refactor: extract rate formatting logic to RateService and add tests

routes/console.php

@@ -4,4 +4,18 @@ use Illuminate\Support\Facades\Schedule;
 
 Schedule::command('currency:fetch --today')
     ->everySixHours()
-    ->appendOutputTo(storage_path('logs/currency-fetch.log'));
+    ->appendOutputTo(storage_path('logs/currency-fetch.log'))
+    ->onFailure(function () {
+        // TODO: set the correct sender email
+        // TODO: set the correct recipient email
+         
+        // \Illuminate\Support\Facades\Mail::raw(
+        //     "Currency fetching failed!\n\nCheck the page: https://boqash.com/price-currency\nAnd review the logs for more details.",
+        //     function (\Illuminate\Mail\Message $message) {
+        //         $message
+        //             ->from(config('mail.from.address')) 
+        //             ->to(config('mail.admin.address'))   
+        //             ->subject('Currency Fetching Failed!');
+        //     }
+        // );
+    });