PhuocNTB
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64 lines
1.9 KiB
TypeScript
64 lines
1.9 KiB
TypeScript
let audioCtx: AudioContext | null = null;
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function getAudioCtx(): AudioContext | null {
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if (audioCtx) return audioCtx;
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try {
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const Ctx = window.AudioContext || (window as unknown as { webkitAudioContext: typeof AudioContext }).webkitAudioContext;
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audioCtx = new Ctx();
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return audioCtx;
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} catch {
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return null;
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}
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}
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/** Short two-tone ping for chat notifications */
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export function playChatSound() {
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const ctx = getAudioCtx();
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if (!ctx) return;
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if (ctx.state === 'suspended') {
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void ctx.resume();
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}
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const playTone = (freq: number, start: number, duration: number) => {
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const osc = ctx.createOscillator();
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const gain = ctx.createGain();
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osc.type = 'sine';
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osc.frequency.value = freq;
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gain.gain.setValueAtTime(0.0001, start);
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gain.gain.exponentialRampToValueAtTime(0.12, start + 0.02);
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gain.gain.exponentialRampToValueAtTime(0.0001, start + duration);
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osc.connect(gain);
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gain.connect(ctx.destination);
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osc.start(start);
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osc.stop(start + duration + 0.02);
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};
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const t = ctx.currentTime;
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playTone(880, t, 0.12);
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playTone(1174, t + 0.14, 0.14);
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}
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/** Louder alert for student violations (quit / kill app) */
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export function playAlertSound() {
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const ctx = getAudioCtx();
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if (!ctx) return;
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if (ctx.state === 'suspended') {
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void ctx.resume();
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}
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const playTone = (freq: number, start: number, duration: number) => {
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const osc = ctx.createOscillator();
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const gain = ctx.createGain();
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osc.type = 'square';
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osc.frequency.value = freq;
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gain.gain.setValueAtTime(0.0001, start);
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gain.gain.exponentialRampToValueAtTime(0.1, start + 0.02);
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gain.gain.exponentialRampToValueAtTime(0.0001, start + duration);
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osc.connect(gain);
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gain.connect(ctx.destination);
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osc.start(start);
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osc.stop(start + duration + 0.02);
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};
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const t = ctx.currentTime;
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playTone(520, t, 0.16);
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playTone(390, t + 0.18, 0.2);
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playTone(520, t + 0.4, 0.18);
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}
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