import { error } from '@sveltejs/kit';
import type { RequestHandler } from './$types';
import { getYouTubeMetadata, streamYouTube } from '$lib/server/ytdlp';
import { isURLValid, logger, mimeTypeMap } from '$lib/server/helpers';

const validateRequest = (url: URL) => {
	// Get query params
	const link = url.searchParams.get('link');
	const format = url.searchParams.get('format'); // mp3, mp4
	const source = url.searchParams.get('source'); // youtube or spotify

	// Validate input
	if (!link || !format || !source) {
		throw error(400, 'Missing required query parameters: link, format, or source');
	}

	if (source !== 'youtube') {
		throw error(400, 'Currently, only YouTube is supported');
	}

	if (!isURLValid(link)) {
		throw error(400, 'URL not valid');
	}

	if (!mimeTypeMap.get(format)) {
		throw error(400, 'format not valid');
	}

	logger.debug(`Request is valid`);

	return {
		link,
		format,
		source
	};
};
export const GET: RequestHandler = async ({ url }) => {
	const { format, link } = validateRequest(url);
	let filename = '';

	logger.debug(`Requested: ${link}`);

	try {
		logger.debug(`Fetching video data to set filename`);
		// Fetch metadata for filename
		const ytMetadata = await getYouTubeMetadata(link);
		const { title, uploader } = ytMetadata;
		const safeTitle = `${uploader} - ${title}`;
		filename = `${safeTitle}.${format}`;
	} catch (err) {
		logger.error(err);
		logger.error('Error fetching metadata:');
		throw error(500, 'Failed to fetch video metadata');
	}

	try {
		// Stream video/audio
		return new Response(streamYouTube(link, format), {
			headers: {
				'Content-Type': `${mimeTypeMap.get(format)}`,
				'Content-Disposition': `attachment; filename="${filename}"`
			}
		});
	} catch (err) {
		logger.error(err);
		logger.error('Filed to stream file');
		throw error(500, 'Failed to stream file');
	}
};