package puppetagent

import (
	"fmt"
	"gopkg.in/yaml.v2"
	"io/ioutil"
	"os"
	"reflect"
	"strings"

	"github.com/influxdata/telegraf"
	"github.com/influxdata/telegraf/plugins/inputs"
)

// PuppetAgent is a PuppetAgent plugin
type PuppetAgent struct {
	Location string
}

var sampleConfig = `
  ## Location of puppet last run summary file
  location = "/var/lib/puppet/state/last_run_summary.yaml"
`

type State struct {
	Events    event
	Resources resource
	Changes   change
	Time      time
	Version   version
}

type event struct {
	Failure int64 `yaml:"failure"`
	Total   int64 `yaml:"total"`
	Success int64 `yaml:"success"`
}

type resource struct {
	Failed          int64 `yaml:"failed"`
	Scheduled       int64 `yaml:"scheduled"`
	Changed         int64 `yaml:"changed"`
	Skipped         int64 `yaml:"skipped"`
	Total           int64 `yaml:"total"`
	FailedToRestart int64 `yaml:"failed_to_restart"`
	Restarted       int64 `yaml:"restarted"`
	OutOfSync       int64 `yaml:"out_of_sync"`
}

type change struct {
	Total int64 `yaml:"total"`
}

type time struct {
	User             float64 `yaml:"user"`
	Schedule         float64 `yaml:"schedule"`
	FileBucket       float64 `yaml:"filebucket"`
	File             float64 `yaml:"file"`
	Exec             float64 `yaml:"exec"`
	Anchor           float64 `yaml:"anchor"`
	SSHAuthorizedKey float64 `yaml:"ssh_authorized_key"`
	Service          float64 `yaml:"service"`
	Package          float64 `yaml:"package"`
	Total            float64 `yaml:"total"`
	ConfigRetrieval  float64 `yaml:"config_retrieval"`
	LastRun          int64   `yaml:"last_run"`
	Cron             float64 `yaml:"cron"`
}

type version struct {
	ConfigString string `yaml:"config"`
	Puppet       string `yaml:"puppet"`
}

// SampleConfig returns sample configuration message
func (pa *PuppetAgent) SampleConfig() string {
	return sampleConfig
}

// Description returns description of PuppetAgent plugin
func (pa *PuppetAgent) Description() string {
	return `Reads last_run_summary.yaml file and converts to measurements`
}

// Gather reads stats from all configured servers accumulates stats
func (pa *PuppetAgent) Gather(acc telegraf.Accumulator) error {

	if len(pa.Location) == 0 {
		pa.Location = "/var/lib/puppet/state/last_run_summary.yaml"
	}

	if _, err := os.Stat(pa.Location); err != nil {
		return fmt.Errorf("%s", err)
	}

	fh, err := ioutil.ReadFile(pa.Location)
	if err != nil {
		return fmt.Errorf("%s", err)
	}

	var puppetState State

	err = yaml.Unmarshal(fh, &puppetState)
	if err != nil {
		return fmt.Errorf("%s", err)
	}

	tags := map[string]string{"location": pa.Location}
	structPrinter(&puppetState, acc, tags)

	return nil
}

func structPrinter(s *State, acc telegraf.Accumulator, tags map[string]string) {
	e := reflect.ValueOf(s).Elem()

	fields := make(map[string]interface{})
	for tLevelFNum := 0; tLevelFNum < e.NumField(); tLevelFNum++ {
		name := e.Type().Field(tLevelFNum).Name
		nameNumField := e.FieldByName(name).NumField()

		for sLevelFNum := 0; sLevelFNum < nameNumField; sLevelFNum++ {
			sName := e.FieldByName(name).Type().Field(sLevelFNum).Name
			sValue := e.FieldByName(name).Field(sLevelFNum).Interface()

			lname := strings.ToLower(name)
			lsName := strings.ToLower(sName)
			fields[fmt.Sprintf("%s_%s", lname, lsName)] = sValue
		}
	}
	acc.AddFields("puppetagent", fields, tags)
}

func init() {
	inputs.Add("puppetagent", func() telegraf.Input {
		return &PuppetAgent{}
	})
}
