import { promises as fs, readFileSync } from 'fs';
import { posix } from 'path';
import arg from 'arg';
import { globby as glob } from 'globby';
import tar from 'tar';

const { resolve, dirname, sep, join } = posix;

/** @type {import('arg').Spec} */
const spec = {
	'--tgz': Boolean,
};

export default async function copy() {
	let { _: patterns, ['--tgz']: isCompress } = arg(spec);
	patterns = patterns.slice(1);

	if (isCompress) {
		const files = await glob(patterns, { gitignore: true });
		const rootDir = resolveRootDir(files);
		const destDir = rootDir.replace(/^[^/]+/, 'dist');

		const templates = files.reduce((acc, curr) => {
			const name = curr.replace(rootDir, '').slice(1).split(sep)[0];
			if (acc[name]) {
				acc[name].push(resolve(curr));
			} else {
				acc[name] = [resolve(curr)];
			}
			return acc;
		}, {});

		let meta = {};
		return Promise.all(
			Object.entries(templates).map(([template, files]) => {
				const cwd = resolve(join(rootDir, template));
				const dest = join(destDir, `${template}.tgz`);
				const metafile = files.find((f) => f.endsWith('meta.json'));
				if (metafile) {
					files = files.filter((f) => f !== metafile);
					meta[template] = JSON.parse(readFileSync(metafile).toString());
				}
				return fs.mkdir(dirname(dest), { recursive: true }).then(() =>
					tar.create(
						{
							gzip: true,
							portable: true,
							file: dest,
							cwd,
						},
						files.map((f) => f.replace(cwd, '').slice(1))
					)
				);
			})
		).then(() => {
			if (Object.keys(meta).length > 0) {
				return fs.writeFile(resolve(destDir, 'meta.json'), JSON.stringify(meta, null, 2));
			}
		});
	}

	const files = await glob(patterns);
	await Promise.all(
		files.map((file) => {
			const dest = resolve(file.replace(/^[^/]+/, 'dist'));
			return fs
				.mkdir(dirname(dest), { recursive: true })
				.then(() => fs.copyFile(resolve(file), dest));
		})
	);
}

function resolveRootDir(files) {
	return files
		.reduce((acc, curr) => {
			const currParts = curr.split(sep);
			if (acc.length === 0) return currParts;
			const result = [];
			currParts.forEach((part, i) => {
				if (acc[i] === part) result.push(part);
			});
			return result;
		}, [])
		.join(sep);
}