src/lib/components/chat/MessageInput/VoiceRecording.svelte

<script lang="ts">
	import { toast } from 'svelte-sonner';
	import { createEventDispatcher, tick, getContext } from 'svelte';
	import { config, settings } from '$lib/stores';
	import { blobToFile, calculateSHA256, findWordIndices } from '$lib/utils';

	import { transcribeAudio } from '$lib/apis/audio';

	const i18n = getContext('i18n');

	const dispatch = createEventDispatcher();

	export let recording = false;

	let loading = false;
	let confirmed = false;

	let durationSeconds = 0;
	let durationCounter = null;

	let transcription = '';

	const startDurationCounter = () => {
		durationCounter = setInterval(() => {
			durationSeconds++;
		}, 1000);
	};

	const stopDurationCounter = () => {
		clearInterval(durationCounter);
		durationSeconds = 0;
	};

	$: if (recording) {
		startRecording();
	} else {
		stopRecording();
	}

	const formatSeconds = (seconds) => {
		const minutes = Math.floor(seconds / 60);
		const remainingSeconds = seconds % 60;
		const formattedSeconds = remainingSeconds < 10 ? `0${remainingSeconds}` : remainingSeconds;
		return `${minutes}:${formattedSeconds}`;
	};

	let speechRecognition;

	let mediaRecorder;
	let audioChunks = [];

	const MIN_DECIBELS = -45;
	const VISUALIZER_BUFFER_LENGTH = 300;

	let visualizerData = Array(VISUALIZER_BUFFER_LENGTH).fill(0);

	// Function to calculate the RMS level from time domain data
	const calculateRMS = (data: Uint8Array) => {
		let sumSquares = 0;
		for (let i = 0; i < data.length; i++) {
			const normalizedValue = (data[i] - 128) / 128; // Normalize the data
			sumSquares += normalizedValue * normalizedValue;
		}
		return Math.sqrt(sumSquares / data.length);
	};

	const normalizeRMS = (rms) => {
		rms = rms * 10;
		const exp = 1.5; // Adjust exponent value; values greater than 1 expand larger numbers more and compress smaller numbers more
		const scaledRMS = Math.pow(rms, exp);

		// Scale between 0.01 (1%) and 1.0 (100%)
		return Math.min(1.0, Math.max(0.01, scaledRMS));
	};

	const analyseAudio = (stream) => {
		const audioContext = new AudioContext();
		const audioStreamSource = audioContext.createMediaStreamSource(stream);

		const analyser = audioContext.createAnalyser();
		analyser.minDecibels = MIN_DECIBELS;
		audioStreamSource.connect(analyser);

		const bufferLength = analyser.frequencyBinCount;

		const domainData = new Uint8Array(bufferLength);
		const timeDomainData = new Uint8Array(analyser.fftSize);

		let lastSoundTime = Date.now();

		const detectSound = () => {
			const processFrame = () => {
				if (!recording || loading) return;

				if (recording && !loading) {
					analyser.getByteTimeDomainData(timeDomainData);
					analyser.getByteFrequencyData(domainData);

					// Calculate RMS level from time domain data
					const rmsLevel = calculateRMS(timeDomainData);
					// Push the calculated decibel level to visualizerData
					visualizerData.push(normalizeRMS(rmsLevel));

					// Ensure visualizerData array stays within the buffer length
					if (visualizerData.length >= VISUALIZER_BUFFER_LENGTH) {
						visualizerData.shift();
					}

					visualizerData = visualizerData;

					// if (domainData.some((value) => value > 0)) {
					// 	lastSoundTime = Date.now();
					// }

