/* eslint-disable no-console */
export type OnProgress = (downloadedBytes: number, totalBytes: number) => void;

export const downloadFile = async ({
	fileStream,
	url,
	printOutput,
	onProgress,
	signal,
}: {
	fileStream: NodeJS.WritableStream;
	url: string;
	printOutput: boolean;
	onProgress: OnProgress | undefined;
	signal: AbortSignal | null;
}) => {
	const {body, headers} = await fetch(url, {
		signal,
	});
	const contentLength = headers.get('content-length');

	if (body === null) {
		throw new Error('Failed to download whisper model');
	}

	if (contentLength === null) {
		throw new Error('Content-Length header not found');
	}

	let downloaded = 0;
	let lastPrinted = 0;

	const totalFileSize = parseInt(contentLength, 10);

	const reader = body.getReader();
	// eslint-disable-next-line no-async-promise-executor
	await new Promise<void>(async (resolve, reject) => {
		try {
			while (true) {
				const {done, value} = await reader.read();

				if (value) {
					downloaded += value.length;

					if (
						printOutput &&
						(downloaded - lastPrinted > 1024 * 1024 * 10 ||
							downloaded === totalFileSize)
					) {
						console.log(
							`Downloaded ${downloaded} of ${contentLength} bytes (${(
								(downloaded / Number(contentLength)) *
								100
							).toFixed(2)}%)`,
						);
						lastPrinted = downloaded;
					}

					fileStream.write(value, () => {
						onProgress?.(downloaded, totalFileSize);
						if (downloaded === totalFileSize) {
							fileStream.end();
							resolve();
						}
					});
				}

				if (done) {
					break;
				}
			}
		} catch (e) {
			reject(e);
		}
	});
};