package metrics

import (
	"fmt"
	"strings"
	"time"

	"github.com/prometheus/client_golang/prometheus"
)

const objectSubsystem = "object"

type (
	methodCount struct {
		success prometheus.Counter
		total   prometheus.Counter
	}

	objectServiceMetrics struct {
		getCounter       methodCount
		putCounter       methodCount
		headCounter      methodCount
		searchCounter    methodCount
		deleteCounter    methodCount
		rangeCounter     methodCount
		rangeHashCounter methodCount

		getDuration       prometheus.Counter
		putDuration       prometheus.Counter
		headDuration      prometheus.Counter
		searchDuration    prometheus.Counter
		deleteDuration    prometheus.Counter
		rangeDuration     prometheus.Counter
		rangeHashDuration prometheus.Counter

		putPayload prometheus.Counter
		getPayload prometheus.Counter

		shardMetrics   *prometheus.GaugeVec
		shardsReadonly *prometheus.GaugeVec
	}
)

const (
	shardIDLabelKey     = "shard"
	counterTypeLabelKey = "type"
	containerIDLabelKey = "cid"
)

func newObjectMethodCallCounter(name string) methodCount {
	return methodCount{
		success: prometheus.NewCounter(prometheus.CounterOpts{
			Namespace: namespace,
			Subsystem: objectSubsystem,
			Name:      fmt.Sprintf("%s_req_count_success", name),
			Help:      fmt.Sprintf("The number of successful %s requests processed", name),
		}),
		total: prometheus.NewCounter(prometheus.CounterOpts{
			Namespace: namespace,
			Subsystem: objectSubsystem,
			Name:      fmt.Sprintf("%s_req_count", name),
			Help:      fmt.Sprintf("Total number of %s requests processed", name),
		}),
	}
}

func (m methodCount) mustRegister() {
	prometheus.MustRegister(m.success)
	prometheus.MustRegister(m.total)
}

func (m methodCount) Inc(success bool) {
	m.total.Inc()
	if success {
		m.success.Inc()
	}
}

func newObjectServiceMetrics() objectServiceMetrics {
	return objectServiceMetrics{
		getCounter:        newObjectMethodCallCounter("get"),
		putCounter:        newObjectMethodCallCounter("put"),
		headCounter:       newObjectMethodCallCounter("head"),
		searchCounter:     newObjectMethodCallCounter("search"),
		deleteCounter:     newObjectMethodCallCounter("delete"),
		rangeCounter:      newObjectMethodCallCounter("range"),
		rangeHashCounter:  newObjectMethodCallCounter("range_hash"),
		getDuration:       newObjectMethodDurationCounter("get"),
		putDuration:       newObjectMethodDurationCounter("put"),
		headDuration:      newObjectMethodDurationCounter("head"),
		searchDuration:    newObjectMethodDurationCounter("search"),
		deleteDuration:    newObjectMethodDurationCounter("delete"),
		rangeDuration:     newObjectMethodDurationCounter("range"),
		rangeHashDuration: newObjectMethodDurationCounter("range_hash"),
		putPayload:        newObjectMethodPayloadCounter("put"),
		getPayload:        newObjectMethodPayloadCounter("get"),
		shardMetrics:      newObjectGaugeVector("counter", "Objects counters per shards", []string{shardIDLabelKey, counterTypeLabelKey}),
		shardsReadonly:    newObjectGaugeVector("readonly", "Shard state", []string{shardIDLabelKey}),
	}
}

func newObjectMethodPayloadCounter(method string) prometheus.Counter {
	return prometheus.NewCounter(prometheus.CounterOpts{
		Namespace: namespace,
		Subsystem: objectSubsystem,
		Name:      fmt.Sprintf("%s_payload", method),
		Help:      fmt.Sprintf("Accumulated payload size at object %s method", strings.ReplaceAll(method, "_", " ")),
	})
}

func newObjectMethodDurationCounter(method string) prometheus.Counter {
	return prometheus.NewCounter(prometheus.CounterOpts{
		Namespace: namespace,
		Subsystem: objectSubsystem,
		Name:      fmt.Sprintf("%s_req_duration", method),
		Help:      fmt.Sprintf("Accumulated %s request process duration", strings.ReplaceAll(method, "_", " ")),
	})
}

