VFS perf fixes, icon/stylesheet compat, download filename fix

VFS:
- Open backing fd at mo2_open time for read-only handles so mo2_read can
  splice without re-opening the file on every read call.
- Bump RLIMIT_NOFILE at mount time to fit the resulting fd pressure when
  the game keeps hundreds of BSAs open.
- Dedicated node_cache_mutex so resolveByInode / mo2_lookup stop racing
  unordered_map writes while multiple tree_mutex readers are active.
- max_read=1MB + matching conn->max_read and raised max_readahead/max_write
  so the kernel merges Wine's small sequential reads into bigger FUSE
  requests.
- Per-op wall-clock counters in mo2_init() logs so we can distinguish VFS
  latency from game-side work.

Proton launch:
- Write dxvk.conf to the prefix and set DXVK_CONFIG_FILE to force
  dxvk.enableGraphicsPipelineLibrary=False, avoiding long GPL compile
  stalls on first run.

UI / plugin compat:
- Clamp IconDelegate's per-icon width to [8, 16] so narrow content
  columns don't trigger QIcon::pixmap(0,0) returning null and logging
  "failed to load icon" every repaint.
- Pre-create lowercase symlinks in the stylesheet directory so QSS files
  authored on Windows resolve url(foo.svg) when on-disk files are Foo.svg.
- Flip content icons empty-chessboard.png and facegen.png to 8-bit RGBA
  so Qt's built-in PNG reader loads them uniformly.
- Add mobase.Version.canonicalString shim for legacy Python plugins that
  still call the old VersionInfo method on appVersion()'s return.
- BSPluginList: compare normalized plugin name lists instead of byte
  hashes so the post-run case-fix refresh stops spuriously firing the
  "load order changed" dialog.
- BSPluginList disabled by default.

Download manager:
- Parse CDN URL with QUrl + QUrlQuery and read the filename from the
  response-content-disposition query param (RFC 6266 quoted / unquoted /
  ext-value forms), not QFileInfo on the raw URL.
- When the API or URL gives us a CDN object key (no archive extension),
  prefer the actual Content-Disposition header from the live response in
  metaDataChanged and downloadFinished.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

9 files changed, 840 insertions, 0 deletions

diff --git a/libs/installer_bsplugins/src/MOPlugin/BSPlugins.cpp b/libs/installer_bsplugins/src/MOPlugin/BSPlugins.cpp
new file mode 100644
index 0000000..442fbcf
--- /dev/null
+++ b/libs/installer_bsplugins/src/MOPlugin/BSPlugins.cpp
@@ -0,0 +1,79 @@
+#include "BSPlugins.h"
+
+#include "BSPluginList/PluginsWidget.h"
+#include "Settings.h"
+
+using namespace Qt::Literals::StringLiterals;
+
+bool BSPlugins::initPlugin(MOBase::IOrganizer* organizer)
+{
+  m_Organizer = organizer;
+  Settings::init(organizer);
+  return true;
+}
+
+QString BSPlugins::name() const
+{
+  return NAME;
+}
+
+std::vector<std::shared_ptr<const MOBase::IPluginRequirement>>
+BSPlugins::requirements() const
+{
+  return {Requirements::gameDependency(
+      {u"Oblivion"_s, u"Fallout 3"_s, u"New Vegas"_s, u"Skyrim"_s, u"Enderal"_s,
+       u"Fallout 4"_s, u"Skyrim Special Edition"_s, u"Enderal Special Edition"_s,
+       u"Skyrim VR"_s, u"Fallout 4 VR"_s, u"Starfield"_s, u"Oblivion Remastered"_s})};
+}
+
+QString BSPlugins::author() const
+{
+  return u"Parapets"_s;
+}
+
+QString BSPlugins::description() const
+{
+  return tr("Manages plugin load order for BGS game engines");
+}
+
+MOBase::VersionInfo BSPlugins::version() const
+{
+  return MOBase::VersionInfo(0, 1, 5, 0, MOBase::VersionInfo::RELEASE_BETA);
+}
+
+QList<MOBase::PluginSetting> BSPlugins::settings() const
