inferon/src/main.zig

//! inferon — voice interface daemon for Letta Code agents.
//! Phase 2: pw-record subprocess capture wired into the state machine.

const std = @import("std");
const Io = std.Io;
const whisper = @import("whisper.zig");
const melo = @import("melo.zig");
const playback = @import("playback.zig");
const qt6 = @import("libqt6zig");
const QApplication = qt6.QApplication;
const QSystemTrayIcon = qt6.QSystemTrayIcon;
const QWidget = qt6.QWidget;
const QMenu = qt6.QMenu;
const QAction = qt6.QAction;
const QPixmap = qt6.QPixmap;
const QIcon = qt6.QIcon;
const QColor = qt6.QColor;
const QPainter = qt6.QPainter;
const QBrush = qt6.QBrush;
const QRectF = qt6.QRectF;
const threading = qt6.threading;
const letta = @import("letta.zig");
const overlay_mod = @import("overlay.zig");

// ------------------------------------------------------------- constants ---

const RECORDER_BIN = "pw-record";
const RECORDINGS_DIR = "/tmp/inferon";
/// whisper.cpp wants 16 kHz mono S16 LE.
const RECORD_RATE = "16000";
const RECORD_CHANNELS = "1";
const RECORD_FORMAT = "s16";
const LETTA_AGENT_ID = "agent-local-f69432ca-1bcd-42eb-b7f9-cf18d187282c";
// ---------------------------------------------------------------- states ---

const State = enum {
    idle, // not listening, waiting for user toggle
    recording, // mic capture in progress
    transcribing, // audio -> whisper server
    thinking, // agent processing
    speaking, // TTS playback
    error_backend, // whisper/LLM unreachable

    fn label(s: State) []const u8 {
        return switch (s) {
            .idle => "idle",
            .recording => "rec",
            .transcribing => "stt",
            .thinking => "think",
            .speaking => "say",
            .error_backend => "err",
        };
    }

    /// Tray icon color per state (RGB).
    fn color(s: State) [3]u8 {
        return switch (s) {
            .idle => .{ 90, 90, 110 }, // muted grey
            .recording => .{ 220, 60, 60 }, // red
            .transcribing => .{ 220, 160, 60 }, // orange
            .thinking => .{ 90, 160, 230 }, // blue
            .speaking => .{ 120, 210, 110 }, // green
            .error_backend => .{ 180, 40, 180 }, // magenta
        };
    }
};

var state: State = .idle;
var tray_icon: QSystemTrayIcon = undefined;
var allocator: std.mem.Allocator = undefined;

var conversation_active: bool = false;
var agent_menu: QMenu = undefined;
var conv_menu: QMenu = undefined;
var current_agent: []const u8 = LETTA_AGENT_ID;
var current_conversation: []const u8 = "default";

// ---------------------------------------------------------------- prefs ---

var prefs_dir_buf: [512]u8 = undefined;
var prefs_path_buf: [576]u8 = undefined;
var PREFS_DIR: []const u8 = "";
var PREFS_PATH: []const u8 = "";

/// Resolve prefs paths from $HOME once at startup.
fn initPrefsPaths() void {
    const home = std.c.getenv("HOME") orelse return;
    const home_s = std.mem.span(home);
    PREFS_DIR = std.fmt.bufPrint(&prefs_dir_buf, "{s}/.local/inferon", .{home_s}) catch return;
    PREFS_PATH = std.fmt.bufPrint(&prefs_path_buf, "{s}/prefs.json", .{PREFS_DIR}) catch return;
}

var prefs_agent_buf: ?[]u8 = null;
var prefs_convo_buf: ?[]u8 = null;

fn setPrefsAgent(id: []const u8) void {
    if (allocator.dupe(u8, id)) |d| {
        if (prefs_agent_buf) |old| allocator.free(old);
        prefs_agent_buf = d;
        current_agent = d;
    } else |_| {}
}

fn setPrefsConvo(id: []const u8) void {
    if (allocator.dupe(u8, id)) |d| {
        if (prefs_convo_buf) |old| allocator.free(old);
        prefs_convo_buf = d;
        current_conversation = d;
    } else |_| {}
}

