/*  Copyright 2016-2018 Adrian Todorov, Oxalide ato@oxalide.com
Original project author: https://github.com/cblomart
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"log"
	"math"
	"net/url"
	"os"
	"path"
	"regexp"
	"strings"
	"time"

	"github.com/davecgh/go-spew/spew"
	influxclient "github.com/influxdata/influxdb/client/v2"
	"github.com/vmware/govmomi"
	"github.com/vmware/govmomi/property"
	"github.com/vmware/govmomi/vim25/methods"
	"github.com/vmware/govmomi/vim25/mo"
	"github.com/vmware/govmomi/vim25/types"
	"golang.org/x/net/context"
)

const (
	// name of the service
	name        = "vsphere-influxdb"
	description = "send vsphere stats to influxdb"
)

// Configuration is used to store config data
type Configuration struct {
	VCenters []*VCenter
	Metrics  []Metric
	Interval int
	Domain   string
	InfluxDB InfluxDB
}

// InfluxDB is used for InfluxDB connections
type InfluxDB struct {
	Hostname string
	Username string
	Password string
	Database string
	Prefix   string
}

// VCenter for VMware vCenter connections
type VCenter struct {
	Hostname     string
	Username     string
	Password     string
	MetricGroups []*MetricGroup
	client       *govmomi.Client
}

// MetricDef metric definition
type MetricDef struct {
	Metric    string
	Instances string
	Key       int32
}

// Metric is used for metrics retrieval
type Metric struct {
	ObjectType []string
	Definition []MetricDef
}

// MetricGroup is used for grouping metrics retrieval
type MetricGroup struct {
	ObjectType string
	Metrics    []MetricDef
	Mor        []types.ManagedObjectReference
}

// EntityQuery are informations to query about an entity
type EntityQuery struct {
	Name    string
	Entity  types.ManagedObjectReference
	Metrics []int32
}

var getversion, debug, test bool
var stdlog, errlog *log.Logger
var version = "master"

// Connect to the actual vCenter connection used to query data
func (vcenter *VCenter) Connect() error {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	stdlog.Println("Connecting to vcenter:", vcenter.Hostname)
	u, err := url.Parse("https://" + vcenter.Username + ":" + vcenter.Password + "@" + vcenter.Hostname + "/sdk")
	if err != nil {
		errlog.Println("Could not parse vcenter url:", vcenter.Hostname)
		errlog.Println("Error:", err)
		return err
	}

	client, err := govmomi.NewClient(ctx, u, true)
	if err != nil {
		errlog.Println("Could not connect to vcenter:", vcenter.Hostname)
		errlog.Println("Error:", err)
		return err
	}

	vcenter.client = client

	return nil
}

// Disconnect from the vCenter
func (vcenter *VCenter) Disconnect() error {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	if vcenter.client != nil {
		if err := vcenter.client.Logout(ctx); err != nil {
			errlog.Println("Could not disconnect properly from vcenter:", vcenter.Hostname, err)
			return err
		}
	}

	return nil
}

// Init the VCenter connection
func (vcenter *VCenter) Init(config Configuration) error {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	client := vcenter.client

	// Print version
	if debug {
		aboutInfo := client.Client.ServiceContent.About
		stdlog.Println("Version:", aboutInfo.FullName)
	}

	var perfmanager mo.PerformanceManager
	err := client.RetrieveOne(ctx, *client.ServiceContent.PerfManager, nil, &perfmanager)
	if err != nil {
		errlog.Println("Could not get performance manager")
		errlog.Println("Error:", err)
		return err
	}

	// Print PerformanceManager interval collection level
	if debug {
		stdlog.Println("PerformanceManager interval collection level")
		spew.Dump(perfmanager.HistoricalInterval)
	}

	for _, perf := range perfmanager.PerfCounter {
		groupinfo := perf.GroupInfo.GetElementDescription()
		nameinfo := perf.NameInfo.GetElementDescription()
		identifier := groupinfo.Key + "." + nameinfo.Key + "." + fmt.Sprint(perf.RollupType)
		for _, metric := range config.Metrics {
			for _, metricdef := range metric.Definition {
				if metricdef.Metric == identifier {
					metricd := MetricDef{Metric: metricdef.Metric, Instances: metricdef.Instances, Key: perf.Key}
					for _, mtype := range metric.ObjectType {
						added := false
						for _, metricgroup := range vcenter.MetricGroups {
							if metricgroup.ObjectType == mtype {
								metricgroup.Metrics = append(metricgroup.Metrics, metricd)
								added = true
								break
							}
						}
						if added == false {
							metricgroup := MetricGroup{ObjectType: mtype, Metrics: []MetricDef{metricd}}
							vcenter.MetricGroups = append(vcenter.MetricGroups, &metricgroup)
						}
					}
				}
			}
		}
	}
	return nil
}