+{
+  return {
+      {u"enable_sort_button"_s, u"Enable the Sort button in the Plugins panel"_s, false},
+      {u"external_change_warning"_s,
+       u"Warn if load order changes while running an executable"_s, true},
+      {u"loot_show_dirty"_s,
+       u"LOOT: Show information about plugins that can be cleaned"_s, true},
+      {u"loot_show_messages"_s,
+       u"LOOT: Show general information and warning messages"_s, true},
+      {u"loot_show_problems"_s,
+       u"LOOT: Show information about incompatibilities and missing masters"_s, true},
+  };
+}
+
+bool BSPlugins::enabledByDefault() const
+{
+  return false;
+}
+
+QWidget* BSPlugins::createWidget(IPanelInterface* panelInterface, QWidget* parent)
+{
+  const auto widget =
+      new BSPluginList::PluginsWidget(m_Organizer, panelInterface, parent);
+  return widget;
+}
+
+QString BSPlugins::label() const
+{
+  return tr("Plugins");
+}
+
+IPluginPanel::Position BSPlugins::position() const
+{
+  return Position::inPlaceOf(u"espTab"_s);
+}
diff --git a/libs/installer_bsplugins/src/MOPlugin/BSPlugins.h b/libs/installer_bsplugins/src/MOPlugin/BSPlugins.h
new file mode 100644
index 0000000..81248d7
--- /dev/null
+++ b/libs/installer_bsplugins/src/MOPlugin/BSPlugins.h
@@ -0,0 +1,39 @@
+#ifndef BSPLUGINS_H
+#define BSPLUGINS_H
+
+#include "IPluginPanel.h"
+
+class BSPlugins final : public IPluginPanel
+{
+  Q_OBJECT
+  Q_INTERFACES(MOBase::IPlugin IPluginPanel)
+  Q_PLUGIN_METADATA(IID "org.tannin.BSPlugins" FILE "bsplugins.json")
+
+public:
+  inline static const QString NAME = QStringLiteral("Bethesda Plugin Manager");
+
+  BSPlugins() = default;
+
+  // IPlugin
+
+  QString name() const override;
+  std::vector<std::shared_ptr<const MOBase::IPluginRequirement>>
+  requirements() const override;
+  QString author() const override;
+  QString description() const override;
+  MOBase::VersionInfo version() const override;
+  QList<MOBase::PluginSetting> settings() const override;
+  bool enabledByDefault() const override;
+
+  // IPluginPanel
+
+  bool initPlugin(MOBase::IOrganizer* organizer);
+  QWidget* createWidget(IPanelInterface* panelInterface, QWidget* parent) override;
+  QString label() const override;
+  Position position() const override;
+
+private:
+  MOBase::IOrganizer* m_Organizer;
+};
+
+#endif  // BSPLUGINS_H
diff --git a/libs/installer_bsplugins/src/MOPlugin/IPanelInterface.h b/libs/installer_bsplugins/src/MOPlugin/IPanelInterface.h
new file mode 100644
index 0000000..2904e8e
--- /dev/null
+++ b/libs/installer_bsplugins/src/MOPlugin/IPanelInterface.h
@@ -0,0 +1,30 @@
+#ifndef IPANELINTERFACE_H
+#define IPANELINTERFACE_H
+
+#include <QList>
+#include <QString>
+#include <functional>
+
+class IPanelInterface
+{
+public:
+  // user selected files in the panel whose origins should be highlighted
+  //
+  virtual void setSelectedFiles(const QList<QString>& selectedFiles) = 0;
+
+  // request mod info dialog for origin of file
+  //
+  virtual void displayOriginInformation(const QString& file) = 0;
+
+  virtual bool onPanelActivated(const std::function<void()>& func) = 0;
+
+  virtual bool
+  onSelectedOriginsChanged(const std::function<void(const QList<QString>&)>& func) = 0;
+
+  // HACK: this shouldn't be here, but the MOBase::IPluginList::setState function does
+  // not cause the list to notify its onPluginStateChanged listeners, so this will work
+  // around that
+  virtual void setPluginState(const QString& name, bool enable) = 0;
+};
+
+#endif  // IPANELINTERFACE_H
