editor: Implement drag and drop where it makes sense

src/editor/work/part_row.rs

@@ -1,13 +1,17 @@
 use std::cell::{OnceCell, RefCell};
 
 use adw::{prelude::*, subclass::prelude::*};
-use gtk::glib::{self, clone, subclass::Signal, Properties};
+use gtk::{
+    gdk,
+    glib::{self, clone, subclass::Signal, Properties},
+};
 use once_cell::sync::Lazy;
 
-use crate::{db::models::Work, editor::work::WorkEditor, library::Library};
+use crate::{
+    db::models::Work, editor::work::WorkEditor, library::Library, util::drag_widget::DragWidget,
+};
 
 mod imp {
-
     use super::*;
 
     #[derive(Properties, Debug, Default, gtk::CompositeTemplate)]
@@ -42,11 +46,59 @@ mod imp {
     #[glib::derived_properties]
     impl ObjectImpl for WorkEditorPartRow {
         fn signals() -> &'static [Signal] {
-            static SIGNALS: Lazy<Vec<Signal>> =
-                Lazy::new(|| vec![Signal::builder("remove").build()]);
+            static SIGNALS: Lazy<Vec<Signal>> = Lazy::new(|| {
+                vec![
+                    Signal::builder("remove").build(),
+                    Signal::builder("move")
+                        .param_types([super::WorkEditorPartRow::static_type()])
+                        .build(),
+                ]
+            });
 
             SIGNALS.as_ref()
         }
+
+        fn constructed(&self) {
+            self.parent_constructed();
+
+            let drag_source = gtk::DragSource::builder()
+                .actions(gdk::DragAction::MOVE)
+                .content(&gdk::ContentProvider::for_value(&self.obj().to_value()))
+                .build();
+
+            drag_source.connect_drag_begin(clone!(
+                #[weak(rename_to = obj)]
+                self.obj(),
+                move |_, drag| {
+                    let icon = gtk::DragIcon::for_drag(drag);
+                    icon.set_child(Some(&DragWidget::new(&obj)));
+                }
+            ));
+
+            self.obj().add_controller(drag_source);
+
+            let drop_target = gtk::DropTarget::builder()
+                .actions(gdk::DragAction::MOVE)
+                .build();
+            drop_target.set_types(&[Self::Type::static_type()]);
+
+            drop_target.connect_drop(clone!(
+                #[weak(rename_to = obj)]
+                self.obj(),
+                #[upgrade_or]
+                false,
+                move |_, value, _, _| {
+                    if let Ok(row) = value.get::<Self::Type>() {
+                        obj.emit_by_name::<()>("move", &[&row]);
+                        true
+                    } else {
+                        false
+                    }
+                }
+            ));
+
+            self.obj().add_controller(drop_target);
+        }
     }
 
     impl WidgetImpl for WorkEditorPartRow {}
@@ -71,6 +123,15 @@ impl WorkEditorPartRow {
         obj
     }
 
+    pub fn connect_move<F: Fn(&Self, Self) + 'static>(&self, f: F) -> glib::SignalHandlerId {
+        self.connect_local("move", true, move |values| {
+            let obj = values[0].get::<Self>().unwrap();
+            let source = values[1].get::<Self>().unwrap();
+            f(&obj, source);
+            None
+        })
+    }
+
     pub fn connect_remove<F: Fn(&Self) + 'static>(&self, f: F) -> glib::SignalHandlerId {
         self.connect_local("remove", true, move |values| {
             let obj = values[0].get::<Self>().unwrap();