'use strict';

// This program will connect to one or more SNMP Agents

// example configuration in /etc/netdata/snmp.conf
/*
{
    "enable_autodetect": false,
    "update_every": 5,
    "max_request_size": 50,
    "servers": [
        {
            "hostname": "10.11.12.8",
            "community": "public",
            "update_every": 10,
            "max_request_size": 50,
            "options": { "timeout": 10000 },
            "charts": {
                "snmp_switch.bandwidth_port1": {
                    "title": "Switch Bandwidth for port 1",
                    "units": "kilobits/s",
                    "type": "area",
                    "priority": 1,
                    "dimensions": {
                        "in": {
                            "oid": ".1.3.6.1.2.1.2.2.1.10.1",
                            "algorithm": "incremental",
                            "multiplier": 8,
                            "divisor": 1024
                        },
                        "out": {
                            "oid": ".1.3.6.1.2.1.2.2.1.16.1",
                            "algorithm": "incremental",
                            "multiplier": -8,
                            "divisor": 1024
                        }
                    }
                },
                "snmp_switch.bandwidth_port2": {
                    "title": "Switch Bandwidth for port 2",
                    "units": "kilobits/s",
                    "type": "area",
                    "priority": 1,
                    "dimensions": {
                        "in": {
                            "oid": ".1.3.6.1.2.1.2.2.1.10.2",
                            "algorithm": "incremental",
                            "multiplier": 8,
                            "divisor": 1024
                        },
                        "out": {
                            "oid": ".1.3.6.1.2.1.2.2.1.16.2",
                            "algorithm": "incremental",
                            "multiplier": -8,
                            "divisor": 1024
                        }
                    }
                }
            }
        }
    ]
}
*/

// You can also give ranges of charts like the following.
// This will append 1-24 to id, title, oid (on each dimension)
// so that 24 charts will be created.
/*
{
    "enable_autodetect": false,
    "update_every": 10,
    "max_request_size": 50,
    "servers": [
        {
            "hostname": "10.11.12.8",
            "community": "public",
            "update_every": 10,
            "max_request_size": 50,
            "options": { "timeout": 20000 },
            "charts": {
                "snmp_switch.bandwidth_port": {
                    "title": "Switch Bandwidth for port ",
                    "units": "kilobits/s",
                    "type": "area",
                    "priority": 1,
                    "multiply_range": [ 1, 24 ],
                    "dimensions": {
                        "in": {
                            "oid": ".1.3.6.1.2.1.2.2.1.10.",
                            "algorithm": "incremental",
                            "multiplier": 8,
                            "divisor": 1024
                        },
                        "out": {
                            "oid": ".1.3.6.1.2.1.2.2.1.16.",
                            "algorithm": "incremental",
                            "multiplier": -8,
                            "divisor": 1024
                        }
                    }
                }
            }
        }
    ]
}
*/

var net_snmp = require('net-snmp');
var extend = require('extend');
var netdata = require('netdata');

if(netdata.options.DEBUG === true) netdata.debug('loaded ' + __filename + ' plugin');

netdata.processors.snmp = {
    name: 'snmp',

    fixoid: function(oid) {
        if(typeof oid !== 'string')
            return oid;

        if(oid.charAt(0) === '.')
            return oid.substring(1, oid.length);

        return oid;
    },

    prepare: function(service) {
        if(typeof service.snmp_oids === 'undefined' || service.snmp_oids === null || service.snmp_oids.length === 0) {
            // this is the first time we see this service

            if(netdata.options.DEBUG === true)
                netdata.debug(service.module.name + ': ' + service.name + ': preparing ' + this.name + ' OIDs');

            // build an index of all OIDs
            service.snmp_oids_index = {};
            for(var c in service.request.charts) {
                // for each chart

                if(netdata.options.DEBUG === true)
                    netdata.debug(service.module.name + ': ' + service.name + ': indexing ' + this.name + ' chart: ' + c);

                if(typeof service.request.charts[c].titleoid !== 'undefined') {
                        service.snmp_oids_index[this.fixoid(service.request.charts[c].titleoid)] = {
                            type: 'title',
                            link: service.request.charts[c]
                        };
                    }

                for(var d in service.request.charts[c].dimensions) {
                    // for each dimension in the chart

                    var oid = this.fixoid(service.request.charts[c].dimensions[d].oid);
                    var oidname = this.fixoid(service.request.charts[c].dimensions[d].oidname);
                    
                    if(netdata.options.DEBUG === true)
                        netdata.debug(service.module.name + ': ' + service.name + ': indexing ' + this.name + ' chart: ' + c + ', dimension: ' + d + ', OID: ' + oid + ", OID name: " + oidname);