fn savePrefs() void {
    const io = io_ctx orelse return;
    Io.Dir.createDirAbsolute(io, PREFS_DIR, .default_dir) catch {};
    const f = Io.Dir.createFileAbsolute(io, PREFS_PATH, .{ .truncate = true }) catch return;
    var buf: [1024]u8 = undefined;
    const body = std.fmt.bufPrint(&buf,
        "{{\"agent\": \"{s}\", \"conversation\": \"{s}\"}}\n",
        .{ current_agent, current_conversation },
    ) catch return;
    var wbuf: [1024]u8 = undefined;
    var w = f.writer(io, &wbuf);
    w.interface.writeAll(body) catch {};
    w.interface.flush() catch {};
    f.close(io);
}

fn loadPrefs() void {
    const io = io_ctx orelse return;
    var f = Io.Dir.openFileAbsolute(io, PREFS_PATH, .{}) catch return;
    defer f.close(io);
    var buf: [1024]u8 = undefined;
    var rbuf: [1024]u8 = undefined;
    var r = f.reader(io, &rbuf);
    const n = r.interface.readSliceShort(&buf) catch return;
    if (letta.jsonStr(allocator, buf[0..n], 0, "agent")) |a| {
        setPrefsAgent(a.val);
        allocator.free(a.val);
    }
    if (letta.jsonStr(allocator, buf[0..n], 0, "conversation")) |c| {
        setPrefsConvo(c.val);
        allocator.free(c.val);
    }
}
var last_user_text: ?[]u8 = null;

fn setLastUserText(text: []u8) void {
    if (last_user_text) |old| allocator.free(old);
    last_user_text = text;
}
// ------------------------------------------------------------------ icon ---

var current_icon: ?QIcon = null;
var current_pixmap: ?QPixmap = null;

var main_thread_id: std.Thread.Id = 0;
var pending_state: State = .idle;

// --------------------------------------------------------------- overlay ---

var overlay: ?overlay_mod.Overlay = null;

const OverlayKind = enum { begin, user, step, chunk };
const OverlayMsg = struct { kind: OverlayKind, text: ?[]u8 };

/// Worker-thread side: queue an overlay update onto the Qt main loop.
fn pushOverlay(kind: OverlayKind, text: ?[]u8) void {
    const msg = allocator.create(OverlayMsg) catch {
        if (text) |t| allocator.free(t);
        return;
    };
    msg.* = .{ .kind = kind, .text = text };
    threading.async(msg, onOverlayMsg);
}

fn onOverlayMsg(ctx: ?*anyopaque) callconv(.c) void {
    const msg: *OverlayMsg = @ptrCast(@alignCast(ctx orelse return));
    defer allocator.destroy(msg);
    if (overlay) |*ov| switch (msg.kind) {
        .begin => ov.begin(),
        .user => ov.user(msg.text orelse ""),
        .step => ov.step(msg.text orelse ""),
        .chunk => ov.chunk(msg.text orelse ""),
    };
    if (msg.text) |t| allocator.free(t);
}


fn onLettaEvent(_: ?*anyopaque, ev: letta.Event) void {
    switch (ev) {
        .step => |s| {
            const dup = allocator.dupe(u8, s) catch return;
            pushOverlay(.step, dup);
        },
        .chunk => |c| {
            const dup = allocator.dupe(u8, c) catch return;
            pushOverlay(.chunk, dup);
            // Stream voice: queue each sentence as it completes.
            sentence_buf.appendSlice(allocator, c) catch {};
            if (c.len > 0) {
                const last = c[c.len - 1];
                if (last == '.' or last == '!' or last == '?') flushSentence(false);
            }
        },
    }
}

/// Must run on the Qt main thread (touches QSystemTrayIcon / QPixmap).
fn setStateMainThread(next: State) void {
    state = next;

    // Circle icon drawn with QPainter — a bare pixmap.fill rendered blank
    // on the KDE SNI host.
    const c = next.color();
    const color = QColor.new5(c[0], c[1], c[2]);
    defer color.delete();
    const pen_color = QColor.new5(20, 20, 26);
    defer pen_color.delete();
    const transparent = QColor.new8("transparent");
    defer transparent.delete();

    const pixmap = QPixmap.new2(128, 128);
    pixmap.fill1(transparent);

    const brush = QBrush.new3(color);
    defer brush.delete();

