docs(llm): request for useeffect documentation

apps/client/src/views/timer/Timer.scss

@@ -195,6 +195,24 @@
     font-weight: 600;
   }
 
+  .sound-prompt {
+    position: absolute;
+    bottom: $view-block-padding;
+    left: $view-inline-padding;
+    padding: 0.5em 0.75em;
+    border-radius: $element-border-radius;
+    background-color: $viewer-card-bg-color;
+    color: $viewer-secondary-color;
+    font-size: $timer-label-size;
+    text-transform: uppercase;
+    pointer-events: none;
+    transition: opacity $viewer-transition-time;
+
+    &--hidden {
+      opacity: 0;
+    }
+  }
+
   /* =================== LOGO ===================*/
   .logo {
     position: absolute;

apps/client/src/views/timer/Timer.tsx

@@ -8,6 +8,7 @@ import TitleCard from '../../common/components/title-card/TitleCard';
 import ViewLogo from '../../common/components/view-logo/ViewLogo';
 import ViewParamsEditor from '../../common/components/view-params-editor/ViewParamsEditor';
 import { useAutoTickingClock } from '../../common/hooks/useAutoTickingClock';
+import { useFadeOutOnInactivity } from '../../common/hooks/useFadeOutOnInactivity';
 import { useTimerSocket } from '../../common/hooks/useSocket';
 import { useWindowTitle } from '../../common/hooks/useWindowTitle';
 import { cx } from '../../common/utils/styleUtils';
@@ -30,6 +31,7 @@ import {
   getTotalTime,
 } from './timer.utils';
 import { TimerData, useTimerData } from './useTimerData';
+import { useTimerSound } from './useTimerSound';
 
 import './Timer.scss';
 
@@ -66,6 +68,7 @@ function Timer({ customFields, projectData, isMirrored, settings, viewSettings,
     freezeOvertime,
     freezeMessage,
     hidePhase,
+    endSound,
     font,
     keyColour,
     timerColour,
@@ -75,6 +78,8 @@ function Timer({ customFields, projectData, isMirrored, settings, viewSettings,
   const { getLocalizedString } = useTranslation();
   const localisedMinutes = getLocalizedString('common.minutes');
 
+  const showSoundPrompt = useTimerSound(time.phase, endSound);
+
   // gather modifiers
   const viewTimerType = timerType ?? timerTypeNow;
   const showOverlay = getShowMessage(message.timer);
@@ -156,6 +161,8 @@ function Timer({ customFields, projectData, isMirrored, settings, viewSettings,
 
       <ViewParamsEditor target={OntimeView.Timer} viewOptions={timerOptions} />
 
+      {showSoundPrompt && <SoundPermissionPrompt />}
+
       <div className={cx(['blackout', message.timer.blackout && 'blackout--active'])} />
 
       {!hideMessage && (
@@ -227,3 +234,13 @@ function TimerAutoTickingClock({ clockFormat }: { clockFormat: MaybeString }) {
     </div>
   );
 }
+
+function SoundPermissionPrompt() {
+  const isUserActive = useFadeOutOnInactivity(true);
+
+  return (
+    <div className={cx(['sound-prompt', !isUserActive && 'sound-prompt--hidden'])} aria-live='polite'>
+      Interact with the page (click/tap or press any key) to enable sound
+    </div>
+  );
+}

