var express = require('express');
var router = express.Router();
var EventEmitter = require('events');
var util = require('util');
var itemController = require('../controllers/itemController');

const { Pool } = require('pg')
const pool = new Pool({
  user: 'postgres',
  host: 'localhost',
  database: 'stuffsharing',
  password: 'postgres',
  port: 5432,
});

const sqlQuery = 'SELECT * from Stuff where stuffid=$1';
const borrowQuery = 'INSERT INTO Transactions(transId, loaner, loanee, stuffid, loanerNum, loanerEmail, startDate, endDate, status, cost, bid) values($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11)'

function DbEventEmitter(){
  EventEmitter.call(this);
}

util.inherits(DbEventEmitter, EventEmitter);
var dbEventEmitter = new DbEventEmitter;

router.get('/', isLoggedIn, function(req, res) {
    const id = req.query.stuffId;
    const user = req.app.get('current user');
    let displayMsg = "";
    let isBorrowed = false;

    pool.query('SELECT stuffid FROM Transactions WHERE $1 = stuffid AND $2 = status EXCEPT (SELECT ' +
            'stuffId FROM Services WHERE $1 = stuffId UNION SELECT stuffId FROM Intangibles WHERE ' +
            '$1 = stuffId);', [id, 'ONGOING'], (err, datum) => {
        if (err) {
            console.error("Error executing query", err.stack);
            return 0;
        }

        if(datum.rowCount == 0) {
            displayMsg = "Wanna borrow it? Fill out our form and click borrow now!";
        } else {
            displayMsg = "Sorry, this item is currently borrowed";
            isBorrowed = true;
        }

        pool.query('SELECT * FROM Stuff WHERE $1 = stuffId;', [id], (err, ownerRes) => {
            if (err) {
                console.log("Error executing query", err.stack);
                return 0;
            }
            console.log(ownerRes);
            const loaner = ownerRes.rows[0].owner;
            if (loaner == req.user.rows[0].username) {
                displayMsg = "This item belongs to you";
                isBorrowed = true;
            }
            pool.query(sqlQuery, [id], (err, result) => {
                if (err) {
                    console.error("Error executing query", err.stack);
                    return 0;
                }

                res.render('item', {
                    title: 'Item',
                    value: result.rows[0],
                    displayMsg: displayMsg,
                    isBorrowed: isBorrowed
                });
                console.log(result.rows[0]);
                return 0;
            });
        });
    });
});

router.post('/borrow', function(req, res) {
    const stuffId = req.query.stuffId;
    const num = req.body.number;
    const email = req.body.email;
    const startDate = req.body.startDate;
    const endDate = req.body.endDate;
    const bid = req.body.bid;
    const user = req.user.rows[0].username;

    pool.query('BEGIN', function(err, data1) {
        pool.query('SELECT MAX(transId) as transId FROM Transactions;', (err, data2) => {
            if (err) {
                return console.log(err);
            }
            var transId = data2.rows[0].transid + 1;
            console.log("transId = " + transId);
            pool.query('SELECT * FROM Stuff WHERE stuffId = $1;',  [stuffId], (err, data3) => {
                if (err) {
                    return console.log(err);
                }
                console.log(user + " this is the current user");
                const loaner = data3.rows[0].owner;
                const cost = data3.rows[0].price;
                console.log("Loaner: " + loaner);
                pool.query(borrowQuery, [transId, loaner, user, stuffId, num, email, startDate, endDate, "PENDING", cost, bid], (err, result) => {
                    if (err) {
                        return console.error("Error executing query", err.stack);
                    }

                    // Define the event handlers for each channel name
                    dbEventEmitter.on('overdue_loan', (msg) => {
                      // Custom logic for reacting to the event e.g. firing a webhook, writing a log entry etc
                      console.log('Overdue received: ' + msg);
                    });

                    // Connect to Postgres (replace with your own connection string)
                    Pool.connect('postgres://postgres:postgres@localhost:5432/stuffsharing', function(err, client) {
                      if(err) {
                        console.log(err);
                      }

                      // Listen for all pg_notify channel messages
                      client.on('notification', function(msg) {
                        let payload = JSON.parse(msg.payload);
                        dbEventEmitter.emit(msg.channel, payload);
                      });

                      // Designate which channels we are listening on. Add additional channels with multiple lines.
                      client.query('LISTEN overdue_loan');
                    });

                    pool.query('COMMIT', function(err, data4) {
                        if(err) console.log('error1');
                    });

                    res.redirect('/');
                    return console.log(result.rows);
                });
            });
        });
    });
});

// route middleware to make sure a user is logged in
function isLoggedIn(req, res, next) {

  // if user is authenticated in the session, carry on
  if (req.isAuthenticated())
      return next();

  // if they aren't redirect them to the home page
  res.redirect('/login');
}

module.exports = router;