Update AccountService, add setLastActive method

app/Services/AccountService.php

@@ -166,7 +166,7 @@ class AccountService
     public static function usernameToId($username)
     {
         $key = self::CACHE_KEY . 'u2id:' . hash('sha256', $username);
-		return Cache::remember($key, 900, function() use($username) {
+        return Cache::remember($key, 14400, function() use($username) {
             $s = Str::of($username);
             if($s->contains('@') && !$s->startsWith('@')) {
                 $username = "@{$username}";
@@ -220,4 +220,18 @@ class AccountService
             return false;
         });
     }
+
+    public static function setLastActive($id = false)
+    {
+        if(!$id) { return; }
+        $key = 'user:last_active_at:id:' . $id;
+        if(!Cache::has($key)) {
+            $user = User::find($id);
+            if(!$user) { return; }
+            $user->last_active_at = now();
+            $user->save();
+            Cache::put($key, 1, 14400);
+        }
+        return;
+    }
 }