    const painter = QPainter.new();
    _ = painter.begin(pixmap);
    painter.setRenderHint(1); // Antialiasing
    painter.setPen(pen_color);
    painter.setBrush(brush);
    const rect = QRectF.new6(16, 16, 96, 96);
    defer rect.delete();
    painter.drawEllipse(rect);
    _ = painter.end();
    painter.delete();

    const icon = QIcon.new2(pixmap);

    if (current_icon) |old| old.delete();
    if (current_pixmap) |old| old.delete();
    current_icon = icon;
    current_pixmap = pixmap;

    tray_icon.setIcon(icon);

    const tip = std.fmt.allocPrint(allocator, "inferon — {s}", .{next.label()}) catch return;
    defer allocator.free(tip);
    tray_icon.setToolTip(tip);
}

fn onStateFromWorker(_: ?*anyopaque) callconv(.c) void {
    setStateMainThread(pending_state);
}

/// Thread-safe state transition: runs directly on the main thread, or
/// marshals through Qt's event loop when called from the pipeline worker.
fn setState(next: State) void {
    if (std.Thread.getCurrentId() == main_thread_id) {
        setStateMainThread(next);
    } else {
        pending_state = next;
        threading.async(null, onStateFromWorker);
    }
}

/// Buffer for sentence-split streaming into the playback pipeline.
var sentence_buf: std.ArrayList(u8) = .empty;

fn flushSentence(final_flush: bool) void {
    const a = allocator;
    if (sentence_buf.items.len == 0) {
        if (final_flush) playback.endReply();
        return;
    }
    // Sentences end on . ! ? — hold back a bare trailing terminator-less tail
    // unless this is the end of the reply.
    if (!final_flush) {
        const last = sentence_buf.items[sentence_buf.items.len - 1];
        if (last != '.' and last != '!' and last != '?') return;
    }
    const s = sentence_buf.toOwnedSlice(a) catch return;
    playback.push(s);
    if (final_flush) playback.endReply();
}

// --------------------------------------------------------------- capture ---

var recorder: ?std.process.Child = null;
var recording_path: ?[]const u8 = null;
var io_ctx: ?std.Io = null;

fn startRecording() void {
    const io = io_ctx orelse return;
    Io.Dir.createDirAbsolute(io, RECORDINGS_DIR, .default_dir) catch |e| switch (e) {
        error.PathAlreadyExists => {},
        else => {
            std.debug.print("inferon: cannot create {s}: {s}\n", .{ RECORDINGS_DIR, @errorName(e) });
            setState(.error_backend);
            return;
        },
    };

    const path = std.fmt.allocPrint(
        allocator,
        "{s}/utterance-{d}.wav",
        .{ RECORDINGS_DIR, Io.Clock.now(.real, io).nanoseconds },
    ) catch {
        setState(.error_backend);
        return;
    };
    recording_path = path;

    // pw-record finalizes the WAV header on SIGTERM — kill() sends it.
    // stderr goes to a log so failures aren't silent.
    const stderr_log = std.fmt.allocPrint(allocator, "{s}/pw-record.log", .{RECORDINGS_DIR}) catch null;
    defer if (stderr_log) |sl| allocator.free(sl);
    const stderr_file: ?Io.File = if (stderr_log) |lp|
        Io.Dir.cwd().createFile(io, lp[1..], .{ .truncate = true }) catch null
    else
        null;

    recorder = std.process.spawn(io, .{
        .argv = &.{
            RECORDER_BIN,
            "--rate",
            RECORD_RATE,
            "--channels",
            RECORD_CHANNELS,
            "--format",
            RECORD_FORMAT,
            path,
        },
        .stdin = .ignore,
        .stdout = .ignore,
        .stderr = if (stderr_file) |f| .{ .file = f } else .ignore,
    }) catch |e| {
        std.debug.print("inferon: failed to spawn {s}: {s}\n", .{ RECORDER_BIN, @errorName(e) });
        allocator.free(path);
        recording_path = null;
        setState(.error_backend);
        return;
    };
    setState(.recording);
}

/// Stop pw-record. kill() delivers SIGTERM (pw-record finalizes the WAV
/// header) and reaps the child itself — no separate wait() needed.
fn stopRecording() void {
    const io = io_ctx orelse return;
    const child = &(recorder orelse return);

    child.kill(io);
    recorder = null;
}

fn onQuit(_: QAction) callconv(.c) void {
    if (recorder != null) stopRecording();
    whisper.stop(); // whisper-server dies with us
    melo.stop();
    QApplication.quit();
}