diff --git a/libs/installer_bsplugins/src/MOPlugin/IPluginPanel.cpp b/libs/installer_bsplugins/src/MOPlugin/IPluginPanel.cpp
new file mode 100644
index 0000000..904f049
--- /dev/null
+++ b/libs/installer_bsplugins/src/MOPlugin/IPluginPanel.cpp
@@ -0,0 +1,99 @@
+#include "IPluginPanel.h"
+#include "MOPanelInterface.h"
+
+#include <QTabWidget>
+
+using namespace Qt::Literals::StringLiterals;
+
+IPluginPanel::Position IPluginPanel::Position::before(const QString& panelName)
+{
+  return {Order::Before, panelName};
+}
+
+IPluginPanel::Position IPluginPanel::Position::after(const QString& panelName)
+{
+  return {Order::After, panelName};
+}
+
+IPluginPanel::Position IPluginPanel::Position::inPlaceOf(const QString& panelName)
+{
+  return {Order::InPlaceOf, panelName};
+}
+
+IPluginPanel::Position IPluginPanel::Position::atStart()
+{
+  return {Order::AtStart, {}};
+}
+
+IPluginPanel::Position IPluginPanel::Position::atEnd()
+{
+  return {Order::AtEnd, {}};
+}
+
+bool IPluginPanel::init(MOBase::IOrganizer* organizer)
+{
+  if (organizer == nullptr) {
+    return false;
+  }
+
+  organizer->onUserInterfaceInitialized([this, organizer](QMainWindow* mainWindow) {
+    const auto tabWidget = mainWindow->findChild<QTabWidget*>(u"tabWidget"_s);
+
+    if (tabWidget == nullptr) {
+      return;
+    }
+
+    const auto intfc    = new MOPanelInterface(organizer, mainWindow);
+    const auto widget   = this->createWidget(intfc, tabWidget);
+    const auto label    = this->label();
+    const auto position = this->position();
+
+    switch (position.order_) {
+    case Order::Before: {
+      const auto refTab = !position.reference_.isNull()
+                              ? tabWidget->findChild<QWidget*>(position.reference_)
+                              : nullptr;
+      if (refTab != nullptr) {
+        if (const int index = tabWidget->indexOf(refTab); index != -1) {
+          const int currentIndex = tabWidget->currentIndex();
+          tabWidget->insertTab(index, widget, label);
+          if (index <= currentIndex) {
+            tabWidget->setCurrentIndex(currentIndex);
+          }
+        }
+        break;
+      }
+    }
+      [[fallthrough]];
+    case Order::AtStart: {
+      const int currentIndex = tabWidget->currentIndex();
+      tabWidget->insertTab(0, widget, label);
+      tabWidget->setCurrentIndex(currentIndex);
+    } break;
+    case Order::InPlaceOf:
+    case Order::After: {
+      const auto refTab = !position.reference_.isNull()
+                              ? tabWidget->findChild<QWidget*>(position.reference_)
+                              : nullptr;
+
+      if (refTab != nullptr) {
+        if (const int index = tabWidget->indexOf(refTab); index != -1) {
+          tabWidget->insertTab(index + 1, widget, label);
+          if (position.order_ == Order::InPlaceOf) {
+            tabWidget->removeTab(index);
+          }
+        }
+        break;
+      }
+    }
+      [[fallthrough]];
+    case Order::AtEnd: {
+      tabWidget->addTab(widget, label);
+    } break;
+    }
+
+    intfc->assignWidget(tabWidget, widget);
+  });
+
+  return this->initPlugin(organizer);
+}
diff --git a/libs/installer_bsplugins/src/MOPlugin/IPluginPanel.h b/libs/installer_bsplugins/src/MOPlugin/IPluginPanel.h
new file mode 100644
index 0000000..0c73a9c
--- /dev/null
+++ b/libs/installer_bsplugins/src/MOPlugin/IPluginPanel.h
@@ -0,0 +1,47 @@
+#ifndef IPLUGINPANEL_H
+#define IPLUGINPANEL_H
+
+#include "IPanelInterface.h"
+
+#include <iplugin.h>
+
+class IPluginPanel : public QObject, public MOBase::IPlugin
+{
+  Q_INTERFACES(MOBase::IPlugin)
