/*
Real-time Online/Offline Charging System (OCS) for Telecom & ISP environments
Copyright (C) ITsysCOM GmbH

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero 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 Affero General Public License for more details.

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

package engine

import (
	"errors"
	"fmt"
	"math"
	"slices"
	"strconv"
	"strings"
	"time"

	"maps"

	"github.com/cgrates/cgrates/config"
	"github.com/cgrates/cgrates/utils"
)

// ACDHelper structure
type DurationWithCompress struct {
	Duration       time.Duration
	CompressFactor int
}

// Clone creates a deep copy of DurationWithCompress
func (dwc *DurationWithCompress) Clone() *DurationWithCompress {
	if dwc == nil {
		return nil
	}
	return &DurationWithCompress{
		Duration:       dwc.Duration,
		CompressFactor: dwc.CompressFactor,
	}
}

// ACDHelper structure
type StatWithCompress struct {
	Stat           float64
	CompressFactor int
}

// Clone creates a deep copy of StatWithCompress
func (swc *StatWithCompress) Clone() *StatWithCompress {
	if swc == nil {
		return nil
	}
	return &StatWithCompress{
		Stat:           swc.Stat,
		CompressFactor: swc.CompressFactor,
	}
}

// NewStatMetric instantiates the StatMetric
// cfg serves as general purpose container to pass config options to metric
func NewStatMetric(metricID string, minItems int, filterIDs []string) (sm StatMetric, err error) {
	metrics := map[string]func(int, string, []string) (StatMetric, error){
		utils.MetaASR:      NewASR,
		utils.MetaACD:      NewACD,
		utils.MetaTCD:      NewTCD,
		utils.MetaACC:      NewACC,
		utils.MetaTCC:      NewTCC,
		utils.MetaPDD:      NewPDD,
		utils.MetaDDC:      NewDDC,
		utils.MetaSum:      NewStatSum,
		utils.MetaAverage:  NewStatAverage,
		utils.MetaDistinct: NewStatDistinct,
		utils.MetaHighest:  NewStatHighest,
		utils.MetaLowest:   NewStatLowest,
		utils.MetaREPSC:    NewStatREPSC,
		utils.MetaREPFC:    NewStatREPFC,
	}
	// split the metricID
	// in case of *sum we have *sum#~*req.FieldName
	metricSplit := strings.Split(metricID, utils.HashtagSep)
	if _, has := metrics[metricSplit[0]]; !has {
		return nil, fmt.Errorf("unsupported metric type <%s>", metricSplit[0])
	}
	var extraParams string
	if len(metricSplit[1:]) > 0 {
		extraParams = metricSplit[1]
	}
	return metrics[metricSplit[0]](minItems, extraParams, filterIDs)
}

// StatMetric is the interface which a metric should implement
type StatMetric interface {
	GetValue(roundingDecimal int) any
	GetStringValue(roundingDecimal int) (val string)
	GetFloat64Value(roundingDecimal int) (val float64)
	AddEvent(evID string, ev utils.DataProvider) error
	AddOneEvent(ev utils.DataProvider) error
	RemEvent(evTenantID string)
	Marshal(ms Marshaler) (marshaled []byte, err error)
	LoadMarshaled(ms Marshaler, marshaled []byte) (err error)
	GetFilterIDs() (filterIDs []string)
	GetMinItems() (minIts int)
	Compress(queueLen int64, defaultID string, roundingDec int) (eventIDs []string)
	GetCompressFactor(events map[string]int) map[string]int
	Clone() StatMetric
}

func NewASR(minItems int, extraParams string, filterIDs []string) (StatMetric, error) {
	return &StatASR{Events: make(map[string]*StatWithCompress),
		MinItems: minItems, FilterIDs: filterIDs}, nil
}

// ASR implements AverageSuccessRatio metric
type StatASR struct {
	FilterIDs []string
	Answered  float64
	Count     int64
	Events    map[string]*StatWithCompress // map[EventTenantID]Answered
	MinItems  int
	val       *float64 // cached ASR value
}

// Clone creates a deep copy of StatASR
func (s *StatASR) Clone() StatMetric {
	if s == nil {
		return nil
	}
	clone := &StatASR{
		Answered: s.Answered,
		Count:    s.Count,
		MinItems: s.MinItems,
	}
	if s.FilterIDs != nil {
		clone.FilterIDs = make([]string, len(s.FilterIDs))
		copy(clone.FilterIDs, s.FilterIDs)
	}
	if s.Events != nil {
		clone.Events = make(map[string]*StatWithCompress, len(s.Events))
		for k, v := range s.Events {
			if v != nil {
				clone.Events[k] = &StatWithCompress{Stat: v.Stat, CompressFactor: v.CompressFactor}
			}
		}
	}
	if s.val != nil {
		val := *s.val
		clone.val = &val
	}
	return clone
}

// getValue returns asr.val
func (asr *StatASR) getValue(roundingDecimal int) float64 {
	if asr.val == nil {
		if (asr.MinItems > 0 && asr.Count < int64(asr.MinItems)) || (asr.Count == 0) {
			asr.val = utils.Float64Pointer(utils.StatsNA)
		} else {
			asr.val = utils.Float64Pointer(utils.Round((asr.Answered / float64(asr.Count) * 100.0),
				roundingDecimal, utils.MetaRoundingMiddle))
		}
	}
	return *asr.val
}

// GetValue returns the ASR value as part of StatMetric interface
func (asr *StatASR) GetValue(roundingDecimal int) (v any) {
	return asr.getValue(roundingDecimal)
}

func (asr *StatASR) GetStringValue(roundingDecimal int) (valStr string) {
	if val := asr.getValue(roundingDecimal); val == utils.StatsNA {
		valStr = utils.NotAvailable
	} else {
		valStr = fmt.Sprintf("%v%%", asr.getValue(roundingDecimal))
	}
	return
}

// GetFloat64Value is part of StatMetric interface
func (asr *StatASR) GetFloat64Value(roundingDecimal int) (val float64) {
	return asr.getValue(roundingDecimal)
}

func (asr *StatASR) getFieldVal(ev utils.DataProvider) (answered int, err error) {
	var val any
	if val, err = ev.FieldAsInterface([]string{utils.MetaReq, utils.AnswerTime}); err != nil {
		if err != utils.ErrNotFound {
			return answered, err
		}
	} else if at, err := utils.IfaceAsTime(val,
		config.CgrConfig().GeneralCfg().DefaultTimezone); err != nil {
		return answered, err
	} else if !at.IsZero() {
		answered = 1
	}
	return answered, nil
}

// AddEvent is part of StatMetric interface
func (asr *StatASR) AddEvent(evID string, ev utils.DataProvider) (err error) {
	var answered int
	if answered, err = asr.getFieldVal(ev); err != nil {
		return
	}
	if val, has := asr.Events[evID]; !has {
		asr.Events[evID] = &StatWithCompress{Stat: float64(answered), CompressFactor: 1}
	} else {
		val.Stat = (val.Stat*float64(val.CompressFactor) + float64(answered)) / float64(val.CompressFactor+1)
		val.CompressFactor = val.CompressFactor + 1
	}
	asr.Count++
	if answered == 1 {
		asr.Answered++
	}
	asr.val = nil
	return
}

// AddOneEvent aggregates the  metric value without storing the events
func (asr *StatASR) AddOneEvent(ev utils.DataProvider) (err error) {
	var answered int
	if answered, err = asr.getFieldVal(ev); err != nil {
		return
	}
	asr.Count++
	if answered == 1 {
		asr.Answered++
	}
	asr.val = nil
	return
}

// RemEvent deletes  a stored event and  decrements statistics of the metric for recalculation
func (asr *StatASR) RemEvent(evID string) {
	val, has := asr.Events[evID]
	if !has {
		return
	}
	ans := 0
	if val.Stat > 0.5 {
		ans = 1
		asr.Answered--
	}
	asr.Count--
	if val.CompressFactor <= 1 {
		delete(asr.Events, evID)
	} else {
		val.Stat = (val.Stat*float64(val.CompressFactor) - float64(ans)) / (float64(val.CompressFactor - 1))
		val.CompressFactor = val.CompressFactor - 1
	}
	asr.val = nil
}

// Marshal is part of StatMetric interface
func (asr *StatASR) Marshal(ms Marshaler) (marshaled []byte, err error) {
	return ms.Marshal(asr)
}

// LoadMarshaled is part of StatMetric interface
func (asr *StatASR) LoadMarshaled(ms Marshaler, marshaled []byte) (err error) {
	return ms.Unmarshal(marshaled, &asr)
}

// GetFilterIDs is part of StatMetric interface
func (asr *StatASR) GetFilterIDs() []string {
	return asr.FilterIDs
}

// GetMinItems returns the minim items for the metric
func (asr *StatASR) GetMinItems() (minIts int) { return asr.MinItems }

// Compress is part of StatMetric interface
func (asr *StatASR) Compress(queueLen int64, defaultID string, roundingDecimal int) (eventIDs []string) {
	if asr.Count < queueLen {
		for id := range asr.Events {
			eventIDs = append(eventIDs, id)
		}
		return
	}
	stat := &StatWithCompress{
		Stat: utils.Round(asr.Answered/float64(asr.Count),
			roundingDecimal, utils.MetaRoundingMiddle),
		CompressFactor: int(asr.Count),
	}
	asr.Events = map[string]*StatWithCompress{defaultID: stat}
	return []string{defaultID}
}

// Compress is part of StatMetric interface
func (asr *StatASR) GetCompressFactor(events map[string]int) map[string]int {
	for id, val := range asr.Events {
		if _, has := events[id]; !has {
			events[id] = val.CompressFactor
		}
		if events[id] < val.CompressFactor {
			events[id] = val.CompressFactor
		}
	}
	return events
}

func NewACD(minItems int, extraParams string, filterIDs []string) (StatMetric, error) {
	return &StatACD{Events: make(map[string]*DurationWithCompress), MinItems: minItems, FilterIDs: filterIDs}, nil
}

// ACD implements AverageCallDuration metric
type StatACD struct {
	FilterIDs []string
	Sum       time.Duration
	Count     int64
	Events    map[string]*DurationWithCompress // map[EventTenantID]Duration
	MinItems  int
	val       *time.Duration // cached ACD value
}