					// if (recording && Date.now() - lastSoundTime > 3000) {
					// 	if ($settings?.speechAutoSend ?? false) {
					// 		confirmRecording();
					// 	}
					// }
				}

				window.requestAnimationFrame(processFrame);
			};

			window.requestAnimationFrame(processFrame);
		};

		detectSound();
	};

	const transcribeHandler = async (audioBlob) => {
		// Create a blob from the audio chunks

		await tick();
		const file = blobToFile(audioBlob, 'recording.wav');

		const res = await transcribeAudio(localStorage.token, file).catch((error) => {
			toast.error(error);
			return null;
		});

		if (res) {
			console.log(res.text);
			dispatch('confirm', res.text);
		}
	};

	const saveRecording = (blob) => {
		const url = URL.createObjectURL(blob);
		const a = document.createElement('a');
		document.body.appendChild(a);
		a.style = 'display: none';
		a.href = url;
		a.download = 'recording.wav';
		a.click();
		window.URL.revokeObjectURL(url);
	};

	const startRecording = async () => {
		startDurationCounter();

		const stream = await navigator.mediaDevices.getUserMedia({ audio: true });
		mediaRecorder = new MediaRecorder(stream);
		mediaRecorder.onstart = () => {
			console.log('Recording started');
			audioChunks = [];
			analyseAudio(stream);
		};
		mediaRecorder.ondataavailable = (event) => audioChunks.push(event.data);
		mediaRecorder.onstop = async () => {
			console.log('Recording stopped');
			if (($settings?.audio?.stt?.engine ?? '') === 'web') {
				audioChunks = [];
			} else {
				if (confirmed) {
					const audioBlob = new Blob(audioChunks, { type: 'audio/wav' });

					await transcribeHandler(audioBlob);

					confirmed = false;
					loading = false;
				}
				audioChunks = [];
				recording = false;
			}
		};
		mediaRecorder.start();
		if ($config.audio.stt.engine === 'web' || ($settings?.audio?.stt?.engine ?? '') === 'web') {
			if ('SpeechRecognition' in window || 'webkitSpeechRecognition' in window) {
				// Create a SpeechRecognition object
				speechRecognition = new (window.SpeechRecognition || window.webkitSpeechRecognition)();

				// Set continuous to true for continuous recognition
				speechRecognition.continuous = true;

				// Set the timeout for turning off the recognition after inactivity (in milliseconds)
				const inactivityTimeout = 2000; // 3 seconds

				let timeoutId;
				// Start recognition
				speechRecognition.start();

				// Event triggered when speech is recognized
				speechRecognition.onresult = async (event) => {
					// Clear the inactivity timeout
					clearTimeout(timeoutId);

					// Handle recognized speech
					console.log(event);
					const transcript = event.results[Object.keys(event.results).length - 1][0].transcript;

					transcription = `${transcription}${transcript}`;

					await tick();
					document.getElementById('chat-textarea')?.focus();

					// Restart the inactivity timeout
					timeoutId = setTimeout(() => {
						console.log('Speech recognition turned off due to inactivity.');
						speechRecognition.stop();
					}, inactivityTimeout);
				};

				// Event triggered when recognition is ended
				speechRecognition.onend = function () {
					// Restart recognition after it ends
					console.log('recognition ended');

					confirmRecording();
					dispatch('confirm', transcription);

					confirmed = false;
					loading = false;
				};

				// Event triggered when an error occurs
				speechRecognition.onerror = function (event) {
					console.log(event);
					toast.error($i18n.t(`Speech recognition error: {{error}}`, { error: event.error }));
					dispatch('cancel');

					stopRecording();
				};
			}
		}
	};

	const stopRecording = async () => {
		if (recording && mediaRecorder) {
			await mediaRecorder.stop();
		}
		stopDurationCounter();
		audioChunks = [];
	};

	const confirmRecording = async () => {
		loading = true;
		confirmed = true;

		if (recording && mediaRecorder) {
			await mediaRecorder.stop();
		}
		clearInterval(durationCounter);
	};
</script>

<div
	class="{loading
		? ' bg-gray-100/50 dark:bg-gray-850/50'
		: 'bg-indigo-300/10 dark:bg-indigo-500/10 '} rounded-full flex p-2.5"
>
	<div class="flex items-center mr-1">
		<button
			type="button"
			class="p-1.5

            {loading
				? ' bg-gray-200 dark:bg-gray-700/50'
				: 'bg-indigo-400/20 text-indigo-600 dark:text-indigo-300 '} 


             rounded-full"
			on:click={async () => {
				dispatch('cancel');
				stopRecording();
			}}
		>
			<svg
				xmlns="http://www.w3.org/2000/svg"
				fill="none"
				viewBox="0 0 24 24"
				stroke-width="3"
				stroke="currentColor"
				class="size-4"
			>
				<path stroke-linecap="round" stroke-linejoin="round" d="M6 18 18 6M6 6l12 12" />
			</svg>
		</button>
	</div>

