package main

import (
	"flag"
	"fmt"
	"log"
	"net/http"
	"strings"

	"github.com/helium-blockchain-exporter/heliumapi"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promhttp"
)

// metricInfo is a metric exported by the helium blockchain exporter
type metricInfo struct {
	Desc *prometheus.Desc
	Type prometheus.ValueType
}

// Exporter collect metrics from the helium blockchain api and exports them as prometheus metrics.
type Exporter struct {
	Accounts []string
}

const (
	namespace = "helium"
)

var (
	// lables
	commonAccountLabels = []string{"account"}
	commonHotspotLabels = append(commonAccountLabels, "hotspot", "hotspot_name")

	// exporter metrics

	// helium oracle metrics
	oraclePrice = metricInfo{
		prometheus.NewDesc(
			prometheus.BuildFQName(namespace, "oracle", "price_usd"),
			"The oracle price of an HNT token in USD.",
			nil, nil,
		),
		prometheus.GaugeValue,
	}

	// helium stats metrics
	statsValidators = metricInfo{
		prometheus.NewDesc(
			prometheus.BuildFQName(namespace, "stats", "validators"),
			"The number of validators.",
			nil, nil,
		),
		prometheus.GaugeValue,
	}
	statsOuis = metricInfo{
		prometheus.NewDesc(
			prometheus.BuildFQName(namespace, "stats", "ouis"),
			"The number of organization unique identifiers.",
			nil, nil,
		),
		prometheus.GaugeValue,
	}
	statsHotspotsDataOnly = metricInfo{
		prometheus.NewDesc(
			prometheus.BuildFQName(namespace, "stats", "hotspots_dataonly"),
			"The number of data only hotspots.",
			nil, nil,
		),
		prometheus.GaugeValue,
	}
	statsBlocks = metricInfo{
		prometheus.NewDesc(
			prometheus.BuildFQName(namespace, "stats", "blocks"),
			"The height/number of blocks in the blockchain.",
			nil, nil,
		),
		prometheus.GaugeValue,
	}
	statsChallenges = metricInfo{
		prometheus.NewDesc(
			prometheus.BuildFQName(namespace, "stats", "challenges"),
			"The number of challenges.",
			nil, nil,
		),
		prometheus.GaugeValue,
	}
	statsCities = metricInfo{
		prometheus.NewDesc(
			prometheus.BuildFQName(namespace, "stats", "cities"),
			"The number of cities with at least one helium hotspot.",
			nil, nil,
		),
		prometheus.GaugeValue,
	}
	statsConsensusGroups = metricInfo{
		prometheus.NewDesc(
			prometheus.BuildFQName(namespace, "stats", "consensus_groups"),
			"The number of consensus groups.",
			nil, nil,
		),
		prometheus.GaugeValue,
	}
	statsCountries = metricInfo{
		prometheus.NewDesc(
			prometheus.BuildFQName(namespace, "stats", "countries"),
			"The number of countries with at least on helium hotspot.",
			nil, nil,
		),
		prometheus.GaugeValue,
	}
	statsHotspots = metricInfo{
		prometheus.NewDesc(
			prometheus.BuildFQName(namespace, "stats", "hotspots"),
			"The number of hotspots.",
			nil, nil,
		),
		prometheus.GaugeValue,
	}
	statsTokenSupply = metricInfo{
		prometheus.NewDesc(
			prometheus.BuildFQName(namespace, "stats", "token_supply"),
			"The total supply of HNT tokens in circulation.",
			nil, nil,
		),
		prometheus.GaugeValue,
	}

	// helium account metrics
	accountBalanceHnt = metricInfo{
		prometheus.NewDesc(
			prometheus.BuildFQName(namespace, "account", "balance_hnt"),
			"The number of HNT token owned by the account.",
			commonAccountLabels, nil,
		),
		prometheus.GaugeValue,
	}
	accountActivity = metricInfo{
		prometheus.NewDesc(
			prometheus.BuildFQName(namespace, "account", "activity_total"),
			"The total number of time an activity occurred in an account.",
			append(commonAccountLabels, "type"), nil,
		),
		prometheus.CounterValue,
	}
	accountRewardsHnt = metricInfo{
		prometheus.NewDesc(
			prometheus.BuildFQName(namespace, "account", "reward_hnt"),
			"The number of HNT token rewarded to this account.",
			commonAccountLabels, nil,
		),
		prometheus.GaugeValue,
	}
	accountDepositsHnt = metricInfo{
		prometheus.NewDesc(
			prometheus.BuildFQName(namespace, "account", "deposits_hnt_total"),
			"The number of HNT token deposited to this account.",
			commonAccountLabels, nil,
		),
		prometheus.CounterValue,
	}
	accountWithdrawalsHnt = metricInfo{
		prometheus.NewDesc(
			prometheus.BuildFQName(namespace, "account", "withdrawals_hnt_total"),
			"The number of HNT token withdrawn from this account.",
			commonAccountLabels, nil,
		),
		prometheus.CounterValue,
	}

// helium hotspot metrics
)