// Query a vcenter
func (vcenter *VCenter) Query(config Configuration, InfluxDBClient influxclient.Client, nowTime time.Time) {
	stdlog.Println("Setting up query inventory of vcenter:", vcenter.Hostname)

	// Create the contect
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// Get the client
	client := vcenter.client

	// Create the view manager
	var viewManager mo.ViewManager
	err := client.RetrieveOne(ctx, *client.ServiceContent.ViewManager, nil, &viewManager)
	if err != nil {
		errlog.Println("Could not get view manager from vcenter:", vcenter.Hostname)
		errlog.Println("Error: ", err)
		return
	}

	// Get the Datacenters from root folder
	var rootFolder mo.Folder
	err = client.RetrieveOne(ctx, client.ServiceContent.RootFolder, nil, &rootFolder)
	if err != nil {
		errlog.Println("Could not get root folder from vcenter:", vcenter.Hostname)
		errlog.Println("Error:", err)
		return
	}

	datacenters := []types.ManagedObjectReference{}
	for _, child := range rootFolder.ChildEntity {
		//if child.Type == "Datacenter" {
		datacenters = append(datacenters, child)
		//}
	}
	// Get intresting object types from specified queries
	objectTypes := []string{}
	for _, group := range vcenter.MetricGroups {
		objectTypes = append(objectTypes, group.ObjectType)
	}
	objectTypes = append(objectTypes, "ClusterComputeResource")
	objectTypes = append(objectTypes, "ResourcePool")
	objectTypes = append(objectTypes, "Datastore")

	// Loop trought datacenters and create the intersting object reference list
	mors := []types.ManagedObjectReference{}
	for _, datacenter := range datacenters {
		// Create the CreateContentView request
		req := types.CreateContainerView{This: viewManager.Reference(), Container: datacenter, Type: objectTypes, Recursive: true}
		res, err := methods.CreateContainerView(ctx, client.RoundTripper, &req)
		if err != nil {
			errlog.Println("Could not create container view from vcenter:", vcenter.Hostname)
			errlog.Println("Error:", err)
			continue
		}
		// Retrieve the created ContentView
		var containerView mo.ContainerView
		err = client.RetrieveOne(ctx, res.Returnval, nil, &containerView)
		if err != nil {
			errlog.Println("Could not get container view from vcenter:", vcenter.Hostname)
			errlog.Println("Error:", err)
			continue
		}
		// Add found object to object list
		mors = append(mors, containerView.View...)
	}

	// Create MORS for each object type
	vmRefs := []types.ManagedObjectReference{}
	hostRefs := []types.ManagedObjectReference{}
	clusterRefs := []types.ManagedObjectReference{}
	respoolRefs := []types.ManagedObjectReference{}
	datastoreRefs := []types.ManagedObjectReference{}

	newMors := []types.ManagedObjectReference{}

	if debug {
		spew.Dump(mors)
	}
	// Assign each MORS type to a specific array
	for _, mor := range mors {
		if mor.Type == "VirtualMachine" {
			vmRefs = append(vmRefs, mor)
			newMors = append(newMors, mor)
		} else if mor.Type == "HostSystem" {
			hostRefs = append(hostRefs, mor)
			newMors = append(newMors, mor)
		} else if mor.Type == "ClusterComputeResource" {
			clusterRefs = append(clusterRefs, mor)
		} else if mor.Type == "ResourcePool" {
			respoolRefs = append(respoolRefs, mor)
		} else if mor.Type == "Datastore" {
			datastoreRefs = append(datastoreRefs, mor)
		}
	}

	// Copy the mors without the clusters
	mors = newMors
	pc := property.DefaultCollector(client.Client)

	// govmomi segfaults when the list objects to retrieve is empty, so check everything

