Calendar: Move MonthListModel into Calendar.h

Previously, we had two versions of MonthListModel for the AddEventDialog
and the DatePickerDialog. Now, a unified version is in the Calendar.h
file, which can be used easily by anyone. Since that model and the
MeridiemListModel weren't used anymore in the AddEventDialog, I have
also removed them from there.

Userland/Applications/Calendar/AddEventDialog.cpp

@@ -45,7 +45,7 @@ AddEventDialog::AddEventDialog(Core::DateTime date_time, EventManager& event_man
     event_title_textbox->set_focus(true);
 
     auto starting_month_input = widget->find_descendant_of_type_named<GUI::ComboBox>("start_month");
-    starting_month_input->set_model(MonthListModel::create());
+    starting_month_input->set_model(GUI::MonthListModel::create());
     starting_month_input->set_selected_index(m_start_date_time.month() - 1);
 
     auto starting_day_input = widget->find_descendant_of_type_named<GUI::SpinBox>("start_day");
@@ -65,7 +65,7 @@ AddEventDialog::AddEventDialog(Core::DateTime date_time, EventManager& event_man
     starting_meridiem_input->set_selected_index(0);
 
     auto ending_month_input = widget->find_descendant_of_type_named<GUI::ComboBox>("end_month");
-    ending_month_input->set_model(MonthListModel::create());
+    ending_month_input->set_model(GUI::MonthListModel::create());
     ending_month_input->set_selected_index(m_end_date_time.month() - 1);
 
     auto ending_day_input = widget->find_descendant_of_type_named<GUI::SpinBox>("end_day");
@@ -172,26 +172,11 @@ ErrorOr<void> AddEventDialog::add_event_to_calendar()
     return {};
 }
 
-int AddEventDialog::MonthListModel::row_count(const GUI::ModelIndex&) const
-{
-    return 12;
-}
-
 int AddEventDialog::MeridiemListModel::row_count(const GUI::ModelIndex&) const
 {
     return 2;
 }
 
-ErrorOr<String> AddEventDialog::MonthListModel::column_name(int column) const
-{
-    switch (column) {
-    case Column::Month:
-        return "Month"_string;
-    default:
-        VERIFY_NOT_REACHED();
-    }
-}
-
 ErrorOr<String> AddEventDialog::MeridiemListModel::column_name(int column) const
 {
     switch (column) {
@@ -202,25 +187,6 @@ ErrorOr<String> AddEventDialog::MeridiemListModel::column_name(int column) const
     }
 }
 
-GUI::Variant AddEventDialog::MonthListModel::data(const GUI::ModelIndex& index, GUI::ModelRole role) const
-{
-    constexpr Array short_month_names = {
-        "Jan", "Feb", "Mar", "Apr", "May", "Jun",
-        "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
-    };
-
-    auto& month = short_month_names[index.row()];
-    if (role == GUI::ModelRole::Display) {
-        switch (index.column()) {
-        case Column::Month:
-            return month;
-        default:
-            VERIFY_NOT_REACHED();
-        }
-    }
-    return {};
-}
-
 GUI::Variant AddEventDialog::MeridiemListModel::data(const GUI::ModelIndex& index, GUI::ModelRole role) const
 {
     constexpr Array meridiem_names = {

Userland/Applications/Calendar/AddEventDialog.h

@@ -31,25 +31,6 @@ private:
 
     ErrorOr<void> add_event_to_calendar();
 
-    class MonthListModel final : public GUI::Model {
-    public:
-        enum Column {
-            Month,
-            __Count,
-        };
-
-        static NonnullRefPtr<MonthListModel> create() { return adopt_ref(*new MonthListModel); }
-        virtual ~MonthListModel() override = default;
-
-        virtual int row_count(const GUI::ModelIndex& = GUI::ModelIndex()) const override;
-        virtual int column_count(const GUI::ModelIndex& = GUI::ModelIndex()) const override { return Column::__Count; }
-        virtual ErrorOr<String> column_name(int) const override;
-        virtual GUI::Variant data(const GUI::ModelIndex&, GUI::ModelRole) const override;
-
-    private:
-        MonthListModel() = default;
-    };
-
     class MeridiemListModel final : public GUI::Model {
     public:
         enum Column {