// -------------------------------------------------------------- handlers ---

/// Delete a temp file if it exists. Best-effort — /tmp cleanup, not critical.
fn cleanupFile(path: []const u8) void {
    const io = io_ctx orelse return;
    Io.Dir.deleteFileAbsolute(io, path) catch {};
}

/// Full pipeline after recording stops: transcribe -> infer -> speak.
/// All blocking on the UI thread for now (same as before); states advance
/// automatically, no manual clicking between stages.
fn processUtterance() void {
    const io = io_ctx orelse return;
    const wav_in = recording_path orelse return;
    defer {
        cleanupFile(wav_in);
        allocator.free(wav_in);
        recording_path = null;
    }

    setState(.transcribing);
    const text: []u8 = whisper.transcribe(allocator, io, wav_in) catch |e| {
        std.debug.print("inferon: transcription failed: {s}\n", .{@errorName(e)});
        setState(.error_backend);
        return;
    };
    std.debug.print("inferon: transcript: \"{s}\"\n", .{text});
    setLastUserText(text);

    // --- agent ---
    setState(.thinking);

    pushOverlay(.begin, null);
    if (allocator.dupe(u8, text) catch null) |user_dup| pushOverlay(.user, user_dup);
    const response = letta.streamInferConv(io, allocator, current_agent, current_conversation, text, null, onLettaEvent) catch |err| {
        std.log.err("letta failed: {s}", .{@errorName(err)});
        setState(.idle);
        return;
    };
    defer allocator.free(response);
    std.debug.print("[INFERON]\n{s}\n\n", .{response});

    // --- tts + playback: sentences already streaming; flush the tail ---
    setState(.speaking);
    flushSentence(true);
    playback.waitDrained();

    // After speaking: back to idle-but-in-conversation. User clicks when
    // they want to talk again.
    setState(.idle);
}

fn onTrayActivated(_: QSystemTrayIcon, reason: i32) callconv(.c) void {
    // Trigger = 3 (click). Only toggle on left click; context menu handles the rest.
    if (reason != 3) return;

    switch (state) {
        .idle => {
            conversation_active = true;
            startRecording();
        },
        .recording => {
            stopRecording();
            setState(.transcribing); // claim the pipeline slot before spawning
            // Pipeline runs on a worker thread; the Qt event loop stays
            // responsive (icon repaints, menu works) while whisper/letta/melo
            // block. setState marshals back to the main thread.
            const worker = std.Thread.spawn(.{}, processUtterance, .{}) catch |e| {
                std.debug.print("inferon: failed to spawn worker: {s}\n", .{@errorName(e)});
                setState(.error_backend);
                return;
            };
            worker.detach();
        },
        // Clicks during the pipeline are no-ops now — states advance on their own.
        .transcribing, .thinking, .speaking => {},
        .error_backend => setState(.idle),
    }
}

fn onToggleWindow(a: QAction) callconv(.c) void {
    if (a.isChecked()) {
        if (overlay) |*ov| ov.window.show();
    } else {
        if (overlay) |*ov| ov.hide();
    }
}

const AgentEntry = struct { action: QAction, id: []u8 };
var agent_entries: std.ArrayList(AgentEntry) = .empty;

fn onPickAgent(a: QAction) callconv(.c) void {
    for (agent_entries.items) |e| {
        e.action.setChecked(e.action.ptr == a.ptr);
        if (e.action.ptr == a.ptr) setPrefsAgent(e.id);
    }
    setPrefsConvo("default");
    populateConvMenu();
    savePrefs();
    std.debug.print("inferon: agent -> {s}\n", .{current_agent});
}

fn onConvMenuShow(_: QMenu) callconv(.c) void {
    populateConvMenu();
}

fn populateAgentMenu() void {
    for (agent_entries.items) |e| allocator.free(e.id);
    agent_entries.clearRetainingCapacity();
    agent_menu.clear();

