introduce global event sink to trigger updates across threads

src/queue.rs

@@ -3,24 +3,44 @@ use std::collections::VecDeque;
 
 use rspotify::spotify::model::track::FullTrack;
 
+use events::{Event, EventSender};
+
 pub struct Queue {
     queue: VecDeque<FullTrack>,
+    ev_sink: EventSender,
 }
 
 impl Queue {
-    pub fn new() -> Queue {
+    pub fn new(ev_sink: EventSender) -> Queue {
         Queue {
             queue: VecDeque::new(),
+            ev_sink: ev_sink,
         }
     }
+    fn send_event(&self) {
+        self.ev_sink.send(Event::QueueUpdate);
+    }
     pub fn remove(&mut self, index: usize) -> Option<FullTrack> {
-        self.queue.remove(index)
+        match self.queue.remove(index) {
+            Some(track) => {
+                self.send_event();
+                Some(track)
+            },
+            None => None
+        }
     }
     pub fn enqueue(&mut self, track: FullTrack) {
         self.queue.push_back(track);
+        self.send_event();
     }
     pub fn dequeue(&mut self) -> Option<FullTrack> {
-        self.queue.pop_front()
+        match self.queue.pop_front() {
+            Some(track) => {
+                self.send_event();
+                Some(track)
+            },
+            None => None
+        }
     }
     pub fn iter(&self) -> Iter<FullTrack> {
         self.queue.iter()