Add media key interception, preferences UI, dynamic menu bar icon

- Play key (F8) launches preferred player when no player is running
- Blocks Apple Music auto-launch (hide + forceTerminate, like noTunes)
- Preferences window: player picker with app icons, "Choose Other App..."
- Known players: Spotify, Apple Music, Yandex Music, VLC, IINA, Vox
- Start at login via LaunchAgent
- Menu bar icon dynamically reflects current volume level and mute state

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Sources/HUDini/AppDelegate.swift

@@ -4,35 +4,70 @@ import SwiftUI
 class AppDelegate: NSObject, NSApplicationDelegate {
     private var statusItem: NSStatusItem!
     private var volumeMonitor: VolumeMonitor!
+    private var mediaKeyMonitor: MediaKeyMonitor!
     private var hudPanel: HUDPanel!
+    private var prefsWindow: NSWindow?
 
     func applicationDidFinishLaunching(_ notification: Notification) {
-        // Hide from Dock
         NSApp.setActivationPolicy(.accessory)
 
         setupStatusBar()
         setupHUD()
         setupVolumeMonitor()
+        setupMediaKeyMonitor()
+    }
+
+    private func updateStatusIcon(volume: Float, isMuted: Bool) {
+        guard let button = statusItem?.button else { return }
+        let iconName: String
+        if isMuted || volume == 0 {
+            iconName = "speaker.slash.fill"
+        } else if volume < 0.33 {
+            iconName = "speaker.wave.1.fill"
+        } else if volume < 0.66 {
+            iconName = "speaker.wave.2.fill"
+        } else {
+            iconName = "speaker.wave.3.fill"
+        }
+        button.image = NSImage(systemSymbolName: iconName, accessibilityDescription: "HUDini")
+        button.image?.size = NSSize(width: 18, height: 18)
     }
 
     private func setupStatusBar() {
         statusItem = NSStatusBar.system.statusItem(withLength: NSStatusItem.squareLength)
 
+        // Set initial icon based on current volume
         if let button = statusItem.button {
             button.image = NSImage(systemSymbolName: "speaker.wave.2.fill", accessibilityDescription: "HUDini")
             button.image?.size = NSSize(width: 18, height: 18)
         }
 
         let menu = NSMenu()
-        menu.addItem(NSMenuItem(title: "HUDini", action: nil, keyEquivalent: ""))
+
+        let titleItem = NSMenuItem(title: "HUDini", action: nil, keyEquivalent: "")
+        menu.addItem(titleItem)
         menu.addItem(NSMenuItem.separator())
 
-        let enabledItem = NSMenuItem(title: "Enabled", action: #selector(toggleEnabled(_:)), keyEquivalent: "e")
+        let hudItem = NSMenuItem(title: "Volume HUD", action: #selector(toggleHUD(_:)), keyEquivalent: "")
-        enabledItem.state = .on
+        hudItem.state = .on
-        enabledItem.target = self
+        hudItem.target = self
-        menu.addItem(enabledItem)
+        hudItem.tag = 100
+        menu.addItem(hudItem)
+
+        let mediaItem = NSMenuItem(title: "Play Key Launch", action: #selector(toggleMediaKeys(_:)), keyEquivalent: "")
+        mediaItem.state = .on
+        mediaItem.target = self
+        mediaItem.tag = 200
+        menu.addItem(mediaItem)
 
         menu.addItem(NSMenuItem.separator())
+
+        let prefsItem = NSMenuItem(title: "Preferences...", action: #selector(openPreferences), keyEquivalent: ",")
+        prefsItem.target = self
+        menu.addItem(prefsItem)
+
+        menu.addItem(NSMenuItem.separator())
+
         let quitItem = NSMenuItem(title: "Quit", action: #selector(quit), keyEquivalent: "q")
         quitItem.target = self
         menu.addItem(quitItem)
@@ -48,12 +83,30 @@ class AppDelegate: NSObject, NSApplicationDelegate {
         volumeMonitor = VolumeMonitor { [weak self] volume, isMuted in
             DispatchQueue.main.async {
                 self?.hudPanel.show(volume: volume, isMuted: isMuted)
+                self?.updateStatusIcon(volume: volume, isMuted: isMuted)
             }
         }
         volumeMonitor.start()
+
+        // Set initial icon from current volume
+        let vol = volumeMonitor.getVolume()
+        let muted = volumeMonitor.isMuted()
+        updateStatusIcon(volume: vol, isMuted: muted)
     }
 