+
+public:
+  enum class Order
+  {
+    Before,
+    AtStart,
+    InPlaceOf,
+    After,
+    AtEnd,
+  };
+
+  struct Position
+  {
+    Order order_;
+    QString reference_;
+
+    static Position before(const QString& panelName);
+    static Position after(const QString& panelName);
+    static Position inPlaceOf(const QString& panelName);
+    static Position atStart();
+    static Position atEnd();
+  };
+
+  bool init(MOBase::IOrganizer* organizer) final;
+
+  virtual bool initPlugin(MOBase::IOrganizer* organizer) = 0;
+
+  virtual QWidget* createWidget(IPanelInterface* callbacks, QWidget* parent) = 0;
+
+  virtual QString label() const = 0;
+
+  virtual Position position() const = 0;
+};
+
+Q_DECLARE_INTERFACE(IPluginPanel, "org.tannin.IPluginPanel/1.0")
+
+#endif  // IPLUGINPANEL_H
diff --git a/libs/installer_bsplugins/src/MOPlugin/MOPanelInterface.cpp b/libs/installer_bsplugins/src/MOPlugin/MOPanelInterface.cpp
new file mode 100644
index 0000000..c8bb242
--- /dev/null
+++ b/libs/installer_bsplugins/src/MOPlugin/MOPanelInterface.cpp
@@ -0,0 +1,144 @@
+#include "MOPanelInterface.h"
+
+#include <log.h>
+
+#include <algorithm>
+#include <functional>
+#include <iterator>
+
+using namespace Qt::Literals::StringLiterals;
+
+MOPanelInterface::MOPanelInterface(MOBase::IOrganizer* organizer,
+                                   QMainWindow* mainWindow)
+    : m_ModList{organizer->modList()}, m_PluginList{organizer->pluginList()},
+      m_ModListView{mainWindow->findChild<QTreeView*>(u"modList"_s)},
+      m_PluginListView{mainWindow->findChild<QTreeView*>(u"espList"_s)}
+{
+  if (m_ModListView) {
+    QObject::connect(m_ModListView, &QTreeView::collapsed, this,
+                     &MOPanelInterface::onModSeparatorCollapsed);
+    QObject::connect(m_ModListView, &QTreeView::expanded, this,
+                     &MOPanelInterface::onModSeparatorExpanded);
+    QObject::connect(m_ModListView->selectionModel(),
+                     &QItemSelectionModel::selectionChanged, this,
+                     &MOPanelInterface::onModSelectionChanged);
+  }
+}
+
+MOPanelInterface::~MOPanelInterface() noexcept
+{
+  m_SelectedOriginsChanged.disconnect_all_slots();
+}
+
+void MOPanelInterface::assignWidget(QTabWidget* tabWidget, QWidget* panel)
+{
+  QObject::connect(tabWidget, &QTabWidget::currentChanged,
+                   [this, tabWidget, panel](int index) {
+                     QWidget* const currentWidget = tabWidget->widget(index);
+                     if (currentWidget == panel) {
+                       m_PanelActivated();
+                     }
+                   });
+}
+
+void MOPanelInterface::setSelectedFiles(const QList<QString>& selectedFiles)
+{
+  if (!m_PluginListView) {
+    return;
+  }
+
+  QItemSelection selection;
+  const auto model = m_PluginListView->model();
+  for (int row = 0, count = model->rowCount(); row < count; ++row) {
+    const auto index = model->index(row, 0);
+    if (selectedFiles.contains(index.data(Qt::DisplayRole))) {
+      const auto end = model->index(row, model->columnCount() - 1);
+      selection.select(index, end);
+    }
+  }
+
+  m_PluginListView->selectionModel()->select(selection,
+                                             QItemSelectionModel::ClearAndSelect);
+}
+
+// FIXME: only works for files in the plugins panel
+void MOPanelInterface::displayOriginInformation(const QString& file)
+{
+  const auto model = m_PluginListView->model();
+  for (int row = 0, count = model->rowCount(); row < count; ++row) {