	// Retrieve properties for all vms
	var vmmo []mo.VirtualMachine
	if len(vmRefs) > 0 {
		err = pc.Retrieve(ctx, vmRefs, []string{"summary"}, &vmmo)
		if err != nil {
			fmt.Println(err)
			return
		}
	}

	// Retrieve properties for hosts
	var hsmo []mo.HostSystem
	if len(hostRefs) > 0 {
		err = pc.Retrieve(ctx, hostRefs, []string{"parent", "summary"}, &hsmo)
		if err != nil {
			fmt.Println(err)
			return
		}
	}

	//Retrieve properties for Cluster(s)
	var clmo []mo.ClusterComputeResource
	if len(clusterRefs) > 0 {
		err = pc.Retrieve(ctx, clusterRefs, []string{"name", "configuration", "host"}, &clmo)
		if err != nil {
			fmt.Println(err)
			return
		}
	}

	//Retrieve properties for ResourcePool
	var rpmo []mo.ResourcePool
	if len(respoolRefs) > 0 {
		err = pc.Retrieve(ctx, respoolRefs, []string{"summary"}, &rpmo)
		if err != nil {
			fmt.Println(err)
			return
		}
	}

	// Retrieve summary property for all datastores
	var dss []mo.Datastore
	if len(datastoreRefs) > 0 {
		err = pc.Retrieve(ctx, datastoreRefs, []string{"summary"}, &dss)
		if err != nil {
			log.Fatal(err)
			return
		}
	}

	// Initialize the map that will hold the VM MOR to ResourcePool reference
	vmToPool := make(map[types.ManagedObjectReference]string)

	var respool []mo.ResourcePool
	// Retrieve properties for ResourcePools
	if len(respoolRefs) > 0 {
		if debug {
			stdlog.Println("Going inside ResourcePools")
		}
		err = pc.Retrieve(ctx, respoolRefs, []string{"name", "config", "vm"}, &respool)
		if err != nil {
			fmt.Println(err)
			return
		}
		for _, pool := range respool {
			if debug {
				stdlog.Println("---resourcepool name - you should see every resourcepool here (+VMs inside)----")
				stdlog.Println(pool.Name)
				stdlog.Println(pool.Config.MemoryAllocation.GetResourceAllocationInfo().Limit)
				stdlog.Println(pool.Config.CpuAllocation.GetResourceAllocationInfo().Limit)
			}
			for _, vm := range pool.Vm {
				if debug {
					stdlog.Println("--VM ID - you should see every VM ID here--")
					stdlog.Println(vm)
				}
				vmToPool[vm] = pool.Name
			}
		}
	}

	// Initialize the map that will hold the VM MOR to cluster reference
	vmToCluster := make(map[types.ManagedObjectReference]string)

	// Initialize the map that will hold the host MOR to cluster reference
	hostToCluster := make(map[types.ManagedObjectReference]string)

	// Initialize the map that will hold the vDisk UUID per VM MOR to datastore reference
	vDiskToDatastore := make(map[types.ManagedObjectReference]map[string]string)

	// Retrieve properties for clusters, if any
	if len(clusterRefs) > 0 {
		if debug {
			stdlog.Println("Going inside clusters")
		}

		// Step 1 : Get ObjectContents and Host info for VM
		//          The host is found under the runtime structure.

		// Step 2 : Step 2: Get the ManagedObjectReference from the Host we just got.

		// Step 3 : Get a list all the clusters that vCenter knows about, and for each one, also get the host

		// Step 4 : Loop through all clusters that exist (which we got in step 3), and loop through each host
		//          and see if that host matches the host we got in step 2 as the host of the vm.
		//          If we find it, return it, otherwise we return null.

		for _, vm := range vmmo {
			// check if VM is a clone in progress and skip it
			if vm.Summary.Runtime.Host == nil {
				continue
			}
			vmhost := vm.Summary.Runtime.Host

			for _, cl := range clmo {
				for _, host := range cl.Host {
					hostToCluster[host] = cl.Name

					if *vmhost == host {
						vmToCluster[vm.Self] = cl.Name
					}
				}
			}
		}

	}

	// Retrieve properties for the pools
	respoolSummary := make(map[types.ManagedObjectReference]map[string]string)
	for _, pools := range rpmo {
		respoolSummary[pools.Self] = make(map[string]string)
		respoolSummary[pools.Self]["name"] = pools.Summary.GetResourcePoolSummary().Name
	}