func newObjectGaugeVector(name, help string, labels []string) *prometheus.GaugeVec {
	return prometheus.NewGaugeVec(prometheus.GaugeOpts{
		Namespace: namespace,
		Subsystem: objectSubsystem,
		Name:      name,
		Help:      help,
	}, labels)
}

func (m objectServiceMetrics) register() {
	m.getCounter.mustRegister()
	m.putCounter.mustRegister()
	m.headCounter.mustRegister()
	m.searchCounter.mustRegister()
	m.deleteCounter.mustRegister()
	m.rangeCounter.mustRegister()
	m.rangeHashCounter.mustRegister()

	prometheus.MustRegister(m.getDuration)
	prometheus.MustRegister(m.putDuration)
	prometheus.MustRegister(m.headDuration)
	prometheus.MustRegister(m.searchDuration)
	prometheus.MustRegister(m.deleteDuration)
	prometheus.MustRegister(m.rangeDuration)
	prometheus.MustRegister(m.rangeHashDuration)

	prometheus.MustRegister(m.putPayload)
	prometheus.MustRegister(m.getPayload)

	prometheus.MustRegister(m.shardMetrics)
	prometheus.MustRegister(m.shardsReadonly)
}

func (m objectServiceMetrics) IncGetReqCounter(success bool) {
	m.getCounter.Inc(success)
}

func (m objectServiceMetrics) IncPutReqCounter(success bool) {
	m.putCounter.Inc(success)
}

func (m objectServiceMetrics) IncHeadReqCounter(success bool) {
	m.headCounter.Inc(success)
}

func (m objectServiceMetrics) IncSearchReqCounter(success bool) {
	m.searchCounter.Inc(success)
}

func (m objectServiceMetrics) IncDeleteReqCounter(success bool) {
	m.deleteCounter.Inc(success)
}

func (m objectServiceMetrics) IncRangeReqCounter(success bool) {
	m.rangeCounter.Inc(success)
}

func (m objectServiceMetrics) IncRangeHashReqCounter(success bool) {
	m.rangeHashCounter.Inc(success)
}

func (m objectServiceMetrics) AddGetReqDuration(d time.Duration) {
	m.getDuration.Add(float64(d))
}

func (m objectServiceMetrics) AddPutReqDuration(d time.Duration) {
	m.putDuration.Add(float64(d))
}

func (m objectServiceMetrics) AddHeadReqDuration(d time.Duration) {
	m.headDuration.Add(float64(d))
}

func (m objectServiceMetrics) AddSearchReqDuration(d time.Duration) {
	m.searchDuration.Add(float64(d))
}

func (m objectServiceMetrics) AddDeleteReqDuration(d time.Duration) {
	m.deleteDuration.Add(float64(d))
}

func (m objectServiceMetrics) AddRangeReqDuration(d time.Duration) {
	m.rangeDuration.Add(float64(d))
}

func (m objectServiceMetrics) AddRangeHashReqDuration(d time.Duration) {
	m.rangeHashDuration.Add(float64(d))
}

func (m objectServiceMetrics) AddPutPayload(ln int) {
	m.putPayload.Add(float64(ln))
}

func (m objectServiceMetrics) AddGetPayload(ln int) {
	m.getPayload.Add(float64(ln))
}

func (m objectServiceMetrics) AddToObjectCounter(shardID, objectType string, delta int) {
	m.shardMetrics.With(
		prometheus.Labels{
			shardIDLabelKey:     shardID,
			counterTypeLabelKey: objectType,
		},
	).Add(float64(delta))
}

func (m objectServiceMetrics) SetObjectCounter(shardID, objectType string, v uint64) {
	m.shardMetrics.With(
		prometheus.Labels{
			shardIDLabelKey:     shardID,
			counterTypeLabelKey: objectType,
		},
	).Set(float64(v))
}

func (m objectServiceMetrics) SetReadonly(shardID string, readonly bool) {
	var flag float64
	if readonly {
		flag = 1
	}
	m.shardsReadonly.With(
		prometheus.Labels{
			shardIDLabelKey: shardID,
		},
	).Set(flag)
}