ThemeEditor: Extract most logic into a MainWidget class

4 files changed, 476 insertions, 386 deletions

diff --git a/Userland/Applications/ThemeEditor/CMakeLists.txt b/Userland/Applications/ThemeEditor/CMakeLists.txt
index 0ccc03e470..92698eeee7 100644
--- a/Userland/Applications/ThemeEditor/CMakeLists.txt
+++ b/Userland/Applications/ThemeEditor/CMakeLists.txt
@@ -6,8 +6,9 @@ serenity_component(
 compile_gml(ThemeEditor.gml ThemeEditorGML.h theme_editor_gml)
 
 set(SOURCES
-    PreviewWidget.cpp
     main.cpp
+    MainWidget.cpp
+    PreviewWidget.cpp
     ThemeEditorGML.h
 )
 
diff --git a/Userland/Applications/ThemeEditor/MainWidget.cpp b/Userland/Applications/ThemeEditor/MainWidget.cpp
new file mode 100644
index 0000000000..4e613e13f2
--- /dev/null
+++ b/Userland/Applications/ThemeEditor/MainWidget.cpp
@@ -0,0 +1,421 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2021, Jakob-Niklas See <git@nwex.de>
+ * Copyright (c) 2021-2022, Sam Atkins <atkinssj@serenityos.org>
+ * Copyright (c) 2021, Antonio Di Stefano <tonio9681@gmail.com>
+ * Copyright (c) 2022, Filiph Sandström <filiph.sandstrom@filfatstudios.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "MainWidget.h"
+#include <Applications/ThemeEditor/ThemeEditorGML.h>
+#include <LibFileSystemAccessClient/Client.h>
+#include <LibGUI/ActionGroup.h>
+#include <LibGUI/Application.h>
+#include <LibGUI/BoxLayout.h>
+#include <LibGUI/Button.h>
+#include <LibGUI/CheckBox.h>
+#include <LibGUI/ColorInput.h>
+#include <LibGUI/ComboBox.h>
+#include <LibGUI/FilePicker.h>
+#include <LibGUI/Frame.h>
+#include <LibGUI/Icon.h>
+#include <LibGUI/ItemListModel.h>
+#include <LibGUI/Menu.h>
+#include <LibGUI/Menubar.h>
+#include <LibGUI/MessageBox.h>
+#include <LibGUI/SpinBox.h>
+#include <LibGUI/TextBox.h>
+#include <LibGfx/Filters/ColorBlindnessFilter.h>
+
+namespace ThemeEditor {
+
+template<typename T>
+class RoleModel final : public GUI::ItemListModel<T> {
+public:
+    static ErrorOr<NonnullRefPtr<RoleModel>> try_create(Vector<T> const& data)
+    {
+        return adopt_nonnull_ref_or_enomem(new (nothrow) RoleModel<T>(data));
+    }
+
+    virtual GUI::Variant data(GUI::ModelIndex const& index, GUI::ModelRole role) const override
+    {
+        if (role == GUI::ModelRole::Display)
+            return Gfx::to_string(this->m_data[index.row()]);
+        if (role == GUI::ModelRole::Custom)
+            return this->m_data[index.row()];
+
+        return GUI::ItemListModel<T>::data(index, role);
+    }
+
+private:
+    explicit RoleModel(Vector<T> const& data)
+        : GUI::ItemListModel<T>(data)
+    {
+    }
+};
+
+class AlignmentModel final : public GUI::Model {
+public:
+    static ErrorOr<NonnullRefPtr<AlignmentModel>> try_create()
+    {
+        return adopt_nonnull_ref_or_enomem(new (nothrow) AlignmentModel());
+    }
+
+    virtual ~AlignmentModel() = default;
+
+    virtual int row_count(GUI::ModelIndex const& = GUI::ModelIndex()) const override { return 3; }
+    virtual int column_count(GUI::ModelIndex const& = GUI::ModelIndex()) const override { return 2; }
+
+    virtual GUI::Variant data(GUI::ModelIndex const& index, GUI::ModelRole role) const override
+    {
+        if (role == GUI::ModelRole::Display)
+            return m_alignments[index.row()].title;
+        if (role == GUI::ModelRole::Custom)
+            return m_alignments[index.row()].setting_value;
+
+        return {};
+    }
+
+private:
+    AlignmentModel() = default;
+
+    struct AlignmentValue {
+        String title;
+        Gfx::TextAlignment setting_value;
+    };
+    Vector<AlignmentValue> m_alignments {
+        { "Center", Gfx::TextAlignment::Center },
+        { "Left", Gfx::TextAlignment::CenterLeft },
+        { "Right", Gfx::TextAlignment::CenterRight },
+    };
+};
+
+MainWidget::MainWidget(Optional<String> path, Gfx::Palette startup_preview_palette)
+    : m_path(path)
+{
+    load_from_gml(theme_editor_gml);
+
+#define __ENUMERATE_COLOR_ROLE(role) m_color_roles.append(Gfx::ColorRole::role);
+    ENUMERATE_COLOR_ROLES(__ENUMERATE_COLOR_ROLE)
+#undef __ENUMERATE_COLOR_ROLE
+
+#define __ENUMERATE_ALIGNMENT_ROLE(role) m_alignment_roles.append(Gfx::AlignmentRole::role);
+    ENUMERATE_ALIGNMENT_ROLES(__ENUMERATE_ALIGNMENT_ROLE)
+#undef __ENUMERATE_ALIGNMENT_ROLE
+
+#define __ENUMERATE_FLAG_ROLE(role) m_flag_roles.append(Gfx::FlagRole::role);
+    ENUMERATE_FLAG_ROLES(__ENUMERATE_FLAG_ROLE)
+#undef __ENUMERATE_FLAG_ROLE
+
+#define __ENUMERATE_METRIC_ROLE(role) m_metric_roles.append(Gfx::MetricRole::role);
+    ENUMERATE_METRIC_ROLES(__ENUMERATE_METRIC_ROLE)
+#undef __ENUMERATE_METRIC_ROLE
+
+#define __ENUMERATE_PATH_ROLE(role) m_path_roles.append(Gfx::PathRole::role);
+    ENUMERATE_PATH_ROLES(__ENUMERATE_PATH_ROLE)
+#undef __ENUMERATE_PATH_ROLE
+
+    m_preview_widget = find_descendant_of_type_named<GUI::Frame>("preview_frame")
+                           ->add<ThemeEditor::PreviewWidget>(startup_preview_palette);
+    auto& color_combo_box = *find_descendant_of_type_named<GUI::ComboBox>("color_combo_box");
+    auto& color_input = *find_descendant_of_type_named<GUI::ColorInput>("color_input");
+
+    auto& alignment_combo_box = *find_descendant_of_type_named<GUI::ComboBox>("alignment_combo_box");
+    auto& alignment_input = *find_descendant_of_type_named<GUI::ComboBox>("alignment_input");
+
+    auto& flag_combo_box = *find_descendant_of_type_named<GUI::ComboBox>("flag_combo_box");
+    auto& flag_input = *find_descendant_of_type_named<GUI::CheckBox>("flag_input");