apps/client/src/views/timer/__tests__/timer.utils.test.ts

@@ -0,0 +1,34 @@
+import { TimerPhase } from 'ontime-types';
+
+import { shouldPlayEndSound } from '../timer.utils';
+
+describe('shouldPlayEndSound()', () => {
+  test.each([TimerPhase.Default, TimerPhase.Warning, TimerPhase.Danger])(
+    'sounds when a running timer goes into overtime from %s',
+    (previousPhase) => {
+      expect(shouldPlayEndSound(previousPhase, TimerPhase.Overtime)).toBe(true);
+    },
+  );
+
+  it('stays silent on the first phase we see, a client could be joining mid-overtime', () => {
+    expect(shouldPlayEndSound(null, TimerPhase.Overtime)).toBe(false);
+  });
+
+  it('stays silent when the phase was reset, a reload during overtime starts from none', () => {
+    expect(shouldPlayEndSound(TimerPhase.None, TimerPhase.Overtime)).toBe(false);
+  });
+
+  it('stays silent for a roll timer waiting to start', () => {
+    expect(shouldPlayEndSound(TimerPhase.Pending, TimerPhase.Overtime)).toBe(false);
+  });
+
+  it('sounds once, not on every update while in overtime', () => {
+    expect(shouldPlayEndSound(TimerPhase.Overtime, TimerPhase.Overtime)).toBe(false);
+  });
+
+  it('stays silent on phases which are not the end of the timer', () => {
+    expect(shouldPlayEndSound(TimerPhase.Default, TimerPhase.Warning)).toBe(false);
+    expect(shouldPlayEndSound(TimerPhase.Warning, TimerPhase.Danger)).toBe(false);
+    expect(shouldPlayEndSound(TimerPhase.Overtime, TimerPhase.None)).toBe(false);
+  });
+});

apps/client/src/views/timer/timer.options.ts

@@ -16,6 +16,7 @@ import { ViewOption } from '../../common/components/view-params-editor/viewParam
 import { makeOptionsFromCustomFields } from '../../common/components/view-params-editor/viewParams.utils';
 import { PresetContext } from '../../common/context/PresetContext';
 import { isStringBoolean, makeColourString } from '../common/viewUtils';
+import { endSoundOptions, isEndSound, type EndSound } from './timer.sound';
 
 // manually match the properties of TimerType excluding the None
 const timerDisplayOptions: SelectOption[] = [
@@ -76,6 +77,15 @@ export const getTimerOptions = (timeFormat: string, customFields: CustomFields):
           type: 'boolean',
           defaultValue: false,
         },
+        {
+          id: 'endSound',
+          title: 'Play sound on timer end',
+          description:
+            'Plays a sound in this screen when the timer reaches zero. The screen must be interacted with once before it can play',
+          type: 'option',
+          values: endSoundOptions,
+          defaultValue: 'none',
+        },
       ],
     },
     {
@@ -193,6 +203,7 @@ type TimerOptions = {
   freezeOvertime: boolean;
   freezeMessage: string;
   hidePhase: boolean;
+  endSound: EndSound;
   font?: string;
   keyColour?: string;
   timerColour?: string;
@@ -208,6 +219,7 @@ function getOptionsFromParams(searchParams: URLSearchParams, defaultValues?: URL
 
   // Get timerType from either source
   const timerType = validateTimerType(getValue('timerType'), TimerType.None);
+  const endSoundValue = getValue('endSound');
 
   return {
     hideClock: isStringBoolean(getValue('hideClock')),
@@ -227,6 +239,7 @@ function getOptionsFromParams(searchParams: URLSearchParams, defaultValues?: URL
     freezeOvertime: isStringBoolean(getValue('freezeOvertime')),
     freezeMessage: getValue('freezeMessage') ?? '',
     hidePhase: isStringBoolean(getValue('hidePhase')),
+    endSound: isEndSound(endSoundValue) ? endSoundValue : 'none',
 
     font: getValue('font') ?? undefined,
     keyColour: makeColourString(getValue('keyColour')),

apps/client/src/views/timer/timer.sound.ts

@@ -0,0 +1,20 @@
+import arpeggio from '../../assets/sounds/arpeggio.wav';
+import bell from '../../assets/sounds/bell.wav';
+import chime from '../../assets/sounds/chime.wav';
+import type { SelectOption } from '../../common/components/select/Select';
+
+// synthesised tones bundled with the app, no external source or licence to track
+export const endSoundSources = { chime, bell, arpeggio } as const;
+
+export type EndSound = 'none' | keyof typeof endSoundSources;
+
+export const endSoundOptions: SelectOption[] = [
+  { value: 'none', label: 'None' },
+  { value: 'chime', label: 'Chime' },
+  { value: 'bell', label: 'Bell' },
+  { value: 'arpeggio', label: 'Arpeggio' },
+];
+
+export function isEndSound(value: string | null): value is EndSound {
+  return value === 'none' || value === 'chime' || value === 'bell' || value === 'arpeggio';
+}