+    const auto index = model->index(row, 0);
+    const auto other = index.data(Qt::DisplayRole).toString();
+    if (file.compare(other, Qt::CaseInsensitive) == 0) {
+      m_PluginListView->selectionModel()->select(
+          QItemSelection(index, model->index(row, model->columnCount() - 1)),
+          QItemSelectionModel::ClearAndSelect);
+      m_PluginListView->selectionModel()->setCurrentIndex(index,
+                                                          QItemSelectionModel::Current);
+      m_PluginListView->doubleClicked(index);
+      return;
+    }
+  }
+
+  MOBase::log::warn("failed to open origin info for \"{}\"", file);
+}
+
+bool MOPanelInterface::onPanelActivated(const std::function<void()>& func)
+{
+  auto connection = m_PanelActivated.connect(func);
+  return connection.connected();
+}
+
+bool MOPanelInterface::onSelectedOriginsChanged(
+    const std::function<void(const QList<QString>&)>& func)
+{
+  auto connection = m_SelectedOriginsChanged.connect(func);
+  return connection.connected();
+}
+
+void MOPanelInterface::setPluginState(const QString& name, bool enable)
+{
+  const auto model = m_PluginListView->model();
+  for (int i = 0, count = model->rowCount(); i < count; ++i) {
+    const auto index = model->index(i, 0);
+    if (index.data().toString().compare(name, Qt::CaseInsensitive) == 0) {
+      model->setData(index, enable ? Qt::Checked : Qt::Unchecked, Qt::CheckStateRole);
+    }
+  }
+}
+
+void MOPanelInterface::onModSeparatorCollapsed(const QModelIndex& index)
+{
+  if (m_ModListView->selectionModel()->isSelected(index)) {
+    onModSelectionChanged();
+  }
+}
+
+void MOPanelInterface::onModSeparatorExpanded(const QModelIndex& index)
+{
+  if (m_ModListView->selectionModel()->isSelected(index)) {
+    onModSelectionChanged();
+  }
+}
+
+void MOPanelInterface::onModSelectionChanged()
+{
+  QList<QString> origins;
+  std::function<void(const QModelIndex&)> addOrigins;
+  addOrigins = [&](const QModelIndex& index) {
+    if (index.model()->hasChildren(index)) {
+      if (m_ModListView->isExpanded(index)) {
+        return;
+      }
+
+      for (int i = 0, count = index.model()->rowCount(index); i < count; ++i) {
+        addOrigins(index.model()->index(i, 0, index));
+      }
+    } else {
+      origins.append(index.data(Qt::DisplayRole).toString());
+    }
+  };
+
+  const auto indexes = m_ModListView->selectionModel()->selectedRows();
+  std::ranges::for_each(indexes, addOrigins);
+  m_SelectedOriginsChanged(origins);
+}
diff --git a/libs/installer_bsplugins/src/MOPlugin/MOPanelInterface.h b/libs/installer_bsplugins/src/MOPlugin/MOPanelInterface.h
new file mode 100644
index 0000000..184d087
--- /dev/null
+++ b/libs/installer_bsplugins/src/MOPlugin/MOPanelInterface.h
@@ -0,0 +1,60 @@
+#ifndef MOPANELINTERFACE_H
+#define MOPANELINTERFACE_H
+
+#include "IPanelInterface.h"
+
+#include <imoinfo.h>
+
+#include <boost/signals2.hpp>
+
+#include <QMainWindow>
+#include <QTreeView>
+
+class MOPanelInterface final : public QObject, public IPanelInterface
+{
+  Q_OBJECT
+
+public:
+  using SignalPanelActivated = boost::signals2::signal<void()>;
+  using SignalSelectedOriginsChanged =
+      boost::signals2::signal<void(const QList<QString>&)>;
+
+  MOPanelInterface(MOBase::IOrganizer* organizer, QMainWindow* mainWindow);
+
+  MOPanelInterface(const MOPanelInterface&) = delete;
+  MOPanelInterface(MOPanelInterface&&)      = delete;
+
+  ~MOPanelInterface() noexcept;
+
+  MOPanelInterface& operator=(const MOPanelInterface&) = delete;
+  MOPanelInterface& operator=(MOPanelInterface&&)      = delete;