+
+    auto& metric_combo_box = *find_descendant_of_type_named<GUI::ComboBox>("metric_combo_box");
+    auto& metric_input = *find_descendant_of_type_named<GUI::SpinBox>("metric_input");
+
+    auto& path_combo_box = *find_descendant_of_type_named<GUI::ComboBox>("path_combo_box");
+    auto& path_input = *find_descendant_of_type_named<GUI::TextBox>("path_input");
+    auto& path_picker_button = *find_descendant_of_type_named<GUI::Button>("path_picker_button");
+
+    color_combo_box.set_model(MUST(RoleModel<Gfx::ColorRole>::try_create(m_color_roles)));
+    color_combo_box.on_change = [&](auto&, auto& index) {
+        auto role = index.model()->data(index, GUI::ModelRole::Custom).to_color_role();
+        color_input.set_color(m_preview_widget->preview_palette().color(role), GUI::AllowCallback::No);
+    };
+    color_combo_box.set_selected_index((size_t)Gfx::ColorRole::Window - 1);
+
+    color_input.on_change = [&] {
+        auto role = color_combo_box.model()->index(color_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_color_role();
+        auto preview_palette = m_preview_widget->preview_palette();
+        preview_palette.set_color(role, color_input.color());
+        m_preview_widget->set_preview_palette(preview_palette);
+    };
+    color_input.set_color(startup_preview_palette.color(Gfx::ColorRole::Window), GUI::AllowCallback::No);
+
+    alignment_combo_box.set_model(MUST(RoleModel<Gfx::AlignmentRole>::try_create(m_alignment_roles)));
+    alignment_combo_box.on_change = [&](auto&, auto& index) {
+        auto role = index.model()->data(index, GUI::ModelRole::Custom).to_alignment_role();
+        alignment_input.set_selected_index((size_t)m_preview_widget->preview_palette().alignment(role), GUI::AllowCallback::No);
+    };
+    alignment_combo_box.set_selected_index((size_t)Gfx::AlignmentRole::TitleAlignment - 1);
+
+    alignment_input.set_only_allow_values_from_model(true);
+    alignment_input.set_model(MUST(AlignmentModel::try_create()));
+    alignment_input.set_selected_index((size_t)startup_preview_palette.alignment(Gfx::AlignmentRole::TitleAlignment), GUI::AllowCallback::No);
+    alignment_input.on_change = [&](auto&, auto& index) {
+        auto role = alignment_combo_box.model()->index(alignment_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_alignment_role();
+        auto preview_palette = m_preview_widget->preview_palette();
+
+        preview_palette.set_alignment(role, index.data(GUI::ModelRole::Custom).to_text_alignment(Gfx::TextAlignment::CenterLeft));
+        m_preview_widget->set_preview_palette(preview_palette);
+    };
+
+    flag_combo_box.set_model(MUST(RoleModel<Gfx::FlagRole>::try_create(m_flag_roles)));
+    flag_combo_box.on_change = [&](auto&, auto& index) {
+        auto role = index.model()->data(index, GUI::ModelRole::Custom).to_flag_role();
+        flag_input.set_checked(m_preview_widget->preview_palette().flag(role), GUI::AllowCallback::No);
+    };
+    flag_combo_box.set_selected_index((size_t)Gfx::FlagRole::IsDark - 1);
+
+    flag_input.on_checked = [&](bool checked) {
+        auto role = flag_combo_box.model()->index(flag_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_flag_role();
+        auto preview_palette = m_preview_widget->preview_palette();
+        preview_palette.set_flag(role, checked);
+        m_preview_widget->set_preview_palette(preview_palette);
+    };
+    flag_input.set_checked(startup_preview_palette.flag(Gfx::FlagRole::IsDark), GUI::AllowCallback::No);
+
+    metric_combo_box.set_model(MUST(RoleModel<Gfx::MetricRole>::try_create(m_metric_roles)));
+    metric_combo_box.on_change = [&](auto&, auto& index) {
+        auto role = index.model()->data(index, GUI::ModelRole::Custom).to_metric_role();
+        metric_input.set_value(m_preview_widget->preview_palette().metric(role), GUI::AllowCallback::No);
+    };
+    metric_combo_box.set_selected_index((size_t)Gfx::MetricRole::TitleButtonHeight - 1);
+
+    metric_input.on_change = [&](int value) {
+        auto role = metric_combo_box.model()->index(metric_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_metric_role();
+        auto preview_palette = m_preview_widget->preview_palette();
+        preview_palette.set_metric(role, value);
+        m_preview_widget->set_preview_palette(preview_palette);
+    };
+    metric_input.set_value(startup_preview_palette.metric(Gfx::MetricRole::TitleButtonHeight), GUI::AllowCallback::No);
+
+    path_combo_box.set_model(MUST(RoleModel<Gfx::PathRole>::try_create(m_path_roles)));
+    path_combo_box.on_change = [&](auto&, auto& index) {
+        auto role = index.model()->data(index, GUI::ModelRole::Custom).to_path_role();
+        path_input.set_text(m_preview_widget->preview_palette().path(role), GUI::AllowCallback::No);
+    };
+    path_combo_box.set_selected_index((size_t)Gfx::PathRole::TitleButtonIcons - 1);
+
+    path_input.on_change = [&] {
+        auto role = path_combo_box.model()->index(path_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_path_role();
+        auto preview_palette = m_preview_widget->preview_palette();
+        preview_palette.set_path(role, path_input.text());
+        m_preview_widget->set_preview_palette(preview_palette);
+    };
+    path_input.set_text(startup_preview_palette.path(Gfx::PathRole::TitleButtonIcons), GUI::AllowCallback::No);
+
+    path_picker_button.on_click = [&](auto) {
