(function () {
	'use strict';

	self.window = self; // egregious hack to get magic-string to work in a worker

	let fulfil_ready;
	const ready = new Promise(f => {
		fulfil_ready = f;
	});

	self.addEventListener('message', async event => {
		switch (event.data.type) {
			case 'init':
				importScripts(`${event.data.svelteUrl}/compiler.js`);
				fulfil_ready();
				break;

			case 'compile':
				await ready;
				postMessage(compile(event.data));
				break;
		}
	});

	const common_options = {
		dev: false,
		css: false
	};

	function compile({ id, source, options }) {
		try {
			const { js, css } = svelte.compile(
				source,
				Object.assign({}, common_options, options)
			);

			return {
				id,
				result: {
					js: js.code,
					css: css.code || `/* Add a <sty` + `le> tag to see compiled CSS */`
				}
			};
		} catch (err) {
			let message = `/* Error compiling component\n\n${err.message}`;
			if (err.frame) message += `\n${err.frame}`;
			message += `\n\n*/`;

			return {
				id,
				result: {
					js: message,
					css: message
				}
			};
		}
	}

}());