+
+  void assignWidget(QTabWidget* tabWidget, QWidget* panel);
+
+  void setSelectedFiles(const QList<QString>& selectedFiles) override;
+
+  void displayOriginInformation(const QString& file) override;
+
+  bool onPanelActivated(const std::function<void()>& func) override;
+
+  bool onSelectedOriginsChanged(
+      const std::function<void(const QList<QString>&)>& func) override;
+
+  void setPluginState(const QString& name, bool enable) override;
+
+private slots:
+  void onModSeparatorCollapsed(const QModelIndex& index);
+  void onModSeparatorExpanded(const QModelIndex& index);
+  void onModSelectionChanged();
+
+private:
+  MOBase::IModList* m_ModList;
+  MOBase::IPluginList* m_PluginList;
+  QTreeView* m_ModListView;
+  QTreeView* m_PluginListView;
+
+  SignalPanelActivated m_PanelActivated;
+  SignalSelectedOriginsChanged m_SelectedOriginsChanged;
+};
+
+#endif  // MOPANELINTERFACE_H
diff --git a/libs/installer_bsplugins/src/MOPlugin/Settings.cpp b/libs/installer_bsplugins/src/MOPlugin/Settings.cpp
new file mode 100644
index 0000000..8ca77ec
--- /dev/null
+++ b/libs/installer_bsplugins/src/MOPlugin/Settings.cpp
@@ -0,0 +1,254 @@
+#include "Settings.h"
+#include "BSPlugins.h"
+
+#include <QDir>
+#include <QStandardPaths>
+#include <QTreeView>
+
+Settings* Instance = nullptr;
+
+static QString findIniPath(MOBase::IOrganizer* organizer)
+{
+  // FIXME: we can't find non-portable instance paths
+  return QDir(organizer->basePath()).filePath("ModOrganizer.ini");
+}
+
+Settings::Settings(MOBase::IOrganizer* organizer)
+    : Organizer{organizer}, MOSettings{findIniPath(organizer), QSettings::IniFormat}
+{
+  organizer->onPluginSettingChanged(
+      std::bind_front(&Settings::onPluginSettingChanged, this));
+}
+
+void Settings::init(MOBase::IOrganizer* organizer)
+{
+  Instance = new Settings(organizer);
+}
+
+Settings* Settings::instance()
+{
+  return Instance;
+}
+
+void Settings::set(const QString& setting, const QVariant& value)
+{
+  Organizer->setPersistent(BSPlugins::NAME, setting, value);
+}
+
+[[nodiscard]] QVariant Settings::get(const QString& setting, const QVariant& def) const
+{
+  return Organizer->persistent(BSPlugins::NAME, setting, def);
+}
+
+bool Settings::onSettingChanged(
+    const std::function<void(const QString&, const QVariant&, const QVariant&)>& func)
+{
+  auto connection = SettingChanged.connect(func);
+  return connection.connected();
+}
+
+QColor Settings::overwrittenLooseFilesColor() const
+{
+  return MOSettings.value("Settings/overwrittenLooseFilesColor", QColor(0, 255, 0, 64))
+      .value<QColor>();
+}
+
+QColor Settings::overwritingLooseFilesColor() const
+{
+  return MOSettings.value("Settings/overwritingLooseFilesColor", QColor(255, 0, 0, 64))
+      .value<QColor>();
+}
+
+QColor Settings::overwrittenArchiveFilesColor() const
+{
+  return MOSettings
+      .value("Settings/overwrittenArchiveFilesColor", QColor(0, 255, 255, 64))
+      .value<QColor>();
+}
+
+QColor Settings::overwritingArchiveFilesColor() const
+{
+  return MOSettings
+      .value("Settings/overwritingArchiveFilesColor", QColor(255, 0, 255, 64))
+      .value<QColor>();
+}
+
+QColor Settings::containedColor() const
+{
+  return MOSettings.value("Settings/containedColor", QColor(0, 0, 255, 64))
+      .value<QColor>();
+}
+
+bool Settings::offlineMode() const
+{
+  return MOSettings.value("Settings/offline_mode", false).value<bool>();
+}
+
+lootcli::LogLevels Settings::lootLogLevel() const
+{
+  // LOOT integration removed for Fluorine port — return default.
