WiimoteControllersWidget: Fix UI hang on opening

Fix the UI hanging for several seconds when opening the Controllers
window.

Move the scan for Bluetooth adapters onto a separate thread so the Host
thread doesn't have to wait for it.

Only automatically scan for adapters once, when opening the Controllers
window for the first time. Add a Refresh button to let the user refresh
the adapter list afterward.

3 files changed, 75 insertions, 11 deletions

diff --git a/Source/Core/DolphinQt/Config/ControllersWindow.cpp b/Source/Core/DolphinQt/Config/ControllersWindow.cpp
index bb0e7a0489..2470910e8e 100644
--- a/Source/Core/DolphinQt/Config/ControllersWindow.cpp
+++ b/Source/Core/DolphinQt/Config/ControllersWindow.cpp
@@ -27,7 +27,6 @@ void ControllersWindow::showEvent(QShowEvent* event)
 {
   QDialog::showEvent(event);
   m_wiimote_controllers->UpdateBluetoothAvailableStatus();
-  m_wiimote_controllers->RefreshBluetoothAdapters();
 }
 
 void ControllersWindow::CreateMainLayout()
diff --git a/Source/Core/DolphinQt/Config/WiimoteControllersWidget.cpp b/Source/Core/DolphinQt/Config/WiimoteControllersWidget.cpp
index 69de3837ad..960cfac080 100644
--- a/Source/Core/DolphinQt/Config/WiimoteControllersWidget.cpp
+++ b/Source/Core/DolphinQt/Config/WiimoteControllersWidget.cpp
@@ -19,6 +19,7 @@
 #include <optional>
 
 #include "Common/Config/Config.h"
+#include "Common/WorkQueueThread.h"
 
 #include "Core/Config/MainSettings.h"
 #include "Core/Config/WiimoteSettings.h"
@@ -35,6 +36,7 @@
 #include "DolphinQt/Config/Mapping/MappingWindow.h"
 #include "DolphinQt/QtUtils/ModalMessageBox.h"
 #include "DolphinQt/QtUtils/NonDefaultQPushButton.h"
+#include "DolphinQt/QtUtils/QueueOnObject.h"
 #include "DolphinQt/QtUtils/SetWindowDecorations.h"
 #include "DolphinQt/QtUtils/SignalBlocking.h"
 #include "DolphinQt/Settings.h"
@@ -51,6 +53,14 @@ WiimoteControllersWidget::WiimoteControllersWidget(QWidget* parent) : QWidget(pa
   connect(&Settings::Instance(), &Settings::EmulationStateChanged, this,
           [this](Core::State state) { LoadSettings(state); });
   LoadSettings(Core::GetState(Core::System::GetInstance()));
+
+  m_bluetooth_adapter_refresh_thread.Reset("Bluetooth Adapter Refresh Thread");
+  StartBluetoothAdapterRefresh();
+}
+
+WiimoteControllersWidget::~WiimoteControllersWidget()
+{
+  m_bluetooth_adapter_refresh_thread.WaitForCompletion();
 }
 
 void WiimoteControllersWidget::UpdateBluetoothAvailableStatus()
@@ -58,17 +68,46 @@ void WiimoteControllersWidget::UpdateBluetoothAvailableStatus()
   m_bluetooth_unavailable->setHidden(WiimoteReal::IsScannerReady());
 }
 
-void WiimoteControllersWidget::RefreshBluetoothAdapters()
+void WiimoteControllersWidget::StartBluetoothAdapterRefresh()
 {
+  if (m_bluetooth_adapter_scan_in_progress)
+    return;
+
   m_bluetooth_adapters->clear();
+  m_bluetooth_adapters->setDisabled(true);
+  m_bluetooth_adapters->addItem(tr("Scanning for adapters..."));
+
+  m_bluetooth_adapter_scan_in_progress = true;
+
+  const auto scan_func = [this]() {
+    INFO_LOG_FMT(COMMON, "Refreshing Bluetooth adapter list...");
+    auto device_list = IOS::HLE::BluetoothRealDevice::ListDevices();
+    INFO_LOG_FMT(COMMON, "{} Bluetooth adapters available.", device_list.size());
+    const auto refresh_complete_func = [this, devices = std::move(device_list)]() {
+      OnBluetoothAdapterRefreshComplete(devices);
+    };
+    QueueOnObject(this, refresh_complete_func);
+  };
+
+  m_bluetooth_adapter_refresh_thread.Push(scan_func);
+}
 
