/*
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 agents

import (
	"fmt"
	"strings"
	"time"

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

func NewSMAsteriskEvent(ariEv map[string]any, asteriskIP, asteriskAlias string) *SMAsteriskEvent {
	smsmaEv := &SMAsteriskEvent{
		ariEv:         ariEv,
		asteriskIP:    asteriskIP,
		asteriskAlias: asteriskAlias,
		cachedFields:  make(map[string]string),
		opts:          make(map[string]any),
	}
	smsmaEv.parseStasisArgs() // Populate appArgs
	return smsmaEv
}

type SMAsteriskEvent struct { // Standalone struct so we can cache the fields while we parse them
	ariEv         map[string]any // stasis event
	asteriskIP    string
	asteriskAlias string
	cachedFields  map[string]string // Cache replies here
	opts          map[string]any
}

// Clone returns a deep copy of SMAsteriskEvent.
func (e *SMAsteriskEvent) Clone() *SMAsteriskEvent {
	ariEvClone := make(map[string]any, len(e.ariEv))
	for k, v := range e.ariEv {
		ariEvClone[k] = v
	}
	cachedFieldsClone := make(map[string]string, len(e.cachedFields))
	for k, v := range e.cachedFields {
		cachedFieldsClone[k] = v
	}
	optsClone := make(map[string]any, len(e.opts))
	for k, v := range e.opts {
		optsClone[k] = v
	}
	return &SMAsteriskEvent{
		ariEv:         ariEvClone,
		asteriskIP:    e.asteriskIP,
		asteriskAlias: e.asteriskAlias,
		cachedFields:  cachedFieldsClone,
		opts:          optsClone,
	}
}

// parseStasisArgs will convert the args passed to Stasis into CGRateS attribute/value pairs understood by CGRateS and store them in cachedFields
// args need to be in the form of []string{"key=value", "key2=value2"}
func (smaEv *SMAsteriskEvent) parseStasisArgs() {
	args, _ := smaEv.ariEv["args"].([]any)
	for _, arg := range args {
		if splt := strings.Split(arg.(string), "="); len(splt) > 1 {
			if !utils.CGROptionsSet.Has(splt[0]) {
				smaEv.cachedFields[splt[0]] = splt[1]
			} else {
				smaEv.opts[splt[0]] = splt[1]
			}
		}
	}
}

func (smaEv *SMAsteriskEvent) OriginatorIP() string {
	return smaEv.asteriskIP
}

func (smaEv *SMAsteriskEvent) EventType() string {
	cachedKey := eventType
	cachedVal, hasIt := smaEv.cachedFields[cachedKey]
	if !hasIt {
		cachedVal, _ = smaEv.ariEv["type"].(string)
		smaEv.cachedFields[cachedKey] = cachedVal
	}
	return cachedVal
}

func (smaEv *SMAsteriskEvent) ChannelID() string {
	cachedKey := channelID
	cachedVal, hasIt := smaEv.cachedFields[cachedKey]
	if !hasIt {
		channelData, _ := smaEv.ariEv["channel"].(map[string]any)
		cachedVal, _ = channelData["id"].(string)
		smaEv.cachedFields[cachedKey] = cachedVal
	}
	return cachedVal
}

func (smaEv *SMAsteriskEvent) Timestamp() string {
	cachedKey := timestamp
	cachedVal, hasIt := smaEv.cachedFields[cachedKey]
	if !hasIt {
		cachedVal, _ = smaEv.ariEv["timestamp"].(string)
		smaEv.cachedFields[cachedKey] = cachedVal
	}
	return cachedVal
}

func (smaEv *SMAsteriskEvent) ChannelState() string {
	cachedKey := channelState
	cachedVal, hasIt := smaEv.cachedFields[cachedKey]
	if !hasIt {
		channelData, _ := smaEv.ariEv["channel"].(map[string]any)
		cachedVal, _ = channelData["state"].(string)
	}
	return cachedVal
}

func (smaEv *SMAsteriskEvent) SetupTime() string {
	cachedKey := utils.SetupTime
	cachedVal, hasIt := smaEv.cachedFields[cachedKey]
	if !hasIt {
		channelData, _ := smaEv.ariEv["channel"].(map[string]any)
		cachedVal, _ = channelData["creationtime"].(string)
		smaEv.cachedFields[cachedKey] = cachedVal
	}
	return cachedVal
}