// Clone creates a deep copy of StatACD
func (s *StatACD) Clone() StatMetric {
	if s == nil {
		return nil
	}
	clone := &StatACD{
		Sum:      s.Sum,
		Count:    s.Count,
		MinItems: s.MinItems,
	}
	if s.FilterIDs != nil {
		clone.FilterIDs = make([]string, len(s.FilterIDs))
		copy(clone.FilterIDs, s.FilterIDs)
	}
	if s.Events != nil {
		clone.Events = make(map[string]*DurationWithCompress, len(s.Events))
		for k, v := range s.Events {
			if v != nil {
				clone.Events[k] = &DurationWithCompress{
					Duration:       v.Duration,
					CompressFactor: v.CompressFactor,
				}
			}
		}
	}
	if s.val != nil {
		val := *s.val
		clone.val = &val
	}
	return clone
}

// getValue returns acd.val
func (acd *StatACD) getValue(roundingDecimal int) time.Duration {
	if acd.val == nil {
		if (acd.MinItems > 0 && acd.Count < int64(acd.MinItems)) || (acd.Count == 0) {
			acd.val = utils.DurationPointer(-time.Nanosecond)
		} else {
			acd.val = utils.DurationPointer(utils.RoundStatDuration(
				time.Duration(acd.Sum.Nanoseconds()/acd.Count),
				roundingDecimal))
		}
	}
	return *acd.val
}

func (acd *StatACD) GetStringValue(roundingDecimal int) (valStr string) {
	if val := acd.getValue(roundingDecimal); val == -time.Nanosecond {
		valStr = utils.NotAvailable
	} else {
		valStr = fmt.Sprintf("%+v", acd.getValue(roundingDecimal))
	}
	return
}

func (acd *StatACD) GetValue(roundingDecimal int) (v any) {
	return acd.getValue(roundingDecimal)
}

func (acd *StatACD) GetFloat64Value(roundingDecimal int) (v float64) {
	if val := acd.getValue(roundingDecimal); val == -time.Nanosecond {
		v = utils.StatsNA
	} else {
		v = float64(acd.getValue(roundingDecimal).Nanoseconds())
	}
	return
}

func (acd *StatACD) getFieldVal(ev utils.DataProvider) (dur time.Duration, err error) {
	var val any
	if val, err = ev.FieldAsInterface([]string{utils.MetaReq, utils.Usage}); err != nil {
		if err == utils.ErrNotFound {
			err = utils.ErrPrefix(err, utils.Usage)
		}
		return
	} else if dur, err = utils.IfaceAsDuration(val); err != nil {
		return
	}
	return
}

func (acd *StatACD) AddEvent(evID string, ev utils.DataProvider) (err error) {
	var dur time.Duration
	if dur, err = acd.getFieldVal(ev); err != nil {
		return
	}
	acd.Sum += dur
	if val, has := acd.Events[evID]; !has {
		acd.Events[evID] = &DurationWithCompress{Duration: dur, CompressFactor: 1}
	} else {
		val.Duration = time.Duration((float64(val.Duration.Nanoseconds())*float64(val.CompressFactor) + float64(dur.Nanoseconds())) / float64(val.CompressFactor+1))
		val.CompressFactor = val.CompressFactor + 1
	}
	acd.Count++
	acd.val = nil
	return
}

func (acd *StatACD) AddOneEvent(ev utils.DataProvider) (err error) {
	var dur time.Duration
	if dur, err = acd.getFieldVal(ev); err != nil {
		return
	}
	acd.Sum += dur
	acd.Count++
	acd.val = nil
	return
}

func (acd *StatACD) RemEvent(evID string) {
	val, has := acd.Events[evID]
	if !has {
		return
	}
	if val.Duration != 0 {
		acd.Sum -= val.Duration
	}
	acd.Count--
	if val.CompressFactor <= 1 {
		delete(acd.Events, evID)
	} else {
		val.CompressFactor = val.CompressFactor - 1
	}
	acd.val = nil
}

func (acd *StatACD) Marshal(ms Marshaler) (marshaled []byte, err error) {
	return ms.Marshal(acd)
}
func (acd *StatACD) LoadMarshaled(ms Marshaler, marshaled []byte) (err error) {
	return ms.Unmarshal(marshaled, &acd)
}

// GetFilterIDs is part of StatMetric interface
func (acd *StatACD) GetFilterIDs() []string {
	return acd.FilterIDs
}

// GetMinItems returns the minim items for the metric
func (acd *StatACD) GetMinItems() (minIts int) { return acd.MinItems }

// Compress is part of StatMetric interface
func (acd *StatACD) Compress(queueLen int64, defaultID string, roundingDecimal int) (eventIDs []string) {
	if acd.Count < queueLen {
		for id := range acd.Events {
			eventIDs = append(eventIDs, id)
		}
		return
	}
	stat := &DurationWithCompress{
		Duration: utils.RoundStatDuration(time.Duration(acd.Sum.Nanoseconds()/acd.Count),
			roundingDecimal),
		CompressFactor: int(acd.Count),
	}
	acd.Events = map[string]*DurationWithCompress{defaultID: stat}
	return []string{defaultID}
}

// Compress is part of StatMetric interface
func (acd *StatACD) GetCompressFactor(events map[string]int) map[string]int {
	for id, val := range acd.Events {
		if _, has := events[id]; !has {
			events[id] = val.CompressFactor
		}
		if events[id] < val.CompressFactor {
			events[id] = val.CompressFactor
		}
	}
	return events
}

func NewTCD(minItems int, extraParams string, filterIDs []string) (StatMetric, error) {
	return &StatTCD{Events: make(map[string]*DurationWithCompress), MinItems: minItems, FilterIDs: filterIDs}, nil
}

// TCD implements TotalCallDuration metric
type StatTCD struct {
	FilterIDs []string
	Sum       time.Duration
	Count     int64
	Events    map[string]*DurationWithCompress // map[EventTenantID]Duration
	MinItems  int
	val       *time.Duration // cached TCD value
}

// Clone creates a deep copy of StatTCD
func (s *StatTCD) Clone() StatMetric {
	if s == nil {
		return nil
	}
	clone := &StatTCD{
		Sum:      s.Sum,
		Count:    s.Count,
		MinItems: s.MinItems,
	}
	if s.FilterIDs != nil {
		clone.FilterIDs = make([]string, len(s.FilterIDs))
		copy(clone.FilterIDs, s.FilterIDs)
	}
	if s.Events != nil {
		clone.Events = make(map[string]*DurationWithCompress, len(s.Events))
		for k, v := range s.Events {
			if v != nil {
				clone.Events[k] = &DurationWithCompress{
					Duration:       v.Duration,
					CompressFactor: v.CompressFactor,
				}
			}
		}
	}
	if s.val != nil {
		val := *s.val
		clone.val = &val
	}
	return clone
}

// getValue returns tcd.val
func (tcd *StatTCD) getValue(roundingDecimal int) time.Duration {
	if tcd.val == nil {
		if (tcd.MinItems > 0 && tcd.Count < int64(tcd.MinItems)) || (tcd.Count == 0) {
			tcd.val = utils.DurationPointer(-time.Nanosecond)
		} else {
			tcd.val = utils.DurationPointer(utils.RoundStatDuration(
				time.Duration(tcd.Sum.Nanoseconds()),
				roundingDecimal))

		}
	}
	return *tcd.val
}

func (tcd *StatTCD) GetStringValue(roundingDecimal int) (valStr string) {
	if val := tcd.getValue(roundingDecimal); val == -time.Nanosecond {
		valStr = utils.NotAvailable
	} else {
		valStr = fmt.Sprintf("%+v", tcd.getValue(roundingDecimal))
	}
	return
}

func (tcd *StatTCD) GetValue(roundingDecimal int) (v any) {
	return tcd.getValue(roundingDecimal)
}

func (tcd *StatTCD) GetFloat64Value(roundingDecimal int) (v float64) {
	if val := tcd.getValue(roundingDecimal); val == -time.Nanosecond {
		v = utils.StatsNA
	} else {
		v = float64(tcd.getValue(roundingDecimal).Nanoseconds())
	}
	return
}

func (tcd *StatTCD) getFieldVal(ev utils.DataProvider) (dur time.Duration, err error) {
	var val any
	if val, err = ev.FieldAsInterface([]string{utils.MetaReq, utils.Usage}); err != nil {
		if err == utils.ErrNotFound {
			err = utils.ErrPrefix(err, utils.Usage)
		}
		return
	} else if dur, err = utils.IfaceAsDuration(val); err != nil {
		return
	}
	return
}

func (tcd *StatTCD) AddEvent(evID string, ev utils.DataProvider) (err error) {
	var dur time.Duration
	if dur, err = tcd.getFieldVal(ev); err != nil {
		return
	}
	tcd.Sum += dur
	if val, has := tcd.Events[evID]; !has {
		tcd.Events[evID] = &DurationWithCompress{Duration: dur, CompressFactor: 1}
	} else {
		val.Duration = time.Duration((float64(val.Duration.Nanoseconds())*float64(val.CompressFactor) + float64(dur.Nanoseconds())) / float64(val.CompressFactor+1))
		val.CompressFactor = val.CompressFactor + 1
	}
	tcd.Count++
	tcd.val = nil
	return
}

func (tcd *StatTCD) AddOneEvent(ev utils.DataProvider) (err error) {
	var dur time.Duration
	if dur, err = tcd.getFieldVal(ev); err != nil {
		return
	}
	tcd.Sum += dur
	tcd.Count++
	tcd.val = nil
	return
}

func (tcd *StatTCD) RemEvent(evID string) {
	val, has := tcd.Events[evID]
	if !has {
		return
	}
	if val.Duration != 0 {
		tcd.Sum -= val.Duration
	}
	tcd.Count--
	if val.CompressFactor <= 1 {
		delete(tcd.Events, evID)
	} else {
		val.CompressFactor = val.CompressFactor - 1
	}
	tcd.val = nil
}

func (tcd *StatTCD) Marshal(ms Marshaler) (marshaled []byte, err error) {
	return ms.Marshal(tcd)
}

func (tcd *StatTCD) LoadMarshaled(ms Marshaler, marshaled []byte) (err error) {
	return ms.Unmarshal(marshaled, &tcd)
}

// GetFilterIDs is part of StatMetric interface
func (tcd *StatTCD) GetFilterIDs() []string {
	return tcd.FilterIDs
}

// GetMinItems returns the minim items for the metric
func (tcd *StatTCD) GetMinItems() (minIts int) { return tcd.MinItems }

// Compress is part of StatMetric interface
func (tcd *StatTCD) Compress(queueLen int64, defaultID string, roundingDecimal int) (eventIDs []string) {
	if tcd.Count < queueLen {
		for id := range tcd.Events {
			eventIDs = append(eventIDs, id)
		}
		return
	}
	stat := &DurationWithCompress{
		Duration: utils.RoundStatDuration(time.Duration(tcd.Sum.Nanoseconds()/tcd.Count),
			roundingDecimal),
		CompressFactor: int(tcd.Count),
	}
	tcd.Events = map[string]*DurationWithCompress{defaultID: stat}
	return []string{defaultID}
}