+void WiimoteControllersWidget::OnBluetoothAdapterRefreshComplete(
+    const std::vector<IOS::HLE::BluetoothRealDevice::BluetoothDeviceInfo>& devices)
+{
   const int configured_vid = Config::Get(Config::MAIN_BLUETOOTH_PASSTHROUGH_VID);
   const int configured_pid = Config::Get(Config::MAIN_BLUETOOTH_PASSTHROUGH_PID);
   bool found_configured_device = configured_vid == -1 || configured_pid == -1;
 
+  m_bluetooth_adapters->clear();
+  m_bluetooth_adapter_scan_in_progress = false;
+
+  const auto state = Core::GetState(Core::System::GetInstance());
+  UpdateBluetoothAdapterWidgetsEnabled(state);
+
   m_bluetooth_adapters->addItem(tr("Automatic"));
 
-  for (auto& device : IOS::HLE::BluetoothRealDevice::ListDevices())
+  for (auto& device : devices)
   {
     std::string name = device.name.empty() ? tr("Unknown Device").toStdString() : device.name;
     QString device_info =
@@ -149,8 +188,9 @@ void WiimoteControllersWidget::CreateLayout()
   m_wiimote_box->setLayout(m_wiimote_layout);
 
   m_wiimote_passthrough = new QRadioButton(tr("Passthrough a Bluetooth adapter"));
-  m_bluetooth_adapters_label = new QLabel(tr("Bluetooth adapter"));
+  m_bluetooth_adapters_label = new QLabel(tr("Adapter"));
   m_bluetooth_adapters = new QComboBox();
+  m_bluetooth_adapters_refresh = new NonDefaultQPushButton(tr("Refresh"));
   m_wiimote_sync = new NonDefaultQPushButton(tr("Sync"));
   m_wiimote_reset = new NonDefaultQPushButton(tr("Reset"));
   m_wiimote_refresh = new NonDefaultQPushButton(tr("Refresh"));
@@ -172,7 +212,8 @@ void WiimoteControllersWidget::CreateLayout()
 
   int adapter_row = m_wiimote_layout->rowCount();
   m_wiimote_layout->addWidget(m_bluetooth_adapters_label, adapter_row, 1, 1, 1);
-  m_wiimote_layout->addWidget(m_bluetooth_adapters, adapter_row, 2, 1, 2);
+  m_wiimote_layout->addWidget(m_bluetooth_adapters, adapter_row, 2, 1, 1);
+  m_wiimote_layout->addWidget(m_bluetooth_adapters_refresh, adapter_row, 3, 1, 1);
 
   int sync_row = m_wiimote_layout->rowCount();
   m_wiimote_layout->addWidget(m_wiimote_pt_labels[0], sync_row, 1, 1, 2);
@@ -242,6 +283,8 @@ void WiimoteControllersWidget::ConnectWidgets()
           &WiimoteControllersWidget::SaveSettings);
   connect(m_bluetooth_adapters, &QComboBox::activated, this,
           &WiimoteControllersWidget::OnBluetoothPassthroughDeviceChanged);
+  connect(m_bluetooth_adapters_refresh, &QPushButton::clicked, this,
+          &WiimoteControllersWidget::StartBluetoothAdapterRefresh);
   connect(m_wiimote_sync, &QPushButton::clicked, this,
           &WiimoteControllersWidget::OnBluetoothPassthroughSyncPressed);
   connect(m_wiimote_reset, &QPushButton::clicked, this,
@@ -339,6 +382,19 @@ void WiimoteControllersWidget::OnWiimoteConfigure(size_t index)
   window->show();
 }
 