                    // link it to the point we need to set the value to
                    service.snmp_oids_index[oid] = {
                        type: 'value',
                        link: service.request.charts[c].dimensions[d]
                    };

                    if(typeof oidname !== 'undefined')
                        service.snmp_oids_index[oidname] = {
                            type: 'name',
                            link: service.request.charts[c].dimensions[d]
                        };

                    // and set the value to null
                    service.request.charts[c].dimensions[d].value = null;
                }
            }

            if(netdata.options.DEBUG === true)
                netdata.debug(service.module.name + ': ' + service.name + ': indexed ' + this.name + ' OIDs: ' + netdata.stringify(service.snmp_oids_index));

            // now create the array of OIDs needed by net-snmp
            service.snmp_oids = new Array();
            for(var o in service.snmp_oids_index)
                service.snmp_oids.push(o);

            if(netdata.options.DEBUG === true)
                netdata.debug(service.module.name + ': ' + service.name + ': final list of ' + this.name + ' OIDs: ' + netdata.stringify(service.snmp_oids));

            service.snmp_oids_cleaned = 0;
        }
        else if(service.snmp_oids_cleaned === 0) {
            service.snmp_oids_cleaned = 1;

            // the second time, keep only values
            service.snmp_oids = new Array();
            for(var o in service.snmp_oids_index)
                if(service.snmp_oids_index[o].type === 'value')
                    service.snmp_oids.push(o);
        }
    },

    getdata: function(service, index, ok, failed, callback) {
        var that = this;

        if(index >= service.snmp_oids.length) {
            callback((ok > 0)?{ ok: ok, failed: failed }:null);
            return;
        }

        var slice;
        if(service.snmp_oids.length <= service.request.max_request_size) {
            slice = service.snmp_oids;
            index = service.snmp_oids.length;
        }
        else if(service.snmp_oids.length - index <= service.request.max_request_size) {
            slice = service.snmp_oids.slice(index, service.snmp_oids.length);
            index = service.snmp_oids.length;
        }
        else {
            slice = service.snmp_oids.slice(index, index + service.request.max_request_size);
            index += service.request.max_request_size;
        }

        if(netdata.options.DEBUG === true)
            netdata.debug(service.module.name + ': ' + service.name + ': making ' + slice.length + ' entries request, max is: ' + service.request.max_request_size);

        service.snmp_session.get(slice, function(error, varbinds) {
            if(error) {
                service.error('Received error = ' + netdata.stringify(error) + ' varbinds = ' + netdata.stringify(varbinds));

                // make all values null
                var len = slice.length;
                while(len--)
                    service.snmp_oids_index[slice[len]].value = null;
            }
            else {
                if(netdata.options.DEBUG === true)
                    netdata.debug(service.module.name + ': ' + service.name + ': got valid ' + service.module.name + ' response: ' + netdata.stringify(varbinds));

                for(var i = 0; i < varbinds.length; i++) {
                    var value = null;

                    if(net_snmp.isVarbindError(varbinds[i])) {
                        if(netdata.options.DEBUG === true)
                            netdata.debug(service.module.name + ': ' + service.name + ': failed ' + service.module.name + ' get for OIDs ' + varbinds[i].oid);

                        service.error('OID ' + varbinds[i].oid + ' gave error: ' + snmp.varbindError(varbinds[i]));
                        value = null;
                        failed++;
                    }
                    else {
                        if(netdata.options.DEBUG === true)
                            netdata.debug(service.module.name + ': ' + service.name + ': found ' + service.module.name + ' value of OIDs ' + varbinds[i].oid + " = " + varbinds[i].value);

                        value = varbinds[i].value;
                        ok++;
                    }

                    if(value !== null) {
                        switch(service.snmp_oids_index[varbinds[i].oid].type) {
                            case 'title': service.snmp_oids_index[varbinds[i].oid].link.title += ' ' + value; break;
                            case 'name' : service.snmp_oids_index[varbinds[i].oid].link.name = value; break;
                            case 'value': service.snmp_oids_index[varbinds[i].oid].link.value = value; break;
                        }
                    }
                }

                if(netdata.options.DEBUG === true)
                    netdata.debug(service.module.name + ': ' + service.name + ': finished ' + service.module.name + ' with ' + ok + ' successful and ' + failed + ' failed values');
            }
            that.getdata(service, index, ok, failed, callback);
        });
    },

    process: function(service, callback) {
        this.prepare(service);

        if(service.snmp_oids.length === 0) {
            // no OIDs found for this service

            if(netdata.options.DEBUG === true)
                service.error('no OIDs to process.');

            callback(null);
            return;
        }

        if(typeof service.snmp_session === 'undefined' || service.snmp_session === null) {
            // no SNMP session has been created for this service
            // the SNMP session is just the initialization of NET-SNMP

            if(netdata.options.DEBUG === true)
                netdata.debug(service.module.name + ': ' + service.name + ': opening ' + this.name + ' session on ' + service.request.hostname + ' community ' + service.request.community + ' options ' + netdata.stringify(service.request.options));

