fix: wrong OAuth url building (#587)

Author: 2paperstar

lib/app/modules/auth/data/repositories/web_auth_2_oauth_repository.dart

@@ -34,18 +34,24 @@ abstract class WebAuth2OAuthRepository implements OAuthRepository {
       'offline_access',
     ];
     final prompt = recentLogout ? 'login' : 'consent';
-    final url = '${Strings.idpBaseUrl}/authorize'
-        '?client_id=$clientId'
-        '&redirect_uri=${Strings.idPRedirectUri}'
-        '&scope=${scopes.join('%20')}'
-        '&response_type=code'
-        '&state=$state'
-        '&code_challenge=$codeChallenge'
-        '&code_challenge_method=S256'
-        '&prompt=$prompt';
+    final authorizeUri = Uri(
+      scheme: Uri.parse(Strings.idpBaseUrl).scheme,
+      host: Uri.parse(Strings.idpBaseUrl).host,
+      path: '/authorize',
+      queryParameters: {
+        'client_id': clientId,
+        'redirect_uri': Strings.idPRedirectUri,
+        'scope': scopes.join(' '),
+        'response_type': 'code',
+        'state': state,
+        'code_challenge': codeChallenge,
+        'code_challenge_method': 'S256',
+        'prompt': prompt,
+      },
+    );
 
     final result = await FlutterWebAuth2.authenticate(
-      url: url,
+      url: authorizeUri.toString(),
       callbackUrlScheme: Strings.idpRedirectScheme,
     );
     final uri = Uri.parse(result);