import { Settings } from '@material-ui/icons';
import { randomBytes } from 'crypto';
import { existsSync, readFileSync, writeFileSync } from 'fs';
import { Permission } from './permission/permission';

export type Setting = {
    /**
     * if true, server will bind on '127.0.0.1' rather than '0.0.0.0'
     */
    localmode: 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:Setting = {

    localmode: true,
    guest:[],
    jwt_secretkey:"itsRandom",
    port:8080,
    mode:"production",
    cli:false,
    forbid_remote_admin_login:true,
}
let setting: null|Setting = null;

const setEmptyToDefault = (target:any,default_table:Setting)=>{
    let diff_occur = false;
    for(const key in default_table){
        if(key === undefined || key in target){
            continue;
        }
        target[key] = default_table[key as keyof Setting];
        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 Setting;
}
export function get_setting():Setting{
    if(setting === null){
        setting = read_setting_from_file();
        const env = process.env.NODE_ENV || 'development';
        if(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;
}