feat(dev): run dev alongside release with shared app data (#866)

* feat(dev): run dev alongside release with shared app data

Skip tauri-plugin-single-instance in debug builds so `tauri dev` can run
while an installed release instance is open. Keep the same bundle identifier
and data directory; label the dev window "Psysonic (Dev)".

* fix(dev): gate on_second_instance behind release cfg

Avoid dead_code warning in debug builds where single-instance is skipped.

* feat(dev): red sidebar brand and monochrome titlebar chrome

Tag the document in Vite dev and style the logo header with a red
background plus gray window controls so dev is obvious at a glance.

* feat(dev): skip OS hotkeys and add mobile DEV markers

Debug builds no longer register global shortcuts, MPRIS, or Windows
taskbar media controls so release keeps system input when both run.
Flip the tray icon horizontally in dev and show a fixed DEV badge on
narrow layouts.

* docs(changelog): note PR #866 parallel dev alongside release

* fix(dev): satisfy clippy needless_return in debug-only paths

src-tauri/src/lib.rs

@@ -38,6 +38,28 @@ const MAX_DL_CONCURRENCY: usize = 4;
 /// `None` if souvlaki failed to initialize (e.g. no D-Bus session on Linux).
 type MprisControls = Mutex<Option<souvlaki::MediaControls>>;
 
+/// Release builds only: focus or CLI-hand off when a second instance is launched.
+#[cfg(not(debug_assertions))]
+fn on_second_instance<R: tauri::Runtime>(
+    app: &tauri::AppHandle<R>,
+    argv: Vec<String>,
+    _cwd: String,
+) {
+    if !crate::cli::handle_cli_on_primary_instance(app, &argv) {
+        let window = app.get_webview_window("main").expect("no main window");
+        // The window may have been hidden via the close-to-tray path,
+        // which injects PAUSE_RENDERING_JS (sets `__psyHidden=true`,
+        // pauses CSS animations). Tray-icon restore mirrors this with
+        // RESUME_RENDERING_JS — second-launch restore must do the same,
+        // otherwise the webview comes back with rendering still paused
+        // and navigation looks blank (issue #497).
+        let _ = window.eval(RESUME_RENDERING_JS);
+        let _ = window.show();
+        let _ = window.unminimize();
+        let _ = window.set_focus();
+    }
+}
+
 pub fn run() {
     // Linux: second `psysonic --player …` forwards over D-Bus before heavy startup.
     #[cfg(target_os = "linux")]
@@ -57,7 +79,7 @@ pub fn run() {
 
     let (audio_engine, _audio_thread) = audio::create_engine();
 
-    tauri::Builder::default()
+    let builder = tauri::Builder::default()
         .manage(audio_engine)
         .manage(ShortcutMap::default())
         .manage(discord::DiscordState::new())
@@ -78,24 +100,18 @@ pub fn run() {
         .plugin(tauri_plugin_global_shortcut::Builder::new().build())
         .plugin(tauri_plugin_store::Builder::default().build())
         .plugin(tauri_plugin_dialog::init())
-        .plugin(tauri_plugin_fs::init())
-        .plugin(tauri_plugin_single_instance::init(|app, argv, _cwd| {
-            if !crate::cli::handle_cli_on_primary_instance(app, &argv) {
-                let window = app.get_webview_window("main").expect("no main window");
-                // The window may have been hidden via the close-to-tray path,
-                // which injects PAUSE_RENDERING_JS (sets `__psyHidden=true`,
-                // pauses CSS animations). Tray-icon restore mirrors this with
-                // RESUME_RENDERING_JS — second-launch restore must do the same,
-                // otherwise the webview comes back with rendering still paused
-                // and navigation looks blank (issue #497).
-                let _ = window.eval(RESUME_RENDERING_JS);
-                let _ = window.show();
-                let _ = window.unminimize();
-                let _ = window.set_focus();
-            }
-        }))
+        .plugin(tauri_plugin_fs::init());
 
+    #[cfg(not(debug_assertions))]
+    let builder = builder.plugin(tauri_plugin_single_instance::init(on_second_instance));
+
+    builder
         .setup(|app| {
+            #[cfg(debug_assertions)]
+            if let Some(window) = app.get_webview_window("main") {
+                let _ = window.set_title("Psysonic (Dev)");
+            }
+
             // ── Analysis cache (SQLite) ───────────────────────────────────
             {
                 let cache = analysis_cache::AnalysisCache::init(app.handle())
@@ -386,6 +402,8 @@ pub fn run() {
             }
 
