LibGUI+Calendar: Move date control logic to the calendar widget

Userland/Applications/Calendar/main.cpp

@@ -49,33 +49,11 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     auto calendar = main_widget->find_descendant_of_type_named<GUI::Calendar>("calendar");
 
     auto prev_date_action = GUI::Action::create({}, TRY(Gfx::Bitmap::load_from_file("/res/icons/16x16/go-back.png"sv)), [&](const GUI::Action&) {
-        unsigned view_month = calendar->view_month();
+        calendar->show_previous_date();
-        unsigned view_year = calendar->view_year();
-        if (calendar->mode() == GUI::Calendar::Month) {
-            view_month--;
-            if (calendar->view_month() == 1) {
-                view_month = 12;
-                view_year--;
-            }
-        } else {
-            view_year--;
-        }
-        calendar->update_tiles(view_year, view_month);
     });
 
     auto next_date_action = GUI::Action::create({}, TRY(Gfx::Bitmap::load_from_file("/res/icons/16x16/go-forward.png"sv)), [&](const GUI::Action&) {
-        unsigned view_month = calendar->view_month();
+        calendar->show_next_date();
-        unsigned view_year = calendar->view_year();
-        if (calendar->mode() == GUI::Calendar::Month) {
-            view_month++;
-            if (calendar->view_month() == 12) {
-                view_month = 1;
-                view_year++;
-            }
-        } else {
-            view_year++;
-        }
-        calendar->update_tiles(view_year, view_month);
     });
 
     auto add_event_action = GUI::Action::create("&Add Event", {}, TRY(Gfx::Bitmap::load_from_file("/res/icons/16x16/add-event.png"sv)), [&](const GUI::Action&) {

Userland/Libraries/LibGUI/Calendar.cpp

@@ -82,6 +82,38 @@ void Calendar::toggle_mode()
     invalidate_layout();
 }
 
+void Calendar::show_previous_date()
+{
+    unsigned view_month = m_view_month;
+    unsigned view_year = m_view_year;
+    if (m_mode == GUI::Calendar::Month) {
+        --view_month;
+        if (view_month == 0) {
+            view_month = 12;
+            --view_year;
+        }
+    } else {
+        --view_year;
+    }
+    update_tiles(view_year, view_month);
+}
+
+void Calendar::show_next_date()
+{
+    unsigned view_month = m_view_month;
+    unsigned view_year = m_view_year;
+    if (m_mode == GUI::Calendar::Month) {
+        ++view_month;
+        if (view_month == 13) {
+            view_month = 1;
+            ++view_year;
+        }
+    } else {
+        ++view_year;
+    }
+    update_tiles(view_year, view_month);
+}
+
 void Calendar::resize_event(GUI::ResizeEvent& event)
 {
     m_event_size.set_width(event.size().width() - (frame_thickness() * 2));

Userland/Libraries/LibGUI/Calendar.h

@@ -64,6 +64,9 @@ public:
     void set_show_days_of_the_week(bool b) { m_show_days = b; }
     bool is_showing_days_of_the_week() const { return m_show_days; }
 
+    void show_previous_date();
+    void show_next_date();
+
     Gfx::IntSize unadjusted_tile_size() const { return m_unadjusted_tile_size; }
     void set_unadjusted_tile_size(int width, int height)
     {

Userland/Services/Taskbar/ClockWidget.cpp

@@ -53,18 +53,7 @@ ClockWidget::ClockWidget()
     m_prev_date->set_fixed_size(24, 24);
     m_prev_date->set_icon(Gfx::Bitmap::load_from_file("/res/icons/16x16/go-back.png"sv).release_value_but_fixme_should_propagate_errors());
     m_prev_date->on_click = [&](auto) {
-        unsigned view_month = m_calendar->view_month();
+        m_calendar->show_previous_date();
-        unsigned view_year = m_calendar->view_year();
-        if (m_calendar->mode() == GUI::Calendar::Month) {
-            view_month--;
-            if (m_calendar->view_month() == 1) {
-                view_month = 12;
-                view_year--;
-            }
-        } else {
-            view_year--;
-        }
-        m_calendar->update_tiles(view_year, view_month);
         if (m_calendar->mode() == GUI::Calendar::Year)
             m_selected_calendar_button->set_text(m_calendar->formatted_date(GUI::Calendar::YearOnly).release_value_but_fixme_should_propagate_errors());
         else
@@ -87,18 +76,7 @@ ClockWidget::ClockWidget()
     m_next_date->set_fixed_size(24, 24);
     m_next_date->set_icon(Gfx::Bitmap::load_from_file("/res/icons/16x16/go-forward.png"sv).release_value_but_fixme_should_propagate_errors());
     m_next_date->on_click = [&](auto) {
-        unsigned view_month = m_calendar->view_month();
+        m_calendar->show_next_date();
-        unsigned view_year = m_calendar->view_year();
-        if (m_calendar->mode() == GUI::Calendar::Month) {
-            view_month++;
-            if (m_calendar->view_month() == 12) {
-                view_month = 1;
-                view_year++;
-            }
-        } else {
-            view_year++;
-        }
-        m_calendar->update_tiles(view_year, view_month);
         if (m_calendar->mode() == GUI::Calendar::Year)
             m_selected_calendar_button->set_text(m_calendar->formatted_date(GUI::Calendar::YearOnly).release_value_but_fixme_should_propagate_errors());
         else