    const agents = letta.listAgents(io_ctx.?, allocator) catch return;
    defer {
        for (agents) |ag| {
            allocator.free(ag.id);
            allocator.free(ag.name);
        }
        allocator.free(agents);
    }
    for (agents) |ag| {
        const label = std.fmt.allocPrint(allocator, "{s}", .{ag.name}) catch continue;
        defer allocator.free(label);
        const a = QAction.new5(label, QWidget{ .ptr = null });
        a.setCheckable(true);
        a.setChecked(std.mem.eql(u8, ag.id, current_agent));
        a.onTriggered(onPickAgent);
        agent_menu.addAction(a);
        const id_dup = allocator.dupe(u8, ag.id) catch continue;
        agent_entries.append(allocator, .{ .action = a, .id = id_dup }) catch allocator.free(id_dup);
    }
}

const ConvEntry = struct { action: QAction, id: []u8, preview: []u8 };
var conv_entries: std.ArrayList(ConvEntry) = .empty;

fn onPickConv(a: QAction) callconv(.c) void {
    for (conv_entries.items) |e| {
        e.action.setChecked(e.action.ptr == a.ptr);
        if (e.action.ptr == a.ptr) setPrefsConvo(e.id);
    }
    savePrefs();
    std.debug.print("inferon: conversation -> {s}\n", .{current_conversation});
}

fn populateConvMenu() void {
    for (conv_entries.items) |e| {
        allocator.free(e.id);
        allocator.free(e.preview);
    }
    conv_entries.clearRetainingCapacity();
    conv_menu.clear();

    const convs = letta.listConversations(io_ctx.?, allocator, current_agent) catch return;
    defer {
        for (convs) |c| {
            allocator.free(c.id);
            allocator.free(c.preview);
        }
        allocator.free(convs);
    }
    for (convs) |c| {
        const trunc = if (c.preview.len > 60) c.preview[0..60] else c.preview;
        const label = if (trunc.len > 0)
            std.fmt.allocPrint(allocator, "{s} — {s}", .{ c.id, trunc }) catch continue
        else
            allocator.dupe(u8, c.id) catch continue;
        defer allocator.free(label);
        const a = QAction.new5(label, QWidget{ .ptr = null });
        a.setCheckable(true);
        a.setChecked(std.mem.eql(u8, c.id, current_conversation));
        a.onTriggered(onPickConv);
        conv_menu.addAction(a);
        const id_dup = allocator.dupe(u8, c.id) catch continue;
        const prev_dup = allocator.dupe(u8, c.preview) catch {
            allocator.free(id_dup);
            continue;
        };
        conv_entries.append(allocator, .{ .id = id_dup, .action = a, .preview = prev_dup }) catch {
            allocator.free(id_dup);
            allocator.free(prev_dup);
        };
    }
}

fn onEndConversation(_: QAction) callconv(.c) void {
    if (recorder != null) stopRecording();
    conversation_active = false;
    if (last_user_text) |t| allocator.free(t);
    last_user_text = null;
    if (overlay) |*ov| {
        ov.reset();
        ov.hide();
    }
    setState(.idle);
}

// --------------------------------------------------------------- signals ---

/// Async-signal-safe teardown: raw kill() of children only, no Io calls.
/// Children are orphan-reaped by init when we exit right after.
const SigType = @TypeOf(std.posix.SIG.INT);

fn handleFatalSignal(sig: SigType) callconv(.c) void {
    if (whisper.pid()) |p| {
        std.posix.kill(p, std.posix.SIG.TERM) catch {};
    }
    if (melo.pid()) |p| {
        std.posix.kill(p, std.posix.SIG.TERM) catch {};
    }
    if (recorder) |c| {
        if (c.id) |p| std.posix.kill(p, std.posix.SIG.TERM) catch {};
    }
    // Restore default handler and re-raise so the exit status is truthful.
    const act = std.posix.Sigaction{
        .handler = .{ .handler = std.posix.SIG.DFL },
        .mask = std.posix.sigemptyset(),
        .flags = 0,
    };
    std.posix.sigaction(sig, &act, null);
    std.posix.raise(sig) catch {};
}

fn installSignalHandlers() void {
    const act = std.posix.Sigaction{
        .handler = .{ .handler = handleFatalSignal },
        .mask = std.posix.sigemptyset(),
        .flags = 0, // no SA_RESTART: let blocking syscalls die too
    };
    std.posix.sigaction(std.posix.SIG.INT, &act, null);
    std.posix.sigaction(std.posix.SIG.TERM, &act, null);
}

