'use strict';

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

var mongo = require('mongodb'),
    MongoClient = mongo.MongoClient,
    async = require('async'),
    util = require('util'),
    dbs = {},
    options = {
            debug: false,
            prefix: true,
            size: 100,
            max: 2610,
            name: 'statsd',
            host: 'mongodb',
            port: 27017
    };

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();
});

var result = [];
app.all('/search', function (req, res) {
    setCORSHeaders(res);
    mongo.connect("mongodb://" + options.host + "/" + options.name, function (err, db) {
        if (err) {
            console.log(err);
        }
        if (options.debug) {
            console.log("Connected successfully to server");
        }
        db.listCollections().toArray(function(err, collInfos) {
            result = [];
            for (var i = 0; i <= collInfos.length -1; i++) {
                if (collInfos[i]) {
                    result.push(collInfos[i].name);
                }
            } 
        });
        res.json(result);
        res.end();
    });
});

var tsResult = [];
app.all('/query', function (req, 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 name = names.join('", "');
    var interval = req.body.intervalMs / 1000;
    var maxDataPoints = req.body.maxDataPoints;

    mongo.connect("mongodb://" + options.host + "/" + options.name, function (err, db) {
        if (err) {
            console.log(err);
        }
//        https://docs.mongodb.com/manual/reference/method/db.collection.find/#db.collection.find
        db.collection(""+name).find({ time: { $gte: from_str, $lte: to_str } }, { type: 1, time: 1, count:1, durations: 1, gauge: 1, set: 1, $slice: maxDataPoints }).sort({ time: 1 }).toArray(function (err, docs) {
            if (err) {
                console.log(err);
            }
            var result = {};
            result[name] = new Array();
            _.each(docs, function (d) {
                var value = 0;
                if (d.type == 'counters') {
                    value = d.count;
                } else if (d.type == 'timers') {
                    value = d.durations;
                } else if (d.type == 'gauges') {
                    value = d.gauge;
                } else if (d.type == 'sets') {
                    value = d.set;
                }
                (result[name]).push([value, 1000 * d.time]);
            });

            tsResult = [];
            _.each(_.keys(result), function (d) {
                var data = {
                    target: d,
                    datapoints: result[d]
                };
                tsResult.push(data);
            });
            
            setCORSHeaders(res);
            res.json(tsResult);
            res.end();
        });
    });
});

app.listen(8000);

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