// Describe describes all the metrics ever exported by the helium blockchain exporter.
// implements prometheus.Collector.
func (e *Exporter) Describe(ch chan<- *prometheus.Desc) {
	ch <- oraclePrice.Desc

	ch <- statsValidators.Desc
	ch <- statsOuis.Desc
	ch <- statsHotspotsDataOnly.Desc
	ch <- statsBlocks.Desc
	ch <- statsChallenges.Desc
	ch <- statsCities.Desc
	ch <- statsConsensusGroups.Desc
	ch <- statsCountries.Desc
	ch <- statsHotspots.Desc
	ch <- statsTokenSupply.Desc

	ch <- accountBalanceHnt.Desc
	ch <- accountActivity.Desc
	ch <- accountRewardsHnt.Desc
	ch <- accountDepositsHnt.Desc
	ch <- accountWithdrawalsHnt.Desc
}

// Collect fetches the data from the helium blockchain api and delivers them as Prometheus metrics.
// implements prometheus.Collector.
func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
	e.collectOracleMetrics(ch)
	e.collectStatsMetrics(ch)
	for _, account := range e.Accounts {
		e.collectAccountMetrics(ch, account)
	}
}

// collectOracleMetrics collect metrics in the oracle group from the helium api
func (e *Exporter) collectOracleMetrics(ch chan<- prometheus.Metric) {
	currentOraclePrice, err := heliumapi.GetCurrentOraclePrice()
	if err != nil {
		fmt.Println(err)
		return
	}

	ch <- prometheus.MustNewConstMetric(
		oraclePrice.Desc, oraclePrice.Type, float64(currentOraclePrice.Data.Price)/100000000,
	)
}

// collectStatsMetrics collect metrics in the stats group from the helium api
func (e *Exporter) collectStatsMetrics(ch chan<- prometheus.Metric) {
	blockchainStats, err := heliumapi.GetBlockchainStats()
	if err != nil {
		fmt.Println(err)
		return
	}

	ch <- prometheus.MustNewConstMetric(
		statsValidators.Desc, statsValidators.Type, float64(blockchainStats.Data.Counts.Validators),
	)
	ch <- prometheus.MustNewConstMetric(
		statsOuis.Desc, statsOuis.Type, float64(blockchainStats.Data.Counts.Ouis),
	)
	ch <- prometheus.MustNewConstMetric(
		statsHotspotsDataOnly.Desc, statsHotspotsDataOnly.Type, float64(blockchainStats.Data.Counts.HotspotsDataonly),
	)
	ch <- prometheus.MustNewConstMetric(
		statsBlocks.Desc, statsBlocks.Type, float64(blockchainStats.Data.Counts.Blocks),
	)
	ch <- prometheus.MustNewConstMetric(
		statsChallenges.Desc, statsChallenges.Type, float64(blockchainStats.Data.Counts.Challenges),
	)
	ch <- prometheus.MustNewConstMetric(
		statsCities.Desc, statsCities.Type, float64(blockchainStats.Data.Counts.Cities),
	)
	ch <- prometheus.MustNewConstMetric(
		statsConsensusGroups.Desc, statsConsensusGroups.Type, float64(blockchainStats.Data.Counts.ConsensusGroups),
	)
	ch <- prometheus.MustNewConstMetric(
		statsCountries.Desc, statsCountries.Type, float64(blockchainStats.Data.Counts.Countries),
	)
	ch <- prometheus.MustNewConstMetric(
		statsHotspots.Desc, statsHotspots.Type, float64(blockchainStats.Data.Counts.Hotspots),
	)
	ch <- prometheus.MustNewConstMetric(
		statsTokenSupply.Desc, statsTokenSupply.Type, blockchainStats.Data.TokenSupply,
	)
}

// collectStatsMetrics collect metrics in the account group from the helium api
func (e *Exporter) collectAccountMetrics(ch chan<- prometheus.Metric, account string) {
	accountForAddress, err := heliumapi.GetAccountForAddress(account)
	if err != nil {
		fmt.Println(err)
		return
	}

	ch <- prometheus.MustNewConstMetric(
		accountBalanceHnt.Desc, accountBalanceHnt.Type, float64(accountForAddress.Data.Balance),
		account,
	)
}

// NewExporter returns an initialized Exporter
func NewExporter(accounts []string) (*Exporter, error) {
	return &Exporter{
		Accounts: accounts,
	}, nil
}

func main() {
	fHeliumAccounts := flag.String("accounts", "", "A comma-delimited list of helium accounts to scrape.")
	fMetricsPath := flag.String("metricpath", "/metrics", "The metrics path")
	fListenAddress := flag.String("listenAddress", "0.0.0.0", "The http server listen address")
	fListenPort := flag.String("listenPort", "9111", "The http server listen port")
	flag.Parse()

	heliumAccounts := make([]string, 0)
	if *fHeliumAccounts != "" {
		heliumAccounts = strings.Split(*fHeliumAccounts, ",")
	}
	serverAddr := *fListenAddress + ":" + *fListenPort

	e, err := NewExporter(heliumAccounts)
	if err != nil {
		log.Fatalf("failed to start exporter: %s", err.Error())
	}

	r := prometheus.NewRegistry()
	r.MustRegister(e)

	// setup http route
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		_, _ = w.Write([]byte(`<html>
             <head><title>Helium blockchain exporter</title></head>
             <body>
             <h1>Helium blockchain exporter</h1>
             <p><a href='` + *fMetricsPath + `'>Metrics</a></p>
             </body>
             </html>`))
	})

	http.Handle(*fMetricsPath, promhttp.HandlerFor(r, promhttp.HandlerOpts{}))
	fmt.Printf("exporter listening on %v\n", serverAddr)
	http.ListenAndServe(serverAddr, nil)
}