From 960c829744409c8b52507f02b0f128882c354a19 Mon Sep 17 00:00:00 2001
From: gm <nitro820@gmail.com>
Date: Fri, 26 Jun 2026 13:38:10 +0900
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Web Audio API로 E5→C5 두음 벨소리 합성 (외부 파일 불필요).
표시판 화면에 소리 켜짐/꺼짐 토글 버튼 추가.
AudioContext는 역할 선택 클릭 시 초기화 (브라우저 autoplay 정책 대응).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 public/index.html | 54 +++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 52 insertions(+), 2 deletions(-)

diff --git a/public/index.html b/public/index.html
index 266e94c..2af028d 100644
--- a/public/index.html
+++ b/public/index.html
@@ -320,6 +320,7 @@
   <div class="display-label">현재 호출 번호</div>
   <div class="display-num" id="display-num">-</div>
   <div class="display-sub" id="display-sub">대기 중 0명</div>
+  <button class="btn" id="display-mute-btn" style="bottom:60px">🔔 소리 켜짐</button>
   <button class="btn" id="display-back-btn">역할 변경</button>
 </div>
 
@@ -329,6 +330,49 @@ const socket = io();
 let currentPin = '';
 let currentRole = '';
 let myTicketNumber = null;
+let lastCalledCount = 0;
+
+// ── 소리 ──────────────────────────────────────
+let audioCtx = null;
+let soundMuted = false;
+
+function initAudio() {
+  if (audioCtx) return;
+  audioCtx = new (window.AudioContext || window.webkitAudioContext)();
+}
+
+function playDingDong() {
+  if (soundMuted || !audioCtx) return;
+  if (audioCtx.state === 'suspended') audioCtx.resume();
+  const t = audioCtx.currentTime;
+
+  function bell(freq, start, dur, vol) {
+    const osc = audioCtx.createOscillator();
+    const gain = audioCtx.createGain();
+    osc.connect(gain);
+    gain.connect(audioCtx.destination);
+    osc.type = 'sine';
+    osc.frequency.setValueAtTime(freq, start);
+    gain.gain.setValueAtTime(0, start);
+    gain.gain.linearRampToValueAtTime(vol, start + 0.012);
+    gain.gain.exponentialRampToValueAtTime(0.0001, start + dur);
+    osc.start(start);
+    osc.stop(start + dur + 0.05);
+  }
+
+  // 띵 (E5 + 옥타브 배음)
+  bell(659, t,        1.1, 0.40);
+  bell(1318, t,       1.1, 0.12);
+  // 동 (C5 + 옥타브 배음) — 0.45초 후
+  bell(523, t + 0.45, 1.4, 0.40);
+  bell(1046, t + 0.45, 1.4, 0.12);
+}
+
+document.getElementById('display-mute-btn').addEventListener('click', () => {
+  soundMuted = !soundMuted;
+  document.getElementById('display-mute-btn').textContent =
+    soundMuted ? '🔇 소리 꺼짐' : '🔔 소리 켜짐';
+});
 
 // ── 유틸 ──────────────────────────────────────
 function showScreen(id) {
@@ -376,7 +420,9 @@ document.getElementById('role-issue').addEventListener('click', () => {
   showScreen('screen-issue');
 });
 document.getElementById('role-display').addEventListener('click', () => {
-  currentRole = 'display'; showScreen('screen-display');
+  currentRole = 'display';
+  initAudio(); // 사용자 인터랙션 직후 AudioContext 생성 (autoplay 정책)
+  showScreen('screen-display');
 });
 
 // 역할 변경
@@ -424,8 +470,12 @@ function applyState(s) {
     displayEl.classList.remove('flash');
     void displayEl.offsetWidth; // reflow
     displayEl.textContent = newVal;
-    if (s.calledCount > 0) displayEl.classList.add('flash');
+    if (s.calledCount > 0) {
+      displayEl.classList.add('flash');
+      if (currentRole === 'display') playDingDong();
+    }
   }
+  lastCalledCount = s.calledCount;
   document.getElementById('display-sub').textContent = `대기 중 ${s.waitingCount}명`;
 }