Add cliamp.message plugin API for status bar messages

Plugins can now call cliamp.message(text, duration_secs?) to display
transient messages in the UI status bar. Closes #175.

Delivery flows through prog.Send to the Bubbletea model thread, so
plugin timers and event handlers never touch UI state directly.

Author: bjarneo

docs/plugins.md

@@ -297,6 +297,16 @@ cliamp.notify("Song Title", "Artist Name") -- notification with title and body
 
 Sends a desktop notification via `notify-send`. Works with mako, dunst, and other notification daemons.
 
+### cliamp.message
+
+```lua
+cliamp.message("Scrobble Sent")        -- show for default duration
+cliamp.message("Syncing Library", 5)   -- show for 5 seconds
+```
+
+Displays a transient message in the status bar at the bottom of the UI. The
+duration argument is optional (seconds); omit it to use the default TTL. Durations above 60 seconds are clamped.
+
 ### cliamp.sleep
 
 ```lua

luaplugin/api_message.go

@@ -0,0 +1,30 @@
+package luaplugin
+
+import (
+	"time"
+
+	lua "github.com/yuin/gopher-lua"
+)
+
+// messageMaxDuration caps how long a plugin-supplied status message can stay on
+// screen. Plugins can request longer durations, but they get clamped so a
+// runaway script cannot pin the status bar indefinitely.
+const messageMaxDuration = 60 * time.Second
+
+// registerMessageAPI adds cliamp.message(text, duration_secs?) which displays a
+// temporary message in the status bar at the bottom of the UI. A missing or
+// non-positive duration falls back to the default status TTL (set by the UI).
+func registerMessageAPI(L *lua.LState, cliamp *lua.LTable, ui *UIProvider) {
+	L.SetField(cliamp, "message", L.NewFunction(func(L *lua.LState) int {
+		if ui.ShowMessage == nil {
+			return 0
+		}
+		text := L.CheckString(1)
+		var dur time.Duration
+		if secs := float64(L.OptNumber(2, 0)); secs > 0 {
+			dur = min(time.Duration(secs*float64(time.Second)), messageMaxDuration)
+		}
+		ui.ShowMessage(text, dur)
+		return 0
+	}))
+}

luaplugin/api_message_test.go

@@ -0,0 +1,81 @@
+package luaplugin
+
+import (
+	"testing"
+	"time"
+)
+
+func TestMessageAPIDeliversTextAndDuration(t *testing.T) {
+	m := newTestManager()
+	var gotText string
+	var gotDur time.Duration
+	m.SetUIProvider(UIProvider{
+		ShowMessage: func(text string, duration time.Duration) {
+			gotText = text
+			gotDur = duration
+		},
+	})
+
+	loadTestPlugin(t, m, "msg-test", `
+		plugin.register({name = "msg-test", type = "hook"})
+		cliamp.message("Scrobble Sent", 2)
+	`)
+
+	if gotText != "Scrobble Sent" {
+		t.Fatalf("text = %q, want %q", gotText, "Scrobble Sent")
+	}
+	if gotDur != 2*time.Second {
+		t.Fatalf("duration = %v, want 2s", gotDur)
+	}
+}
+
+func TestMessageAPIDefaultsDurationToZero(t *testing.T) {
+	m := newTestManager()
+	var gotDur time.Duration
+	seen := false
+	m.SetUIProvider(UIProvider{
+		ShowMessage: func(_ string, duration time.Duration) {
+			gotDur = duration
+			seen = true
+		},
+	})
+
+	loadTestPlugin(t, m, "msg-default", `
+		plugin.register({name = "msg-default", type = "hook"})
+		cliamp.message("hello")
+	`)
+
+	if !seen {
+		t.Fatal("ShowMessage was not called")
+	}
+	if gotDur != 0 {
+		t.Fatalf("duration = %v, want 0 (UI decides default)", gotDur)
+	}
+}
+
+func TestMessageAPIClampsMaxDuration(t *testing.T) {
+	m := newTestManager()
+	var gotDur time.Duration
+	m.SetUIProvider(UIProvider{
+		ShowMessage: func(_ string, duration time.Duration) { gotDur = duration },
+	})
+
+	loadTestPlugin(t, m, "msg-clamp", `
+		plugin.register({name = "msg-clamp", type = "hook"})
+		cliamp.message("long", 9999)
+	`)
+
+	if gotDur != messageMaxDuration {
+		t.Fatalf("duration = %v, want %v (clamped)", gotDur, messageMaxDuration)
+	}
+}
+
+func TestMessageAPIWithoutProviderIsNoop(t *testing.T) {
+	m := newTestManager()
+	// No SetUIProvider call — ShowMessage is nil.
+	loadTestPlugin(t, m, "msg-noop", `
+		plugin.register({name = "msg-noop", type = "hook"})
+		cliamp.message("nobody listening")
+	`)
+	// Success = no panic / no error from loadPlugin above.
+}

luaplugin/luaplugin.go

@@ -10,6 +10,7 @@ import (
 	"sort"
 	"strings"
 	"sync"
+	"time"
 
 	lua "github.com/yuin/gopher-lua"
 
@@ -69,6 +70,12 @@ type ControlProvider struct {