+        auto role = path_combo_box.model()->index(path_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_path_role();
+        bool open_folder = (role == Gfx::PathRole::TitleButtonIcons);
+        auto window_title = String::formatted(open_folder ? "Select {} folder" : "Select {} file", path_combo_box.text());
+        auto target_path = path_input.text();
+        if (Core::File::exists(target_path)) {
+            if (!Core::File::is_directory(target_path))
+                target_path = LexicalPath::dirname(target_path);
+        } else {
+            target_path = "/res/icons";
+        }
+        auto result = GUI::FilePicker::get_open_filepath(window(), window_title, target_path, open_folder);
+        if (!result.has_value())
+            return;
+        path_input.set_text(*result);
+    };
+
+    m_preview_widget->on_palette_change = [&] {
+        window()->set_modified(true);
+    };
+
+    m_preview_widget->on_theme_load_from_file = [&](String const& new_path) {
+        set_path(new_path);
+
+        auto selected_color_role = color_combo_box.model()->index(color_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_color_role();
+        color_input.set_color(m_preview_widget->preview_palette().color(selected_color_role), GUI::AllowCallback::No);
+
+        auto selected_alignment_role = alignment_combo_box.model()->index(alignment_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_alignment_role();
+        alignment_input.set_selected_index((size_t)(m_preview_widget->preview_palette().alignment(selected_alignment_role), GUI::AllowCallback::No));
+
+        auto selected_flag_role = flag_combo_box.model()->index(flag_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_flag_role();
+        flag_input.set_checked(m_preview_widget->preview_palette().flag(selected_flag_role), GUI::AllowCallback::No);
+
+        auto selected_metric_role = metric_combo_box.model()->index(metric_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_metric_role();
+        metric_input.set_value(m_preview_widget->preview_palette().metric(selected_metric_role), GUI::AllowCallback::No);
+
+        auto selected_path_role = path_combo_box.model()->index(path_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_path_role();
+        path_input.set_text(m_preview_widget->preview_palette().path(selected_path_role), GUI::AllowCallback::No);
+
+        m_last_modified_time = Time::now_monotonic();
+        window()->set_modified(false);
+    };
+}
+
+ErrorOr<void> MainWidget::initialize_menubar(GUI::Window& window)
+{
+    auto file_menu = TRY(window.try_add_menu("&File"));
+    TRY(file_menu->try_add_action(GUI::CommonActions::make_open_action([&](auto&) {
+        auto response = FileSystemAccessClient::Client::the().try_open_file(&window, "Select theme file", "/res/themes");
+        if (response.is_error())
+            return;
+        m_preview_widget->set_theme_from_file(*response.value());
+    })));
+
+    m_save_action = GUI::CommonActions::make_save_action([&](auto&) {
+        if (m_path.has_value()) {
+            auto result = FileSystemAccessClient::Client::the().try_request_file(&window, *m_path, Core::OpenMode::ReadWrite | Core::OpenMode::Truncate);
+            if (result.is_error())
+                return;
+            save_to_file(result.value());
+        } else {
+            auto result = FileSystemAccessClient::Client::the().try_save_file(&window, "Theme", "ini", Core::OpenMode::ReadWrite | Core::OpenMode::Truncate);
+            if (result.is_error())
+                return;
+            save_to_file(result.value());
+        }
+    });
+    TRY(file_menu->try_add_action(*m_save_action));
+
+    TRY(file_menu->try_add_action(GUI::CommonActions::make_save_as_action([&](auto&) {
+        auto result = FileSystemAccessClient::Client::the().try_save_file(&window, "Theme", "ini", Core::OpenMode::ReadWrite | Core::OpenMode::Truncate);
+        if (result.is_error())
+            return;
+        save_to_file(result.value());
+    })));
+
+    TRY(file_menu->try_add_separator());
+    TRY(file_menu->try_add_action(GUI::CommonActions::make_quit_action([&](auto&) { GUI::Application::the()->quit(); })));
+
+    auto accessibility_menu = TRY(window.try_add_menu("&Accessibility"));
+
+    auto default_accessibility_action = GUI::Action::create_checkable("Default - non-impaired", { Mod_AltGr, Key_1 }, [&](auto&) {
+        m_preview_widget->set_color_filter(nullptr);
+    });
+    default_accessibility_action->set_checked(true);
+
+    auto pratanopia_accessibility_action = GUI::Action::create_checkable("Protanopia", { Mod_AltGr, Key_2 }, [&](auto&) {
+        m_preview_widget->set_color_filter(Gfx::ColorBlindnessFilter::create_protanopia());
+    });
+
+    auto pratanomaly_accessibility_action = GUI::Action::create_checkable("Protanomaly", { Mod_AltGr, Key_3 }, [&](auto&) {
+        m_preview_widget->set_color_filter(Gfx::ColorBlindnessFilter::create_protanomaly());
+    });
+
+    auto tritanopia_accessibility_action = GUI::Action::create_checkable("Tritanopia", { Mod_AltGr, Key_4 }, [&](auto&) {
+        m_preview_widget->set_color_filter(Gfx::ColorBlindnessFilter::create_tritanopia());
+    });
+
+    auto tritanomaly_accessibility_action = GUI::Action::create_checkable("Tritanomaly", { Mod_AltGr, Key_5 }, [&](auto&) {
+        m_preview_widget->set_color_filter(Gfx::ColorBlindnessFilter::create_tritanomaly());
+    });
+
+    auto deuteranopia_accessibility_action = GUI::Action::create_checkable("Deuteranopia", { Mod_AltGr, Key_6 }, [&](auto&) {