-    @objc private func toggleEnabled(_ sender: NSMenuItem) {
+    private func setupMediaKeyMonitor() {
+        mediaKeyMonitor = MediaKeyMonitor()
+        let ok = mediaKeyMonitor.start()
+        if !ok {
+            DispatchQueue.main.asyncAfter(deadline: .now() + 3) { [weak self] in
+                _ = self?.mediaKeyMonitor.start()
+            }
+        }
+    }
+
+    // MARK: - Actions
+
+    @objc private func toggleHUD(_ sender: NSMenuItem) {
         if sender.state == .on {
             sender.state = .off
             volumeMonitor.stop()
@@ -63,8 +116,65 @@ class AppDelegate: NSObject, NSApplicationDelegate {
         }
     }
 
+    @objc private func toggleMediaKeys(_ sender: NSMenuItem) {
+        if sender.state == .on {
+            sender.state = .off
+            mediaKeyMonitor.isEnabled = false
+        } else {
+            sender.state = .on
+            mediaKeyMonitor.isEnabled = true
+        }
+    }
+
+    @objc private func openPreferences() {
+        if let window = prefsWindow {
+            window.makeKeyAndOrderFront(nil)
+            NSApp.activate(ignoringOtherApps: true)
+            return
+        }
+
+        let prefsView = PreferencesView(
+            currentBundleID: mediaKeyMonitor.preferredBundleID,
+            startAtLogin: LoginItemManager.isEnabled,
+            onSave: { [weak self] bundleID in
+                self?.mediaKeyMonitor.preferredBundleID = bundleID
+            },
+            onStartAtLoginChanged: { enabled in
+                // Use the .app bundle path from current process
+                let appPath = Bundle.main.bundlePath
+                // If running from .build, try to find the .app bundle
+                let finalPath: String
+                if appPath.contains(".build") {
+                    let projectDir = (appPath as NSString)
+                        .components(separatedBy: ".build").first ?? ""
+                    let bundlePath = projectDir + "HUDini.app"
+                    finalPath = FileManager.default.fileExists(atPath: bundlePath)
+                        ? bundlePath : "/Applications/HUDini.app"
+                } else {
+                    finalPath = appPath
+                }
+                LoginItemManager.setEnabled(enabled, appPath: finalPath)
+            }
+        )
+
+        let window = NSWindow(
+            contentRect: NSRect(x: 0, y: 0, width: 320, height: 420),
+            styleMask: [.titled, .closable],
+            backing: .buffered,
+            defer: false
+        )
+        window.title = "HUDini"
+        window.contentView = NSHostingView(rootView: prefsView)
+        window.center()
+        window.isReleasedWhenClosed = false
+        window.makeKeyAndOrderFront(nil)
+        NSApp.activate(ignoringOtherApps: true)
+        prefsWindow = window
+    }
+
     @objc private func quit() {
         volumeMonitor.stop()
+        mediaKeyMonitor.stop()
         NSApp.terminate(nil)
     }
 }