// Compress is part of StatMetric interface
func (tcd *StatTCD) GetCompressFactor(events map[string]int) map[string]int {
	for id, val := range tcd.Events {
		if _, has := events[id]; !has {
			events[id] = val.CompressFactor
		}
		if events[id] < val.CompressFactor {
			events[id] = val.CompressFactor
		}
	}
	return events
}

func NewACC(minItems int, extraParams string, filterIDs []string) (StatMetric, error) {
	return &StatACC{Events: make(map[string]*StatWithCompress), MinItems: minItems, FilterIDs: filterIDs}, nil
}

// ACC implements AverageCallCost metric
type StatACC struct {
	FilterIDs []string
	Sum       float64
	Count     int64
	Events    map[string]*StatWithCompress // map[EventTenantID]Cost
	MinItems  int
	val       *float64 // cached ACC value
}

// Clone creates a deep copy of StatACC
func (s *StatACC) Clone() StatMetric {
	if s == nil {
		return nil
	}
	clone := &StatACC{
		Sum:      s.Sum,
		Count:    s.Count,
		MinItems: s.MinItems,
	}
	if s.FilterIDs != nil {
		clone.FilterIDs = make([]string, len(s.FilterIDs))
		copy(clone.FilterIDs, s.FilterIDs)
	}
	if s.Events != nil {
		clone.Events = make(map[string]*StatWithCompress, len(s.Events))
		for k, v := range s.Events {
			if v != nil {
				clone.Events[k] = &StatWithCompress{Stat: v.Stat, CompressFactor: v.CompressFactor}
			}
		}
	}
	if s.val != nil {
		val := *s.val
		clone.val = &val
	}
	return clone
}

// getValue returns tcd.val
func (acc *StatACC) getValue(roundingDecimal int) float64 {
	if acc.val == nil {
		if (acc.MinItems > 0 && acc.Count < int64(acc.MinItems)) || (acc.Count == 0) {
			acc.val = utils.Float64Pointer(utils.StatsNA)
		} else {
			acc.val = utils.Float64Pointer(utils.Round(acc.Sum/float64(acc.Count),
				roundingDecimal, utils.MetaRoundingMiddle))
		}
	}
	return *acc.val
}

func (acc *StatACC) GetStringValue(roundingDecimal int) (valStr string) {
	if val := acc.getValue(roundingDecimal); val == utils.StatsNA {
		valStr = utils.NotAvailable
	} else {
		valStr = strconv.FormatFloat(acc.getValue(roundingDecimal), 'f', -1, 64)
	}
	return

}

func (acc *StatACC) GetValue(roundingDecimal int) (v any) {
	return acc.getValue(roundingDecimal)
}

func (acc *StatACC) GetFloat64Value(roundingDecimal int) (v float64) {
	return acc.getValue(roundingDecimal)
}

func (acc *StatACC) getFieldVal(ev utils.DataProvider) (cost float64, err error) {
	var val any
	if val, err = ev.FieldAsInterface([]string{utils.MetaReq, utils.Cost}); err != nil {
		if err == utils.ErrNotFound {
			err = utils.ErrPrefix(err, utils.Cost)
		}
		return
	} else if cost, err = utils.IfaceAsFloat64(val); err != nil {
		return
	} else if cost < 0 {
		return cost, utils.ErrPrefix(utils.ErrNegative, utils.Cost)
	}
	return
}

func (acc *StatACC) AddEvent(evID string, ev utils.DataProvider) (err error) {
	var cost float64
	if cost, err = acc.getFieldVal(ev); err != nil {
		return
	}
	acc.Sum += cost
	if val, has := acc.Events[evID]; !has {
		acc.Events[evID] = &StatWithCompress{Stat: cost, CompressFactor: 1}
	} else {
		val.Stat = (val.Stat*float64(val.CompressFactor) + cost) / float64(val.CompressFactor+1)
		val.CompressFactor = val.CompressFactor + 1
	}
	acc.Count++
	acc.val = nil
	return
}

func (acc *StatACC) AddOneEvent(ev utils.DataProvider) (err error) {
	var cost float64
	if cost, err = acc.getFieldVal(ev); err != nil {
		return
	}

	acc.Sum += cost
	acc.Count++
	acc.val = nil
	return
}

func (acc *StatACC) RemEvent(evID string) {
	cost, has := acc.Events[evID]
	if !has {
		return
	}
	acc.Sum -= cost.Stat
	acc.Count--
	if cost.CompressFactor <= 1 {
		delete(acc.Events, evID)
	} else {
		cost.CompressFactor = cost.CompressFactor - 1
	}
	acc.val = nil
}

func (acc *StatACC) Marshal(ms Marshaler) (marshaled []byte, err error) {
	return ms.Marshal(acc)
}

func (acc *StatACC) LoadMarshaled(ms Marshaler, marshaled []byte) (err error) {
	return ms.Unmarshal(marshaled, &acc)
}

// GetFilterIDs is part of StatMetric interface
func (acc *StatACC) GetFilterIDs() []string {
	return acc.FilterIDs
}

// GetMinItems returns the minim items for the metric
func (acc *StatACC) GetMinItems() (minIts int) { return acc.MinItems }

// Compress is part of StatMetric interface
func (acc *StatACC) Compress(queueLen int64, defaultID string, roundingDecimal int) (eventIDs []string) {
	if acc.Count < queueLen {
		for id := range acc.Events {
			eventIDs = append(eventIDs, id)
		}
		return
	}
	stat := &StatWithCompress{
		Stat: utils.Round(acc.Sum/float64(acc.Count),
			roundingDecimal, utils.MetaRoundingMiddle),
		CompressFactor: int(acc.Count),
	}
	acc.Events = map[string]*StatWithCompress{defaultID: stat}
	return []string{defaultID}
}

// Compress is part of StatMetric interface
func (acc *StatACC) GetCompressFactor(events map[string]int) map[string]int {
	for id, val := range acc.Events {
		if _, has := events[id]; !has {
			events[id] = val.CompressFactor
		}
		if events[id] < val.CompressFactor {
			events[id] = val.CompressFactor
		}
	}
	return events
}

func NewTCC(minItems int, extraParams string, filterIDs []string) (StatMetric, error) {
	return &StatTCC{Events: make(map[string]*StatWithCompress), MinItems: minItems, FilterIDs: filterIDs}, nil
}

// TCC implements TotalCallCost metric
type StatTCC struct {
	FilterIDs []string
	Sum       float64
	Count     int64
	Events    map[string]*StatWithCompress // map[EventTenantID]Cost
	MinItems  int
	val       *float64 // cached TCC value
}

// Clone creates a deep copy of StatTCC
func (s *StatTCC) Clone() StatMetric {
	if s == nil {
		return nil
	}
	clone := &StatTCC{
		Sum:      s.Sum,
		Count:    s.Count,
		MinItems: s.MinItems,
	}
	if s.FilterIDs != nil {
		clone.FilterIDs = make([]string, len(s.FilterIDs))
		copy(clone.FilterIDs, s.FilterIDs)
	}
	if s.Events != nil {
		clone.Events = make(map[string]*StatWithCompress, len(s.Events))
		for k, v := range s.Events {
			if v != nil {
				clone.Events[k] = &StatWithCompress{Stat: v.Stat, CompressFactor: v.CompressFactor}
			}
		}
	}
	if s.val != nil {
		val := *s.val
		clone.val = &val
	}
	return clone
}

// getValue returns tcd.val
func (tcc *StatTCC) getValue(roundingDecimal int) float64 {
	if tcc.val == nil {
		if (tcc.MinItems > 0 && tcc.Count < int64(tcc.MinItems)) || (tcc.Count == 0) {
			tcc.val = utils.Float64Pointer(utils.StatsNA)
		} else {
			tcc.val = utils.Float64Pointer(utils.Round(tcc.Sum,
				roundingDecimal,
				utils.MetaRoundingMiddle))
		}
	}
	return *tcc.val
}

func (tcc *StatTCC) GetStringValue(roundingDecimal int) (valStr string) {
	if val := tcc.getValue(roundingDecimal); val == utils.StatsNA {
		valStr = utils.NotAvailable
	} else {
		valStr = strconv.FormatFloat(tcc.getValue(roundingDecimal), 'f', -1, 64)
	}
	return
}

func (tcc *StatTCC) GetValue(roundingDecimal int) (v any) {
	return tcc.getValue(roundingDecimal)
}

func (tcc *StatTCC) GetFloat64Value(roundingDecimal int) (v float64) {
	return tcc.getValue(roundingDecimal)
}

func (tcc *StatTCC) getFieldVal(ev utils.DataProvider) (cost float64, err error) {
	var val any
	if val, err = ev.FieldAsInterface([]string{utils.MetaReq, utils.Cost}); err != nil {
		if err == utils.ErrNotFound {
			err = utils.ErrPrefix(err, utils.Cost)
		}
		return
	} else if cost, err = utils.IfaceAsFloat64(val); err != nil {
		return
	} else if cost < 0 {
		return cost, utils.ErrPrefix(utils.ErrNegative, utils.Cost)
	}
	return
}

func (tcc *StatTCC) AddEvent(evID string, ev utils.DataProvider) (err error) {
	var cost float64
	if cost, err = tcc.getFieldVal(ev); err != nil {
		return
	}
	tcc.Sum += cost
	if val, has := tcc.Events[evID]; !has {
		tcc.Events[evID] = &StatWithCompress{Stat: cost, CompressFactor: 1}
	} else {
		val.Stat = (val.Stat*float64(val.CompressFactor) + cost) / float64(val.CompressFactor+1)
		val.CompressFactor = val.CompressFactor + 1
	}
	tcc.Count++
	tcc.val = nil
	return
}

func (tcc *StatTCC) AddOneEvent(ev utils.DataProvider) (err error) {
	var cost float64
	if cost, err = tcc.getFieldVal(ev); err != nil {
		return
	}

	tcc.Sum += cost
	tcc.Count++
	tcc.val = nil
	return
}

func (tcc *StatTCC) RemEvent(evID string) {
	cost, has := tcc.Events[evID]
	if !has {
		return
	}
	if cost.Stat != 0 {
		tcc.Sum -= cost.Stat
	}
	tcc.Count--
	if cost.CompressFactor <= 1 {
		delete(tcc.Events, evID)
	} else {
		cost.CompressFactor = cost.CompressFactor - 1
	}
	tcc.val = nil
}

func (tcc *StatTCC) Marshal(ms Marshaler) (marshaled []byte, err error) {
	return ms.Marshal(tcc)
}

func (tcc *StatTCC) LoadMarshaled(ms Marshaler, marshaled []byte) (err error) {
	return ms.Unmarshal(marshaled, &tcc)
}