	// Initialize the maps that will hold the extra tags and metrics for VMs
	hostSummary := make(map[types.ManagedObjectReference]map[string]string)
	hostExtraMetrics := make(map[types.ManagedObjectReference]map[string]int64)

	for _, host := range hsmo {

		// Extra tags per host
		hostSummary[host.Self] = make(map[string]string)
		hostSummary[host.Self]["name"] = host.Summary.Config.Name
		hostSummary[host.Self]["cluster"] = hostToCluster[host.Self]

		// Extra metrics per host
		hostExtraMetrics[host.Self] = make(map[string]int64)
		hostExtraMetrics[host.Self]["uptime"] = int64(host.Summary.QuickStats.Uptime)
		hostExtraMetrics[host.Self]["cpu_corecount_total"] = int64(host.Summary.Hardware.NumCpuThreads)
	}

	// Initialize the maps that will hold the extra tags and metrics for VMs
	vmSummary := make(map[types.ManagedObjectReference]map[string]string)
	vmExtraMetrics := make(map[types.ManagedObjectReference]map[string]int64)

	// Assign extra details per VM in vmSummary
	for _, vm := range vmmo {
		// extra tags per VM
		vmSummary[vm.Self] = make(map[string]string)
		// Ugly way to extract datastore value
		re, err := regexp.Compile(`\[(.*?)\]`)
		if err != nil {
			fmt.Println(err)
		}
		vmSummary[vm.Self]["datastore"] = strings.Replace(strings.Replace(re.FindString(fmt.Sprintln(vm.Summary.Config)), "[", "", -1), "]", "", -1)

		// List all devices to get vDisks
		for _, device := range vm.Config.Hardware.Device {
			// Hacky way to check if it's a vDisk and if it's datastore is different than the main one for VM
			if device.Backing.FileName != nil && device.Backing.Datastore.Name != vmSummary[vm.Self]["datastore"] {
				if vDiskToDatastore[vm.Self] == nil {
					vDiskToDatastore[vm.Self] = make(map[string]string)
				}
				vDiskToDatastore[vm.Self][device.diskObjectId] = device.Backing.Datastore.Name
			}
		}

		if vmToCluster[vm.Self] != "" {
			vmSummary[vm.Self]["cluster"] = vmToCluster[vm.Self]
		}
		if vmToPool[vm.Self] != "" {
			vmSummary[vm.Self]["respool"] = vmToPool[vm.Self]
		}
		if vm.Summary.Runtime.Host != nil {
			vmSummary[vm.Self]["esx"] = hostSummary[*vm.Summary.Runtime.Host]["name"]
		}

		// Extra metrics per VM
		vmExtraMetrics[vm.Self] = make(map[string]int64)
		vmExtraMetrics[vm.Self]["uptime"] = int64(vm.Summary.QuickStats.UptimeSeconds)
	}
	fmt.Println("vDiskDatastore:")
	spew.Dump(vDiskToDatastore)
	// get object names
	objects := []mo.ManagedEntity{}

	//object for propery collection
	propSpec := &types.PropertySpec{Type: "ManagedEntity", PathSet: []string{"name"}}
	var objectSet []types.ObjectSpec
	for _, mor := range mors {
		objectSet = append(objectSet, types.ObjectSpec{Obj: mor, Skip: types.NewBool(false)})
	}

	//retrieve name property
	propreq := types.RetrieveProperties{SpecSet: []types.PropertyFilterSpec{{ObjectSet: objectSet, PropSet: []types.PropertySpec{*propSpec}}}}
	propres, err := client.PropertyCollector().RetrieveProperties(ctx, propreq)
	if err != nil {
		errlog.Println("Could not retrieve object names from vcenter:", vcenter.Hostname)
		errlog.Println("Error:", err)
		return
	}

	//load retrieved properties
	err = mo.LoadRetrievePropertiesResponse(propres, &objects)
	if err != nil {
		errlog.Println("Could not retrieve object names from vcenter:", vcenter.Hostname)
		errlog.Println("Error:", err)
		return
	}

	//create a map to resolve object names
	morToName := make(map[types.ManagedObjectReference]string)
	for _, object := range objects {
		morToName[object.Self] = object.Name
	}