+        m_preview_widget->set_color_filter(Gfx::ColorBlindnessFilter::create_deuteranopia());
+    });
+
+    auto deuteranomaly_accessibility_action = GUI::Action::create_checkable("Deuteranomaly", { Mod_AltGr, Key_7 }, [&](auto&) {
+        m_preview_widget->set_color_filter(Gfx::ColorBlindnessFilter::create_deuteranomaly());
+    });
+
+    auto achromatopsia_accessibility_action = GUI::Action::create_checkable("Achromatopsia", { Mod_AltGr, Key_8 }, [&](auto&) {
+        m_preview_widget->set_color_filter(Gfx::ColorBlindnessFilter::create_achromatopsia());
+    });
+
+    auto achromatomaly_accessibility_action = GUI::Action::create_checkable("Achromatomaly", { Mod_AltGr, Key_9 }, [&](auto&) {
+        m_preview_widget->set_color_filter(Gfx::ColorBlindnessFilter::create_achromatomaly());
+    });
+
+    m_preview_type_action_group = make<GUI::ActionGroup>();
+    m_preview_type_action_group->set_exclusive(true);
+    m_preview_type_action_group->add_action(*default_accessibility_action);
+    m_preview_type_action_group->add_action(*pratanopia_accessibility_action);
+    m_preview_type_action_group->add_action(*pratanomaly_accessibility_action);
+    m_preview_type_action_group->add_action(*tritanopia_accessibility_action);
+    m_preview_type_action_group->add_action(*tritanomaly_accessibility_action);
+    m_preview_type_action_group->add_action(*deuteranopia_accessibility_action);
+    m_preview_type_action_group->add_action(*deuteranomaly_accessibility_action);
+    m_preview_type_action_group->add_action(*achromatopsia_accessibility_action);
+    m_preview_type_action_group->add_action(*achromatomaly_accessibility_action);
+
+    TRY(accessibility_menu->try_add_action(default_accessibility_action));
+    TRY(accessibility_menu->try_add_action(pratanopia_accessibility_action));
+    TRY(accessibility_menu->try_add_action(pratanomaly_accessibility_action));
+    TRY(accessibility_menu->try_add_action(tritanopia_accessibility_action));
+    TRY(accessibility_menu->try_add_action(tritanomaly_accessibility_action));
+    TRY(accessibility_menu->try_add_action(deuteranopia_accessibility_action));
+    TRY(accessibility_menu->try_add_action(deuteranomaly_accessibility_action));
+    TRY(accessibility_menu->try_add_action(achromatopsia_accessibility_action));
+    TRY(accessibility_menu->try_add_action(achromatomaly_accessibility_action));
+
+    auto help_menu = TRY(window.try_add_menu("&Help"));
+    TRY(help_menu->try_add_action(GUI::CommonActions::make_about_action("Theme Editor", GUI::Icon::default_icon("app-theme-editor"), &window)));
+
+    return {};
+}
+
+void MainWidget::update_title()
+{
+    window()->set_title(String::formatted("{}[*] - Theme Editor", m_path.value_or("Untitled")));
+}
+
+GUI::Window::CloseRequestDecision MainWidget::request_close()
+{
+    if (!window()->is_modified())
+        return GUI::Window::CloseRequestDecision::Close;
+
+    auto result = GUI::MessageBox::ask_about_unsaved_changes(window(), m_path.value_or(""), m_last_modified_time);
+    if (result == GUI::MessageBox::ExecResult::Yes) {
+        m_save_action->activate();
+        if (window()->is_modified())
+            return GUI::Window::CloseRequestDecision::StayOpen;
+        return GUI::Window::CloseRequestDecision::Close;
+    }
+
+    if (result == GUI::MessageBox::ExecResult::No)
+        return GUI::Window::CloseRequestDecision::Close;
+
+    return GUI::Window::CloseRequestDecision::StayOpen;
+}
+
+void MainWidget::set_path(String path)
+{
+    m_path = path;
+    update_title();
+}
+
+void MainWidget::save_to_file(Core::File& file)
+{
+    auto theme = Core::ConfigFile::open(file.filename(), file.leak_fd()).release_value_but_fixme_should_propagate_errors();
+    for (auto role : m_color_roles) {
+        theme->write_entry("Colors", to_string(role), m_preview_widget->preview_palette().color(role).to_string());
+    }
+
+    for (auto role : m_flag_roles) {
+        theme->write_bool_entry("Flags", to_string(role), m_preview_widget->preview_palette().flag(role));
+    }
+
+    for (auto role : m_metric_roles) {
+        theme->write_num_entry("Metrics", to_string(role), m_preview_widget->preview_palette().metric(role));
+    }
+
+    for (auto role : m_path_roles) {
+        theme->write_entry("Paths", to_string(role), m_preview_widget->preview_palette().path(role));
+    }
+
+    auto sync_result = theme->sync();
+    if (sync_result.is_error()) {
+        GUI::MessageBox::show_error(window(), String::formatted("Failed to save theme file: {}", sync_result.error()));
+    } else {
+        m_last_modified_time = Time::now_monotonic();
+        set_path(file.filename());
+        window()->set_modified(false);
+    }
+}
+
+}
diff --git a/Userland/Applications/ThemeEditor/MainWidget.h b/Userland/Applications/ThemeEditor/MainWidget.h
new file mode 100644
index 0000000000..250742eed3
--- /dev/null
+++ b/Userland/Applications/ThemeEditor/MainWidget.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2022, Sam Atkins <atkinssj@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include "PreviewWidget.h"
+#include <AK/Time.h>
+#include <LibGUI/Widget.h>
+#include <LibGUI/Window.h>
+#include <LibGfx/SystemTheme.h>
+
+namespace ThemeEditor {
+
+class MainWidget final : public GUI::Widget {
+    C_OBJECT(MainWidget);
+
+public:
+    virtual ~MainWidget() override = default;
+
+    ErrorOr<void> initialize_menubar(GUI::Window&);
