import { existsSync } from 'fs';
import Knex from 'knex';
import {Knex as KnexConfig} from './config';
import { get_setting } from './setting';

export async function connectDB(){
    const config = KnexConfig.config;
    const env = get_setting().mode;
    const init_need = !existsSync(config[env].connection.filename);
    const knex = Knex(config[env]);
    let tries = 0;
    for(;;){
        try{
            console.log("try to connect db");
            await knex.raw('select 1 + 1;');
            console.log("connect success");
        }
        catch(err){
            if(tries < 3){
                tries++;
                console.error(`connection fail ${err} retry...`);
                continue;
            }
            else{
                throw err;
            }
        }
        break;
    }
    if(init_need){
        console.log("first execute: initialize database...");
        const migrate = await import("../migrations/initial");
        await migrate.up(knex);
    }
    return knex;
}