Sources/HUDini/LoginItemManager.swift

@@ -0,0 +1,41 @@
+import Foundation
+
+struct LoginItemManager {
+    private static let plistPath: String = {
+        let home = FileManager.default.homeDirectoryForCurrentUser.path
+        return "\(home)/Library/LaunchAgents/com.grosfrumos.hudini.plist"
+    }()
+
+    static var isEnabled: Bool {
+        FileManager.default.fileExists(atPath: plistPath)
+    }
+
+    static func setEnabled(_ enabled: Bool, appPath: String? = nil) {
+        if enabled {
+            let path = appPath ?? Bundle.main.bundlePath
+            let plist = """
+            <?xml version="1.0" encoding="UTF-8"?>
+            <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+            <plist version="1.0">
+            <dict>
+                <key>Label</key>
+                <string>com.grosfrumos.hudini</string>
+                <key>ProgramArguments</key>
+                <array>
+                    <string>open</string>
+                    <string>\(path)</string>
+                </array>
+                <key>RunAtLoad</key>
+                <true/>
+            </dict>
+            </plist>
+            """
+            // Ensure LaunchAgents dir exists
+            let dir = (plistPath as NSString).deletingLastPathComponent
+            try? FileManager.default.createDirectory(atPath: dir, withIntermediateDirectories: true)
+            try? plist.write(toFile: plistPath, atomically: true, encoding: .utf8)
+        } else {
+            try? FileManager.default.removeItem(atPath: plistPath)
+        }
+    }
+}

