bitcoingui:switch chain

Author: RandyMcMillan

src/qt/bitcoin.cpp

@@ -589,6 +589,11 @@ int GuiMain(int argc, char* argv[])
     // - Do not call Params() before this step
     // - QSettings() will use the new application name after this, resulting in network-specific settings
     // - Needs to be done before createOptionsModel
+
+    QSettings settings;
+    std::string chain = settings.value("chain", "main").toString().toStdString();
+    gArgs.SoftSetArg("-chain", chain);
+
     if (auto error = common::InitConfig(gArgs, ErrorSettingsRead)) {
         InitError(error->message, error->details);
         if (error->status == common::ConfigStatus::FAILED_WRITE) {

src/qt/bitcoingui.cpp

@@ -532,6 +532,46 @@ void BitcoinGUI::createMenuBar()
     }
     settings->addAction(optionsAction);
 
+    // Add chain selection submenu
+    QAction* chain_selection_action = new QAction(tr("&Switch chain"), this);
+    chain_selection_action->setStatusTip(tr("Restart application using a different (test) network"));
+    QMenu* chain_selection_menu = new QMenu(this);
+    chain_selection_action->setMenu(chain_selection_menu);
+
+    connect(chain_selection_menu, &QMenu::aboutToShow, [this, chain_selection_menu] {
+        chain_selection_menu->clear();
+        const std::vector<std::pair<QString, QString>> chains = {{"main", "&Bitcoin"}, {"testnet4", "&Testnet4"}, {"regtest", "&Regtest"}, {"signet", "&Signet"}};
+        const std::string current_chain = Params().GetChainTypeString();
+        for (const auto& chain : chains) {
+        const bool is_current = current_chain == chain.first.toStdString();
+            QAction* action = chain_selection_menu->addAction(chain.second);
+            action->setCheckable(true);
+            action->setChecked(is_current);
+            action->setEnabled(!is_current);
+            connect(action, &QAction::triggered, [this, chain] {
+                //: Switch to the mainnet, testnet, signet or regtest chain.
+                QMessageBox::StandardButton btn_ret_val = QMessageBox::question(this, tr("Switch chain"),
+                    //: Switching between mainnet, testnet, signet or regtest chain requires a restart.
+                    tr("Client restart required to switch chain.\n\nClient will be shut down. Do you want to proceed?"),
+                    QMessageBox::Yes | QMessageBox::Cancel, QMessageBox::Cancel);
+
+                if (btn_ret_val == QMessageBox::Cancel) return;
+
+                // QSettings are stored seperately for each network. Switch application name
+                // to mainnet before storing the selected chain.
+                QScopedPointer<const NetworkStyle> networkStyle(NetworkStyle::instantiate(ChainType::MAIN));
+                assert(!networkStyle.isNull());
+                QApplication::setApplicationName(networkStyle->getAppName());
+
+                QSettings settings;
+                settings.setValue("chain", chain.first);
+                Q_EMIT quitRequested();
+            });
+        }
+    });
+
+    settings->addAction(chain_selection_action);
+
     QMenu* window_menu = appMenuBar->addMenu(tr("&Window"));
 
     QAction* minimize_action = window_menu->addAction(tr("&Minimize"));