Add td_api::canSendMessageToUser.

td/generate/scheme/td_api.tl

@@ -9525,6 +9525,10 @@ setNewChatPrivacySettings settings:newChatPrivacySettings = Ok;
 getNewChatPrivacySettings = NewChatPrivacySettings;
 
 
+//@description Check whether the current user can message another user or try to create a chat with them @user_id Identifier of the other user
+canSendMessageToUser user_id:int53 = Ok;
+
+
 //@description Returns the value of an option by its name. (Check the list of available options on https://core.telegram.org/tdlib/options.) Can be called before authorization. Can be called synchronously for options "version" and "commit_hash"
 //@name The name of the option
 getOption name:string = OptionValue;

td/telegram/ContactsManager.cpp

@@ -5491,6 +5491,27 @@ int32 ContactsManager::get_user_was_online(const User *u, UserId user_id, int32
   return was_online;
 }
 
+void ContactsManager::can_send_message_to_user(UserId user_id, Promise<Unit> &&promise) {
+  if (user_id == get_my_id()) {
+    return promise.set_value(Unit());
+  }
+  const auto *u = get_user(user_id);
+  if (!have_input_peer_user(u, user_id, AccessRights::Write)) {
+    return promise.set_error(Status::Error(400, "Have no write access to the chat"));
+  }
+  if (!u->contact_require_premium || td_->option_manager_->get_option_boolean("is_premium") || u->is_mutual_contact) {
+    return promise.set_value(Unit());
+  }
+  auto user_full = get_user_full_force(user_id, "can_send_message_to_user");
+  if (user_full != nullptr) {
+    if (!user_full->contact_require_premium) {
+      return promise.set_value(Unit());
+    }
+    return promise.set_error(Status::Error(400, "Can't write to the user first"));
+  }
+  return promise.set_value(Unit());
+}
+
 void ContactsManager::load_contacts(Promise<Unit> &&promise) {
   if (td_->auth_manager_->is_bot()) {
     are_contacts_loaded_ = true;

td/telegram/ContactsManager.h

@@ -185,6 +185,8 @@ class ContactsManager final : public Actor {
   int32 get_secret_chat_layer(SecretChatId secret_chat_id) const;
   FolderId get_secret_chat_initial_folder_id(SecretChatId secret_chat_id) const;
 
+  void can_send_message_to_user(UserId user_id, Promise<Unit> &&promise);
+
   void on_imported_contacts(int64 random_id, Result<tl_object_ptr<telegram_api::contacts_importedContacts>> result);
 
   void on_deleted_contacts(const vector<UserId> &deleted_contact_user_ids);

td/telegram/Td.cpp

@@ -6528,6 +6528,12 @@ void Td::on_request(uint64 id, td_api::setNewChatPrivacySettings &request) {
                                                      std::move(promise));
 }
 
+void Td::on_request(uint64 id, const td_api::canSendMessageToUser &request) {
+  CHECK_IS_USER();
+  CREATE_OK_REQUEST_PROMISE();
+  contacts_manager_->can_send_message_to_user(UserId(request.user_id_), std::move(promise));
+}
+
 void Td::on_request(uint64 id, td_api::setChatTitle &request) {
   CLEAN_INPUT_STRING(request.title_);
   CREATE_OK_REQUEST_PROMISE();

td/telegram/Td.h

@@ -1059,6 +1059,8 @@ class Td final : public Actor {
 
   void on_request(uint64 id, td_api::setNewChatPrivacySettings &request);
 
+  void on_request(uint64 id, const td_api::canSendMessageToUser &request);
+
   void on_request(uint64 id, td_api::setChatTitle &request);
 
   void on_request(uint64 id, const td_api::setChatPhoto &request);

td/telegram/cli.cpp

@@ -5449,6 +5449,10 @@ class CliClient final : public Actor {
       get_args(args, allow_new_chats_from_unknown_users);
       auto settings = td_api::make_object<td_api::newChatPrivacySettings>(allow_new_chats_from_unknown_users);
       send_request(td_api::make_object<td_api::setNewChatPrivacySettings>(std::move(settings)));
+    } else if (op == "csmtu") {
+      UserId user_id;
+      get_args(args, user_id);
+      send_request(td_api::make_object<td_api::canSendMessageToUser>(user_id));
     } else if (op == "sct") {
       ChatId chat_id;
       string title;