Sources/HUDini/MediaKeyMonitor.swift

@@ -0,0 +1,214 @@
+import Cocoa
+import CoreGraphics
+
+struct MediaPlayer: Equatable {
+    let name: String
+    let bundleID: String
+
+    static let known: [MediaPlayer] = [
+        MediaPlayer(name: "Spotify", bundleID: "com.spotify.client"),
+        MediaPlayer(name: "Apple Music", bundleID: "com.apple.Music"),
+        MediaPlayer(name: "Yandex Music", bundleID: "ru.yandex.music.mac.universal"),
+        MediaPlayer(name: "VLC", bundleID: "org.videolan.vlc"),
+        MediaPlayer(name: "IINA", bundleID: "com.colliderli.iina"),
+        MediaPlayer(name: "Vox", bundleID: "com.coppertino.Vox"),
+    ]
+}
+
+class MediaKeyMonitor {
+    var eventTap: CFMachPort?
+    private var runLoopSource: CFRunLoopSource?
+    private var launchObserver: NSObjectProtocol?
+    var isEnabled: Bool = true {
+        didSet { isEnabled ? startWatching() : stopWatching() }
+    }
+
+    private let prefsKey = "preferredMediaPlayer"
+    private let appleMusicBundleID = "com.apple.Music"
+
+    // All known player bundle IDs for detection
+    private let allPlayerBundleIDs: Set<String> = Set(MediaPlayer.known.map(\.bundleID) + [
+        "com.apple.iTunes",
+        "com.tidal.desktop",
+        "com.amazon.music",
+        "com.deezer.deezer-desktop",
+        "com.plexamp.Plexamp",
+        "app.foobar2000.mac",
+    ])
+
+    var preferredBundleID: String {
+        get { UserDefaults.standard.string(forKey: prefsKey) ?? "com.spotify.client" }
+        set { UserDefaults.standard.set(newValue, forKey: prefsKey) }
+    }
+
+    func start() -> Bool {
+        startWatching()
+        startEventTap()
+        return true
+    }
+
+    func stop() {
+        stopWatching()
+        stopEventTap()
+    }
+
+    // MARK: - App Launch Watcher (main mechanism, like noTunes)
+    // Watches for Apple Music launching and kills it + launches preferred player
+
+    private func startWatching() {
+        guard launchObserver == nil else { return }
+
+        // Kill Apple Music if it's already running and we don't want it
+        if preferredBundleID != appleMusicBundleID {
+            killAppleMusic()
+        }
+
+        launchObserver = NSWorkspace.shared.notificationCenter.addObserver(
+            forName: NSWorkspace.didLaunchApplicationNotification,
+            object: nil,
+            queue: .main
+        ) { [weak self] notification in
+            self?.handleAppLaunch(notification)
+        }
+    }
+
+    private func stopWatching() {
+        if let observer = launchObserver {
+            NSWorkspace.shared.notificationCenter.removeObserver(observer)
+            launchObserver = nil
+        }
+    }
+
+    private func handleAppLaunch(_ notification: Notification) {
+        guard isEnabled else { return }
+        guard preferredBundleID != appleMusicBundleID else { return }
+
+        guard let app = notification.userInfo?[NSWorkspace.applicationUserInfoKey] as? NSRunningApplication,
+              app.bundleIdentifier == appleMusicBundleID else { return }
+
+        // Hide immediately to prevent visual flash, then force-kill
+        app.hide()
+        app.forceTerminate()
+
+        // Launch preferred player if not already running
+        if !isPreferredPlayerRunning() {
+            launchPreferredPlayer()
+        }
+    }
+
+    private func killAppleMusic() {
+        for app in NSWorkspace.shared.runningApplications {
+            if app.bundleIdentifier == appleMusicBundleID {
+                app.hide()
+                app.forceTerminate()
+            }
+        }
+    }
+
+    // MARK: - CGEvent Tap (supplementary — intercepts key before rcd when possible)