+  return lootcli::LogLevels::Info;
+}
+
+bool Settings::externalChangeWarning() const
+{
+  return Organizer->pluginSetting(BSPlugins::NAME, "external_change_warning")
+      .value<bool>();
+}
+
+bool Settings::enableSortButton() const
+{
+  return Organizer->pluginSetting(BSPlugins::NAME, "enable_sort_button").value<bool>();
+}
+
+bool Settings::lootShowDirty() const
+{
+  return Organizer->pluginSetting(BSPlugins::NAME, "loot_show_dirty").value<bool>();
+}
+
+bool Settings::lootShowMessages() const
+{
+  return Organizer->pluginSetting(BSPlugins::NAME, "loot_show_messages").value<bool>();
+}
+
+bool Settings::lootShowProblems() const
+{
+  return Organizer->pluginSetting(BSPlugins::NAME, "loot_show_problems").value<bool>();
+}
+
+static QString stateSettingName(const QHeaderView* header)
+{
+  return header->parent()->objectName() + "_header";
+}
+
+static void visitRows(const QAbstractItemModel* model,
+                      std::function<void(const QModelIndex&)> visit,
+                      const QModelIndex& root = QModelIndex())
+{
+  if (root.isValid()) {
+    visit(root);
+  }
+
+  for (int i = 0, count = model->rowCount(root); i < count; ++i) {
+    const auto idx = model->index(i, 0, root);
+    visitRows(model, visit, idx);
+  }
+}
+
+void Settings::saveTreeExpandState(const QTreeView* view)
+{
+  QVariantList expanded;
+  visitRows(view->model(), [&expanded, view](const QModelIndex& index) {
+    if (view->isExpanded(index)) {
+      expanded.append(index.data());
+    }
+  });
+
+  Organizer->setPersistent(BSPlugins::NAME, view->objectName() + "_expanded", expanded);
+}
+
+void Settings::restoreTreeExpandState(QTreeView* view) const
+{
+  // empty is serialized as invalid
+  const QVariant state = Organizer->persistent(
+      BSPlugins::NAME, view->objectName() + "_expanded", QVariantList());
+
+  if (!state.isValid()) {
+    view->collapseAll();
+  } else {
+    const auto expanded = state.toList();
+    if (!expanded.isEmpty()) {
+      view->collapseAll();
+      visitRows(view->model(), [&expanded, view](const QModelIndex& index) {
+        if (expanded.contains(index.data())) {
+          view->expand(index);
+        }
+      });
+    }
+  }
+}
+
+void Settings::saveState(const QHeaderView* header)
+{
+  Organizer->setPersistent(BSPlugins::NAME, stateSettingName(header),
+                           header->saveState());
+}
+
+void Settings::restoreState(QHeaderView* header) const
+{
+  const auto state =
+      Organizer->persistent(BSPlugins::NAME, stateSettingName(header)).toByteArray();
+  if (!state.isEmpty()) {
+    header->restoreState(state);
+  }
+}
+
+static QString stateSettingName(const QSplitter* splitter)
+{
+  return splitter->parentWidget()->objectName() + "_splitter";
+}
+
+void Settings::saveState(const QSplitter* splitter)
+{
+  Organizer->setPersistent(BSPlugins::NAME, stateSettingName(splitter),
+                           splitter->saveState());
+}
+
+void Settings::restoreState(QSplitter* splitter) const
+{
+  const auto state =
+      Organizer->persistent(BSPlugins::NAME, stateSettingName(splitter)).toByteArray();
+  if (!state.isEmpty()) {
+    splitter->restoreState(state);
+  }
+}
+
+static QString stateSettingName(const MOBase::ExpanderWidget* expander)
+{
+  return expander->button()->objectName() + "_state";
+}
+
+void Settings::saveState(const MOBase::ExpanderWidget* expander)
+{
+  Organizer->setPersistent(BSPlugins::NAME, stateSettingName(expander),
+                           expander->saveState());
+}
+
+void Settings::restoreState(MOBase::ExpanderWidget* expander) const
+{
+  const auto state =
+      Organizer->persistent(BSPlugins::NAME, stateSettingName(expander)).toByteArray();
+  if (!state.isEmpty()) {
+    expander->restoreState(state);
+  }
+}
+
+static QString geometrySettingName(const QDialog* dialog)
+{
+  return dialog->objectName() + "_geometry";
+}
+
+void Settings::saveGeometry(const QDialog* dialog)
