import { cp } from 'fs/promises';
import { resolve } from 'path';
import { Argv } from 'yargs';

const copyFiles = async () => {
	const srcPath = resolve(__dirname, '..', '..', '..', 'src', 'next');
	const destPath = resolve(__dirname, '..', '..', '..', '.amanuensis', 'next');
	await cp(srcPath, destPath, { recursive: true });
};

interface PackageManager {
	name: string;
	testCmd: [string, string[]];
	installCmd: [string, string[]];
}

const packageManagers: PackageManager[] = [
	{
		name: 'pnpm',
		testCmd: ['pnpm', ['--version']],
		installCmd: ['pnpm', ['install', '--ignore-workspace']],
	},
	{
		name: 'yarn',
		testCmd: ['yarn', ['--version']],
		installCmd: ['yarn', ['install']],
	},
	{
		name: 'npm',
		testCmd: ['npm', ['--version']],
		installCmd: ['npm', ['install']],
	},
];

const installDependencies = async () => {
	const { execa } = await import('execa');

	const selectedPackageManagerIndex = await packageManagers.reduce(
		async (prevPmPromise, pkgm, i) => {
			const prevPm = await prevPmPromise;
			const { testCmd } = pkgm;
			const testPm = await execa(...testCmd);
			if (testPm.exitCode === 0 && prevPm === -1) {
				return i;
			}
			return prevPm;
		},
		Promise.resolve(-1),
	);

	if (selectedPackageManagerIndex < 0) {
		process.stderr.write('No package manager found\n');
		process.exit(-1);
	}

	const { [selectedPackageManagerIndex]: selectedPackageManager } = packageManagers;
	const cwd = resolve(__dirname, '..', '..', '..', '.amanuensis', 'next');
	process.stdout.write(`In path: ${cwd}\n`);
	process.stdout.write(`Installing dependencies with ${selectedPackageManager.name}\n`);
	await execa(
		selectedPackageManager.installCmd[0],
		selectedPackageManager.installCmd[1],
		{ cwd },
	);
};

export const description = 'Initialize a new Amanuensis project' as const;

export const builder = (yargsBuilder: Argv) => yargsBuilder;

const init = async () => {
	await copyFiles();
	await installDependencies();
	return 0;
};

export default init;