	<div
		class="flex flex-1 self-center items-center justify-between ml-2 mx-1 overflow-hidden h-6"
		dir="rtl"
	>
		<div class="flex-1 flex items-center gap-0.5 h-6">
			{#each visualizerData.slice().reverse() as rms}
				<div
					class="w-[2px]
                    
                    {loading
						? ' bg-gray-500 dark:bg-gray-400   '
						: 'bg-indigo-500 dark:bg-indigo-400  '} 
                    
                    inline-block h-full"
					style="height: {Math.min(100, Math.max(14, rms * 100))}%;"
				/>
			{/each}
		</div>
	</div>

	<div class="  mx-1.5 pr-1 flex justify-center items-center">
		<div
			class="text-sm
        
        
        {loading ? ' text-gray-500  dark:text-gray-400  ' : ' text-indigo-400 '} 
       font-medium flex-1 mx-auto text-center"
		>
			{formatSeconds(durationSeconds)}
		</div>
	</div>

	<div class="flex items-center mr-1">
		{#if loading}
			<div class=" text-gray-500 rounded-full cursor-not-allowed">
				<svg
					width="24"
					height="24"
					viewBox="0 0 24 24"
					xmlns="http://www.w3.org/2000/svg"
					fill="currentColor"
					><style>
						.spinner_OSmW {
							transform-origin: center;
							animation: spinner_T6mA 0.75s step-end infinite;
						}
						@keyframes spinner_T6mA {
							8.3% {
								transform: rotate(30deg);
							}
							16.6% {
								transform: rotate(60deg);
							}
							25% {
								transform: rotate(90deg);
							}
							33.3% {
								transform: rotate(120deg);
							}
							41.6% {
								transform: rotate(150deg);
							}
							50% {
								transform: rotate(180deg);
							}
							58.3% {
								transform: rotate(210deg);
							}
							66.6% {
								transform: rotate(240deg);
							}
							75% {
								transform: rotate(270deg);
							}
							83.3% {
								transform: rotate(300deg);
							}
							91.6% {
								transform: rotate(330deg);
							}
							100% {
								transform: rotate(360deg);
							}
						}
					</style><g class="spinner_OSmW"
						><rect x="11" y="1" width="2" height="5" opacity=".14" /><rect
							x="11"
							y="1"
							width="2"
							height="5"
							transform="rotate(30 12 12)"
							opacity=".29"
						/><rect
							x="11"
							y="1"
							width="2"
							height="5"
							transform="rotate(60 12 12)"
							opacity=".43"
						/><rect
							x="11"
							y="1"
							width="2"
							height="5"
							transform="rotate(90 12 12)"
							opacity=".57"
						/><rect
							x="11"
							y="1"
							width="2"
							height="5"
							transform="rotate(120 12 12)"
							opacity=".71"
						/><rect
							x="11"
							y="1"
							width="2"
							height="5"
							transform="rotate(150 12 12)"
							opacity=".86"
						/><rect x="11" y="1" width="2" height="5" transform="rotate(180 12 12)" /></g
					></svg
				>
			</div>
		{:else}
			<button
				type="button"
				class="p-1.5 bg-indigo-500 text-white dark:bg-indigo-500 dark:text-blue-950 rounded-full"
				on:click={async () => {
					await confirmRecording();
				}}
			>
				<svg
					xmlns="http://www.w3.org/2000/svg"
					fill="none"
					viewBox="0 0 24 24"
					stroke-width="2.5"
					stroke="currentColor"
					class="size-4"
				>
					<path stroke-linecap="round" stroke-linejoin="round" d="m4.5 12.75 6 6 9-13.5" />
				</svg>
			</button>
		{/if}
	</div>
</div>

<style>
	.visualizer {
		display: flex;
		height: 100%;
	}

	.visualizer-bar {
		width: 2px;
		background-color: #4a5aba; /* or whatever color you need */
	}
</style>