respect currently playing track when shifting queue entries

src/queue.rs

@@ -163,6 +163,29 @@ impl Queue {
         }
     }
 
+    pub fn len(&self) -> usize {
+        self.queue.read().unwrap().len()
+    }
+
+    pub fn shift(&self, from: usize, to: usize) {
+        let mut queue = self.queue.write().unwrap();
+        let item = queue.remove(from);
+        queue.insert(to, item);
+
+        // if the currently playing track is affected by the shift, update its
+        // index
+        let mut current = self.current_track.write().unwrap();
+        if let Some(index) = *current {
+            if index == from {
+                current.replace(to);
+            } else if index == to && from > index {
+                current.replace(to + 1);
+            } else if index == to && from < index {
+                current.replace(to - 1);
+            }
+        }
+    }
+
     pub fn play(&self, index: usize, reshuffle: bool) {
         if let Some(track) = &self.queue.read().unwrap().get(index) {
             self.spotify.load(&track);

src/ui/listview.rs

@@ -20,7 +20,6 @@ pub struct ListView<I: 'static + ListItem> {
     last_size: Vec2,
     scrollbar: ScrollBase,
     queue: Arc<Queue>,
-    shiftable: bool,
 }
 
 impl<I: ListItem> ListView<I> {
@@ -32,15 +31,9 @@ impl<I: ListItem> ListView<I> {
             last_size: Vec2::new(0, 0),
             scrollbar: ScrollBase::new(),
             queue,
-            shiftable: false,
         }
     }
 
-    pub fn shiftable(mut self) -> Self {
-        self.shiftable = true;
-        self
-    }
-
     pub fn get_selected_index(&self) -> usize {
         self.selected
     }
@@ -55,11 +48,6 @@ impl<I: ListItem> ListView<I> {
         let new = self.selected as i32 + delta;
         self.move_focus_to(max(new, 0) as usize);
     }
-
-    pub fn swap(&mut self, a: usize, b: usize) {
-        let mut content = self.content.write().expect("can't writelock content");
-        content.swap(a, b);
-    }
 }
 
 impl<I: ListItem> View for ListView<I> {
@@ -208,7 +196,7 @@ impl<I: ListItem> ViewExt for ListView<I> {
             return Ok(CommandResult::Consumed(None));
         }
 
-        if cmd == "move" || cmd == "shift" {
+        if cmd == "move" {
             if let Some(dir) = args.get(0) {
                 let amount: usize = args
                     .get(1)
@@ -216,22 +204,14 @@ impl<I: ListItem> ViewExt for ListView<I> {
                     .parse()
                     .map_err(|e| format!("{:?}", e))?;
 
-                let shift = cmd == "shift" && self.shiftable;
-                let selected = self.selected;
                 let len = self.content.read().unwrap().len();
 
                 if dir == "up" && self.selected > 0 {
-                    if shift {
-                        self.swap(selected, selected.saturating_sub(amount));
-                    }
                     self.move_focus(-(amount as i32));
                     return Ok(CommandResult::Consumed(None));
                 }
 
                 if dir == "down" && self.selected < len.saturating_sub(1) {
-                    if shift {
-                        self.swap(selected, min(selected + amount as usize, len - 1));
-                    }
                     self.move_focus(amount as i32);
                     return Ok(CommandResult::Consumed(None));
                 }

src/ui/queue.rs

@@ -4,6 +4,7 @@ use cursive::view::ViewWrapper;
 use cursive::views::{Dialog, EditView, ScrollView, SelectView};
 use cursive::Cursive;
 
+use std::cmp::min;
 use std::sync::Arc;
 
 use commands::CommandResult;
@@ -22,7 +23,7 @@ pub struct QueueView {
 
 impl QueueView {
     pub fn new(queue: Arc<Queue>, playlists: Arc<Playlists>) -> QueueView {
-        let list = ListView::new(queue.queue.clone(), queue.clone()).shiftable();
+        let list = ListView::new(queue.queue.clone(), queue.clone());
 
         QueueView {
             list,
@@ -124,6 +125,28 @@ impl ViewExt for QueueView {
             return Ok(CommandResult::Consumed(None));
         }
 
+        if cmd == "shift" {
+            if let Some(dir) = args.get(0) {
+                let amount: usize = args
+                    .get(1)
+                    .unwrap_or(&"1".to_string())
+                    .parse()
+                    .map_err(|e| format!("{:?}", e))?;
+                let selected = self.list.get_selected_index();
+                let len = self.queue.len();
+                if dir == "up" && selected > 0 {
+                    self.queue.shift(selected, selected.saturating_sub(amount));
+                    self.list.move_focus(-(amount as i32));
+                    return Ok(CommandResult::Consumed(None));
+                } else if dir == "down" && selected < len.saturating_sub(1) {
+                    self.queue
+                        .shift(selected, min(selected + amount as usize, len - 1));
+                    self.list.move_focus(amount as i32);
+                    return Ok(CommandResult::Consumed(None));
+                }
+            }
+        }
+
         self.with_view_mut(move |v| v.on_command(s, cmd, args))
             .unwrap()
     }