import { randomBytes } from "crypto";
import { existsSync, readFileSync, writeFileSync } from "fs";
import { Permission } from "./permission/permission";

export interface SettingConfig {
	/**
	 * if true, server will bind on '127.0.0.1' rather than '0.0.0.0'
	 */
	localmode: boolean;
	/**
	 * secure only
	 */
	secure: boolean;

	/**
	 * guest permission
	 */
	guest: Permission[];
	/**
	 * JWT secret key. if you change its value, all access tokens are invalidated.
	 */
	jwt_secretkey: string;
	/**
	 * the port which running server is binding on.
	 */
	port: number;

	mode: "development" | "production";
	/**
	 * if true, do not show 'electron' window and show terminal only.
	 */
	cli: boolean;
	/** forbid to login admin from remote client. but, it do not invalidate access token.
	 * if you want to invalidate access token, change 'jwt_secretkey'. */
	forbid_remote_admin_login: boolean;
}
const default_setting: SettingConfig = {
	localmode: true,
	secure: true,
	guest: [],
	jwt_secretkey: "itsRandom",
	port: 8080,
	mode: "production",
	cli: false,
	forbid_remote_admin_login: true,
};
let setting: null | SettingConfig = null;

const setEmptyToDefault = (target: any, default_table: SettingConfig) => {
	let diff_occur = false;
	for (const key in default_table) {
		if (key === undefined || key in target) {
			continue;
		}
		target[key] = default_table[key as keyof SettingConfig];
		diff_occur = true;
	}
	return diff_occur;
};

export const read_setting_from_file = () => {
	let ret = existsSync("settings.json") ? JSON.parse(readFileSync("settings.json", { encoding: "utf8" })) : {};
	const partial_occur = setEmptyToDefault(ret, default_setting);
	if (partial_occur) {
		writeFileSync("settings.json", JSON.stringify(ret));
	}
	return ret as SettingConfig;
};
export function get_setting(): SettingConfig {
	if (setting === null) {
		setting = read_setting_from_file();
		const env = process.env.NODE_ENV;
		if (env !== undefined && env != "production" && env != "development") {
			throw new Error('process unknown value in NODE_ENV: must be either "development" or "production"');
		}
		setting.mode = env ?? setting.mode;
	}
	return setting;
}