 	Prev        func()                                // injected via prog.Send
 }
 
+// UIProvider supplies callbacks that surface plugin output in the TUI.
+// Not permission-gated — these are low-risk, output-only operations.
+type UIProvider struct {
+	ShowMessage func(text string, duration time.Duration) // injected via prog.Send
+}
+
 // Manager owns all loaded plugins and dispatches events to them.
 type Manager struct {
 	plugins  []*Plugin
@@ -77,6 +84,7 @@ type Manager struct {
 	visMap   map[string]*luaVis    // name -> Lua visualizer
 	state    StateProvider
 	control  ControlProvider
+	ui       UIProvider
 	timers   *timerManager
 	logger   *pluginLogger
 	mu       sync.RWMutex
@@ -336,6 +344,7 @@ func (m *Manager) registerCliampAPI(L *lua.LState, p *Plugin) {
 	registerTimerAPI(L, cliamp, m.timers, p)
 	registerNotifyAPI(L, cliamp, m.logger, p.Name)
 	registerControlAPI(L, cliamp, &m.control, p, m.logger)
+	registerMessageAPI(L, cliamp, &m.ui)
 	registerSleepAPI(L, cliamp)
 	L.SetGlobal("cliamp", cliamp)
 }
@@ -352,6 +361,11 @@ func (m *Manager) SetControlProvider(cp ControlProvider) {
 	m.control = cp
 }
 
+// SetUIProvider sets the function pointers for UI output (status messages).
+func (m *Manager) SetUIProvider(up UIProvider) {
+	m.ui = up
+}
+
 // Close fires the "app.quit" event synchronously and shuts down all Lua VMs.
 func (m *Manager) Close() {
 	m.EmitSync(EventAppQuit, nil)

main.go

@@ -302,6 +302,11 @@ func run(overrides config.Overrides, positional []string) error {
 			Next: func() { prog.Send(playback.NextMsg{}) },
 			Prev: func() { prog.Send(playback.PrevMsg{}) },
 		})
+		luaMgr.SetUIProvider(luaplugin.UIProvider{
+			ShowMessage: func(text string, duration time.Duration) {
+				prog.Send(model.ShowStatusMsg{Text: text, Duration: duration})
+			},
+		})
 	}
 
 	ipcSrv, ipcErr := ipc.NewServer(ipc.DefaultSocketPath(), ipc.DispatcherFunc(func(msg any) { prog.Send(msg) }))

plugins/status-messages.lua

@@ -0,0 +1,43 @@
+-- status-messages.lua — Demo of cliamp.message(): surface playback events
+-- as transient messages in the status bar at the bottom of the UI.
+--
+-- Install by copying (or symlinking) this file to ~/.config/cliamp/plugins/
+-- and restart cliamp.
+
+local p = plugin.register({
+    name = "status-messages",
+    type = "hook",
+    description = "Show playback events in the status bar",
+})
+
+p:on("app.start", function()
+    cliamp.message("cliamp ready", 2)
+end)
+
+p:on("track.change", function(track)
+    local text = track.title or ""
+    if track.artist and track.artist ~= "" then
+        text = track.artist .. " — " .. text
+    end
+    cliamp.message("Now playing: " .. text, 3)
+end)
+
+-- playback.state fires on every tick (~1Hz) during playback, not just on
+-- state transitions. Track the last status locally so the status bar is
+-- only updated when it actually changes.
+local last_status = nil
+p:on("playback.state", function(ev)
+    if ev.status == last_status then
+        return
+    end
+    last_status = ev.status
+    if ev.status == "paused" then
+        cliamp.message("Paused", 1.5)
+    elseif ev.status == "stopped" then
+        cliamp.message("Stopped", 1.5)
+    end
+end)
+
+p:on("track.scrobble", function()
+    cliamp.message("Scrobble sent", 2)
+end)

ui/model/commands.go

@@ -35,6 +35,13 @@ type SetEQPresetMsg struct {
 	Bands *[10]float64 // nil = use built-in preset bands or keep current
 }
 
+// ShowStatusMsg is sent by Lua plugins to display a message in the status bar.
+// Duration <= 0 falls back to the default status TTL.
+type ShowStatusMsg struct {
+	Text     string
+	Duration time.Duration
+}
+
 type tracksLoadedMsg []playlist.Track
 
 // feedsLoadedMsg carries tracks resolved from remote feed/M3U URLs,

ui/model/update.go

@@ -687,6 +687,14 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		m.SetEQPreset(msg.Name, msg.Bands)
 		return m, nil
 
+	case ShowStatusMsg:
+		ttl := statusTTLDefault
+		if msg.Duration > 0 {
+			ttl = statusTTL(msg.Duration)
+		}
+		m.status.Show(msg.Text, ttl)
+		return m, nil
+
 	// IPC-specific messages (PlayMsg, PauseMsg have different semantics from toggle).
 	// Shared types (NextMsg, PrevMsg, StopMsg, PlayPauseMsg) are handled above via
 	// playback.* types.