+    GUI::Window::CloseRequestDecision request_close();
+    void update_title();
+
+private:
+    explicit MainWidget(Optional<String> path, Gfx::Palette startup_preview_palette);
+
+    void save_to_file(Core::File&);
+    void set_path(String);
+
+    RefPtr<PreviewWidget> m_preview_widget;
+    RefPtr<GUI::Action> m_save_action;
+
+    Optional<String> m_path;
+    Time m_last_modified_time { Time::now_monotonic() };
+
+    Vector<Gfx::AlignmentRole> m_alignment_roles;
+    Vector<Gfx::ColorRole> m_color_roles;
+    Vector<Gfx::FlagRole> m_flag_roles;
+    Vector<Gfx::MetricRole> m_metric_roles;
+    Vector<Gfx::PathRole> m_path_roles;
+
+    OwnPtr<GUI::ActionGroup> m_preview_type_action_group;
+};
+
+}
diff --git a/Userland/Applications/ThemeEditor/main.cpp b/Userland/Applications/ThemeEditor/main.cpp
index d020a43c73..5af9fdd4ce 100644
--- a/Userland/Applications/ThemeEditor/main.cpp
+++ b/Userland/Applications/ThemeEditor/main.cpp
@@ -8,93 +8,19 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include "MainWidget.h"
 #include "PreviewWidget.h"
-#include <Applications/ThemeEditor/ThemeEditorGML.h>
 #include <LibCore/ArgsParser.h>
-#include <LibCore/ConfigFile.h>
 #include <LibCore/System.h>
 #include <LibFileSystemAccessClient/Client.h>
-#include <LibGUI/ActionGroup.h>
 #include <LibGUI/Application.h>
-#include <LibGUI/BoxLayout.h>
-#include <LibGUI/Button.h>
-#include <LibGUI/CheckBox.h>
-#include <LibGUI/ColorInput.h>
-#include <LibGUI/ComboBox.h>
-#include <LibGUI/FilePicker.h>
 #include <LibGUI/Icon.h>
-#include <LibGUI/ItemListModel.h>
 #include <LibGUI/Menu.h>
 #include <LibGUI/Menubar.h>
-#include <LibGUI/MessageBox.h>
-#include <LibGUI/SpinBox.h>
-#include <LibGUI/TextBox.h>
 #include <LibGUI/Window.h>
-#include <LibGfx/Filters/ColorBlindnessFilter.h>
 #include <LibMain/Main.h>
 #include <unistd.h>
 
-template<typename T>
-class RoleModel final : public GUI::ItemListModel<T> {
-public:
-    static ErrorOr<NonnullRefPtr<RoleModel>> try_create(Vector<T> const& data)
-    {
-        return adopt_nonnull_ref_or_enomem(new (nothrow) RoleModel<T>(data));
-    }
-
-    virtual GUI::Variant data(GUI::ModelIndex const& index, GUI::ModelRole role) const override
-    {
-        if (role == GUI::ModelRole::Display)
-            return Gfx::to_string(this->m_data[index.row()]);
-        if (role == GUI::ModelRole::Custom)
-            return this->m_data[index.row()];
-
-        return GUI::ItemListModel<T>::data(index, role);
-    }
-
-private:
-    explicit RoleModel(Vector<T> const& data)
-        : GUI::ItemListModel<T>(data)
-    {
-    }
-};
-
-class AlignmentModel final : public GUI::Model {
-public:
-    static ErrorOr<NonnullRefPtr<AlignmentModel>> try_create()
-    {
-        return adopt_nonnull_ref_or_enomem(new (nothrow) AlignmentModel());
-    }
-
-    virtual ~AlignmentModel() = default;
-
-    virtual int row_count(GUI::ModelIndex const& = GUI::ModelIndex()) const override { return 3; }
-    virtual int column_count(GUI::ModelIndex const& = GUI::ModelIndex()) const override { return 2; }
-
-    virtual GUI::Variant data(GUI::ModelIndex const& index, GUI::ModelRole role) const override
-    {
-        if (role == GUI::ModelRole::Display)
-            return m_alignments[index.row()].title;
-        if (role == GUI::ModelRole::Custom)
-            return m_alignments[index.row()].setting_value;
-
-        return {};
-    }
-
-private:
-    AlignmentModel() = default;
-
-    struct AlignmentValue {
-        String title;
-        Gfx::TextAlignment setting_value;
-    };
-    Vector<AlignmentValue> m_alignments {
-        { "Center", Gfx::TextAlignment::Center },
-        { "Left", Gfx::TextAlignment::CenterLeft },
-        { "Right", Gfx::TextAlignment::CenterRight },
-    };
-};
-
 ErrorOr<int> serenity_main(Main::Arguments arguments)
 {
     TRY(Core::System::pledge("stdio recvfd sendfd thread rpath cpath wpath unix"));
@@ -130,319 +56,13 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     Gfx::Palette startup_preview_palette = file_to_edit ? Gfx::Palette(Gfx::PaletteImpl::create_with_anonymous_buffer(Gfx::load_system_theme(*path))) : app->palette();
 
     auto window = GUI::Window::construct();
-    auto last_modified_time = Time::now_monotonic();
-
-    Vector<Gfx::ColorRole> color_roles;
-#define __ENUMERATE_COLOR_ROLE(role) color_roles.append(Gfx::ColorRole::role);
-    ENUMERATE_COLOR_ROLES(__ENUMERATE_COLOR_ROLE)
-#undef __ENUMERATE_COLOR_ROLE
-
-    Vector<Gfx::AlignmentRole> alignment_roles;
-#define __ENUMERATE_ALIGNMENT_ROLE(role) alignment_roles.append(Gfx::AlignmentRole::role);
-    ENUMERATE_ALIGNMENT_ROLES(__ENUMERATE_ALIGNMENT_ROLE)
-#undef __ENUMERATE_ALIGNMENT_ROLE
-
-    Vector<Gfx::FlagRole> flag_roles;
-#define __ENUMERATE_FLAG_ROLE(role) flag_roles.append(Gfx::FlagRole::role);
-    ENUMERATE_FLAG_ROLES(__ENUMERATE_FLAG_ROLE)
-#undef __ENUMERATE_FLAG_ROLE
-
-    Vector<Gfx::MetricRole> metric_roles;
-#define __ENUMERATE_METRIC_ROLE(role) metric_roles.append(Gfx::MetricRole::role);
-    ENUMERATE_METRIC_ROLES(__ENUMERATE_METRIC_ROLE)
-#undef __ENUMERATE_METRIC_ROLE
-
-    Vector<Gfx::PathRole> path_roles;
-#define __ENUMERATE_PATH_ROLE(role) path_roles.append(Gfx::PathRole::role);
-    ENUMERATE_PATH_ROLES(__ENUMERATE_PATH_ROLE)
-#undef __ENUMERATE_PATH_ROLE
-
-    auto main_widget = TRY(window->try_set_main_widget<GUI::Widget>());
-    main_widget->load_from_gml(theme_editor_gml);
-