// ------------------------------------------------------------------ main ---

pub fn main(init: std.process.Init) !void {
    const argv = try qt6.init(init.gpa, init.minimal.args);
    defer qt6.deinit(init.gpa, argv);
    var argc: i32 = @intCast(argv.len);
    const qapp: QApplication = .new(init.arena.allocator(), &argc, argv);
    defer qapp.delete();

    if (!QSystemTrayIcon.isSystemTrayAvailable()) {
        std.debug.print("inferon: no system tray available\n", .{});
        return error.NoSystemTray;
    }

    QApplication.setQuitOnLastWindowClosed(false);
    allocator = init.gpa;
    io_ctx = init.io;

    installSignalHandlers();

    const quit_action = QAction.new5("&Quit", QWidget{ .ptr = null });
    quit_action.onTriggered(onQuit);

    const end_action = QAction.new5("&End conversation", QWidget{ .ptr = null });
    end_action.onTriggered(onEndConversation);

    // Floating-window toggle
    const win_action = QAction.new5("&Floating window", QWidget{ .ptr = null });
    win_action.setCheckable(true);
    win_action.setChecked(true);
    win_action.onTriggered(onToggleWindow);

    initPrefsPaths();
    letta.initConversationsDir();
    loadPrefs();
    agent_menu = QMenu.new(QWidget{ .ptr = null });
    agent_menu.setTitle("Agent");
    conv_menu = QMenu.new(QWidget{ .ptr = null });
    conv_menu.setTitle("Conversation");
    populateAgentMenu();
    populateConvMenu();
    conv_menu.onAboutToShow(onConvMenuShow);

    const tray_menu = QMenu.new(QWidget{ .ptr = null });
    _ = tray_menu.addMenu(agent_menu);
    _ = tray_menu.addMenu(conv_menu);
    _ = tray_menu.addSeparator();
    tray_menu.addAction(win_action);
    tray_menu.addAction(end_action);
    _ = tray_menu.addSeparator();
    tray_menu.addAction(quit_action);

    tray_icon = .new3(QWidget{ .ptr = null });
    tray_icon.setContextMenu(tray_menu);
    tray_icon.onActivated(onTrayActivated);

    setState(.idle);
    tray_icon.show();
    main_thread_id = std.Thread.getCurrentId();

    var ov = overlay_mod.Overlay.create(allocator);
    overlay = ov;
    ov.window.show(); // visible from startup per Pierre
    _ = &ov;

    // Own the whisper-server lifecycle: spawn AFTER the tray exists (setState
    // touches tray_icon). Create the log dir first.
    Io.Dir.createDirAbsolute(init.io, RECORDINGS_DIR, .default_dir) catch {};
    whisper.start(allocator, init.io, RECORDINGS_DIR) catch |e| {
        std.debug.print("inferon: failed to start whisper-server: {s}\n", .{@errorName(e)});
        setState(.error_backend);
    };
    if (whisper.waitReady(init.io)) {
        std.debug.print("inferon: whisper-server ready on :{d}\n", .{whisper.WHISPER_PORT});
    } else {
        std.debug.print("inferon: whisper-server NOT ready after {d}s\n", .{whisper.READY_TIMEOUT_S});
    }

    // TTS backend: melo_server.py (fails soft — notifications still work).
    melo.start(allocator, init.io) catch |e| {
        std.debug.print("inferon: failed to start melo server: {s}\n", .{@errorName(e)});
    };
    if (melo.waitReady(allocator, init.io)) {
        std.debug.print("inferon: melo ready\n", .{});
        playback.start(allocator, init.io);
    } else {
        std.debug.print("inferon: melo NOT ready\n", .{});
    }

    _ = QApplication.exec();

    // Session-lifetime buffers: free so the debug allocator doesn't squawk.
    if (last_user_text) |t| allocator.free(t);
    last_user_text = null;
    sentence_buf.deinit(allocator);
    if (prefs_agent_buf) |b| allocator.free(b);
    if (prefs_convo_buf) |b| allocator.free(b);
    for (agent_entries.items) |e| allocator.free(e.id);
    agent_entries.deinit(allocator);
    for (conv_entries.items) |e| {
        allocator.free(e.id);
        allocator.free(e.preview);
    }
    conv_entries.deinit(allocator);
    overlay_mod.Overlay.shutdownMem(); // static, no instance needed
    playback.shutdown();

    whisper.stop();
    melo.stop();
}