->userRepo = $userRepo;
     }
 
     /**
@@ -190,6 +195,19 @@ public function update($id, UpdateRankRequest $request)
      */
     public function destroy($id)
     {
+        $rank_in_use = $this->userRepo->findWhere(['rank_id' => $id])->count();
+        if ($rank_in_use > 0) {
+            Flash::error('Rank cannot be deleted since it\'s already assigned to one or more pilots!');
+
+            return redirect(route('admin.ranks.index'));
+        }
+
+        if ($this->rankRepository->count() === 1) {
+            Flash::error('Rank cannot be deleted since it\'s the only remaining rank in your database!');
+
+            return redirect(route('admin.ranks.index'));
+        }
+
         $rank = $this->rankRepository->findWithoutFail($id);
 
         if (empty($rank)) {