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

export type Setting = {
    path: string[],
    localmode: boolean,
    guest: boolean,
    jwt_secretkey: string,
    port:number,
    mode:"development"|"production",
    cli:boolean,
}
const default_setting:Setting = {
    path:[],
    localmode: true,
    guest:false,
    jwt_secretkey:"itsRandom",
    port:8080,
    mode:"production",
    cli:false
}
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;
}