// GetFilterIDs is part of StatMetric interface
func (tcc *StatTCC) GetFilterIDs() []string {
	return tcc.FilterIDs
}

// GetMinItems returns the minim items for the metric
func (tcc *StatTCC) GetMinItems() (minIts int) { return tcc.MinItems }

// Compress is part of StatMetric interface
func (tcc *StatTCC) Compress(queueLen int64, defaultID string, roundingDecimal int) (eventIDs []string) {
	if tcc.Count < queueLen {
		for id := range tcc.Events {
			eventIDs = append(eventIDs, id)
		}
		return
	}
	stat := &StatWithCompress{
		Stat: utils.Round((tcc.Sum / float64(tcc.Count)),
			roundingDecimal, utils.MetaRoundingMiddle),
		CompressFactor: int(tcc.Count),
	}
	tcc.Events = map[string]*StatWithCompress{defaultID: stat}
	return []string{defaultID}
}

// Compress is part of StatMetric interface
func (tcc *StatTCC) GetCompressFactor(events map[string]int) map[string]int {
	for id, val := range tcc.Events {
		if _, has := events[id]; !has {
			events[id] = val.CompressFactor
		}
		if events[id] < val.CompressFactor {
			events[id] = val.CompressFactor
		}
	}
	return events
}

func NewPDD(minItems int, extraParams string, filterIDs []string) (StatMetric, error) {
	return &StatPDD{Events: make(map[string]*DurationWithCompress), MinItems: minItems, FilterIDs: filterIDs}, nil
}

// PDD implements Post Dial Delay (average) metric
type StatPDD struct {
	FilterIDs []string
	Sum       time.Duration
	Count     int64
	Events    map[string]*DurationWithCompress // map[EventTenantID]Duration
	MinItems  int
	val       *time.Duration // cached PDD value
}

// Clone creates a deep copy of StatPDD
func (s *StatPDD) Clone() StatMetric {
	if s == nil {
		return nil
	}
	clone := &StatPDD{
		Sum:      s.Sum,
		Count:    s.Count,
		MinItems: s.MinItems,
	}
	if s.FilterIDs != nil {
		clone.FilterIDs = make([]string, len(s.FilterIDs))
		copy(clone.FilterIDs, s.FilterIDs)
	}
	if s.Events != nil {
		clone.Events = make(map[string]*DurationWithCompress, len(s.Events))
		for k, v := range s.Events {
			if v != nil {
				clone.Events[k] = &DurationWithCompress{
					Duration:       v.Duration,
					CompressFactor: v.CompressFactor,
				}
			}
		}
	}
	if s.val != nil {
		val := *s.val
		clone.val = &val
	}
	return clone
}

// getValue returns pdd.val
func (pdd *StatPDD) getValue(roundingDecimal int) time.Duration {
	if pdd.val == nil {
		if (pdd.MinItems > 0 && pdd.Count < int64(pdd.MinItems)) || (pdd.Count == 0) {
			pdd.val = utils.DurationPointer(-time.Nanosecond)
		} else {
			pdd.val = utils.DurationPointer(utils.RoundStatDuration(
				time.Duration(pdd.Sum.Nanoseconds()/pdd.Count),
				roundingDecimal))
		}
	}
	return *pdd.val
}

func (pdd *StatPDD) GetStringValue(roundingDecimal int) (valStr string) {
	if val := pdd.getValue(roundingDecimal); val == -time.Nanosecond {
		valStr = utils.NotAvailable
	} else {
		valStr = fmt.Sprintf("%+v", pdd.getValue(roundingDecimal))
	}
	return
}

func (pdd *StatPDD) GetValue(roundingDecimal int) (v any) {
	return pdd.getValue(roundingDecimal)
}

func (pdd *StatPDD) GetFloat64Value(roundingDecimal int) (v float64) {
	if val := pdd.getValue(roundingDecimal); val == -time.Nanosecond {
		v = utils.StatsNA
	} else {
		v = float64(pdd.getValue(roundingDecimal).Nanoseconds())
	}
	return
}

func (pdd *StatPDD) getFieldVal(ev utils.DataProvider) (dur time.Duration, err error) {
	var val any
	if val, err = ev.FieldAsInterface([]string{utils.MetaReq, utils.PDD}); err != nil {
		if err == utils.ErrNotFound {
			err = utils.ErrPrefix(err, utils.PDD)
		}
		return
	} else if dur, err = utils.IfaceAsDuration(val); err != nil {
		return
	}
	return
}

func (pdd *StatPDD) AddEvent(evID string, ev utils.DataProvider) (err error) {
	var dur time.Duration
	if dur, err = pdd.getFieldVal(ev); err != nil {
		return
	}
	pdd.Sum += dur
	if val, has := pdd.Events[evID]; !has {
		pdd.Events[evID] = &DurationWithCompress{Duration: dur, CompressFactor: 1}
	} else {
		val.Duration = time.Duration((float64(val.Duration.Nanoseconds())*float64(val.CompressFactor) + float64(dur.Nanoseconds())) / float64(val.CompressFactor+1))
		val.CompressFactor = val.CompressFactor + 1
	}
	pdd.Count++
	pdd.val = nil
	return
}
func (pdd *StatPDD) AddOneEvent(ev utils.DataProvider) (err error) {
	var dur time.Duration
	if dur, err = pdd.getFieldVal(ev); err != nil {
		return
	}
	pdd.Sum += dur
	pdd.Count++
	pdd.val = nil
	return
}

func (pdd *StatPDD) RemEvent(evID string) {
	val, has := pdd.Events[evID]
	if !has {
		return
	}
	if val.Duration != 0 {
		pdd.Sum -= val.Duration
	}
	pdd.Count--
	if val.CompressFactor <= 1 {
		delete(pdd.Events, evID)
	} else {
		val.CompressFactor = val.CompressFactor - 1
	}
	pdd.val = nil
}

func (pdd *StatPDD) Marshal(ms Marshaler) (marshaled []byte, err error) {
	return ms.Marshal(pdd)
}
func (pdd *StatPDD) LoadMarshaled(ms Marshaler, marshaled []byte) (err error) {
	return ms.Unmarshal(marshaled, &pdd)
}

// GetFilterIDs is part of StatMetric interface
func (pdd *StatPDD) GetFilterIDs() []string {
	return pdd.FilterIDs
}

// GetMinItems returns the minim items for the metric
func (pdd *StatPDD) GetMinItems() (minIts int) { return pdd.MinItems }

// Compress is part of StatMetric interface
func (pdd *StatPDD) Compress(queueLen int64, defaultID string, roundingDecimal int) (eventIDs []string) {
	if pdd.Count < queueLen {
		for id := range pdd.Events {
			eventIDs = append(eventIDs, id)
		}
		return
	}
	stat := &DurationWithCompress{
		Duration: utils.RoundStatDuration(time.Duration(pdd.Sum.Nanoseconds()/pdd.Count),
			roundingDecimal),
		CompressFactor: int(pdd.Count),
	}
	pdd.Events = map[string]*DurationWithCompress{defaultID: stat}
	return []string{defaultID}
}

// Compress is part of StatMetric interface
func (pdd *StatPDD) GetCompressFactor(events map[string]int) map[string]int {
	for id, val := range pdd.Events {
		if _, has := events[id]; !has {
			events[id] = val.CompressFactor
		}
		if events[id] < val.CompressFactor {
			events[id] = val.CompressFactor
		}
	}
	return events
}

func NewDDC(minItems int, extraParams string, filterIDs []string) (StatMetric, error) {
	return &StatDDC{Events: make(map[string]map[string]int64), FieldValues: make(map[string]utils.StringSet),
		MinItems: minItems, FilterIDs: filterIDs}, nil
}

type StatDDC struct {
	FilterIDs   []string
	FieldValues map[string]utils.StringSet  // map[fieldValue]map[eventID]
	Events      map[string]map[string]int64 // map[EventTenantID]map[fieldValue]compressfactor
	MinItems    int
	Count       int64
}

// Clone creates a deep copy of StatDDC
func (s *StatDDC) Clone() StatMetric {
	if s == nil {
		return nil
	}
	clone := &StatDDC{
		MinItems: s.MinItems,
		Count:    s.Count,
	}
	if s.FilterIDs != nil {
		clone.FilterIDs = make([]string, len(s.FilterIDs))
		copy(clone.FilterIDs, s.FilterIDs)
	}
	if s.FieldValues != nil {
		clone.FieldValues = make(map[string]utils.StringSet, len(s.FieldValues))
		for k, v := range s.FieldValues {
			if v != nil {
				clone.FieldValues[k] = utils.NewStringSet(v.AsSlice())
			}
		}
	}
	if s.Events != nil {
		clone.Events = make(map[string]map[string]int64, len(s.Events))
		for eventID, valueMap := range s.Events {
			if valueMap != nil {
				newValueMap := make(map[string]int64, len(valueMap))
				for fieldValue, compressFactor := range valueMap {
					newValueMap[fieldValue] = compressFactor
				}
				clone.Events[eventID] = newValueMap
			}
		}
	}
	return clone
}

// getValue returns tcd.val
func (ddc *StatDDC) getValue(roundingDecimal int) float64 {
	if ddc.Count == 0 || ddc.Count < int64(ddc.MinItems) {
		return utils.StatsNA
	}
	return float64(len(ddc.FieldValues))
}

func (ddc *StatDDC) GetStringValue(roundingDecimal int) (valStr string) {
	if val := ddc.getValue(roundingDecimal); val == utils.StatsNA {
		valStr = utils.NotAvailable
	} else {
		valStr = strconv.FormatFloat(ddc.getValue(roundingDecimal), 'f', -1, 64)
	}
	return
}

func (ddc *StatDDC) GetValue(roundingDecimal int) (v any) {
	return ddc.getValue(roundingDecimal)
}

func (ddc *StatDDC) GetFloat64Value(roundingDecimal int) (v float64) {
	return ddc.getValue(roundingDecimal)
}

func (ddc *StatDDC) getFieldVal(ev utils.DataProvider) (fieldVal string, err error) {
	if fieldVal, err = ev.FieldAsString([]string{utils.MetaReq, utils.Destination}); err != nil {
		if err == utils.ErrNotFound {
			err = utils.ErrPrefix(err, utils.Destination)
		}
		return
	}
	return
}

func (ddc *StatDDC) AddEvent(evID string, ev utils.DataProvider) (err error) {
	var fieldValue string
	if fieldValue, err = ddc.getFieldVal(ev); err != nil {
		return
	}
	// add to fieldValues
	if _, has := ddc.FieldValues[fieldValue]; !has {
		ddc.FieldValues[fieldValue] = make(utils.StringSet)
	}
	ddc.FieldValues[fieldValue].Add(evID)