-    auto& preview_widget = main_widget->find_descendant_of_type_named<GUI::Frame>("preview_frame")
-                               ->add<ThemeEditor::PreviewWidget>(startup_preview_palette);
-    auto& color_combo_box = *main_widget->find_descendant_of_type_named<GUI::ComboBox>("color_combo_box");
-    auto& color_input = *main_widget->find_descendant_of_type_named<GUI::ColorInput>("color_input");
-
-    auto& alignment_combo_box = *main_widget->find_descendant_of_type_named<GUI::ComboBox>("alignment_combo_box");
-    auto& alignment_input = *main_widget->find_descendant_of_type_named<GUI::ComboBox>("alignment_input");
-
-    auto& flag_combo_box = *main_widget->find_descendant_of_type_named<GUI::ComboBox>("flag_combo_box");
-    auto& flag_input = *main_widget->find_descendant_of_type_named<GUI::CheckBox>("flag_input");
-
-    auto& metric_combo_box = *main_widget->find_descendant_of_type_named<GUI::ComboBox>("metric_combo_box");
-    auto& metric_input = *main_widget->find_descendant_of_type_named<GUI::SpinBox>("metric_input");
-
-    auto& path_combo_box = *main_widget->find_descendant_of_type_named<GUI::ComboBox>("path_combo_box");
-    auto& path_input = *main_widget->find_descendant_of_type_named<GUI::TextBox>("path_input");
-    auto& path_picker_button = *main_widget->find_descendant_of_type_named<GUI::Button>("path_picker_button");
-
-    color_combo_box.set_model(TRY(RoleModel<Gfx::ColorRole>::try_create(color_roles)));
-    color_combo_box.on_change = [&](auto&, auto& index) {
-        auto role = index.model()->data(index, GUI::ModelRole::Custom).to_color_role();
-        color_input.set_color(preview_widget.preview_palette().color(role), GUI::AllowCallback::No);
-    };
-    color_combo_box.set_selected_index((size_t)Gfx::ColorRole::Window - 1);
-
-    color_input.on_change = [&] {
-        auto role = color_combo_box.model()->index(color_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_color_role();
-        auto preview_palette = preview_widget.preview_palette();
-        preview_palette.set_color(role, color_input.color());
-        preview_widget.set_preview_palette(preview_palette);
-    };
-    color_input.set_color(startup_preview_palette.color(Gfx::ColorRole::Window), GUI::AllowCallback::No);
-
-    alignment_combo_box.set_model(TRY(RoleModel<Gfx::AlignmentRole>::try_create(alignment_roles)));
-    alignment_combo_box.on_change = [&](auto&, auto& index) {
-        auto role = index.model()->data(index, GUI::ModelRole::Custom).to_alignment_role();
-        alignment_input.set_selected_index((size_t)preview_widget.preview_palette().alignment(role), GUI::AllowCallback::No);
-    };
-    alignment_combo_box.set_selected_index((size_t)Gfx::AlignmentRole::TitleAlignment - 1);
-
-    alignment_input.set_only_allow_values_from_model(true);
-    alignment_input.set_model(TRY(AlignmentModel::try_create()));
-    alignment_input.set_selected_index((size_t)startup_preview_palette.alignment(Gfx::AlignmentRole::TitleAlignment), GUI::AllowCallback::No);
-    alignment_input.on_change = [&](auto&, auto& index) {
-        auto role = alignment_combo_box.model()->index(alignment_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_alignment_role();
-        auto preview_palette = preview_widget.preview_palette();
-
-        preview_palette.set_alignment(role, index.data(GUI::ModelRole::Custom).to_text_alignment(Gfx::TextAlignment::CenterLeft));
-        preview_widget.set_preview_palette(preview_palette);
-    };
-
-    flag_combo_box.set_model(TRY(RoleModel<Gfx::FlagRole>::try_create(flag_roles)));
-    flag_combo_box.on_change = [&](auto&, auto& index) {
-        auto role = index.model()->data(index, GUI::ModelRole::Custom).to_flag_role();
-        flag_input.set_checked(preview_widget.preview_palette().flag(role), GUI::AllowCallback::No);
-    };
-    flag_combo_box.set_selected_index((size_t)Gfx::FlagRole::IsDark - 1);
-
-    flag_input.on_checked = [&](bool checked) {
-        auto role = flag_combo_box.model()->index(flag_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_flag_role();
-        auto preview_palette = preview_widget.preview_palette();
-        preview_palette.set_flag(role, checked);
-        preview_widget.set_preview_palette(preview_palette);
-    };
-    flag_input.set_checked(startup_preview_palette.flag(Gfx::FlagRole::IsDark), GUI::AllowCallback::No);
-
-    metric_combo_box.set_model(TRY(RoleModel<Gfx::MetricRole>::try_create(metric_roles)));
-    metric_combo_box.on_change = [&](auto&, auto& index) {
-        auto role = index.model()->data(index, GUI::ModelRole::Custom).to_metric_role();
-        metric_input.set_value(preview_widget.preview_palette().metric(role), GUI::AllowCallback::No);
-    };
-    metric_combo_box.set_selected_index((size_t)Gfx::MetricRole::TitleButtonHeight - 1);
-
-    metric_input.on_change = [&](int value) {
-        auto role = metric_combo_box.model()->index(metric_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_metric_role();
-        auto preview_palette = preview_widget.preview_palette();
-        preview_palette.set_metric(role, value);
-        preview_widget.set_preview_palette(preview_palette);
-    };
-    metric_input.set_value(startup_preview_palette.metric(Gfx::MetricRole::TitleButtonHeight), GUI::AllowCallback::No);
-
-    path_combo_box.set_model(TRY(RoleModel<Gfx::PathRole>::try_create(path_roles)));
-    path_combo_box.on_change = [&](auto&, auto& index) {
-        auto role = index.model()->data(index, GUI::ModelRole::Custom).to_path_role();
