Fix config loading, modularize crates, and add valid config template

crates/riptune-mpris/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "riptune-mpris"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+description = "MPRIS2 D-Bus interface so waybar/notification daemons can control riptune"
+
+[dependencies]
+riptune-types = { path = "../riptune-types" }
+tokio = { workspace = true }
+tracing = { workspace = true }
+zbus = { version = "4", default-features = false, features = ["tokio"] }

crates/riptune-mpris/src/lib.rs

@@ -0,0 +1,58 @@
+//! MPRIS2 D-Bus server (org.mpris.MediaPlayer2.riptune).
+//!
+//! Implementing this is what lets waybar's mpris module, GNOME/KDE media
+//! widgets, and hardware media keys control riptune without knowing anything
+//! about Subsonic — they only ever speak the standard MPRIS interface.
+//! Spec: <https://specifications.freedesktop.org/mpris-spec/latest/>
+
+use riptune_types::AudioCommand;
+use std::sync::mpsc::Sender;
+use zbus::{interface, ConnectionBuilder};
+
+pub struct MprisHandle {
+    conn: zbus::Connection,
+}
+
+impl MprisHandle {
+    pub async fn shutdown(self) {
+        drop(self.conn);
+    }
+}
+
+struct Player {
+    // Commands are relayed to the audio thread over this channel; MPRIS itself
+    // never touches audio state directly.
+    #[allow(dead_code)]
+    audio_tx: Sender<AudioCommand>,
+}
+
+#[interface(name = "org.mpris.MediaPlayer2.Player")]
+impl Player {
+    async fn play_pause(&self) {
+        // TODO: relay to audio_tx based on current playback state
+    }
+
+    async fn next(&self) {
+        // TODO: emit AppEvent::NextTrack for app.rs to handle (advance in
+        // playlist, fetch new stream_url, send AudioCommand::Play)
+    }
+
+    async fn previous(&self) {
+        // TODO
+    }
+
+    #[zbus(property)]
+    async fn playback_status(&self) -> String {
+        "Stopped".into() // TODO: reflect real state
+    }
+}
+
+pub async fn spawn(audio_tx: Sender<AudioCommand>) -> zbus::Result<MprisHandle> {
+    let player = Player { audio_tx };
+    let conn = ConnectionBuilder::session()?
+        .name("org.mpris.MediaPlayer2.riptune")?
+        .serve_at("/org/mpris/MediaPlayer2", player)?
+        .build()
+        .await?;
+    Ok(MprisHandle { conn })
+}