             // ── MPRIS2 / OS media controls via souvlaki ──────────────────
+            // Release only: debug builds share the D-Bus name / SMTC slot with prod.
+            #[cfg(not(debug_assertions))]
             {
                 use souvlaki::{MediaControlEvent, MediaControls, PlatformConfig};
 
@@ -474,9 +492,13 @@ pub fn run() {
 
                 app.manage(MprisControls::new(maybe_controls));
             }
+            #[cfg(debug_assertions)]
+            {
+                app.manage(MprisControls::new(None));
+            }
 
             // ── Windows Taskbar Thumbnail Toolbar ────────────────────────
-            #[cfg(target_os = "windows")]
+            #[cfg(all(target_os = "windows", not(debug_assertions)))]
             {
                 use tauri::Manager;
                 if let Some(w) = app.get_webview_window("main") {

src-tauri/src/lib_commands/app_api/integration.rs

@@ -1,3 +1,4 @@
+#[cfg(not(debug_assertions))]
 use tauri::Emitter;
 
 use crate::{MprisControls, ShortcutMap};
@@ -9,32 +10,42 @@ pub(crate) fn register_global_shortcut(
     shortcut: String,
     action: String,
 ) -> Result<(), String> {
-    use tauri_plugin_global_shortcut::{GlobalShortcutExt, Shortcut, ShortcutState};
-
-    let mut map = shortcut_map.lock().unwrap();
-
-    // Idempotent: if this exact shortcut+action is already registered, skip.
-    // This prevents on_shortcut() from accumulating duplicate handlers when
-    // registerAll() is called again after a JS HMR reload or StrictMode double-effect.
-    if map.get(&shortcut).map(|a| a == &action).unwrap_or(false) {
-        return Ok(());
+    // Debug builds run alongside release with shared settings — do not grab OS shortcuts.
+    #[cfg(debug_assertions)]
+    {
+        let _ = (app, shortcut_map, shortcut, action);
+        Ok(())
     }
 
-    // Unregister any existing OS grab for this shortcut before re-registering.
-    if let Ok(s) = shortcut.parse::<Shortcut>() {
-        let _ = app.global_shortcut().unregister(s);
-    }
-    map.insert(shortcut.clone(), action.clone());
-    drop(map); // release lock before the blocking OS call
+    #[cfg(not(debug_assertions))]
+    {
+        use tauri_plugin_global_shortcut::{GlobalShortcutExt, Shortcut, ShortcutState};
 
-    let parsed: Shortcut = shortcut.parse().map_err(|_| format!("Invalid shortcut: {shortcut}"))?;
-    app.global_shortcut()
-        .on_shortcut(parsed, move |app, _shortcut, event| {
-            if event.state == ShortcutState::Pressed {
-                let _ = app.emit("shortcut:global-action", action.clone());
-            }
-        })
-        .map_err(|e| e.to_string())
+        let mut map = shortcut_map.lock().unwrap();
+
+        // Idempotent: if this exact shortcut+action is already registered, skip.
+        // This prevents on_shortcut() from accumulating duplicate handlers when
+        // registerAll() is called again after a JS HMR reload or StrictMode double-effect.
+        if map.get(&shortcut).map(|a| a == &action).unwrap_or(false) {
+            return Ok(());
+        }
+
+        // Unregister any existing OS grab for this shortcut before re-registering.
+        if let Ok(s) = shortcut.parse::<Shortcut>() {
+            let _ = app.global_shortcut().unregister(s);
+        }
+        map.insert(shortcut.clone(), action.clone());
+        drop(map); // release lock before the blocking OS call
+
+        let parsed: Shortcut = shortcut.parse().map_err(|_| format!("Invalid shortcut: {shortcut}"))?;
+        app.global_shortcut()
+            .on_shortcut(parsed, move |app, _shortcut, event| {
+                if event.state == ShortcutState::Pressed {
+                    let _ = app.emit("shortcut:global-action", action.clone());
+                }
+            })
+            .map_err(|e| e.to_string())
+    }
 }
 
