now most of logic works as it should

bin/WebSocketServer.php

@@ -38,7 +38,7 @@ class WebSocketServer implements MessageComponentInterface
     {
         foreach ($this->connectionsData as $connectionData) {
             if ($connectionData["username"] !== $username) {
-                $connectionData["connection"]->send("{\"sender\": \"{$username}\",\"msg\": \"{$msg}\"");
+                $connectionData["connection"]->send("{\"sender\": \"{$username}\",\"msg\": \"{$msg}\"}");
             }
         }
     }
@@ -72,7 +72,7 @@ class WebSocketServer implements MessageComponentInterface
         if ($index === null) return;
 
         if ($this->connectionsData[$index]["username"]) {
-            $msgContent = $decodedMsg["msg"] ?? null;
+            $msgContent = $decodedMsg["message"] ?? null;
             if ($msgContent) {
                 $this->sendToAllAuthenticated($this->connectionsData[$index]["username"], $msgContent);
                 $from->send("{\"success\"}: \"message send\"");

public/index.php

@@ -82,13 +82,13 @@ $html->content = <<<'HTML'
 
             ws.onmessage = (event) => {
                 const text = event.data;
-                if (text === 'authenticated') {
+                if (text === '{"success"}: "authenticated"') {
                     log('Authenticated.', 'system');
                     setAuthenticated(true);
-                } else if (text === 'invalid token') {
+                } else if (text === '{"error"}: "invalid token"') {
                     log('Invalid token. Connection closed.', 'error');
                     ws.close();
-                } else if (text === 'not authenticated') {
+                } else if (text === '{"error"}: "you are not authenticated"') {
                     log('Server: not authenticated', 'error');
                 } else {
                     try {

src/Database/Handler.php

@@ -60,11 +60,11 @@ class Handler
     }
     public function userExists(string $username): bool
     {
-        $statement = $this->pdo->prepare("SELECT * FROM users WHERE username = :username");
+        $statement = $this->pdo->prepare("SELECT 1 FROM users WHERE username = :username");
         $statement->execute([
-           $username
+           "username" => $username
         ]);
-        return $statement->rowCount() > 0;
+        return (bool) $statement->fetchColumn();
     }
     public function getPasswordHash(string $username): string
     {

src/Http/LoginController.php

@@ -27,7 +27,7 @@ class LoginController implements HttpServerInterface
             $responseHead = "400";
             $json = json_encode(["error" => "Not enough params"]);
         }
-        else if (!Handler::getInstance()->userExists($username) == !password_verify($password, Handler::getInstance()->getPasswordHash($username)))
+        else if (!Handler::getInstance()->userExists($username) || !password_verify($password, Handler::getInstance()->getPasswordHash($username)))
         {
             $login = false;
             $responseHead = "409";