	//create a map to resolve metric names
	metricToName := make(map[int32]string)
	for _, metricgroup := range vcenter.MetricGroups {
		for _, metricdef := range metricgroup.Metrics {
			metricToName[metricdef.Key] = metricdef.Metric
		}
	}

	// Create Queries from interesting objects and requested metrics

	queries := []types.PerfQuerySpec{}

	// Common parameters
	intervalIDint := 20
	var intervalID int32
	intervalID = int32(intervalIDint)

	endTime := time.Now().Add(time.Duration(-1) * time.Second)
	startTime := endTime.Add(time.Duration(-config.Interval) * time.Second)

	// Parse objects
	for _, mor := range mors {
		metricIds := []types.PerfMetricId{}
		for _, metricgroup := range vcenter.MetricGroups {
			if metricgroup.ObjectType == mor.Type {
				for _, metricdef := range metricgroup.Metrics {
					metricIds = append(metricIds, types.PerfMetricId{CounterId: metricdef.Key, Instance: metricdef.Instances})
				}
			}
		}
		queries = append(queries, types.PerfQuerySpec{Entity: mor, StartTime: &startTime, EndTime: &endTime, MetricId: metricIds, IntervalId: intervalID})
	}

	// Query the performances
	perfreq := types.QueryPerf{This: *client.ServiceContent.PerfManager, QuerySpec: queries}
	perfres, err := methods.QueryPerf(ctx, client.RoundTripper, &perfreq)
	if err != nil {
		errlog.Println("Could not request perfs from vcenter:", vcenter.Hostname)
		errlog.Println("Error:", err)
		return
	}

	// Get the result
	vcName := strings.Replace(vcenter.Hostname, config.Domain, "", -1)

	//Influx batch points
	bp, err := influxclient.NewBatchPoints(influxclient.BatchPointsConfig{
		Database:  config.InfluxDB.Database,
		Precision: "s",
	})
	if err != nil {
		errlog.Println(err)
		return
	}

	for _, base := range perfres.Returnval {
		pem := base.(*types.PerfEntityMetric)
		entityName := strings.ToLower(pem.Entity.Type)
		name := strings.ToLower(strings.Replace(morToName[pem.Entity], config.Domain, "", -1))

		//Create map for InfluxDB fields
		fields := make(map[string]interface{})

		// Create map for InfluxDB tags
		tags := map[string]string{"host": vcName, "name": name}

		// Add extra per VM tags
		if summary, ok := vmSummary[pem.Entity]; ok {
			for key, tag := range summary {
				tags[key] = tag
			}
		}
		if summary, ok := hostSummary[pem.Entity]; ok {
			for key, tag := range summary {
				tags[key] = tag
			}
		}

		if summary, ok := respoolSummary[pem.Entity]; ok {
			for key, tag := range summary {
				tags[key] = tag
			}
		}

		specialFields := make(map[string]map[string]map[string]map[string]interface{})
		specialTags := make(map[string]map[string]map[string]map[string]string)
		nowTime := time.Now()
		for _, baseserie := range pem.Value {
			serie := baseserie.(*types.PerfMetricIntSeries)
			metricName := strings.ToLower(metricToName[serie.Id.CounterId])
			influxMetricName := strings.Replace(metricName, ".", "_", -1)
			instanceName := strings.ToLower(strings.Replace(serie.Id.Instance, ".", "_", -1))
			measurementName := strings.Split(metricName, ".")[0]

			if strings.Index(influxMetricName, "datastore") != -1 {
				instanceName = ""
			}

			var value int64 = -1
			if strings.HasSuffix(metricName, ".average") {
				value = average(serie.Value...)
			} else if strings.HasSuffix(metricName, ".maximum") {
				value = max(serie.Value...)
			} else if strings.HasSuffix(metricName, ".minimum") {
				value = min(serie.Value...)
			} else if strings.HasSuffix(metricName, ".latest") {
				value = serie.Value[len(serie.Value)-1]
			} else if strings.HasSuffix(metricName, ".summation") {
				value = sum(serie.Value...)
			}

			if instanceName == "" {
				fields[influxMetricName] = value
			} else {
				// init maps
				if specialFields[measurementName] == nil {
					specialFields[measurementName] = make(map[string]map[string]map[string]interface{})
					specialTags[measurementName] = make(map[string]map[string]map[string]string)