 #[tauri::command]
@@ -43,10 +54,19 @@ pub(crate) fn unregister_global_shortcut(
     shortcut_map: tauri::State<ShortcutMap>,
     shortcut: String,
 ) -> Result<(), String> {
-    use tauri_plugin_global_shortcut::{GlobalShortcutExt, Shortcut};
-    shortcut_map.lock().unwrap().remove(&shortcut);
-    let parsed: Shortcut = shortcut.parse().map_err(|_| format!("Invalid shortcut: {shortcut}"))?;
-    app.global_shortcut().unregister(parsed).map_err(|e| e.to_string())
+    #[cfg(debug_assertions)]
+    {
+        let _ = (app, shortcut_map, shortcut);
+        Ok(())
+    }
+
+    #[cfg(not(debug_assertions))]
+    {
+        use tauri_plugin_global_shortcut::{GlobalShortcutExt, Shortcut};
+        shortcut_map.lock().unwrap().remove(&shortcut);
+        let parsed: Shortcut = shortcut.parse().map_err(|_| format!("Invalid shortcut: {shortcut}"))?;
+        app.global_shortcut().unregister(parsed).map_err(|e| e.to_string())
+    }
 }
 
 #[tauri::command]

src-tauri/src/lib_commands/sync/tray.rs

@@ -10,6 +10,59 @@ use crate::tray_runtime::{
 };
 
 use super::super::ui::{PAUSE_RENDERING_JS, RESUME_RENDERING_JS};
+use tauri::image::Image;
+
+/// Debug builds: mirror the default app icon horizontally so the tray differs from release.
+fn app_tray_icon(app: &tauri::AppHandle) -> Image<'static> {
+    let icon = app.default_window_icon().expect("default window icon");
+    #[cfg(debug_assertions)]
+    {
+        flip_image_horizontal(icon)
+    }
+    #[cfg(not(debug_assertions))]
+    {
+        icon.clone().to_owned()
+    }
+}
+
+#[cfg(debug_assertions)]
+fn flip_image_horizontal(icon: &Image<'_>) -> Image<'static> {
+    let width = icon.width();
+    let height = icon.height();
+    let mut rgba = icon.rgba().to_vec();
+    flip_rgba_horizontal(&mut rgba, width, height);
+    Image::new_owned(rgba, width, height)
+}
+
+#[cfg(debug_assertions)]
+fn flip_rgba_horizontal(rgba: &mut [u8], width: u32, height: u32) {
+    let w = width as usize;
+    let h = height as usize;
+    if w == 0 || h == 0 || rgba.len() < w * h * 4 {
+        return;
+    }
+    for y in 0..h {
+        let row = y * w * 4;
+        for x in 0..w / 2 {
+            let l = row + x * 4;
+            let r = row + (w - 1 - x) * 4;
+            let left = [
+                rgba[l],
+                rgba[l + 1],
+                rgba[l + 2],
+                rgba[l + 3],
+            ];
+            let right = [
+                rgba[r],
+                rgba[r + 1],
+                rgba[r + 2],
+                rgba[r + 3],
+            ];
+            rgba[l..l + 4].copy_from_slice(&right);
+            rgba[r..r + 4].copy_from_slice(&left);
+        }
+    }
+}
 
 pub(crate) fn build_tray_icon(app: &tauri::AppHandle) -> tauri::Result<TrayIcon> {
     let labels = app
@@ -92,7 +145,7 @@ pub(crate) fn build_tray_icon(app: &tauri::AppHandle) -> tauri::Result<TrayIcon>
 
     #[cfg(target_os = "windows")]
     let tray_builder = TrayIconBuilder::new()
-        .icon(app.default_window_icon().unwrap().clone())
+        .icon(app_tray_icon(app))
         .menu(&menu)
         .tooltip(&tooltip_with_icon)
         // tray-icon defaults to opening the context menu on every WM_LBUTTONUP when this is true.
@@ -102,7 +155,7 @@ pub(crate) fn build_tray_icon(app: &tauri::AppHandle) -> tauri::Result<TrayIcon>
         .show_menu_on_left_click(false);
     #[cfg(not(target_os = "windows"))]
     let tray_builder = TrayIconBuilder::new()
-        .icon(app.default_window_icon().unwrap().clone())
+        .icon(app_tray_icon(app))
         .menu(&menu)
         .tooltip(&cached_tooltip);
 
@@ -423,3 +476,22 @@ pub(crate) fn is_tiling_wm() -> bool {
 pub(crate) fn is_tiling_wm_cmd() -> bool {
     is_tiling_wm()
 }
+
+#[cfg(all(test, debug_assertions))]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn flip_rgba_horizontal_mirrors_pixels() {
+        // 3×1: A B C → C B A
+        let mut rgba = vec![
+            1, 0, 0, 255, // A
+            2, 0, 0, 255, // B
+            3, 0, 0, 255, // C
+        ];
+        flip_rgba_horizontal(&mut rgba, 3, 1);
+        assert_eq!(rgba[0], 3);
+        assert_eq!(rgba[4], 2);
+        assert_eq!(rgba[8], 1);
+    }
+}