-        path_input.set_text(preview_widget.preview_palette().path(role), GUI::AllowCallback::No);
-    };
-    path_combo_box.set_selected_index((size_t)Gfx::PathRole::TitleButtonIcons - 1);
-
-    path_input.on_change = [&] {
-        auto role = path_combo_box.model()->index(path_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_path_role();
-        auto preview_palette = preview_widget.preview_palette();
-        preview_palette.set_path(role, path_input.text());
-        preview_widget.set_preview_palette(preview_palette);
-    };
-    path_input.set_text(startup_preview_palette.path(Gfx::PathRole::TitleButtonIcons), GUI::AllowCallback::No);
 
-    path_picker_button.on_click = [&](auto) {
-        auto role = path_combo_box.model()->index(path_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_path_role();
-        bool open_folder = (role == Gfx::PathRole::TitleButtonIcons);
-        auto window_title = String::formatted(open_folder ? "Select {} folder" : "Select {} file", path_combo_box.text());
-        auto target_path = path_input.text();
-        if (Core::File::exists(target_path)) {
-            if (!Core::File::is_directory(target_path))
-                target_path = LexicalPath::dirname(target_path);
-        } else {
-            target_path = "/res/icons";
-        }
-        auto result = GUI::FilePicker::get_open_filepath(window, window_title, target_path, open_folder);
-        if (!result.has_value())
-            return;
-        path_input.set_text(*result);
-    };
-
-    auto file_menu = TRY(window->try_add_menu("&File"));
-
-    auto update_window_title = [&] {
-        window->set_title(String::formatted("{}[*] - Theme Editor", path.value_or("Untitled")));
-    };
-
-    preview_widget.on_palette_change = [&] {
-        window->set_modified(true);
-    };
-
-    preview_widget.on_theme_load_from_file = [&](String const& new_path) {
-        path = new_path;
-        update_window_title();
-
-        auto selected_color_role = color_combo_box.model()->index(color_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_color_role();
-        color_input.set_color(preview_widget.preview_palette().color(selected_color_role), GUI::AllowCallback::No);
-
-        auto selected_alignment_role = alignment_combo_box.model()->index(alignment_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_alignment_role();
-        alignment_input.set_selected_index((size_t)(preview_widget.preview_palette().alignment(selected_alignment_role), GUI::AllowCallback::No));
-
-        auto selected_flag_role = flag_combo_box.model()->index(flag_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_flag_role();
-        flag_input.set_checked(preview_widget.preview_palette().flag(selected_flag_role), GUI::AllowCallback::No);
-
-        auto selected_metric_role = metric_combo_box.model()->index(metric_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_metric_role();
-        metric_input.set_value(preview_widget.preview_palette().metric(selected_metric_role), GUI::AllowCallback::No);
-
-        auto selected_path_role = path_combo_box.model()->index(path_combo_box.selected_index()).data(GUI::ModelRole::Custom).to_path_role();
-        path_input.set_text(preview_widget.preview_palette().path(selected_path_role), GUI::AllowCallback::No);
-
-        last_modified_time = Time::now_monotonic();
-        window->set_modified(false);
-    };
-
-    auto save_to_result = [&](auto const& response) {
-        if (response.is_error())
-            return;
-
-        update_window_title();
-        auto file = response.value();
-        auto theme = Core::ConfigFile::open(file->filename(), file->leak_fd()).release_value_but_fixme_should_propagate_errors();
-        for (auto role : color_roles) {
-            theme->write_entry("Colors", to_string(role), preview_widget.preview_palette().color(role).to_string());
-        }
-
-        for (auto role : flag_roles) {
-            theme->write_bool_entry("Flags", to_string(role), preview_widget.preview_palette().flag(role));
-        }
-
-        for (auto role : metric_roles) {
-            theme->write_num_entry("Metrics", to_string(role), preview_widget.preview_palette().metric(role));
-        }
-
-        for (auto role : path_roles) {
-            theme->write_entry("Paths", to_string(role), preview_widget.preview_palette().path(role));
-        }
-
-        auto sync_result = theme->sync();
-        if (sync_result.is_error()) {
-            GUI::MessageBox::show_error(window, String::formatted("Failed to save theme file: {}", sync_result.error()));
-        } else {
-            last_modified_time = Time::now_monotonic();
-            window->set_modified(false);
-        }
-    };
-
-    TRY(file_menu->try_add_action(GUI::CommonActions::make_open_action([&](auto&) {
-        auto response = FileSystemAccessClient::Client::the().try_open_file(window, "Select theme file", "/res/themes");
-        if (response.is_error())
-            return;
-        preview_widget.set_theme_from_file(*response.value());
-    })));
-
-    auto save_action = GUI::CommonActions::make_save_action([&](auto&) {
-        if (path.has_value()) {
-            save_to_result(FileSystemAccessClient::Client::the().try_request_file(window, *path, Core::OpenMode::ReadWrite | Core::OpenMode::Truncate));
-        } else {
-            save_to_result(FileSystemAccessClient::Client::the().try_save_file(window, "Theme", "ini", Core::OpenMode::ReadWrite | Core::OpenMode::Truncate));