				}

				if specialFields[measurementName][tags["name"]] == nil {
					specialFields[measurementName][tags["name"]] = make(map[string]map[string]interface{})
					specialTags[measurementName][tags["name"]] = make(map[string]map[string]string)
				}

				if specialFields[measurementName][tags["name"]][instanceName] == nil {
					specialFields[measurementName][tags["name"]][instanceName] = make(map[string]interface{})
					specialTags[measurementName][tags["name"]][instanceName] = make(map[string]string)

				}

				specialFields[measurementName][tags["name"]][instanceName][influxMetricName] = value

				for k, v := range tags {
					specialTags[measurementName][tags["name"]][instanceName][k] = v
				}
				specialTags[measurementName][tags["name"]][instanceName]["instance"] = instanceName
			}
		}
		// Create the fields for the hostExtraMetrics
		if metrics, ok := hostExtraMetrics[pem.Entity]; ok {
			for key, value := range metrics {
				fields[key] = value
			}
		}
		// Create the fields for the vmExtraMetrics
		if metrics, ok := vmExtraMetrics[pem.Entity]; ok {
			for key, value := range metrics {
				fields[key] = value
			}
		}

		//create InfluxDB points
		pt, err := influxclient.NewPoint(config.InfluxDB.Prefix+entityName, tags, fields, nowTime)
		if err != nil {
			errlog.Println(err)
			continue
		}
		bp.AddPoint(pt)

		for measurement, v := range specialFields {
			for name, metric := range v {
				for instance, value := range metric {
					pt2, err := influxclient.NewPoint(config.InfluxDB.Prefix+measurement, specialTags[measurement][name][instance], value, time.Now())
					if err != nil {
						errlog.Println(err)
						continue
					}
					bp.AddPoint(pt2)
				}
			}
		}

		for _, pool := range respool {
			respoolFields := map[string]interface{}{
				"cpu_limit":    pool.Config.CpuAllocation.GetResourceAllocationInfo().Limit,
				"memory_limit": pool.Config.MemoryAllocation.GetResourceAllocationInfo().Limit,
			}
			respoolTags := map[string]string{"pool_name": pool.Name}
			pt3, err := influxclient.NewPoint(config.InfluxDB.Prefix+"resourcepool", respoolTags, respoolFields, time.Now())
			if err != nil {
				errlog.Println(err)
				continue
			}
			bp.AddPoint(pt3)
		}

		for _, datastore := range dss {
			datastoreFields := map[string]interface{}{
				"capacity":   datastore.Summary.Capacity,
				"free_space": datastore.Summary.FreeSpace,
			}
			datastoreTags := map[string]string{"ds_name": datastore.Summary.Name, "host": vcName}
			pt4, err := influxclient.NewPoint(config.InfluxDB.Prefix+"datastore", datastoreTags, datastoreFields, time.Now())
			if err != nil {
				errlog.Println(err)
				continue
			}
			bp.AddPoint(pt4)
		}

	}

	//InfluxDB send if not in test mode
	if test != true {
		err = InfluxDBClient.Write(bp)
		if err != nil {
			errlog.Println(err)
			return
		}
		stdlog.Println("Sent data to Influxdb from:", vcenter.Hostname)
	} else {
		spew.Dump(bp)
	}
}

func min(n ...int64) int64 {
	var min int64 = -1
	for _, i := range n {
		if i >= 0 {
			if min == -1 {
				min = i
			} else {
				if i < min {
					min = i
				}
			}
		}
	}
	return min
}
func max(n ...int64) int64 {
	var max int64 = -1
	for _, i := range n {
		if i >= 0 {
			if max == -1 {
				max = i
			} else {
				if i > max {
					max = i
				}
			}
		}
	}
	return max
}

func sum(n ...int64) int64 {
	var total int64
	for _, i := range n {
		if i > 0 {
			total += i
		}
	}
	return total
}

func average(n ...int64) int64 {
	var total int64
	var count int64
	for _, i := range n {
		if i >= 0 {
			count++
			total += i
		}
	}
	favg := float64(total) / float64(count)
	return int64(math.Floor(favg + .5))
}