+
+    private func startEventTap() {
+        guard eventTap == nil else { return }
+
+        let trusted = AXIsProcessTrusted()
+        if !trusted {
+            promptAccessibility()
+            return
+        }
+
+        let mask = CGEventMask(1 << CGEventType(rawValue: 14)!.rawValue) // NX_SYSDEFINED
+        guard let tap = CGEvent.tapCreate(
+            tap: .cgSessionEventTap,
+            place: .headInsertEventTap,
+            options: .defaultTap,
+            eventsOfInterest: mask,
+            callback: mediaKeyCallback,
+            userInfo: Unmanaged.passUnretained(self).toOpaque()
+        ) else { return }
+
+        eventTap = tap
+        runLoopSource = CFMachPortCreateRunLoopSource(nil, tap, 0)
+        CFRunLoopAddSource(CFRunLoopGetMain(), runLoopSource, .commonModes)
+        CGEvent.tapEnable(tap: tap, enable: true)
+    }
+
+    private func stopEventTap() {
+        if let source = runLoopSource {
+            CFRunLoopRemoveSource(CFRunLoopGetMain(), source, .commonModes)
+            runLoopSource = nil
+        }
+        if let tap = eventTap {
+            CGEvent.tapEnable(tap: tap, enable: false)
+            eventTap = nil
+        }
+    }
+
+    // MARK: - Helpers
+
+    func isAnyPlayerRunning() -> Bool {
+        NSWorkspace.shared.runningApplications.contains { app in
+            guard let bid = app.bundleIdentifier else { return false }
+            return allPlayerBundleIDs.contains(bid)
+        }
+    }
+
+    private func isPreferredPlayerRunning() -> Bool {
+        NSWorkspace.shared.runningApplications.contains { $0.bundleIdentifier == preferredBundleID }
+    }
+
+    func launchPreferredPlayer() {
+        guard let url = NSWorkspace.shared.urlForApplication(withBundleIdentifier: preferredBundleID) else { return }
+        NSWorkspace.shared.openApplication(at: url, configuration: .init()) { _, _ in }
+    }
+
+    private func promptAccessibility() {
+        let options = [kAXTrustedCheckOptionPrompt.takeUnretainedValue(): true] as CFDictionary
+        AXIsProcessTrustedWithOptions(options)
+    }
+}
+
+// NX_KEYTYPE constants
+private let NX_KEYTYPE_PLAY: Int32 = 16
+
+private func mediaKeyCallback(
+    proxy: CGEventTapProxy,
+    type: CGEventType,
+    event: CGEvent,
+    userInfo: UnsafeMutableRawPointer?
+) -> Unmanaged<CGEvent>? {
+    guard let userInfo = userInfo else { return Unmanaged.passRetained(event) }
+    let monitor = Unmanaged<MediaKeyMonitor>.fromOpaque(userInfo).takeUnretainedValue()
+
+    // Re-enable if system disabled us
+    if type == .tapDisabledByTimeout || type == .tapDisabledByUserInput {
+        if let tap = monitor.eventTap {
+            CGEvent.tapEnable(tap: tap, enable: true)
+        }
+        return Unmanaged.passRetained(event)
+    }
+
+    guard monitor.isEnabled else { return Unmanaged.passRetained(event) }
+    guard type.rawValue == 14 else { return Unmanaged.passRetained(event) }
+
+    guard let nsEvent = NSEvent(cgEvent: event) else { return Unmanaged.passRetained(event) }
+    guard nsEvent.subtype.rawValue == 8 else { return Unmanaged.passRetained(event) }
+
+    let data1 = nsEvent.data1
+    let keyCode = Int32((data1 & 0xFFFF0000) >> 16)
+    let keyDown = ((data1 & 0x0100) == 0)
+
+    guard keyCode == NX_KEYTYPE_PLAY && keyDown else {
+        return Unmanaged.passRetained(event)
+    }
+
+    // Play pressed — if no player running, launch preferred and consume
+    if !monitor.isAnyPlayerRunning() {
+        DispatchQueue.main.async {
+            monitor.launchPreferredPlayer()
+        }
+        return nil
+    }
+
+    return Unmanaged.passRetained(event)
+}
+

