var express = require('express');
var morgan = require('morgan');
var bodyParser = require('body-parser');
var _ = require('lodash');
var app = express();

var mysql      = require('mysql');
var connection =  mysql.createConnection({
  host     : 'mysql',
  user     : 'root',
  password : '235r2342gtfsw',
  database : 'statsd_db',
  multipleStatements: true
});

app.use(morgan('combined'))

app.use(bodyParser.json());
  
function setCORSHeaders(res) {
  res.setHeader("Access-Control-Allow-Origin", "*");
  res.setHeader("Access-Control-Allow-Methods", "POST");
  res.setHeader("Access-Control-Allow-Headers", "accept, content-type");  
}

app.all('/', function(req, res) {
  setCORSHeaders(res);
  res.send('https://grafana.com/plugins/grafana-simple-json-datasource\n');
  res.end();
});

function search(table, mysql_search_result, value, res)
{
//    connection.query('SELECT DISTINCT(`name`) FROM `' + table + '` WHERE `name` NOT IN ("' + mysql_search_result.join('", "') + '") ORDER BY `name`', function (err, rows, fields) {
    connection.query('SELECT DISTINCT(`name`) FROM `' + table + '` WHERE `name` LIKE ("%' + value + '%") ORDER BY `name`', function (err, rows, fields) {
        if (err) {
            console.log(err);
            throw err;
        }
        for (var i = 0; i < rows.length; i++) {
            if (mysql_search_result.indexOf(rows[i].name) === -1) { // Se agregan solo los name que no esten en result
                mysql_search_result.push(rows[i].name);
            }
        }
        if (res) {
            setCORSHeaders(res);
            res.json(mysql_search_result);
            res.end();
        }
    });
}

app.all('/search', function (req, res) {
    var mysql_search_result = [];
    var target = req.body.target; // metric
    
    search('gauges_statistics', mysql_search_result, target);
    search('counters_statistics', mysql_search_result, target);
    search('timers_statistics', mysql_search_result, target);
    search('sets_statistics', mysql_search_result, target, res);
});

function query(table, req, mysql_query_result, res)
{
    var from = new Date(req.body.range.from);
    var to = new Date(req.body.range.to);
    var from_str = Math.floor(from.getTime() / 1000);
    var to_str = Math.floor(to.getTime() / 1000);
    var names = _.map(req.body.targets, function (t) {
        return t.target;
    });
    
    //var sql = mode + 'SELECT `timestamp`, `name`, AVG(`value`) AS `value` FROM `' + table + '` WHERE (`timestamp` BETWEEN ' + from_str + ' AND ' + to_str + ') AND (`name` IN ("' + names.join('", "') + '"))';
    //var group_by = ' GROUP BY UNIX_TIMESTAMP(`timestamp`) DIV ' + interval;
    
    var interval = req.body.intervalMs / 1000;
    var mode = "SET sql_mode=(SELECT REPLACE(@@sql_mode,'ONLY_FULL_GROUP_BY','')); ";
    var sql = mode + 'SELECT `timestamp`, `name`, `value` FROM `' + table + '` WHERE (`timestamp` BETWEEN ' + from_str + ' AND ' + to_str + ') AND (`name` IN ("' + names.join('", "') + '"))';
    var group_by = '';
    var order_by = ' ORDER BY `timestamp` ASC';
    var maxDataPoints = req.body.maxDataPoints;
    var limit = ' LIMIT ' + maxDataPoints + ';';
    sql += group_by + order_by + limit;  
        
    connection.query(sql, function (err, rows, fields) {
        if (err) {
            console.log(err);
            throw err;
        }
        
        var result = [];
        var results = rows[1];
        for (var i = 0; i < results.length; i++) {
            var name = results[i].name;
            if (name !== undefined) {
                if (result[name] === undefined) {
                    result[name] = [];
                }
                result[name].push([results[i].value, 1000 * results[i].timestamp]);
            }
        }
        var keys = _.keys(result);
        for (var i = 0; i < keys.length; i++) {
            var data = {
                target: keys[i],
                datapoints: result[keys[i]]
            };
            mysql_query_result.push(data);
        }
        if (res !== undefined) {
            setCORSHeaders(res);
            res.json(mysql_query_result);
            res.end();
        }
    });
}

app.all('/query', function (req, res) {
    var mysql_query_result = [];
    
    query('gauges_statistics', req, mysql_query_result);
    query('counters_statistics', req, mysql_query_result);
    query('timers_statistics', req, mysql_query_result);
    query('sets_statistics', req, mysql_query_result, res);
});

app.listen(8000);

console.log("Server is listening to port 8000");