const { request } = require('express');
var config = require('../config.json');

const Pool = require('pg').Pool
const pool = new Pool({
    user: config.user,
    host: config.host,
    database: config.database,
    password: config.password,
    port: config.port
})

const create = (name, hours) => {
    return new Promise((resolve, reject) => {
        pool.query('INSERT INTO subject (id, name, hours_count) VALUES (nextval($1), $2, $3) RETURNING *',
         ["seq_subject", name, hours], (error, result) => {
            if(error)
                reject(error)
            resolve('success added')
        })
    })
}

const del = (id) => {
  return new Promise((resolve, reject) => {
    pool.query('DELETE FROM subject WHERE id = $1', [id], (error, result) => {
        if(error)
          reject(error)
        resolve(result.rows)
    })
  })
}

const update = (id, name, hours) => {
  return new Promise((resolve, reject) => {
    pool.query('UPDATE subject SET name = $1, hours_count = $2 WHERE id = $3', [name, hours, id], (error, result) => {
        if(error)
          reject(error)
        resolve(result.rows)
    })
  })
}

const get = () => {
    return new Promise(function(resolve, reject) {
      pool.query('SELECT * FROM subject', (error, results) => {
        if (error) {
          reject(error)
        }
        resolve(results.rows)
      })
    }) 
  }

module.exports = {
    create,
    get,
    del,
    update
}