Sources/HUDini/PreferencesView.swift

@@ -0,0 +1,228 @@
+import SwiftUI
+import AppKit
+
+// NSImage wrapper that actually renders properly in SwiftUI
+struct AppIconView: NSViewRepresentable {
+    let nsImage: NSImage
+
+    func makeNSView(context: Context) -> NSImageView {
+        let view = NSImageView()
+        view.imageScaling = .scaleProportionallyUpOrDown
+        view.image = nsImage
+        return view
+    }
+
+    func updateNSView(_ nsView: NSImageView, context: Context) {
+        nsView.image = nsImage
+    }
+}
+
+struct PreferencesView: View {
+    @State private var selectedBundleID: String
+    @State private var customAppName: String?
+    @State private var customAppIcon: NSImage?
+    @State private var startAtLogin: Bool
+    let onSave: (String) -> Void
+    let onStartAtLoginChanged: (Bool) -> Void
+
+    init(
+        currentBundleID: String,
+        startAtLogin: Bool,
+        onSave: @escaping (String) -> Void,
+        onStartAtLoginChanged: @escaping (Bool) -> Void
+    ) {
+        _selectedBundleID = State(initialValue: currentBundleID)
+        _startAtLogin = State(initialValue: startAtLogin)
+        self.onSave = onSave
+        self.onStartAtLoginChanged = onStartAtLoginChanged
+
+        if !MediaPlayer.known.contains(where: { $0.bundleID == currentBundleID }) {
+            if let url = NSWorkspace.shared.urlForApplication(withBundleIdentifier: currentBundleID) {
+                _customAppName = State(initialValue: url.deletingPathExtension().lastPathComponent)
+                _customAppIcon = State(initialValue: NSWorkspace.shared.icon(forFile: url.path))
+            }
+        }
+    }
+
+    var body: some View {
+        VStack(spacing: 0) {
+            Text("HUDini Preferences")
+                .font(.headline)
+                .padding(.top, 16)
+                .padding(.bottom, 12)
+
+            Divider()
+
+            VStack(alignment: .leading, spacing: 8) {
+                Text("Launch on Play key:")
+                    .font(.subheadline)
+                    .foregroundColor(.secondary)
+
+                VStack(spacing: 0) {
+                    ForEach(Array(MediaPlayer.known.enumerated()), id: \.element.bundleID) { index, player in
+                        PlayerRow(
+                            player: player,
+                            isSelected: selectedBundleID == player.bundleID,
+                            isInstalled: NSWorkspace.shared.urlForApplication(
+                                withBundleIdentifier: player.bundleID) != nil
+                        ) {
+                            selectedBundleID = player.bundleID
+                            customAppName = nil
+                            customAppIcon = nil
+                            onSave(player.bundleID)
+                        }
+                        if index < MediaPlayer.known.count - 1 {
+                            Divider().padding(.leading, 46)
+                        }
+                    }
+
+                    if let name = customAppName {
+                        Divider().padding(.leading, 46)
+                        CustomPlayerRow(
+                            name: name,
+                            icon: customAppIcon,
+                            isSelected: !MediaPlayer.known.contains(where: { $0.bundleID == selectedBundleID })
+                        ) {
+                            onSave(selectedBundleID)
+                        }
+                    }
+                }
+                .background(Color(nsColor: .controlBackgroundColor))
+                .cornerRadius(8)
+                .overlay(
+                    RoundedRectangle(cornerRadius: 8)
+                        .stroke(Color(nsColor: .separatorColor), lineWidth: 0.5)
+                )
+
+                Button("Choose Other App...") {
+                    chooseCustomApp()
+                }
+                .padding(.top, 4)
+            }
+            .padding(16)
+
+            Divider()
+
+            HStack {
+                Toggle("Start at login", isOn: Binding(
+                    get: { startAtLogin },
+                    set: { newValue in
+                        startAtLogin = newValue
+                        onStartAtLoginChanged(newValue)
+                    }
+                ))
+                Spacer()
+            }
+            .padding(.horizontal, 16)
+            .padding(.vertical, 12)
+
+            Spacer()
+        }
+        .frame(width: 320, height: 440)
+    }
+
+    private func chooseCustomApp() {
+        let panel = NSOpenPanel()
+        panel.title = "Choose Application"
+        panel.allowedContentTypes = [.application]
+        panel.directoryURL = URL(fileURLWithPath: "/Applications")
+        panel.canChooseDirectories = false
+        panel.canChooseFiles = true
+        panel.allowsMultipleSelection = false
+
+        guard panel.runModal() == .OK, let url = panel.url,
+              let bundle = Bundle(url: url), let bid = bundle.bundleIdentifier else { return }
+
+        selectedBundleID = bid
+        customAppName = url.deletingPathExtension().lastPathComponent
+        customAppIcon = NSWorkspace.shared.icon(forFile: url.path)
+        onSave(bid)
+    }
+}
+
+struct PlayerRow: View {
+    let player: MediaPlayer
+    let isSelected: Bool
+    let isInstalled: Bool
+    let onSelect: () -> Void
+
+    var body: some View {
+        Button(action: onSelect) {
+            HStack(spacing: 10) {
+                iconView
+                    .frame(width: 30, height: 30)
+
+                Text(player.name)
+                    .foregroundColor(isInstalled ? .primary : .secondary)
+
+                Spacer()
+
+                if !isInstalled {
+                    Text("not installed")
+                        .font(.caption)
+                        .foregroundColor(.secondary)
+                }
+
+                if isSelected {
+                    Image(systemName: "checkmark")
+                        .foregroundColor(.accentColor)
+                        .fontWeight(.semibold)
+                }
+            }
+            .padding(.horizontal, 12)
+            .padding(.vertical, 5)
+            .contentShape(Rectangle())
+        }
+        .buttonStyle(.plain)
+        .background(isSelected ? Color.accentColor.opacity(0.1) : Color.clear)
+    }
+
+    @ViewBuilder
+    private var iconView: some View {
+        if let url = NSWorkspace.shared.urlForApplication(withBundleIdentifier: player.bundleID) {
+            AppIconView(nsImage: NSWorkspace.shared.icon(forFile: url.path))
+        } else {
+            Image(systemName: "music.note.house")
+                .font(.system(size: 20))
+                .foregroundColor(.secondary)
+                .frame(width: 30, height: 30)
+        }
+    }
+}
+
+struct CustomPlayerRow: View {
+    let name: String
+    let icon: NSImage?
+    let isSelected: Bool
+    let onSelect: () -> Void
+
+    var body: some View {
+        Button(action: onSelect) {
+            HStack(spacing: 10) {
+                if let icon = icon {
+                    AppIconView(nsImage: icon)
+                        .frame(width: 30, height: 30)
+                } else {
+                    Image(systemName: "app.fill")
+                        .font(.system(size: 20))
+                        .foregroundColor(.secondary)
+                        .frame(width: 30, height: 30)
+                }
+
+                Text(name)
+                Spacer()
+
+                if isSelected {
+                    Image(systemName: "checkmark")
+                        .foregroundColor(.accentColor)
+                        .fontWeight(.semibold)
+                }
+            }
+            .padding(.horizontal, 12)
+            .padding(.vertical, 5)
+            .contentShape(Rectangle())
+        }
+        .buttonStyle(.plain)
+        .background(isSelected ? Color.accentColor.opacity(0.1) : Color.clear)
+    }
+}