src/lib/index.ts

// place files you want to import through the `$lib` alias in this folder.

import { majorAirportIATAs } from '$lib/icao';

interface BandwidthCallback {
	(
		elapsedMs: number,
		loadedBytes: number,
		totalBytes: number,
		bytesPerSecond: number,
		done: boolean
	): boolean;
}

export async function bandwidthTest(
	onProgress: BandwidthCallback,
	onLatency: (latency: number) => void,
	onServerLocation: (location: string) => void
) {
	// performance.setResourceTimingBufferSize(100);
	// performance.clearResourceTimings();
	const url = 'https://cdn-test-cloudfront.hf.co/5gb.safetensors';
	// const url = 'https://cdn-test-cloudfront.hf.co/15mb.json';

	// issue HEAD requests to estimate latency (round trip time), and average
	let latencySum = 0;
	const numLatencyTests = 5;
	for (let i = 0; i < numLatencyTests; i++) {
		const startTime = performance.now();
		const response = await fetch(url, { method: 'HEAD' });
		if (!response.ok) {
			throw new Error(`Network response was not ok: ${response.status}`);
		}
		const latency = performance.now() - startTime;
		latencySum += latency;
	}
	onLatency(latencySum / numLatencyTests);

	const startTime = performance.now();
	const response = await fetch(url);
	if (!response.ok) {
		throw new Error(`Network response was not ok: ${response.status}`);
	}
	// setTimeout(() => {
	// 	const entries = performance.getEntriesByType('resource');
	// 	const resourceEntry = entries.find((e) => e.name === url);
	// 	if (!resourceEntry) {
	// 		return
	// 	}
	// 	console.log(resourceEntry);
	// 	const { requestStart, responseStart } = resourceEntry;
	// 	const latency = responseStart - requestStart;
	// 	onLatency(latency);
	// }, 2000);

	// extract content-length
	const contentLengthHeader = response.headers.get('content-length');
	const totalBytes = contentLengthHeader ? parseInt(contentLengthHeader, 10) : 1e99;

	// extract pop location
	let cdnPop = response.headers.get('x-amz-cf-pop');
	if (cdnPop !== null) {
		cdnPop = cdnPop.toUpperCase().slice(0, 3);
		// try to map to IATA
		if (cdnPop in majorAirportIATAs) {
			cdnPop = majorAirportIATAs[cdnPop].city + ', ' + majorAirportIATAs[cdnPop].country;
		} else {
			cdnPop = 'Unknown';
		}
	} else {
		cdnPop = 'Unknown';
	}
	onServerLocation(cdnPop);

	const reader = response.body.getReader();
	let loadedBytes = 0;
	let lastTimestamp = performance.now();
	let lastLoaded = 0;
	const REPORT_INTERVAL_MS = 500;
	onProgress(0, loadedBytes, totalBytes, 0, false);
	let bytesPerSecond = 0;
	while (true) {
		const { done, value } = await reader.read();
		if (done) {
			// stream is finished
			const elapsedMs = performance.now() - startTime;
			onProgress(elapsedMs, loadedBytes, totalBytes, bytesPerSecond, true);
			// send analytics data
			await sendAnalyticsData(bytesPerSecond, latencySum / numLatencyTests, cdnPop, 1.);
			break;
		}

		// `value` is a Uint8Array for this chunk
		loadedBytes += value.byteLength;

		// Current time
		const now = performance.now();
		const deltaMs = now - lastTimestamp;

		if (deltaMs >= REPORT_INTERVAL_MS) {
			// compute bytes downloaded since last report
			const deltaBytes = loadedBytes - lastLoaded;
			// convert ms to seconds
			const deltaSeconds = deltaMs / 1000;
			bytesPerSecond = deltaBytes / deltaSeconds;

			// Invoke callback
			const elapsedMs = performance.now() - startTime;
			const stop = onProgress(elapsedMs, loadedBytes, totalBytes, bytesPerSecond, false);
			if (stop) {
				// stop the test
				console.log(`Stopping bandwidth test at ${loadedBytes} bytes after ${elapsedMs} ms`);
				break;
			}

			// Reset our “last” markers
			lastLoaded = loadedBytes;
			lastTimestamp = now;
		}
	}
}

interface ClientInfo {
	clientIp: string;
	clientLocation: string;
}

export async function getClientInfo(): Promise<ClientInfo> {
	let clientIp = 'Detecting...';
	let clientLocation = 'Detecting...';
	const res = await fetch('https://ipapi.co/json/');
	clientIp = 'Not available';
	clientLocation = 'Not available';
	if (res.ok) {
		const data = await res.json();
		clientIp = data.ip || 'Unknown';
		let location = '';
		if (data.city) location += data.city + ', ';
		if (data.region) location += data.region + ', ';
		if (data.country_name) location += data.country_name;
		clientLocation = location || 'Unknown';
	}
	return new Promise((resolve) =>
		resolve({
			clientIp,
			clientLocation
		})
	);
}

export async function sendAnalyticsData(bytesPerSecond: number, latency: number, location: string, progress: number) {
	// send measurements to analytics API
	const measurements = {
		bandwidth: bytesPerSecond,
		latency,
		location,
		progress
	};
	console.log('Sending analytics data');
	return new Promise((resolve) => {
		fetch('/analytics', {
			method: 'POST',
			headers: {
				'Content-Type': 'application/json'
			},
			body: JSON.stringify(measurements)
		})
			.then((response) => {
				if (!response.ok) {
					throw new Error(`Network response was not ok: ${response.status}`);
				}
				resolve(response);
			})
			.catch((error) => {
				console.error('Error sending bandwidth data:', error);
				resolve(null);
			});
	});
}