apps/client/src/views/timer/timer.utils.ts

@@ -189,3 +189,18 @@ export function getCardData(
     nextSecondary,
   };
 }
+
+/**
+ * Whether the end of timer sound should play for a given phase transition
+ * We only sound the transition into overtime from a phase that was already counting,
+ * which keeps a client that connects or reloads mid-overtime silent
+ */
+export function shouldPlayEndSound(previousPhase: TimerPhase | null, phase: TimerPhase): boolean {
+  if (phase !== TimerPhase.Overtime) {
+    return false;
+  }
+
+  return (
+    previousPhase === TimerPhase.Default || previousPhase === TimerPhase.Warning || previousPhase === TimerPhase.Danger
+  );
+}

apps/client/src/views/timer/useTimerSound.ts

@@ -0,0 +1,99 @@
+import { TimerPhase } from 'ontime-types';
+import { useEffect, useRef, useState } from 'react';
+
+import { endSoundSources, type EndSound } from './timer.sound';
+import { shouldPlayEndSound } from './timer.utils';
+
+/**
+ * Plays a sound when the timer reaches its end
+ *
+ * Browsers reject playback until the document has been interacted with, and that permission
+ * is lost on every page load. Since a timer screen is typically left unattended, we prime the
+ * audio element on the first interaction and let the view prompt for one if it never comes.
+ * Safari grants the permission per element, so priming has to call play() on this element from
+ * inside the event handler, it is not enough to know that an interaction happened.
+ */
+export function useTimerSound(phase: TimerPhase, sound: EndSound): boolean {
+  const audioRef = useRef<HTMLAudioElement | null>(null);
+  const previousPhaseRef = useRef<TimerPhase | null>(null);
+  const [isArmed, setIsArmed] = useState(false);
+
+  const enabled = sound !== 'none';
+
+  // Create and clean up the audio element; changing sounds requires re-arming it in Safari.
+  useEffect(() => {
+    setIsArmed(false);
+
+    if (sound === 'none') {
+      return;
+    }
+
+    const audio = new Audio(endSoundSources[sound]);
+    audioRef.current = audio;
+
+    return () => {
+      audio.pause();
+      audioRef.current = null;
+    };
+  }, [sound]);
+
+  // Listen for user interaction until muted playback succeeds and arms the selected audio element.
+  useEffect(() => {
+    if (!enabled || isArmed) {
+      return;
+    }
+
+    const controller = new AbortController();
+    const prime = () => {
+      const audio = audioRef.current;
+      if (!audio) {
+        return;
+      }
+
+      const wasMuted = audio.muted;
+      audio.muted = true;
+      audio
+        .play()
+        .then(() => {
+          if (audioRef.current !== audio) {
+            return;
+          }
+          audio.pause();
+          audio.currentTime = 0;
+          setIsArmed(true);
+        })
+        .catch(() => {
+          // playback is still blocked, a later interaction will try again
+        })
+        .finally(() => {
+          audio.muted = wasMuted;
+        });
+    };
+
+    document.addEventListener('pointerdown', prime, { capture: true, signal: controller.signal });
+    document.addEventListener('keydown', prime, { capture: true, signal: controller.signal });
+
+    return () => {
+      controller.abort();
+    };
+  }, [enabled, isArmed]);
+
+  // Track phase transitions and play only when a running timer enters overtime.
+  useEffect(() => {
+    const previousPhase = previousPhaseRef.current;
+    previousPhaseRef.current = phase;
+
+    if (!enabled || !shouldPlayEndSound(previousPhase, phase)) {
+      return;
+    }
+    const audio = audioRef.current;
+    if (!audio) return;
+
+    audio.currentTime = 0;
+    audio.play().catch(() => {
+      // the screen has not been interacted with, the view shows a prompt for it
+    });
+  }, [enabled, phase]);
+
+  return enabled && !isArmed;
+}

docs/agent-guides/code-quality.md

@@ -36,6 +36,10 @@ Remove comments that:
 
 Update adjacent comments with code. Stale comments are defects.
 
+Add a short comment immediately above every React `useEffect` describing the external synchronization or lifecycle
+responsibility it owns. Explain non-obvious reasons or constraints when they matter; for files with multiple effects, a
+brief responsibility label is useful even when the mechanics are straightforward.
+
 ## Naming and types
 
 - Prefer Ontime terms over vague `data`, `result`, `item`.