	// add to events
	if _, has := ddc.Events[evID]; !has {
		ddc.Events[evID] = make(map[string]int64)
	}
	ddc.Count++
	if _, has := ddc.Events[evID][fieldValue]; !has {
		ddc.Events[evID][fieldValue] = 1
		return
	}
	ddc.Events[evID][fieldValue] = ddc.Events[evID][fieldValue] + 1
	return
}

func (ddc *StatDDC) AddOneEvent(ev utils.DataProvider) (err error) {
	var fieldValue string
	if fieldValue, err = ddc.getFieldVal(ev); err != nil {
		return
	}

	if _, has := ddc.FieldValues[fieldValue]; !has {
		ddc.FieldValues[fieldValue] = make(utils.StringSet)
	}
	ddc.Count++
	return
}

func (ddc *StatDDC) RemEvent(evID string) {
	fieldValues, has := ddc.Events[evID]
	if !has {
		return
	}
	if len(fieldValues) == 0 {
		delete(ddc.Events, evID)
		return
	}
	// decrement events
	var fieldValue string
	for k := range fieldValues {
		fieldValue = k
		break
	}
	ddc.Count--
	if fieldValues[fieldValue] > 1 {
		ddc.Events[evID][fieldValue] = ddc.Events[evID][fieldValue] - 1
		return // do not delete the reference until it reaches 0
	}
	delete(ddc.Events[evID], fieldValue)
	// remove from fieldValues
	if _, has := ddc.FieldValues[fieldValue]; !has {
		return
	}
	ddc.FieldValues[fieldValue].Remove(evID)
	if ddc.FieldValues[fieldValue].Size() <= 0 {
		delete(ddc.FieldValues, fieldValue)
	}
}

func (ddc *StatDDC) Marshal(ms Marshaler) (marshaled []byte, err error) {
	return ms.Marshal(ddc)
}

func (ddc *StatDDC) LoadMarshaled(ms Marshaler, marshaled []byte) (err error) {
	return ms.Unmarshal(marshaled, &ddc)
}

// GetFilterIDs is part of StatMetric interface
func (ddc *StatDDC) GetFilterIDs() []string {
	return ddc.FilterIDs
}

// GetMinItems returns the minim items for the metric
func (ddc *StatDDC) GetMinItems() (minIts int) { return ddc.MinItems }

func (ddc *StatDDC) Compress(queueLen int64, defaultID string, roundingDecimal int) (eventIDs []string) {
	for id := range ddc.Events {
		eventIDs = append(eventIDs, id)
	}
	return
}

////////////////////

// Compress is part of StatMetric interface
func (ddc *StatDDC) GetCompressFactor(events map[string]int) map[string]int {
	for id, ev := range ddc.Events {
		compressFactor := 0
		for _, fields := range ev {
			compressFactor += int(fields)
		}
		if _, has := events[id]; !has {
			events[id] = compressFactor
		}
		if events[id] < compressFactor {
			events[id] = compressFactor
		}
	}
	return events
}

func NewStatSum(minItems int, extraParams string, filterIDs []string) (StatMetric, error) {
	flds, err := config.NewRSRParsers(extraParams, utils.InfieldSep)
	if err != nil {
		return nil, err
	}
	return &StatSum{
		Events:    make(map[string]*StatWithCompress),
		MinItems:  minItems,
		Fields:    flds,
		FilterIDs: filterIDs,
	}, nil
}

type StatSum struct {
	FilterIDs []string
	Sum       float64
	Count     int64
	Events    map[string]*StatWithCompress // map[EventTenantID]Cost
	MinItems  int
	Fields    config.RSRParsers
	val       *float64 // cached sum value
}

// Clone creates a deep copy of StatSum
func (s *StatSum) Clone() StatMetric {
	if s == nil {
		return nil
	}
	clone := &StatSum{
		Sum:      s.Sum,
		Count:    s.Count,
		MinItems: s.MinItems,
		Fields:   s.Fields,
	}
	if s.FilterIDs != nil {
		clone.FilterIDs = make([]string, len(s.FilterIDs))
		copy(clone.FilterIDs, s.FilterIDs)
	}
	if s.Events != nil {
		clone.Events = make(map[string]*StatWithCompress, len(s.Events))
		for k, v := range s.Events {
			if v != nil {
				clone.Events[k] = &StatWithCompress{Stat: v.Stat, CompressFactor: v.CompressFactor}
			}
		}
	}
	if s.val != nil {
		val := *s.val
		clone.val = &val
	}
	return clone
}

// getValue returns tcd.val
func (sum *StatSum) getValue(roundingDecimal int) float64 {
	if sum.val == nil {
		if sum.Count < int64(sum.MinItems) {
			sum.val = utils.Float64Pointer(utils.StatsNA)
		} else {
			sum.val = utils.Float64Pointer(utils.Round(sum.Sum,
				roundingDecimal,
				utils.MetaRoundingMiddle))
		}
	}
	return *sum.val
}

func (sum *StatSum) GetStringValue(roundingDecimal int) (valStr string) {
	if val := sum.getValue(roundingDecimal); val == utils.StatsNA {
		valStr = utils.NotAvailable
	} else {
		valStr = strconv.FormatFloat(sum.getValue(roundingDecimal), 'f', -1, 64)
	}
	return
}

func (sum *StatSum) GetValue(roundingDecimal int) (v any) {
	return sum.getValue(roundingDecimal)
}

func (sum *StatSum) GetFloat64Value(roundingDecimal int) (v float64) {
	return sum.getValue(roundingDecimal)
}

func (sum *StatSum) getFieldVal(ev utils.DataProvider) (float64, error) {
	ival, err := sum.Fields.ParseDataProvider(ev)
	if err != nil {
		return 0, err
	}
	return utils.IfaceAsFloat64(ival)
}

func (sum *StatSum) AddEvent(evID string, ev utils.DataProvider) (err error) {
	var val float64
	if val, err = sum.getFieldVal(ev); err != nil {
		return
	}

	sum.Sum += val
	if v, has := sum.Events[evID]; !has {
		sum.Events[evID] = &StatWithCompress{Stat: val, CompressFactor: 1}
	} else {
		v.Stat = (v.Stat*float64(v.CompressFactor) + val) / float64(v.CompressFactor+1)
		v.CompressFactor = v.CompressFactor + 1
	}
	sum.Count++
	sum.val = nil
	return
}

func (sum *StatSum) AddOneEvent(ev utils.DataProvider) (err error) {
	var val float64
	if val, err = sum.getFieldVal(ev); err != nil {
		return
	}

	sum.Sum += val
	sum.Count++
	sum.val = nil
	return
}

func (sum *StatSum) RemEvent(evID string) {
	val, has := sum.Events[evID]
	if !has {
		return
	}
	if val.Stat != 0 {
		sum.Sum -= val.Stat
	}
	sum.Count--
	if val.CompressFactor <= 1 {
		delete(sum.Events, evID)
	} else {
		val.CompressFactor = val.CompressFactor - 1
	}
	sum.val = nil
}

func (sum *StatSum) Marshal(ms Marshaler) (marshaled []byte, err error) {
	return ms.Marshal(sum)
}

func (sum *StatSum) LoadMarshaled(ms Marshaler, marshaled []byte) (err error) {
	return ms.Unmarshal(marshaled, &sum)
}

// GetFilterIDs is part of StatMetric interface
func (sum *StatSum) GetFilterIDs() []string {
	return sum.FilterIDs
}

// GetMinItems returns the minim items for the metric
func (sum *StatSum) GetMinItems() (minIts int) { return sum.MinItems }

// Compress is part of StatMetric interface
func (sum *StatSum) Compress(queueLen int64, defaultID string, roundingDecimal int) (eventIDs []string) {
	if sum.Count < queueLen {
		for id := range sum.Events {
			eventIDs = append(eventIDs, id)
		}
		return
	}
	stat := &StatWithCompress{
		Stat: utils.Round((sum.Sum / float64(sum.Count)),
			roundingDecimal, utils.MetaRoundingMiddle),
		CompressFactor: int(sum.Count),
	}
	sum.Events = map[string]*StatWithCompress{defaultID: stat}
	return []string{defaultID}
}

// Compress is part of StatMetric interface
func (sum *StatSum) GetCompressFactor(events map[string]int) map[string]int {
	for id, val := range sum.Events {
		if _, has := events[id]; !has {
			events[id] = val.CompressFactor
		}
		if events[id] < val.CompressFactor {
			events[id] = val.CompressFactor
		}
	}
	return events
}

func NewStatAverage(minItems int, extraParams string, filterIDs []string) (StatMetric, error) {
	return &StatAverage{Events: make(map[string]*StatWithCompress),
		MinItems: minItems, FieldName: extraParams, FilterIDs: filterIDs}, nil
}

// StatAverage implements TotalCallCost metric
type StatAverage struct {
	FilterIDs []string
	Sum       float64
	Count     int64
	Events    map[string]*StatWithCompress // map[EventTenantID]Cost
	MinItems  int
	FieldName string
	val       *float64 // cached avg value
}

// Clone creates a deep copy of StatAverage
func (s *StatAverage) Clone() StatMetric {
	if s == nil {
		return nil
	}
	clone := &StatAverage{
		Sum:       s.Sum,
		Count:     s.Count,
		MinItems:  s.MinItems,
		FieldName: s.FieldName,
	}
	if s.FilterIDs != nil {
		clone.FilterIDs = make([]string, len(s.FilterIDs))
		copy(clone.FilterIDs, s.FilterIDs)
	}
	if s.Events != nil {
		clone.Events = make(map[string]*StatWithCompress, len(s.Events))
		for k, v := range s.Events {
			if v != nil {
				clone.Events[k] = &StatWithCompress{Stat: v.Stat, CompressFactor: v.CompressFactor}
			}
		}
	}
	if s.val != nil {
		val := *s.val
		clone.val = &val
	}
	return clone
}

