const express = require('express');
var Pool = require('pg').Pool;
var bodyParser = require('body-parser');

const app = express();
var config = {
    host: 'localhost',
    user: 'armando',
    password: 'Chomusuke',
    database: 'signup'
};

var pool = new Pool(config);

app.set('port', (8080));
app.use(bodyParser.json({type: 'application/json'}));
app.use(bodyParser.urlencoded({extended: true}));

app.get('/api', async (req, res) => {
    try{
        var response = await pool.query('select attendee from attendance');
        console.log(JSON.stringify(response.rows));
      //  res.json({workshops: response.rows});
        let results = response.rows.map(function(attendance){
            return attendance.attendee;
            });
        res.json({attendees: results});
    }
    catch(e) {
        console.error('Error running query ' + e);
    }

});

app.post('/api', async (req, res) =>{
    console.log(req.body);
    var workshop = req.body.workshop;
    var attendee = req.body.attendee;
    var response = await pool.query('select * from attendance where workshop = $1 and attendee = $2', [workshop, attendee]);
    var workshopsearch = await pool.query('select * from workshops where workshop = $1', [workshop]);
    if(!attendee){
        res.json({error: 'parameters not given'});
    }
    else if(!workshop){
        try{
            // var table = await pool.query('select * from workshops');
            // console.log(JSON.stringify(table.rows));
            // res.json(table.rows);
            var response = await pool.query('select workshop from workshops');
            let results = response.rows.map(function(workshops){
                return workshops.workshop;
            });
            res.json({workshops: results});
        }catch(e){
            console.error('Error running query: ' + e);
        }
    }
    else if(response.rows.length == 1){
        res.json('Attendee already enrolled.');
        console.log('attendee already enrolled');
    }
    else if(workshopsearch.rows.length == 0){
        //res.json('Error: Workshop not found');
        //console.log('Error: Workshop not found');
        try{

        var newWorkshop = await pool.query('insert into workshops values ($1)', [workshop]);
        var insertion = await pool.query('insert into attendance values ($1, $2)', [workshop, attendee]);
        res.json('Attendee enrolled');
        }
        catch(e){
            console.log('error creating workshop', e);
        }
    }
    else{
        try{
            var insertion = await pool.query('insert into attendance values ($1, $2)', [workshop, attendee]);
            var response = await pool.query('select * from attendance where workshop = $1 and attendee = $2', [workshop, attendee]);
            res.json({status: 'inserted'});
          //  res.json(response.rows);
        }
        catch(e){
            console.log('Error running insert', e);
        }
    }
});

app.delete('/api', async (req, res) =>{
    console.log(req.body);
    var workshop = req.body.workshop;
    var attendee = req.body.attendee;
    if(!workshop && !attendee){
        res.json({error: 'parameters not given'});
    }
    else if(!attendee){
        var deletion = await pool.query('delete from attendance where attendee is null');
        res.json('non-existant attendee removed');
    }
    else{
        try{
            var response = await pool.query('delete from attendance where workshop = $1 and attendee = $2', [workshop, attendee]);
            res.json({status: 'deleted'});
        }
        catch(e){
            console.log('Error running delete', e);
        }
    }
});
app.listen(app.get('port'), () => {
    console.log('Running');
});