-        }
-    });
-    TRY(file_menu->try_add_action(save_action));
-
-    TRY(file_menu->try_add_action(GUI::CommonActions::make_save_as_action([&](auto&) {
-        save_to_result(FileSystemAccessClient::Client::the().try_save_file(window, "Theme", "ini", Core::OpenMode::ReadWrite | Core::OpenMode::Truncate));
-    })));
-
-    TRY(file_menu->try_add_separator());
-    TRY(file_menu->try_add_action(GUI::CommonActions::make_quit_action([&](auto&) { app->quit(); })));
-
-    auto accessibility_menu = TRY(window->try_add_menu("&Accessibility"));
-
-    auto default_accessibility_action = GUI::Action::create_checkable("Default - non-impaired", { Mod_AltGr, Key_1 }, [&](auto&) {
-        preview_widget.set_color_filter(nullptr);
-    });
-    default_accessibility_action->set_checked(true);
-
-    auto pratanopia_accessibility_action = GUI::Action::create_checkable("Protanopia", { Mod_AltGr, Key_2 }, [&](auto&) {
-        preview_widget.set_color_filter(Gfx::ColorBlindnessFilter::create_protanopia());
-    });
-
-    auto pratanomaly_accessibility_action = GUI::Action::create_checkable("Protanomaly", { Mod_AltGr, Key_3 }, [&](auto&) {
-        preview_widget.set_color_filter(Gfx::ColorBlindnessFilter::create_protanomaly());
-    });
-
-    auto tritanopia_accessibility_action = GUI::Action::create_checkable("Tritanopia", { Mod_AltGr, Key_4 }, [&](auto&) {
-        preview_widget.set_color_filter(Gfx::ColorBlindnessFilter::create_tritanopia());
-    });
-
-    auto tritanomaly_accessibility_action = GUI::Action::create_checkable("Tritanomaly", { Mod_AltGr, Key_5 }, [&](auto&) {
-        preview_widget.set_color_filter(Gfx::ColorBlindnessFilter::create_tritanomaly());
-    });
-
-    auto deuteranopia_accessibility_action = GUI::Action::create_checkable("Deuteranopia", { Mod_AltGr, Key_6 }, [&](auto&) {
-        preview_widget.set_color_filter(Gfx::ColorBlindnessFilter::create_deuteranopia());
-    });
-
-    auto deuteranomaly_accessibility_action = GUI::Action::create_checkable("Deuteranomaly", { Mod_AltGr, Key_7 }, [&](auto&) {
-        preview_widget.set_color_filter(Gfx::ColorBlindnessFilter::create_deuteranomaly());
-    });
-
-    auto achromatopsia_accessibility_action = GUI::Action::create_checkable("Achromatopsia", { Mod_AltGr, Key_8 }, [&](auto&) {
-        preview_widget.set_color_filter(Gfx::ColorBlindnessFilter::create_achromatopsia());
-    });
-
-    auto achromatomaly_accessibility_action = GUI::Action::create_checkable("Achromatomaly", { Mod_AltGr, Key_9 }, [&](auto&) {
-        preview_widget.set_color_filter(Gfx::ColorBlindnessFilter::create_achromatomaly());
-    });
-
-    auto preview_type_action_group = make<GUI::ActionGroup>();
-    preview_type_action_group->set_exclusive(true);
-    preview_type_action_group->add_action(*default_accessibility_action);
-    preview_type_action_group->add_action(*pratanopia_accessibility_action);
-    preview_type_action_group->add_action(*pratanomaly_accessibility_action);
-    preview_type_action_group->add_action(*tritanopia_accessibility_action);
-    preview_type_action_group->add_action(*tritanomaly_accessibility_action);
-    preview_type_action_group->add_action(*deuteranopia_accessibility_action);
-    preview_type_action_group->add_action(*deuteranomaly_accessibility_action);
-    preview_type_action_group->add_action(*achromatopsia_accessibility_action);
-    preview_type_action_group->add_action(*achromatomaly_accessibility_action);
-
-    TRY(accessibility_menu->try_add_action(default_accessibility_action));
-    TRY(accessibility_menu->try_add_action(pratanopia_accessibility_action));
-    TRY(accessibility_menu->try_add_action(pratanomaly_accessibility_action));
-    TRY(accessibility_menu->try_add_action(tritanopia_accessibility_action));
-    TRY(accessibility_menu->try_add_action(tritanomaly_accessibility_action));
-    TRY(accessibility_menu->try_add_action(deuteranopia_accessibility_action));
-    TRY(accessibility_menu->try_add_action(deuteranomaly_accessibility_action));
-    TRY(accessibility_menu->try_add_action(achromatopsia_accessibility_action));
-    TRY(accessibility_menu->try_add_action(achromatomaly_accessibility_action));
-
-    auto help_menu = TRY(window->try_add_menu("&Help"));
-    TRY(help_menu->try_add_action(GUI::CommonActions::make_about_action("Theme Editor", app_icon, window)));
-
-    update_window_title();
+    auto main_widget = TRY(window->try_set_main_widget<ThemeEditor::MainWidget>(path, startup_preview_palette));
+    TRY(main_widget->initialize_menubar(window));
+    main_widget->update_title();
 
     window->on_close_request = [&]() -> GUI::Window::CloseRequestDecision {
-        if (!window->is_modified())
-            return GUI::Window::CloseRequestDecision::Close;
-
-        auto result = GUI::MessageBox::ask_about_unsaved_changes(window, path.value_or(""), last_modified_time);
-        if (result == GUI::MessageBox::ExecResult::Yes) {
-            save_action->activate();
-            if (window->is_modified())
-                return GUI::Window::CloseRequestDecision::StayOpen;
-            return GUI::Window::CloseRequestDecision::Close;
-        }
-
-        if (result == GUI::MessageBox::ExecResult::No)
-            return GUI::Window::CloseRequestDecision::Close;
-
-        return GUI::Window::CloseRequestDecision::StayOpen;
+        return main_widget->request_close();
     };
 
     window->resize(480, 520);