// getValue returns tcd.val
func (avg *StatAverage) getValue(roundingDecimal int) float64 {
	if avg.val == nil {
		if (avg.MinItems > 0 && avg.Count < int64(avg.MinItems)) || (avg.Count == 0) {
			avg.val = utils.Float64Pointer(utils.StatsNA)
		} else {
			avg.val = utils.Float64Pointer(utils.Round((avg.Sum / float64(avg.Count)),
				roundingDecimal, utils.MetaRoundingMiddle))
		}
	}
	return *avg.val
}

func (avg *StatAverage) GetStringValue(roundingDecimal int) (valStr string) {
	if val := avg.getValue(roundingDecimal); val == utils.StatsNA {
		valStr = utils.NotAvailable
	} else {
		valStr = strconv.FormatFloat(avg.getValue(roundingDecimal), 'f', -1, 64)
	}
	return

}

func (avg *StatAverage) GetValue(roundingDecimal int) (v any) {
	return avg.getValue(roundingDecimal)
}

func (avg *StatAverage) GetFloat64Value(roundingDecimal int) (v float64) {
	return avg.getValue(roundingDecimal)
}

func (avg *StatAverage) getFieldVal(ev utils.DataProvider) (val float64, err error) {
	var ival any
	if ival, err = utils.DPDynamicInterface(avg.FieldName, ev); err != nil {
		if err == utils.ErrNotFound {
			err = utils.ErrPrefix(err, avg.FieldName)
		}
		return
	} else if val, err = utils.IfaceAsFloat64(ival); err != nil {
		return
	}
	return
}

func (avg *StatAverage) AddEvent(evID string, ev utils.DataProvider) (err error) {
	var val float64
	if val, err = avg.getFieldVal(ev); err != nil {
		return
	}

	avg.Sum += val
	if v, has := avg.Events[evID]; !has {
		avg.Events[evID] = &StatWithCompress{Stat: val, CompressFactor: 1}
	} else {
		v.Stat = (v.Stat*float64(v.CompressFactor) + val) / float64(v.CompressFactor+1)
		v.CompressFactor = v.CompressFactor + 1
	}
	avg.Count++
	avg.val = nil
	return
}

// simply remove the ~*req. prefix and do normal process
func (avg *StatAverage) AddOneEvent(ev utils.DataProvider) (err error) {
	var val float64
	if val, err = avg.getFieldVal(ev); err != nil {
		return
	}
	avg.Sum += val
	avg.Count++
	avg.val = nil
	return
}

func (avg *StatAverage) RemEvent(evID string) {
	val, has := avg.Events[evID]
	if !has {
		return
	}
	if val.Stat >= 0 {
		avg.Sum -= val.Stat
	}
	avg.Count--
	if val.CompressFactor <= 1 {
		delete(avg.Events, evID)
	} else {
		val.CompressFactor = val.CompressFactor - 1
	}
	avg.val = nil
}

func (avg *StatAverage) Marshal(ms Marshaler) (marshaled []byte, err error) {
	return ms.Marshal(avg)
}

func (avg *StatAverage) LoadMarshaled(ms Marshaler, marshaled []byte) (err error) {
	return ms.Unmarshal(marshaled, &avg)
}

// GetFilterIDs is part of StatMetric interface
func (avg *StatAverage) GetFilterIDs() []string {
	return avg.FilterIDs
}

// GetMinItems returns the minim items for the metric
func (avg *StatAverage) GetMinItems() (minIts int) { return avg.MinItems }

// Compress is part of StatMetric interface
func (avg *StatAverage) Compress(queueLen int64, defaultID string, roundingDecimal int) (eventIDs []string) {
	if avg.Count < queueLen {
		for id := range avg.Events {
			eventIDs = append(eventIDs, id)
		}
		return
	}
	stat := &StatWithCompress{
		Stat: utils.Round((avg.Sum / float64(avg.Count)),
			roundingDecimal, utils.MetaRoundingMiddle),
		CompressFactor: int(avg.Count),
	}
	avg.Events = map[string]*StatWithCompress{defaultID: stat}
	return []string{defaultID}
}

// Compress is part of StatMetric interface
func (avg *StatAverage) GetCompressFactor(events map[string]int) map[string]int {
	for id, val := range avg.Events {
		if _, has := events[id]; !has {
			events[id] = val.CompressFactor
		}
		if events[id] < val.CompressFactor {
			events[id] = val.CompressFactor
		}
	}
	return events
}

func NewStatDistinct(minItems int, extraParams string, filterIDs []string) (StatMetric, error) {
	return &StatDistinct{Events: make(map[string]map[string]int64), FieldValues: make(map[string]utils.StringSet),
		MinItems: minItems, FieldName: extraParams, FilterIDs: filterIDs}, nil
}

type StatDistinct struct {
	FilterIDs   []string
	FieldValues map[string]utils.StringSet  // map[fieldValue]map[eventID]
	Events      map[string]map[string]int64 // map[EventTenantID]map[fieldValue]compressfactor
	MinItems    int
	FieldName   string
	Count       int64
}

// Clone creates a deep copy of StatDistinct
func (s *StatDistinct) Clone() StatMetric {
	if s == nil {
		return nil
	}
	clone := &StatDistinct{
		MinItems:  s.MinItems,
		Count:     s.Count,
		FieldName: s.FieldName,
	}
	if s.FilterIDs != nil {
		clone.FilterIDs = make([]string, len(s.FilterIDs))
		copy(clone.FilterIDs, s.FilterIDs)
	}
	if s.FieldValues != nil {
		clone.FieldValues = make(map[string]utils.StringSet, len(s.FieldValues))
		for k, v := range s.FieldValues {
			if v != nil {
				clone.FieldValues[k] = utils.NewStringSet(v.AsSlice())
			}
		}
	}
	if s.Events != nil {
		clone.Events = make(map[string]map[string]int64, len(s.Events))
		for eventID, valueMap := range s.Events {
			if valueMap != nil {
				newValueMap := make(map[string]int64, len(valueMap))
				maps.Copy(newValueMap, valueMap)
				clone.Events[eventID] = newValueMap
			}
		}
	}

	return clone
}

// getValue returns tcd.val
func (dst *StatDistinct) getValue(roundingDecimal int) float64 {
	if dst.Count == 0 || dst.Count < int64(dst.MinItems) {
		return utils.StatsNA
	}
	return float64(len(dst.FieldValues))
}

func (dst *StatDistinct) GetStringValue(roundingDecimal int) (valStr string) {
	if val := dst.getValue(roundingDecimal); val == utils.StatsNA {
		valStr = utils.NotAvailable
	} else {
		valStr = strconv.FormatFloat(dst.getValue(roundingDecimal), 'f', -1, 64)
	}
	return
}

func (dst *StatDistinct) GetValue(roundingDecimal int) (v any) {
	return dst.getValue(roundingDecimal)
}

func (dst *StatDistinct) GetFloat64Value(roundingDecimal int) (v float64) {
	return dst.getValue(roundingDecimal)
}

func (dst *StatDistinct) getFieldVal(ev utils.DataProvider) (fieldVal string, err error) {
	if !strings.HasPrefix(dst.FieldName, utils.DynamicDataPrefix+utils.MetaReq+utils.NestingSep) {
		return fieldVal, fmt.Errorf("invalid format for field <%s>", dst.FieldName)
	}
	if fieldVal, err = utils.DPDynamicString(dst.FieldName, ev); err != nil {
		if err == utils.ErrNotFound {
			err = utils.ErrPrefix(err, dst.FieldName)
		}
		return
	}
	return
}

func (dst *StatDistinct) AddEvent(evID string, ev utils.DataProvider) (err error) {
	var fieldValue string
	if fieldValue, err = dst.getFieldVal(ev); err != nil {
		return
	}
	// add to fieldValues
	if _, has := dst.FieldValues[fieldValue]; !has {
		dst.FieldValues[fieldValue] = make(utils.StringSet)
	}
	dst.FieldValues[fieldValue].Add(evID)

	// add to events
	if _, has := dst.Events[evID]; !has {
		dst.Events[evID] = make(map[string]int64)
	}
	dst.Count++
	if _, has := dst.Events[evID][fieldValue]; !has {
		dst.Events[evID][fieldValue] = 1
		return
	}
	dst.Events[evID][fieldValue] = dst.Events[evID][fieldValue] + 1
	return
}

func (dst *StatDistinct) AddOneEvent(ev utils.DataProvider) (err error) {
	var fieldValue string
	if fieldValue, err = dst.getFieldVal(ev); err != nil {
		return
	}
	if _, has := dst.FieldValues[fieldValue]; !has {
		dst.FieldValues[fieldValue] = make(utils.StringSet)
	}
	dst.Count++
	return
}

func (dst *StatDistinct) RemEvent(evID string) {
	fieldValues, has := dst.Events[evID]
	if !has {
		return
	}
	if len(fieldValues) == 0 {
		delete(dst.Events, evID)
		return
	}

	// decrement events
	var fieldValue string
	for k := range fieldValues {
		fieldValue = k
		break
	}
	dst.Count--
	if fieldValues[fieldValue] > 1 {
		dst.Events[evID][fieldValue] = dst.Events[evID][fieldValue] - 1
		return // do not delete the reference until it reaches 0
	}
	delete(dst.Events[evID], fieldValue)

	// remove from fieldValues
	if _, has := dst.FieldValues[fieldValue]; !has {
		return
	}
	dst.FieldValues[fieldValue].Remove(evID)
	if dst.FieldValues[fieldValue].Size() <= 0 {
		delete(dst.FieldValues, fieldValue)
	}
}

func (dst *StatDistinct) Marshal(ms Marshaler) (marshaled []byte, err error) {
	return ms.Marshal(dst)
}

func (dst *StatDistinct) LoadMarshaled(ms Marshaler, marshaled []byte) (err error) {
	return ms.Unmarshal(marshaled, &dst)
}

// GetFilterIDs is part of StatMetric interface
func (dst *StatDistinct) GetFilterIDs() []string {
	return dst.FilterIDs
}

// GetMinItems returns the minim items for the metric
func (dst *StatDistinct) GetMinItems() (minIts int) { return dst.MinItems }

func (dst *StatDistinct) Compress(queueLen int64, defaultID string, roundingDecimal int) (eventIDs []string) {
	for id := range dst.Events {
		eventIDs = append(eventIDs, id)
	}
	return
}

// Compress is part of StatMetric interface
func (dst *StatDistinct) GetCompressFactor(events map[string]int) map[string]int {
	for id, ev := range dst.Events {
		compressFactor := 0
		for _, fields := range ev {
			compressFactor += int(fields)
		}
		if _, has := events[id]; !has {
			events[id] = compressFactor
		}
		if events[id] < compressFactor {
			events[id] = compressFactor
		}
	}
	return events
}