Userland/Libraries/LibGUI/Calendar.cpp

@@ -2,6 +2,7 @@
  * Copyright (c) 2019-2020, Ryan Grieb <ryan.m.grieb@gmail.com>
  * Copyright (c) 2020-2022, the SerenityOS developers.
  * Copyright (c) 2022, Tobias Christiansen <tobyase@serenityos.org>
+ * Copyright (c) 2023, David Ganz <david.g.ganz@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -857,4 +858,28 @@ bool Calendar::is_day_in_weekend(DayOfWeek day)
     return day_index < weekend_end_index;
 }
 
+ErrorOr<String> MonthListModel::column_name(int column) const
+{
+    switch (column) {
+    case Column::Month:
+        return "Month"_string;
+    default:
+        VERIFY_NOT_REACHED();
+    }
+}
+
+GUI::Variant MonthListModel::data(const GUI::ModelIndex& index, GUI::ModelRole role) const
+{
+    auto const& month = (m_mode == MonthListModel::DisplayMode::Short ? AK::short_month_names : AK::long_month_names)[index.row()];
+    if (role == GUI::ModelRole::Display) {
+        switch (index.column()) {
+        case Column::Month:
+            return month;
+        default:
+            VERIFY_NOT_REACHED();
+        }
+    }
+    return {};
+}
+
 }

Userland/Libraries/LibGUI/Calendar.h

@@ -2,6 +2,7 @@
  * Copyright (c) 2019-2020, Ryan Grieb <ryan.m.grieb@gmail.com>
  * Copyright (c) 2020-2022, the SerenityOS developers.
  * Copyright (c) 2022, Tobias Christiansen <tobyase@serenityos.org>
+ * Copyright (c) 2023, David Ganz <david.g.ganz@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -13,6 +14,7 @@
 #include <LibCore/DateTime.h>
 #include <LibGUI/AbstractScrollableWidget.h>
 #include <LibGUI/Frame.h>
+#include <LibGUI/Model.h>
 #include <LibGUI/Widget.h>
 
 namespace GUI {
@@ -165,4 +167,33 @@ private:
     int m_weekend_length { 2 };
 };
 
+class MonthListModel final : public GUI::Model {
+public:
+    enum DisplayMode {
+        Short,
+        Long,
+    };
+
+    enum Column {
+        Month,
+        __Count,
+    };
+
+    static NonnullRefPtr<MonthListModel> create(DisplayMode mode = DisplayMode::Short) { return adopt_ref(*new MonthListModel(mode)); }
+    virtual ~MonthListModel() override = default;
+
+    virtual int row_count(const GUI::ModelIndex& = GUI::ModelIndex()) const override { return 12; }
+    virtual int column_count(const GUI::ModelIndex& = GUI::ModelIndex()) const override { return Column::__Count; }
+    virtual ErrorOr<String> column_name(int) const override;
+    virtual GUI::Variant data(const GUI::ModelIndex&, GUI::ModelRole) const override;
+
+private:
+    MonthListModel(DisplayMode mode)
+        : m_mode(mode)
+    {
+    }
+
+    DisplayMode m_mode;
+};
+
 }

Userland/Libraries/LibGUI/DatePicker.h

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2023, David Ganz <david.g.ganz@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/String.h>
+#include <LibCore/DateTime.h>
+#include <LibGUI/Calendar.h>
+#include <LibGUI/Dialog.h>
+#include <LibGUI/Model.h>
+
+namespace GUI {
+
+class DatePicker : public Dialog {
+    C_OBJECT(DatePicker)
+
+public:
+    virtual ~DatePicker() override = default;
+
+    static Optional<Core::DateTime> show(Window* parent_window, String title, Core::DateTime focused_date = Core::DateTime::now());
+
+private:
+    explicit DatePicker(Window* parent_window, String const& title, Core::DateTime focused_date = Core::DateTime::now());
+
+    Core::DateTime m_selected_date;
+    RefPtr<ComboBox> m_month_box;
+    RefPtr<SpinBox> m_year_box;
+};
+
+}