+void WiimoteControllersWidget::UpdateBluetoothAdapterWidgetsEnabled(const Core::State state)
+{
+  const bool running = state != Core::State::Uninitialized;
+  const bool running_wii = running && Core::System::GetInstance().IsWii();
+  const bool enable_adapter_refresh = m_wiimote_passthrough->isChecked() && !running_wii;
+  const bool enable_adapter_selection =
+      enable_adapter_refresh && !m_bluetooth_adapter_scan_in_progress;
+
+  m_bluetooth_adapters_label->setEnabled(enable_adapter_selection);
+  m_bluetooth_adapters->setEnabled(enable_adapter_selection);
+  m_bluetooth_adapters_refresh->setEnabled(enable_adapter_refresh);
+}
+
 void WiimoteControllersWidget::LoadSettings(Core::State state)
 {
   for (size_t i = 0; i < m_wiimote_groups.size(); i++)
@@ -369,15 +425,13 @@ void WiimoteControllersWidget::LoadSettings(Core::State state)
   m_wiimote_passthrough->setEnabled(!running);
 
   const bool running_gc = running && !Core::System::GetInstance().IsWii();
-  const bool running_wii = running && Core::System::GetInstance().IsWii();
   const bool enable_passthrough = m_wiimote_passthrough->isChecked() && !running_gc;
-  const bool enable_adapter_selection = m_wiimote_passthrough->isChecked() && !running_wii;
   const bool enable_emu_bt = !m_wiimote_passthrough->isChecked() && !running_gc;
   const bool is_netplay = NetPlay::IsNetPlayRunning();
   const bool running_netplay = running && is_netplay;
 
-  m_bluetooth_adapters_label->setEnabled(enable_adapter_selection);
-  m_bluetooth_adapters->setEnabled(enable_adapter_selection);
+  UpdateBluetoothAdapterWidgetsEnabled(state);
+
   m_wiimote_sync->setEnabled(enable_passthrough);
   m_wiimote_reset->setEnabled(enable_passthrough);
 
diff --git a/Source/Core/DolphinQt/Config/WiimoteControllersWidget.h b/Source/Core/DolphinQt/Config/WiimoteControllersWidget.h
index bb2f50caad..b174c1b786 100644
--- a/Source/Core/DolphinQt/Config/WiimoteControllersWidget.h
+++ b/Source/Core/DolphinQt/Config/WiimoteControllersWidget.h
@@ -3,9 +3,12 @@
 
 #pragma once
 
+#include <array>
+
 #include <QWidget>
 
-#include <array>
+#include "Common/WorkQueueThread.h"
+#include "Core/IOS/USB/Bluetooth/BTReal.h"
 
 class QCheckBox;
 class QComboBox;
@@ -26,17 +29,21 @@ class WiimoteControllersWidget final : public QWidget
   Q_OBJECT
 public:
   explicit WiimoteControllersWidget(QWidget* parent);
+  ~WiimoteControllersWidget();
 
   void UpdateBluetoothAvailableStatus();
-  void RefreshBluetoothAdapters();
 
 private:
   void SaveSettings();
   void OnBluetoothPassthroughDeviceChanged(int index);
   void OnBluetoothPassthroughSyncPressed();
   void OnBluetoothPassthroughResetPressed();
+  void OnBluetoothAdapterRefreshComplete(
+      const std::vector<IOS::HLE::BluetoothRealDevice::BluetoothDeviceInfo>& devices);
   void OnWiimoteRefreshPressed();
   void OnWiimoteConfigure(size_t index);
+  void StartBluetoothAdapterRefresh();
+  void UpdateBluetoothAdapterWidgetsEnabled(Core::State state);
 
   void CreateLayout();
   void ConnectWidgets();
@@ -50,10 +57,14 @@ private:
   std::array<QHBoxLayout*, 4> m_wiimote_groups;
   std::array<QLabel*, 2> m_wiimote_pt_labels;
 
+  Common::AsyncWorkThreadSP m_bluetooth_adapter_refresh_thread;
+  bool m_bluetooth_adapter_scan_in_progress = false;
+
   QRadioButton* m_wiimote_emu;
   QRadioButton* m_wiimote_passthrough;
   QLabel* m_bluetooth_adapters_label;
   QComboBox* m_bluetooth_adapters;
+  QPushButton* m_bluetooth_adapters_refresh;
   QPushButton* m_wiimote_sync;
   QPushButton* m_wiimote_reset;
   QCheckBox* m_wiimote_continuous_scanning;