package main

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

	"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 {
}

const (
	namespace = "helium"
)

var (
	// 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 hotspots.",
			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

// 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
}

// 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)
}

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,
	)
}

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,
	)
}

// NewExporter returns an initialized Exporter
func NewExporter() (*Exporter, error) {
	return &Exporter{}, nil
}

func main() {
	metricsPath := "/metrics"

	e, err := NewExporter()
	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='` + metricsPath + `'>Metrics</a></p>
             </body>
             </html>`))
	})

	http.Handle(metricsPath, promhttp.HandlerFor(r, promhttp.HandlerOpts{}))
	http.ListenAndServe(":9111", nil)
}