// NewStatHighest creates a StatHighest metric for tracking maximum field values.
func NewStatHighest(minItems int, fieldName string, filterIDs []string) (StatMetric, error) {
	return &StatHighest{
		FilterIDs: filterIDs,
		MinItems:  minItems,
		FieldName: fieldName,
		Events:    make(map[string]float64),
	}, nil
}

// StatHighest tracks the maximum value for a specific field across events.
type StatHighest struct {
	FilterIDs []string // event filters to apply before processing
	FieldName string   // field path to extract from events
	MinItems  int      // minimum events required for valid results

	Highest float64            // current maximum value tracked
	Count   int64              // number of events currently tracked
	Events  map[string]float64 // event values indexed by ID for deletion

	// cachedVal caches the result to avoid recalculation.
	// Always invalidated on any state change to eliminate edge
	// cases (i.e. when crossing MinItems threshold).
	cachedVal *float64
}

// Clone creates a deep copy of StatHighest.
func (s *StatHighest) Clone() StatMetric {
	if s == nil {
		return nil
	}
	clone := &StatHighest{
		FilterIDs: slices.Clone(s.FilterIDs),
		Highest:   s.Highest,
		Count:     s.Count,
		MinItems:  s.MinItems,
		FieldName: s.FieldName,
		Events:    maps.Clone(s.Events),
	}
	if s.cachedVal != nil {
		val := *s.cachedVal
		clone.cachedVal = &val
	}
	return clone
}

func (s *StatHighest) GetStringValue(decimals int) string {
	v := s.getValue(decimals)
	if v == utils.StatsNA {
		return utils.NotAvailable
	}
	return strconv.FormatFloat(v, 'f', -1, 64)
}

func (s *StatHighest) GetValue(decimals int) any {
	return s.getValue(decimals)
}

func (s *StatHighest) GetFloat64Value(decimals int) float64 {
	return s.getValue(decimals)
}

// getValue returns current highest value, calculating if cache is invalid.
func (s *StatHighest) getValue(decimals int) float64 {
	if s.cachedVal != nil {
		return *s.cachedVal
	}
	if s.Count == 0 || s.Count < int64(s.MinItems) {
		s.cachedVal = utils.Float64Pointer(utils.StatsNA)
		return *s.cachedVal
	}
	v := utils.Round(s.Highest, decimals, utils.MetaRoundingMiddle)
	s.cachedVal = &v
	return v
}

// AddEvent processes a new event, updating highest value if necessary
func (s *StatHighest) AddEvent(evID string, ev utils.DataProvider) error {
	val, err := s.getFieldValue(ev)
	if err != nil {
		return err
	}
	if val > s.Highest {
		s.Highest = val
	}

	// Only increment count for new events.
	if _, exists := s.Events[evID]; !exists {
		s.Count++
	}

	s.Events[evID] = val
	s.cachedVal = nil
	return nil
}

// AddOneEvent processes event without storing for removal (used when events
// never expire).
func (s *StatHighest) AddOneEvent(ev utils.DataProvider) error {
	val, err := s.getFieldValue(ev)
	if err != nil {
		return err
	}
	if val > s.Highest {
		s.Highest = val
	}
	s.Count++
	s.cachedVal = nil
	return nil
}

// getFieldValue gets the numeric value from the DataProvider.
func (s *StatHighest) getFieldValue(ev utils.DataProvider) (float64, error) {
	ival, err := utils.DPDynamicInterface(s.FieldName, ev)
	if err != nil {
		if errors.Is(err, utils.ErrNotFound) {
			return 0, utils.ErrPrefix(err, s.FieldName)
			// NOTE: return below might be clearer
			// return 0, fmt.Errorf("field %s: %v", s.FieldName, err)
		}
		return 0, err
	}
	return utils.IfaceAsFloat64(ival)
}

func (s *StatHighest) RemEvent(evID string) {
	v, exists := s.Events[evID]
	if !exists {
		return
	}
	delete(s.Events, evID)
	s.Count--
	if v == s.Highest {
		s.Highest = 0 // reset highest

		// Find new highest among remaining events.
		for _, val := range s.Events {
			if val > s.Highest {
				s.Highest = val
			}
		}
	}
	s.cachedVal = nil
}

func (s *StatHighest) Marshal(ms Marshaler) ([]byte, error) {
	return ms.Marshal(s)
}

func (s *StatHighest) LoadMarshaled(ms Marshaler, marshaled []byte) error {
	return ms.Unmarshal(marshaled, &s)
}

// GetFilterIDs is part of StatMetric interface.
func (s *StatHighest) GetFilterIDs() []string {
	return s.FilterIDs
}

// GetMinItems returns the minimum items for the metric.
func (s *StatHighest) GetMinItems() int { return s.MinItems }

// Compress is part of StatMetric interface.
func (s *StatHighest) Compress(queueLen int64, defaultID string, decimals int) []string {
	eventIDs := make([]string, 0, len(s.Events))
	for id := range s.Events {
		eventIDs = append(eventIDs, id)
	}
	return eventIDs
}

func (s *StatHighest) GetCompressFactor(events map[string]int) map[string]int {
	for id := range s.Events {
		if _, exists := events[id]; !exists {
			events[id] = 1
		}
	}
	return events
}

// NewStatLowest creates a StatLowest metric for tracking minimum field values.
func NewStatLowest(minItems int, fieldName string, filterIDs []string) (StatMetric, error) {
	return &StatLowest{
		FilterIDs: filterIDs,
		MinItems:  minItems,
		FieldName: fieldName,
		Lowest:    math.MaxFloat64,
		Events:    make(map[string]float64),
	}, nil
}

// StatLowest tracks the minimum value for a specific field across events.
type StatLowest struct {
	FilterIDs []string // event filters to apply before processing
	FieldName string   // field path to extract from events
	MinItems  int      // minimum events required for valid results

	Lowest float64            // current minimum value tracked
	Count  int64              // number of events currently tracked
	Events map[string]float64 // event values indexed by ID for deletion

	// cachedVal caches the result to avoid recalculation.
	// Always invalidated on any state change to eliminate edge
	// cases (i.e. when crossing MinItems threshold).
	cachedVal *float64
}

// Clone creates a deep copy of StatLowest.
func (s *StatLowest) Clone() StatMetric {
	if s == nil {
		return nil
	}
	clone := &StatLowest{
		FilterIDs: slices.Clone(s.FilterIDs),
		Lowest:    s.Lowest,
		Count:     s.Count,
		MinItems:  s.MinItems,
		FieldName: s.FieldName,
		Events:    maps.Clone(s.Events),
	}
	if s.cachedVal != nil {
		val := *s.cachedVal
		clone.cachedVal = &val
	}
	return clone
}

func (s *StatLowest) GetStringValue(decimals int) string {
	v := s.getValue(decimals)
	if v == utils.StatsNA {
		return utils.NotAvailable
	}
	return strconv.FormatFloat(v, 'f', -1, 64)
}

func (s *StatLowest) GetValue(decimals int) any {
	return s.getValue(decimals)
}

func (s *StatLowest) GetFloat64Value(decimals int) float64 {
	return s.getValue(decimals)
}

// getValue returns current lowest value, calculating if cache is invalid.
func (s *StatLowest) getValue(decimals int) float64 {
	if s.cachedVal != nil {
		return *s.cachedVal
	}
	if s.Count == 0 || s.Count < int64(s.MinItems) {
		s.cachedVal = utils.Float64Pointer(utils.StatsNA)
		return *s.cachedVal
	}
	v := utils.Round(s.Lowest, decimals, utils.MetaRoundingMiddle)
	s.cachedVal = &v
	return v
}

// AddEvent processes a new event, updating lowest value if necessary.
func (s *StatLowest) AddEvent(evID string, ev utils.DataProvider) error {
	val, err := s.getFieldValue(ev)
	if err != nil {
		return err
	}
	if val < s.Lowest {
		s.Lowest = val
	}

	// Only increment count for new events.
	if _, exists := s.Events[evID]; !exists {
		s.Count++
	}

	s.Events[evID] = val
	s.cachedVal = nil
	return nil
}

// AddOneEvent processes event without storing for removal (used when events
// never expire).
func (s *StatLowest) AddOneEvent(ev utils.DataProvider) error {
	val, err := s.getFieldValue(ev)
	if err != nil {
		return err
	}
	if val < s.Lowest {
		s.Lowest = val
	}
	s.Count++
	s.cachedVal = nil
	return nil
}

// getFieldValue gets the numeric value from the DataProvider.
func (s *StatLowest) getFieldValue(ev utils.DataProvider) (float64, error) {
	ival, err := utils.DPDynamicInterface(s.FieldName, ev)
	if err != nil {
		if errors.Is(err, utils.ErrNotFound) {
			return 0, utils.ErrPrefix(err, s.FieldName)
			// NOTE: return below might be clearer
			// return 0, fmt.Errorf("field %s: %v", s.FieldName, err)
		}
		return 0, err
	}
	return utils.IfaceAsFloat64(ival)
}

func (s *StatLowest) RemEvent(evID string) {
	v, exists := s.Events[evID]
	if !exists {
		return
	}
	delete(s.Events, evID)
	s.Count--
	if v == s.Lowest {
		s.Lowest = math.MaxFloat64 // reset lowest

		// Find new lowest among remaining events.
		for _, val := range s.Events {
			if val < s.Lowest {
				s.Lowest = val
			}
		}
	}
	s.cachedVal = nil
}

func (s *StatLowest) Marshal(ms Marshaler) ([]byte, error) {
	return ms.Marshal(s)
}

func (s *StatLowest) LoadMarshaled(ms Marshaler, marshaled []byte) error {
	return ms.Unmarshal(marshaled, &s)
}

// GetFilterIDs is part of StatMetric interface.
func (s *StatLowest) GetFilterIDs() []string {
	return s.FilterIDs
}

// GetMinItems returns the minimum items for the metric.
func (s *StatLowest) GetMinItems() int { return s.MinItems }

// Compress is part of StatMetric interface.
func (s *StatLowest) Compress(queueLen int64, defaultID string, decimals int) []string {
	eventIDs := make([]string, 0, len(s.Events))
	for id := range s.Events {
		eventIDs = append(eventIDs, id)
	}
	return eventIDs
}

func (s *StatLowest) GetCompressFactor(events map[string]int) map[string]int {
	for id := range s.Events {
		if _, exists := events[id]; !exists {
			events[id] = 1
		}
	}
	return events
}