            // create the SNMP session
            service.snmp_session = net_snmp.createSession (service.request.hostname, service.request.community, service.request.options);

            if(netdata.options.DEBUG === true)
                netdata.debug(service.module.name + ': ' + service.name + ': got ' + this.name + ' session: ' + netdata.stringify(service.snmp_session));

            // if we later need traps, this is how to do it:
            //service.snmp_session.trap(net_snmp.TrapType.LinkDown, function(error) {
            //  if(error) console.error('trap error: ' + netdata.stringify(error));
            //});
        }

        // do it, get the SNMP values for the sessions we need
        this.getdata(service, 0, 0, 0, callback);
    }
};

var snmp = {
    name: __filename,
    enable_autodetect: true,
    update_every: 1,
    base_priority: 50000,

    charts: {},

    processResponse: function(service, data) {
        if(data !== null) {
            if(service.added !== true)
                service.commit();

            for(var c in service.request.charts) {
                var chart = snmp.charts[c];

                if(typeof chart === 'undefined') {
                    chart = service.chart(c, service.request.charts[c]);
                    snmp.charts[c] = chart;
                }

                service.begin(chart);
                
                for( var d in service.request.charts[c].dimensions )
                    if(service.request.charts[c].dimensions[d].value !== null)
                        service.set(d, service.request.charts[c].dimensions[d].value);

                service.end();
            }
        }
    },

    // module.serviceExecute()
    // this function is called only from this module
    // its purpose is to prepare the request and call
    // netdata.serviceExecute()
    serviceExecute: function(conf) {
        if(netdata.options.DEBUG === true)
            netdata.debug(this.name + ': snmp hostname: ' + conf.hostname + ', update_every: ' + conf.update_every);

        var service = netdata.service({
            name: conf.hostname,
            request: conf,
            update_every: conf.update_every,
            module: this,
            processor: netdata.processors.snmp
        });

        // multiply the charts, if required
        for(var c in service.request.charts) {
            if(netdata.options.DEBUG === true)
                netdata.debug(this.name + ': snmp hostname: ' + conf.hostname + ', examining chart: ' + c);

            if(typeof service.request.charts[c].update_every === 'undefined')
                service.request.charts[c].update_every = service.update_every;

            if(typeof service.request.charts[c].multiply_range !== 'undefined') {
                var from = service.request.charts[c].multiply_range[0];
                var to = service.request.charts[c].multiply_range[1];
                var prio = service.request.charts[c].priority || 1;

                if(prio < snmp.base_priority) prio += snmp.base_priority;

                while(from <= to) {
                    var id = c + from.toString();
                    var chart = extend(true, {}, service.request.charts[c]);
                    chart.title += from.toString();
                    
                    if(typeof chart.titleoid !== 'undefined')
                        chart.titleoid += from.toString();

                    chart.priority = prio++;
                    for(var d in chart.dimensions) {
                        chart.dimensions[d].oid += from.toString();

                        if(typeof chart.dimensions[d].oidname !== 'undefined')
                            chart.dimensions[d].oidname += from.toString();
                    }
                    service.request.charts[id] = chart;
                    from++;
                }

                delete service.request.charts[c];
            }
            else {
                if(service.request.charts[c].priority < snmp.base_priority)
                    service.request.charts[c].priority += snmp.base_priority;
            }
        }

        service.execute(this.processResponse);
    },

    configure: function(config) {
        var added = 0;

        if(typeof config.max_request_size === 'undefined')
            config.max_request_size = 50;

        if(typeof(config.servers) !== 'undefined') {
            var len = config.servers.length;
            while(len--) {
                if(typeof config.servers[len].update_every === 'undefined')
                    config.servers[len].update_every = this.update_every;

                if(typeof config.servers[len].max_request_size === 'undefined')
                    config.servers[len].max_request_size = config.max_request_size;

                this.serviceExecute(config.servers[len]);
                added++;
            }
        }

        return added;
    },

    // module.update()
    // this is called repeatidly to collect data, by calling
    // service.execute()
    update: function(service, callback) {
        service.execute(function(serv, data) {
            service.module.processResponse(serv, data);
            callback();
        });
    },
};

module.exports = snmp;