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"use client";
import { useEffect, useRef, useState } from "react";
import { cn } from "@/utils/ui";
import { getActiveVoiceOverRecordingStream } from "@/voiceover/recorder";
const FFT_SIZE = 1024;
const HISTORY_SIZE = 96;
export function VoiceOverLiveWaveform({
recording,
className,
}: {
recording: boolean;
className?: string;
}) {
const canvasRef = useRef<HTMLCanvasElement>(null);
const levelRef = useRef(0);
const historyRef = useRef<number[]>(
Array.from({ length: HISTORY_SIZE }, () => 0),
);
const [level, setLevel] = useState(0);
useEffect(() => {
const canvas = canvasRef.current;
if (!canvas || !recording) {
drawWaveform({
canvas,
history: historyRef.current,
level: 0,
});
setLevel(0);
return;
}
const stream = getActiveVoiceOverRecordingStream();
if (!stream) {
return;
}
const audioContext = createAudioContext();
const source = audioContext.createMediaStreamSource(stream);
const analyser = audioContext.createAnalyser();
analyser.fftSize = FFT_SIZE;
analyser.smoothingTimeConstant = 0.72;
source.connect(analyser);
const samples = new Uint8Array(analyser.fftSize);
let animationFrame = 0;
let lastLevelUpdate = 0;
const render = (timestamp: number) => {
analyser.getByteTimeDomainData(samples);
const rms = getRmsLevel({ samples });
levelRef.current = rms;
historyRef.current = [...historyRef.current.slice(1), rms];
drawWaveform({
canvas,
history: historyRef.current,
level: rms,
});
if (timestamp - lastLevelUpdate > 80) {
lastLevelUpdate = timestamp;
setLevel(rms);
}
animationFrame = requestAnimationFrame(render);
};
animationFrame = requestAnimationFrame(render);
return () => {
cancelAnimationFrame(animationFrame);
source.disconnect();
analyser.disconnect();
void audioContext.close();
};
}, [recording]);
return (
<div className={cn("space-y-2", className)}>
<div className="bg-muted relative h-16 overflow-hidden rounded-sm border">
<canvas ref={canvasRef} className="absolute inset-0 size-full" />
</div>
<div className="bg-muted h-1.5 overflow-hidden rounded-full">
<div
className="bg-primary h-full rounded-full transition-[width]"
style={{ width: `${Math.min(100, Math.round(level * 140))}%` }}
/>
</div>
</div>
);
}
function getRmsLevel({ samples }: { samples: Uint8Array }): number {
let sum = 0;
for (let index = 0; index < samples.length; index++) {
const centered = ((samples[index] ?? 128) - 128) / 128;
sum += centered * centered;
}
return Math.sqrt(sum / samples.length);
}
function drawWaveform({
canvas,
history,
level,
}: {
canvas: HTMLCanvasElement | null;
history: number[];
level: number;
}): void {
if (!canvas) {
return;
}
const rect = canvas.getBoundingClientRect();
const dpr = window.devicePixelRatio || 1;
const width = Math.max(1, Math.round(rect.width * dpr));
const height = Math.max(1, Math.round(rect.height * dpr));
if (canvas.width !== width || canvas.height !== height) {
canvas.width = width;
canvas.height = height;
}
const ctx = canvas.getContext("2d");
if (!ctx) {
return;
}
ctx.setTransform(1, 0, 0, 1, 0, 0);
ctx.clearRect(0, 0, width, height);
const centerY = height / 2;
const step = width / Math.max(1, history.length);
ctx.strokeStyle = "rgba(148, 163, 184, 0.35)";
ctx.lineWidth = 1;
ctx.beginPath();
ctx.moveTo(0, centerY);
ctx.lineTo(width, centerY);
ctx.stroke();
for (let index = 0; index < history.length; index++) {
const value = Math.max(0, history[index] ?? 0);
const barHeight = Math.max(1, Math.min(height, value * height * 2.8));
const x = Math.round(index * step);
const y = Math.round(centerY - barHeight / 2);
ctx.fillStyle =
value > 0.62
? "rgba(239, 68, 68, 0.9)"
: value > 0.32
? "rgba(245, 158, 11, 0.9)"
: "rgba(34, 197, 94, 0.9)";
ctx.fillRect(x, y, Math.max(1, Math.floor(step - 1)), barHeight);
}
if (level > 0.78) {
ctx.fillStyle = "rgba(239, 68, 68, 0.18)";
ctx.fillRect(0, 0, width, height);
}
}
function createAudioContext(): AudioContext {
const AudioContextConstructor =
window.AudioContext ||
(window as typeof window & { webkitAudioContext?: typeof AudioContext })
.webkitAudioContext;
return new AudioContextConstructor();
}
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