feat(mpris): Emit Seeked signal

* Add Seeked signal to Mpris interface

The Mpris2 spec includes a `Seeked` signal which should be fired when
the track position changes in an unexpected way i.e. when the user
seeks to a different part of the track.

This PR implements this signal on seek events and also when a new track
begins. The latter is not strictly required but has been observed in
other players (e.g. VLC).

Closes #1492

* chore: Use `send_mpris()` and `Duration` for conversion

* doc: Update CHANGELOG

---------

Co-authored-by: Henrik Friedrichsen <henrik@affekt.org>

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Emit MPRIS `Seeked` signal
+
 ### Fixed
 
 - Switch to OAuth2 login mechanism

src/mpris.rs

@@ -1,3 +1,5 @@
+#![allow(clippy::use_self)]
+
 use log::info;
 use std::collections::HashMap;
 use std::error::Error;
@@ -6,6 +8,7 @@ use std::time::Duration;
 use tokio::sync::mpsc;
 use tokio_stream::wrappers::UnboundedReceiverStream;
 use tokio_stream::StreamExt;
+use zbus::object_server::SignalContext;
 use zbus::zvariant::{ObjectPath, Value};
 use zbus::{interface, ConnectionBuilder};
 
@@ -314,6 +317,9 @@ impl MprisPlayer {
         self.queue.get_current().is_some()
     }
 
+    #[zbus(signal)]
+    async fn seeked(context: &SignalContext<'_>, position: &i64) -> zbus::Result<()>;
+
     fn next(&self) {
         self.queue.next(true)
     }
@@ -472,6 +478,8 @@ pub enum MprisCommand {
     EmitVolumeStatus,
     /// Emit metadata
     EmitMetadataStatus,
+    /// Emit seeked position
+    EmitSeekedStatus(i64),
 }
 
 /// An MPRIS server that internally manager a thread which can be sent commands. This is internally
@@ -539,6 +547,10 @@ impl MprisManager {
                 Some(MprisCommand::EmitMetadataStatus) => {
                     player_iface.metadata_changed(ctx).await?;
                 }
+                Some(MprisCommand::EmitSeekedStatus(pos)) => {
+                    info!("sending MPRIS seeked signal");
+                    MprisPlayer::seeked(ctx, &pos).await?;
+                }
                 None => break,
             }
         }

src/queue.rs

@@ -313,6 +313,10 @@ impl Queue {
                     move || send_notification(&summary_txt, &body_txt, cover_url)
                 });
             }
+
+            // Send a Seeked signal at start of new track
+            #[cfg(feature = "mpris")]
+            self.spotify.notify_seeked(0);
         }
 
         if reshuffle && self.get_shuffle() {

src/spotify.rs

@@ -415,6 +415,8 @@ impl Spotify {
     /// Seek in the currently played [Playable] played by the [Player].
     pub fn seek(&self, position_ms: u32) {
         self.send_worker(WorkerCommand::Seek(position_ms));
+        #[cfg(feature = "mpris")]
+        self.notify_seeked(position_ms);
     }
 
     /// Seek relatively to the current playback position of the [Player].
@@ -429,6 +431,19 @@ impl Spotify {
         self.cfg.state().volume
     }
 
+    /// Send a Seeked signal on Mpris interface
+    #[cfg(feature = "mpris")]
+    pub fn notify_seeked(&self, position_ms: u32) {
+        let new_position = Duration::from_millis(position_ms.into());
+        let command = MprisCommand::EmitSeekedStatus(
+            new_position
+                .as_micros()
+                .try_into()
+                .expect("track position exceeds MPRIS datatype"),
+        );
+        self.send_mpris(command);
+    }
+
     /// Set the current volume of the [Player]. If `notify` is true, also notify MPRIS clients about
     /// the update.
     pub fn set_volume(&self, volume: u16, notify: bool) {