func (smaEv *SMAsteriskEvent) Account() string {
	cachedKey := utils.CGRAccount
	cachedVal, hasIt := smaEv.cachedFields[cachedKey]
	if !hasIt {
		channelData, _ := smaEv.ariEv["channel"].(map[string]any)
		callerData, _ := channelData["caller"].(map[string]any)
		cachedVal, _ = callerData["number"].(string)
		smaEv.cachedFields[cachedKey] = cachedVal
	}
	return cachedVal
}

func (smaEv *SMAsteriskEvent) Destination() string {
	cachedKey := utils.CGRDestination
	cachedVal, hasIt := smaEv.cachedFields[cachedKey]
	if !hasIt {
		channelData, _ := smaEv.ariEv["channel"].(map[string]any)
		dialplanData, _ := channelData["dialplan"].(map[string]any)
		cachedVal, _ = dialplanData["exten"].(string)
		smaEv.cachedFields[cachedKey] = cachedVal
	}
	return cachedVal
}

func (smaEv *SMAsteriskEvent) RequestType() string {
	return utils.FirstNonEmpty(smaEv.cachedFields[utils.CGRReqType], config.CgrConfig().GeneralCfg().DefaultReqType)
}

func (smaEv *SMAsteriskEvent) Tenant() string {
	return smaEv.cachedFields[utils.CGRTenant]
}

func (smaEv *SMAsteriskEvent) Category() string {
	return smaEv.cachedFields[utils.CGRCategory]
}

func (smaEv *SMAsteriskEvent) Subject() string {
	return smaEv.cachedFields[utils.CGRSubject]
}

func (smaEv *SMAsteriskEvent) PDD() string {
	return smaEv.cachedFields[utils.CGRPdd]
}

func (smaEv *SMAsteriskEvent) Route() string {
	return smaEv.cachedFields[utils.CGRRoute]
}

func (smaEv *SMAsteriskEvent) Subsystems() string {
	return smaEv.cachedFields[utils.CGRFlags]
}

func (smaEv *SMAsteriskEvent) OriginHost() string {
	return smaEv.cachedFields[utils.CGROriginHost]
}

func (smaEv *SMAsteriskEvent) DisconnectCause() string {
	cachedKey := utils.CGRDisconnectCause
	cachedVal, hasIt := smaEv.cachedFields[cachedKey]
	if !hasIt {
		cachedVal, _ = smaEv.ariEv["cause_txt"].(string)
		if len(cachedVal) == 0 {
			cachedVal = utils.IfaceAsString(smaEv.ariEv["cause"])
		}
		smaEv.cachedFields[cachedKey] = cachedVal
	}
	return cachedVal
}

var primaryFields = utils.NewStringSet([]string{eventType, channelID, timestamp, utils.SetupTime, utils.CGRAccount, utils.CGRDestination, utils.CGRReqType,
	utils.CGRTenant, utils.CGRCategory, utils.CGRSubject, utils.CGRPdd, utils.CGRRoute, utils.CGRDisconnectCause})

func (smaEv *SMAsteriskEvent) ExtraParameters() (extraParams map[string]string) {
	extraParams = make(map[string]string)
	for cachedKey, cachedVal := range smaEv.cachedFields {
		if !primaryFields.Has(cachedKey) {
			extraParams[cachedKey] = cachedVal
		}
	}
	return
}

// Will populate CGREvent with required fields restored from the channel variables
func (smaEv *SMAsteriskEvent) RestoreAndUpdateFields(cgrEv *utils.CGREvent) error {
	resCGREv := *cgrEv
	// make sure the channel contains the channelvars field to be recovered
	channvars, has := smaEv.ariEv["channel"].(map[string]any)["channelvars"].(map[string]any)
	if !has {
		return fmt.Errorf("channelvars not found in event <%+v>", smaEv.ariEv["channel"].(map[string]any))
	}
	for key, val := range channvars {
		switch {
		case key == utils.CGRFlags:
			// "+" characters are converted to " " white space characters when put in channel variables, cgr_flags dont contain white spaces so we can convert them back to "+" without a problem
			cgrFlags := strings.ReplaceAll(val.(string), " ", "+")
			resCGREv.Event[utils.CGRFlags] = cgrFlags
		case key == "CDR(answer)":
			resCGREv.Event[utils.AnswerTime] = val.(string)
		case key == "CDR(billsec)":
			resCGREv.Event[utils.Usage] = val.(string) + "s"
		case key == utils.CGRReqType:
			resCGREv.Event[utils.RequestType] = val.(string)
		default:
			resCGREv.Event[key] = val.(string)
		}