+{
+  Organizer->setPersistent(BSPlugins::NAME, geometrySettingName(dialog),
+                           dialog->saveGeometry());
+}
+
+void Settings::restoreGeometry(QDialog* dialog) const
+{
+  const auto geometry =
+      Organizer->persistent(BSPlugins::NAME, geometrySettingName(dialog)).toByteArray();
+  if (!geometry.isEmpty()) {
+    dialog->restoreGeometry(geometry);
+  }
+}
+
+void Settings::onPluginSettingChanged(const QString& pluginName, const QString& key,
+                                      const QVariant& oldValue,
+                                      const QVariant& newValue)
+{
+  if (pluginName != BSPlugins::NAME)
+    return;
+
+  SettingChanged(key, oldValue, newValue);
+}
diff --git a/libs/installer_bsplugins/src/MOPlugin/Settings.h b/libs/installer_bsplugins/src/MOPlugin/Settings.h
new file mode 100644
index 0000000..cf93a29
--- /dev/null
+++ b/libs/installer_bsplugins/src/MOPlugin/Settings.h
@@ -0,0 +1,88 @@
+#ifndef SETTINGS_H
+#define SETTINGS_H
+
+#include "GUI/IGeometrySettings.h"
+#include "GUI/IStateSettings.h"
+
+#include <expanderwidget.h>
+#include <imoinfo.h>
+#include <lootcli/lootcli.h>
+
+#include <boost/signals2.hpp>
+
+#include <QColor>
+#include <QDialog>
+#include <QHeaderView>
+#include <QSettings>
+#include <QSplitter>
+#include <QTreeView>
+
+class Settings final : public GUI::IGeometrySettings<QDialog>,
+                       public GUI::IStateSettings<QHeaderView>,
+                       public GUI::IStateSettings<QSplitter>,
+                       public GUI::IStateSettings<MOBase::ExpanderWidget>
+{
+public:
+  using SignalSettingChanged =
+      boost::signals2::signal<void(const QString&, const QVariant&, const QVariant&)>;
+
+  static void init(MOBase::IOrganizer* organizer);
+
+  [[nodiscard]] static Settings* instance();
+
+  void set(const QString& setting, const QVariant& value);
+
+  [[nodiscard]] QVariant get(const QString& setting, const QVariant& def) const;
+
+  template <typename T>
+  [[nodiscard]] T get(const QString& setting, const QVariant& def) const
+  {
+    return get(setting, def).value<T>();
+  }
+
+  bool onSettingChanged(const std::function<void(const QString&, const QVariant&,
+                                                 const QVariant&)>& func);
+
+  [[nodiscard]] QColor overwrittenLooseFilesColor() const;
+  [[nodiscard]] QColor overwritingLooseFilesColor() const;
+  [[nodiscard]] QColor overwrittenArchiveFilesColor() const;
+  [[nodiscard]] QColor overwritingArchiveFilesColor() const;
+  [[nodiscard]] QColor containedColor() const;
+  [[nodiscard]] bool offlineMode() const;
+  [[nodiscard]] lootcli::LogLevels lootLogLevel() const;
+
+  [[nodiscard]] bool externalChangeWarning() const;
+  [[nodiscard]] bool enableSortButton() const;
+  [[nodiscard]] bool lootShowDirty() const;
+  [[nodiscard]] bool lootShowMessages() const;
+  [[nodiscard]] bool lootShowProblems() const;
+
+  void saveTreeExpandState(const QTreeView* view);
+  void restoreTreeExpandState(QTreeView* view) const;
+
+  void saveState(const QHeaderView* header) override;
+  void restoreState(QHeaderView* header) const override;
+
+  void saveState(const QSplitter* splitter) override;
+  void restoreState(QSplitter* splitter) const override;
+
+  void saveState(const MOBase::ExpanderWidget* expander) override;
+  void restoreState(MOBase::ExpanderWidget* expander) const override;
+
+  // IGeometrySettings<QDialog>
+
+  void saveGeometry(const QDialog* dialog) override;
+  void restoreGeometry(QDialog* dialog) const override;
+
+private:
+  void onPluginSettingChanged(const QString& pluginName, const QString& key,
+                              const QVariant& oldValue, const QVariant& newValue);
+
+  explicit Settings(MOBase::IOrganizer* organizer);
+
+  MOBase::IOrganizer* Organizer;
+  QSettings MOSettings;
+  SignalSettingChanged SettingChanged;
+};
+
+#endif  // SETTINGS_H