// NewStatREPSC creates a StatREPSC metric for counting successful requests.
func NewStatREPSC(minItems int, _ string, filterIDs []string) (StatMetric, error) {
	return &StatREPSC{
		FilterIDs: filterIDs,
		MinItems:  minItems,
		Events:    make(map[string]struct{}),
	}, nil
}

// StatREPSC counts requests where ReplyState equals "OK"
type StatREPSC struct {
	FilterIDs []string            // event filters to apply before processing
	MinItems  int                 // minimum events required for valid results
	Count     int64               // number of successful events tracked
	Events    map[string]struct{} // event IDs indexed for deletion
	cachedVal *float64            // cached result to avoid recalculation
}

// Clone creates a deep copy of StatREPSC.
func (s *StatREPSC) Clone() StatMetric {
	if s == nil {
		return nil
	}
	clone := &StatREPSC{
		FilterIDs: slices.Clone(s.FilterIDs),
		MinItems:  s.MinItems,
		Count:     s.Count,
		Events:    maps.Clone(s.Events),
	}
	if s.cachedVal != nil {
		clone.cachedVal = utils.Float64Pointer(*s.cachedVal)
	}
	return clone
}

func (s *StatREPSC) GetStringValue(decimals int) string {
	v := s.getValue(decimals)
	if v == utils.StatsNA {
		return utils.NotAvailable
	}
	return strconv.FormatFloat(v, 'f', -1, 64)
}

func (s *StatREPSC) GetValue(decimals int) any {
	return s.getValue(decimals)
}

func (s *StatREPSC) GetFloat64Value(decimals int) float64 {
	return s.getValue(decimals)
}

// getValue returns current count value, calculating if cache is invalid.
func (s *StatREPSC) getValue(_ int) float64 {
	if s.cachedVal != nil {
		return *s.cachedVal
	}

	if s.Count == 0 || s.Count < int64(s.MinItems) {
		s.cachedVal = utils.Float64Pointer(utils.StatsNA)
		return *s.cachedVal
	}

	v := float64(s.Count)
	s.cachedVal = &v
	return *s.cachedVal
}

// getFieldValue gets the value of the ReplyState field from the DataProvider.
func (s *StatREPSC) getFieldValue(ev utils.DataProvider) (string, error) {
	ival, err := ev.FieldAsInterface([]string{utils.MetaReq, utils.ReplyState})
	if err != nil {
		if errors.Is(err, utils.ErrNotFound) {
			return "", utils.ErrPrefix(err, utils.ReplyState)
			// NOTE: return below might be clearer
			// return 0, fmt.Errorf("field %s: %v", utils.ReplyState, err)
		}
		return "", err
	}
	return utils.IfaceAsString(ival), nil
}

// AddEvent processes a new event, incrementing count if ReplyState is "OK".
func (s *StatREPSC) AddEvent(evID string, ev utils.DataProvider) error {
	replyState, err := s.getFieldValue(ev)
	if err != nil {
		return err
	}
	if replyState != utils.OK {
		return nil
	}

	// Only increment count for new events.
	if _, exists := s.Events[evID]; !exists {
		s.Events[evID] = struct{}{}
		s.Count++
		s.cachedVal = nil
	}

	return nil
}

// AddOneEvent processes event without storing for removal (used when events
// never expire).
func (s *StatREPSC) AddOneEvent(ev utils.DataProvider) error {
	replyState, err := s.getFieldValue(ev)
	if err != nil {
		return err
	}
	if replyState != utils.OK {
		return nil
	}

	s.Count++
	s.cachedVal = nil
	return nil
}

func (s *StatREPSC) RemEvent(evID string) {
	if _, exists := s.Events[evID]; !exists {
		return
	}
	delete(s.Events, evID)
	s.Count--
	s.cachedVal = nil
}

func (s *StatREPSC) Marshal(ms Marshaler) ([]byte, error) {
	return ms.Marshal(s)
}

func (s *StatREPSC) LoadMarshaled(ms Marshaler, marshaled []byte) error {
	return ms.Unmarshal(marshaled, &s)
}

// GetFilterIDs is part of StatMetric interface.
func (s *StatREPSC) GetFilterIDs() []string {
	return s.FilterIDs
}

// GetMinItems returns the minimum items for the metric.
func (s *StatREPSC) GetMinItems() int {
	return s.MinItems
}

// Compress is part of StatMetric interface.
func (s *StatREPSC) Compress(queueLen int64, defaultID string, decimals int) []string {
	eventIDs := make([]string, 0, len(s.Events))
	for id := range s.Events {
		eventIDs = append(eventIDs, id)
	}
	return eventIDs
}

func (s *StatREPSC) GetCompressFactor(events map[string]int) map[string]int {
	for id := range s.Events {
		if _, exists := events[id]; !exists {
			events[id] = 1
		}
	}
	return events
}

// NewStatREPFC creates a StatREPFC metric for counting failed requests.
func NewStatREPFC(minItems int, errorType string, filterIDs []string) (StatMetric, error) {
	return &StatREPFC{
		FilterIDs: filterIDs,
		MinItems:  minItems,
		ErrorType: errorType,
		Events:    make(map[string]struct{}),
	}, nil
}

// StatREPFC counts requests where ReplyState is not "OK".
type StatREPFC struct {
	FilterIDs []string            // event filters to apply before processing
	MinItems  int                 // minimum events required for valid results
	ErrorType string              // specific error type to filter for (empty = all errors)
	Count     int64               // number of failed events tracked
	Events    map[string]struct{} // event IDs indexed for deletion
	cachedVal *float64            // cached result to avoid recalculation
}

// Clone creates a deep copy of StatREPFC.
func (s *StatREPFC) Clone() StatMetric {
	if s == nil {
		return nil
	}
	clone := &StatREPFC{
		FilterIDs: slices.Clone(s.FilterIDs),
		MinItems:  s.MinItems,
		ErrorType: s.ErrorType,
		Count:     s.Count,
		Events:    maps.Clone(s.Events),
	}
	if s.cachedVal != nil {
		clone.cachedVal = utils.Float64Pointer(*s.cachedVal)
	}
	return clone
}

func (s *StatREPFC) GetStringValue(decimals int) string {
	v := s.getValue(decimals)
	if v == utils.StatsNA {
		return utils.NotAvailable
	}
	return strconv.FormatFloat(v, 'f', -1, 64)
}

func (s *StatREPFC) GetValue(decimals int) any {
	return s.getValue(decimals)
}

func (s *StatREPFC) GetFloat64Value(decimals int) float64 {
	return s.getValue(decimals)
}

// getValue returns current count value, calculating if cache is invalid.
func (s *StatREPFC) getValue(_ int) float64 {
	if s.cachedVal != nil {
		return *s.cachedVal
	}

	if s.Count == 0 || s.Count < int64(s.MinItems) {
		s.cachedVal = utils.Float64Pointer(utils.StatsNA)
		return *s.cachedVal
	}

	v := float64(s.Count)
	s.cachedVal = &v
	return *s.cachedVal
}

// getFieldValue gets the value of the ReplyState field from the DataProvider.
func (s *StatREPFC) getFieldValue(ev utils.DataProvider) (string, error) {
	ival, err := ev.FieldAsInterface([]string{utils.MetaReq, utils.ReplyState})
	if err != nil {
		if errors.Is(err, utils.ErrNotFound) {
			return "", utils.ErrPrefix(err, utils.ReplyState)
			// NOTE: return below might be clearer
			// return 0, fmt.Errorf("field %s: %v", utils.ReplyState, err)
		}
		return "", err
	}
	return utils.IfaceAsString(ival), nil
}

// AddEvent processes a new event, incrementing count if ReplyState is not "OK".
func (s *StatREPFC) AddEvent(evID string, ev utils.DataProvider) error {
	replyState, err := s.getFieldValue(ev)
	if err != nil {
		return err
	}

	// Skip if success when counting all failures, or if not matching specific
	// error type.
	if s.ErrorType == "" && replyState == utils.OK {
		return nil
	}
	// Handle multiple errors separated by ";" (e.g., "ERR_TERMINATE;ERR_CDRS")
	// Use split + exact match instead of strings.Contains to avoid false positives.
	if s.ErrorType != "" {
		errors := strings.Split(replyState, utils.InfieldSep)
		if !slices.Contains(errors, s.ErrorType) {
			return nil
		}
	}

	// Only increment count for new events.
	if _, exists := s.Events[evID]; !exists {
		s.Events[evID] = struct{}{}
		s.Count++
		s.cachedVal = nil
	}

	return nil
}

// AddOneEvent processes event without storing for removal (used when events
// never expire).
func (s *StatREPFC) AddOneEvent(ev utils.DataProvider) error {
	replyState, err := s.getFieldValue(ev)
	if err != nil {
		return err
	}

	// Skip if success when counting all failures, or if not matching specific
	// error type.
	if s.ErrorType == "" && replyState == utils.OK {
		return nil
	}
	// Handle multiple errors separated by ";" (e.g., "ERR_TERMINATE;ERR_CDRS")
	// Use split + exact match instead of strings.Contains to avoid false positives
	if s.ErrorType != "" {
		errors := strings.Split(replyState, utils.InfieldSep)
		if !slices.Contains(errors, s.ErrorType) {
			return nil
		}
	}

	s.Count++
	s.cachedVal = nil
	return nil
}

func (s *StatREPFC) RemEvent(evID string) {
	if _, exists := s.Events[evID]; !exists {
		return
	}
	delete(s.Events, evID)
	s.Count--
	s.cachedVal = nil
}

func (s *StatREPFC) Marshal(ms Marshaler) ([]byte, error) {
	return ms.Marshal(s)
}

func (s *StatREPFC) LoadMarshaled(ms Marshaler, marshaled []byte) error {
	return ms.Unmarshal(marshaled, &s)
}

// GetFilterIDs is part of StatMetric interface.
func (s *StatREPFC) GetFilterIDs() []string {
	return s.FilterIDs
}

// GetMinItems returns the minimum items for the metric.
func (s *StatREPFC) GetMinItems() int {
	return s.MinItems
}

// Compress is part of StatMetric interface.
func (s *StatREPFC) Compress(queueLen int64, defaultID string, decimals int) []string {
	eventIDs := make([]string, 0, len(s.Events))
	for id := range s.Events {
		eventIDs = append(eventIDs, id)
	}
	return eventIDs
}

func (s *StatREPFC) GetCompressFactor(events map[string]int) map[string]int {
	for id := range s.Events {
		if _, exists := events[id]; !exists {
			events[id] = 1
		}
	}
	return events
}
