format request, begin download feature implementation

src/app/browser/window/tab/item/page/content/status/download.rs

@@ -0,0 +1,194 @@
+use adw::StatusPage;
+use gtk::{
+    gio::{Cancellable, File},
+    prelude::{BoxExt, ButtonExt, CancellableExt, WidgetExt},
+    Align,
+    Box,
+    Button,
+    FileDialog,
+    FileLauncher,
+    Label,
+    Orientation,
+    Spinner, // use adw::Spinner; @TODO adw 1.6 / ubuntu 24.10+
+    Window,
+};
+use std::rc::Rc;
+
+const MARGIN: i32 = 16;
+const SPINNER_SIZE: i32 = 32; // 16-64
+
+/// Create new [StatusPage](https://gnome.pages.gitlab.gnome.org/libadwaita/doc/main/class.StatusPage.html)
+/// with progress indication and UI controls
+/// * applies callback function once on destination [File](https://docs.gtk.org/gio/iface.File.html) selected
+/// * requires external IOStream read/write implementation, depending of protocol driver in use
+pub fn new(
+    initial_filename: &str,
+    cancellable: &Cancellable,
+    on_choose: impl Fn(File, Label) + 'static,
+) -> StatusPage {
+    // Init file chooser dialog
+    let dialog = FileDialog::builder().initial_name(initial_filename).build();
+
+    // Init file launcher dialog
+    let file_launcher = FileLauncher::new(File::NONE);
+
+    // Init spinner component
+    let spinner = Spinner::builder()
+        .height_request(SPINNER_SIZE)
+        .visible(false)
+        .width_request(SPINNER_SIZE)
+        .build();
+
+    // Init `status` feature
+    // * indicates current download state in text label
+    let status = Label::builder()
+        .label("Choose location to download")
+        .margin_top(MARGIN)
+        .build();
+
+    // Init `cancel` feature
+    // * applies shared `Cancellable`
+    let cancel = Button::builder()
+        .css_classes(["error"])
+        .halign(Align::Center)
+        .label("Cancel")
+        .margin_top(MARGIN)
+        .visible(false)
+        .build();
+
+    cancel.connect_clicked({
+        let cancellable = cancellable.clone();
+        let spinner = spinner.clone();
+        let status = status.clone();
+        move |this| {
+            // apply cancellable
+            cancellable.cancel();
+
+            // deactivate `spinner`
+            spinner.set_visible(false);
+            spinner.stop();
+
+            // update `status`
+            status.set_css_classes(&["warning"]);
+            status.set_label("Operation cancelled");
+
+            // hide self
+            this.set_visible(false);
+        }
+    });
+
+    // Init `open` feature
+    // * open selected file on download complete
+    let open = Button::builder()
+        .css_classes(["accent"])
+        .halign(Align::Center)
+        .label("Open")
+        .margin_top(MARGIN)
+        .visible(false)
+        .build();
+
+    open.connect_clicked({
+        let file_launcher = file_launcher.clone();
+        let status = status.clone();
+        move |this| {
+            this.set_sensitive(false); // lock
+            file_launcher.launch(Window::NONE, Cancellable::NONE, {
+                let status = status.clone();
+                let this = this.clone();
+                move |result| {
+                    if let Err(ref e) = result {
+                        status.set_css_classes(&["error"]);
+                        status.set_label(e.message())
+                    }
+                    this.set_sensitive(true); // unlock
+                }
+            })
+        }
+    });
+
+    // Init `choose` feature
+    // * select file destination for download
+    let choose = Button::builder()
+        .css_classes(["accent"])
+        .halign(Align::Center)
+        .label("Choose..")
+        .margin_top(MARGIN)
+        .build();
+
+    choose.connect_clicked({
+        // init shared references
+        let cancel = cancel.clone();
+        let dialog = dialog.clone();
+        let file_launcher = file_launcher.clone();
+        let spinner = spinner.clone();
+        let status = status.clone();
+        let on_choose = Rc::new(on_choose);
+        move |this| {
+            // lock choose button to prevent double click
+            this.set_sensitive(false);
+            dialog.save(Window::NONE, Cancellable::NONE, {
+                // delegate shared references
+                let cancel = cancel.clone();
+                let file_launcher = file_launcher.clone();
+                let spinner = spinner.clone();
+                let status = status.clone();
+                let this = this.clone();
+                let on_choose = on_choose.clone();
+                move |result| {
+                    this.set_sensitive(true); // unlock
+                    match result {
+                        Ok(file) => {
+                            // update destination file
+                            file_launcher.set_file(Some(&file));
+
+                            // update `status`
+                            status.set_css_classes(&[]);
+                            status.set_label("Loading...");
+
+                            // show `cancel` button
+                            cancel.set_visible(true);
+
+                            // show `spinner`
+                            spinner.set_visible(true);
+                            spinner.start();
+
+                            // hide self
+                            this.set_visible(false);
+
+                            // callback
+                            on_choose(file, status)
+                        }
+                        Err(e) => {
+                            // update destination file
+                            file_launcher.set_file(File::NONE);
+
+                            // update `spinner`
+                            spinner.set_visible(false);
+                            spinner.stop();
+
+                            // update `status`
+                            status.set_css_classes(&["warning"]);
+                            status.set_label(e.message())
+                        }
+                    }
+                }
+            });
+        }
+    });
+
+    // Init main container
+    let child = Box::builder().orientation(Orientation::Vertical).build();
+
+    child.append(&spinner);
+    child.append(&status);
+    child.append(&cancel);
+    child.append(&choose);
+    child.append(&open);
+
+    // Done
+    StatusPage::builder()
+        .child(&child)
+        .icon_name("document-save-symbolic")
+        .title("Download")
+        .build()
+}