func worker(id int, config Configuration, influxDBClient influxclient.Client, nowTime time.Time, vcenters <-chan *VCenter, results chan<- bool) {
	for vcenter := range vcenters {
		if debug {
			stdlog.Println("Worker", id, "received vcenter", vcenter.Hostname)
		}

		if err := vcenter.Connect(); err != nil {
			errlog.Println("Could not initialize connection to vcenter", vcenter.Hostname, err)
			results <- true
			continue
		}
		if err := vcenter.Init(config); err == nil {
			vcenter.Query(config, influxDBClient, nowTime)
		}

		vcenter.Disconnect()
		results <- true
	}
}

func main() {
	baseName := path.Base(os.Args[0])
	stdlog = log.New(os.Stdout, "", log.Ldate|log.Ltime)
	errlog = log.New(os.Stderr, "", log.Ldate|log.Ltime)

	flag.BoolVar(&debug, "debug", false, "Debug mode")
	flag.BoolVar(&test, "test", false, "Test mode, data will be collected from vCenters, but nothing will be written to InfluxDB, only printed to stdout")
	flag.BoolVar(&getversion, "version", false, "Get version and exit")
	workerCount := flag.Int("workers", 4, "Number of concurrent workers to query vcenters")
	cfgFile := flag.String("config", "/etc/"+baseName+".json", "Config file to use")
	flag.Parse()

	if getversion {
		fmt.Println("Version:", version)
		os.Exit(0)
	}

	stdlog.Println("Starting", baseName, "with config file", *cfgFile)

	// read the configuration
	file, err := os.Open(*cfgFile)
	if err != nil {
		errlog.Println("Could not open configuration file", *cfgFile)
		errlog.Fatalln(err)
	}

	jsondec := json.NewDecoder(file)
	config := Configuration{}
	err = jsondec.Decode(&config)
	if err != nil {
		errlog.Println("Could not decode configuration file", *cfgFile)
		errlog.Fatalln(err)
	}

	// Support environemt variables / overrides for Influx Connection
	if ihostname := os.Getenv("INFLUX_HOSTNAME"); ihostname != "" {
		config.InfluxDB.Hostname = os.Getenv("INFLUX_HOSTNAME")
		config.InfluxDB.Username = os.Getenv("INFLUX_USERNAME")
		config.InfluxDB.Password = os.Getenv("INFLUX_PASSWORD")
		config.InfluxDB.Database = os.Getenv("INFLUX_DATABASE")
	}
	// Support environment variables for VSphere
	// Currently ony one server is supported and added to the list of vSphere servers
	if vhostname := os.Getenv("VSPHERE_HOSTNAME"); vhostname != "" {
		vc := VCenter{
			Hostname: os.Getenv("VSPHERE_HOSTNAME"),
			Username: os.Getenv("VSPHERE_USERNAME"),
			Password: os.Getenv("VSPHERE_PASSWORD"),
		}
		config.VCenters = append(config.VCenters, &vc)
	}

	// Print configuration in debug mode
	if debug {
		stdlog.Println("---Configuration - you should see the config here---")
		spew.Dump(config)
	}

	// Initialize InfluxDB and connect to database
	InfluxDBClient, err := influxclient.NewHTTPClient(influxclient.HTTPConfig{
		Addr:     config.InfluxDB.Hostname,
		Username: config.InfluxDB.Username,
		Password: config.InfluxDB.Password,
	})
	if err != nil {
		errlog.Println("Could not initialize InfluxDB client")
		errlog.Fatalln(err)
	}

	if _, _, err := InfluxDBClient.Ping(0); err != nil {
		errlog.Println("Could not connect to InfluxDB")
		errlog.Fatalln(err)
	}

	defer InfluxDBClient.Close()

	stdlog.Println("Successfully connected to Influx")

	// make the channels, get the time, launch the goroutines
	vcenterCount := len(config.VCenters)
	vcenters := make(chan *VCenter, vcenterCount)
	results := make(chan bool, vcenterCount)
	nowTime := time.Now()

	for i := 0; i < *workerCount; i++ {
		go worker(i, config, InfluxDBClient, nowTime, vcenters, results)
	}

	for _, vcenter := range config.VCenters {
		vcenters <- vcenter
	}
	close(vcenters)

	for i := 0; i < vcenterCount; i++ {
		<-results
	}

}