desktop: Implement MessageDialog in egui

The implemented MessageDialog is meant to replace the rfd MessageDialog
in order to be consistent with other UI elements.

desktop/assets/texts/en-US/message_dialogs.ftl

@@ -0,0 +1,2 @@
+message-dialog-root-movie-load-error-title = Movie Failed to Load
+message-dialog-root-movie-load-error-description = Failed to open or download this movie.

desktop/src/gui.rs

@@ -1,6 +1,6 @@
 mod context_menu;
 mod controller;
-mod dialogs;
+pub mod dialogs;
 mod menu_bar;
 mod movie;
 mod picker;

desktop/src/gui/dialogs.rs

@@ -1,5 +1,6 @@
 mod about_dialog;
 mod bookmarks_dialog;
+pub mod message_dialog;
 mod open_dialog;
 mod open_url_dialog;
 mod preferences_dialog;
@@ -9,6 +10,7 @@ use crate::custom_event::RuffleEvent;
 use crate::player::LaunchOptions;
 use crate::preferences::GlobalPreferences;
 use bookmarks_dialog::{BookmarkAddDialog, BookmarksDialog};
+use message_dialog::{MessageDialog, MessageDialogConfiguration};
 use open_dialog::OpenDialog;
 use open_url_dialog::OpenUrlDialog;
 use preferences_dialog::PreferencesDialog;
@@ -29,6 +31,7 @@ pub struct Dialogs {
     bookmarks_dialog: Option<BookmarksDialog>,
     bookmark_add_dialog: Option<BookmarkAddDialog>,
     open_url_dialog: Option<OpenUrlDialog>,
+    message_dialog: Option<MessageDialog>,
 
     open_dialog: OpenDialog,
     is_open_dialog_visible: bool,
@@ -43,6 +46,7 @@ pub struct Dialogs {
 
 pub enum DialogDescriptor {
     OpenUrl(url::Url),
+    ShowMessage(MessageDialogConfiguration),
 }
 
 impl Dialogs {
@@ -59,6 +63,7 @@ impl Dialogs {
             bookmarks_dialog: None,
             bookmark_add_dialog: None,
             open_url_dialog: None,
+            message_dialog: None,
 
             open_dialog: OpenDialog::new(
                 player_options,
@@ -130,6 +135,9 @@ impl Dialogs {
             DialogDescriptor::OpenUrl(url) => {
                 self.open_url_dialog = Some(OpenUrlDialog::new(url));
             }
+            DialogDescriptor::ShowMessage(config) => {
+                self.message_dialog = Some(MessageDialog::new(config));
+            }
         }
     }
 
@@ -146,6 +154,7 @@ impl Dialogs {
         self.show_volume_controls(locale, egui_ctx, player);
         self.show_about_dialog(locale, egui_ctx);
         self.show_open_url_dialog(locale, egui_ctx);
+        self.show_message_dialog(locale, egui_ctx);
     }
 
     fn show_open_dialog(&mut self, locale: &LanguageIdentifier, egui_ctx: &egui::Context) {
@@ -219,4 +228,15 @@ impl Dialogs {
             self.open_url_dialog = None;
         }
     }
+
+    fn show_message_dialog(&mut self, locale: &LanguageIdentifier, egui_ctx: &egui::Context) {
+        let keep_open = if let Some(dialog) = &mut self.message_dialog {
+            dialog.show(locale, egui_ctx)
+        } else {
+            true
+        };
+        if !keep_open {
+            self.message_dialog = None;
+        }
+    }
 }

desktop/src/gui/dialogs/message_dialog.rs

@@ -0,0 +1,62 @@
+use crate::gui::{text, LocalizableText};
+use egui::{Align2, Ui, Window};
+use unic_langid::LanguageIdentifier;
+
+pub struct MessageDialogConfiguration {
+    title: LocalizableText,
+    body: LocalizableText,
+}
+
+impl MessageDialogConfiguration {
+    pub fn new(title: LocalizableText, body: LocalizableText) -> Self {
+        Self { title, body }
+    }
+}
+
+pub struct MessageDialog {
+    config: MessageDialogConfiguration,
+}
+
+impl MessageDialog {
+    pub fn new(config: MessageDialogConfiguration) -> Self {
+        Self { config }
+    }
+
+    pub fn show(&mut self, locale: &LanguageIdentifier, egui_ctx: &egui::Context) -> bool {
+        let mut keep_open = true;
+        let mut should_close = false;
+
+        Window::new(self.config.title.localize(locale))
+            .open(&mut keep_open)
+            .anchor(Align2::CENTER_CENTER, egui::Vec2::ZERO)
+            .collapsible(false)
+            .resizable(false)
+            .show(egui_ctx, |ui| {
+                egui::ScrollArea::vertical().show(ui, |ui| {
+                    should_close = self.render_window_contents(locale, ui)
+                });
+            });
+
+        keep_open && !should_close
+    }
+
+    pub fn render_window_contents(&mut self, locale: &LanguageIdentifier, ui: &mut Ui) -> bool {
+        let mut should_close = false;
+
+        ui.vertical_centered(|ui| {
+            ui.label("");
+            ui.label(self.config.body.localize(locale));
+            ui.label("");
+        });
+
+        ui.horizontal(|ui| {
+            ui.with_layout(egui::Layout::right_to_left(egui::Align::Center), |ui| {
+                if ui.button(text(locale, "dialog-ok")).clicked() {
+                    should_close = true;
+                }
+            })
+        });
+
+        should_close
+    }
+}

desktop/src/player.rs

@@ -268,6 +268,7 @@ impl ActivePlayer {
             .with_ui(
                 DesktopUiBackend::new(
                     window.clone(),
+                    event_loop.clone(),
                     opt.open_url_mode,
                     font_database,
                     preferences,