/**
 * Config loader
 */

import * as fs from 'node:fs';
import { fileURLToPath } from 'node:url';
import { dirname } from 'node:path';
import * as yaml from 'js-yaml';
import { Source, Mixin, Config } from './types.js';

const _filename = fileURLToPath(import.meta.url);
const _dirname = dirname(_filename);

/**
 * Path of configuration directory
 */
const dir = `${_dirname}/../../../../.config`;

/**
 * Path of configuration file
 */
const path = process.env.NODE_ENV === 'test'
	? `${dir}/test.yml`
	: `${dir}/default.yml`;

export function loadConfig(): Config {
	const meta = JSON.parse(fs.readFileSync(`${_dirname}/../../../../built/meta.json`, 'utf-8'));
	const clientManifest = JSON.parse(fs.readFileSync(`${_dirname}/../../../../built/_client_dist_/manifest.json`, 'utf-8'));
	let config = yaml.load(fs.readFileSync(path, 'utf-8')) as Source;

	if (config.id && config.id !== 'aid') throw new Error('Unsupported ID algorithm. Only "aid" is supported.');

	const mixin = {} as Mixin;

	const url = tryCreateUrl(config.url);

	config.url = url.origin;

	config.port = config.port || parseInt(process.env.PORT || '', 10);

	// set default values
	config.images = Object.assign({
		info: '/twemoji/1f440.svg',
		notFound: '/twemoji/2049.svg',
		error: '/twemoji/1f480.svg',
	}, config.images ?? {});

	config.clusterLimits = Object.assign({
		web: 1,
		queue: 1,
	}, config.clusterLimits ?? {});

	config = Object.assign({
		disableHsts: false,
		deliverJobConcurrency: 128,
		inboxJobConcurrency: 16,
		deliverJobPerSec: -1,
		inboxJobPerSec: 16,
		deliverJobMaxAttempts: 12,
		inboxJobMaxAttempts: 8,
		proxyRemoteFiles: false,
		maxFileSize: 262144000, // 250 MiB
		maxNoteTextLength: 3000,
	}, config);

	mixin.version = meta.version;
	mixin.host = url.host;
	mixin.hostname = url.hostname;
	mixin.scheme = url.protocol.replace(/:$/, '');
	mixin.wsScheme = mixin.scheme.replace('http', 'ws');
	mixin.wsUrl = `${mixin.wsScheme}://${mixin.host}`;
	mixin.apiUrl = `${mixin.scheme}://${mixin.host}/api`;
	mixin.authUrl = `${mixin.scheme}://${mixin.host}/auth`;
	mixin.driveUrl = `${mixin.scheme}://${mixin.host}/files`;
	mixin.userAgent = `FoundKey/${meta.version} (${config.url})`;
	mixin.clientEntry = clientManifest['src/init.ts'];

	if (!config.redis.prefix) config.redis.prefix = mixin.host;

	if (config.clusterLimits.web < 1 || config.clusterLimits.queue < 1) {
		throw new Error('invalid cluster limits');
	}

	return Object.assign(config, mixin);
}

function tryCreateUrl(url: string): URL {
	try {
		return new URL(url);
	} catch (e) {
		throw new Error(`url="${url}" is not a valid URL.`);
	}
}