	}
	resCGREv.Event[utils.EventName] = SMASessionTerminate
	resCGREv.Event[utils.DisconnectCause] = smaEv.DisconnectCause()

	for k, v := range smaEv.opts {
		resCGREv.APIOpts[k] = v
	}
	*cgrEv = resCGREv
	return nil
}

func (smaEv *SMAsteriskEvent) UpdateCGREvent(cgrEv *utils.CGREvent) error {
	resCGREv := *cgrEv
	switch smaEv.EventType() {
	case ARIChannelStateChange:
		resCGREv.Event[utils.EventName] = SMASessionStart
		resCGREv.Event[utils.AnswerTime] = smaEv.Timestamp()
	case ARIChannelDestroyed:
		resCGREv.Event[utils.EventName] = SMASessionTerminate
		resCGREv.Event[utils.DisconnectCause] = smaEv.DisconnectCause()
		if _, hasIt := resCGREv.Event[utils.AnswerTime]; !hasIt {
			resCGREv.Event[utils.Usage] = "0s"
		} else if aTime, err := utils.IfaceAsTime(resCGREv.Event[utils.AnswerTime],
			config.CgrConfig().GeneralCfg().DefaultTimezone); err != nil {
			return err
		} else if aTime.IsZero() {
			resCGREv.Event[utils.Usage] = "0s"
		} else {
			actualTime, err := utils.ParseTimeDetectLayout(smaEv.Timestamp(), "")
			if err != nil {
				return err
			}
			resCGREv.Event[utils.Usage] = actualTime.Sub(aTime).String()
		}
	}
	for k, v := range smaEv.opts {
		resCGREv.APIOpts[k] = v
	}
	*cgrEv = resCGREv
	return nil
}

func (smaEv *SMAsteriskEvent) AsMapStringInterface() (mp map[string]any) {
	mp = make(map[string]any)
	switch smaEv.EventType() {
	case ARIStasisStart:
		mp[utils.EventName] = SMAAuthorization
	case ARIChannelStateChange:
		mp[utils.EventName] = SMASessionStart
	case ARIChannelDestroyed:
		mp[utils.EventName] = SMASessionTerminate
	}
	mp[utils.OriginID] = smaEv.ChannelID()
	if smaEv.RequestType() != "" {
		mp[utils.RequestType] = smaEv.RequestType()
	}
	if smaEv.Tenant() != "" {
		mp[utils.Tenant] = smaEv.Tenant()
	}
	if smaEv.Category() != "" {
		mp[utils.Category] = smaEv.Category()
	}
	if smaEv.Subject() != "" {
		mp[utils.Subject] = smaEv.Subject()
	}
	mp[utils.OriginHost] = utils.FirstNonEmpty(smaEv.OriginHost(), smaEv.asteriskAlias, smaEv.OriginatorIP())
	mp[utils.AccountField] = smaEv.Account()
	mp[utils.Destination] = smaEv.Destination()
	mp[utils.SetupTime] = smaEv.SetupTime()
	if smaEv.Route() != "" {
		mp[utils.Route] = smaEv.Route()
	}
	for extraKey, extraVal := range smaEv.ExtraParameters() { // Append extraParameters
		mp[extraKey] = extraVal
	}
	mp[utils.Source] = utils.AsteriskAgent
	return
}

// AsCGREvent converts AsteriskEvent into CGREvent
func (smaEv *SMAsteriskEvent) AsCGREvent(timezone string) (cgrEv *utils.CGREvent, err error) {
	var setupTime time.Time
	if setupTime, err = utils.ParseTimeDetectLayout(
		smaEv.Timestamp(), timezone); err != nil {
		return
	}
	cgrEv = &utils.CGREvent{
		Tenant: utils.FirstNonEmpty(smaEv.Tenant(),
			config.CgrConfig().GeneralCfg().DefaultTenant),
		ID:      utils.UUIDSha1Prefix(),
		Time:    &setupTime,
		Event:   smaEv.AsMapStringInterface(),
		APIOpts: smaEv.opts,
	}
	return
}

func (smaEv *SMAsteriskEvent) V1AuthorizeArgs() (args *sessions.V1AuthorizeArgs) {
	cgrEv, err := smaEv.AsCGREvent(config.CgrConfig().GeneralCfg().DefaultTimezone)
	if err != nil {
		return
	}
	args = &sessions.V1AuthorizeArgs{
		CGREvent: cgrEv,
	}
	if smaEv.Subsystems() == utils.EmptyString {
		utils.Logger.Warning(fmt.Sprintf("<%s> cgr_flags variable is not set, using defaults",
			utils.AsteriskAgent))
		args.GetMaxUsage = true
		return
	}
	args.ParseFlags(smaEv.Subsystems(), utils.PlusChar)
	return
}

func (smaEv *SMAsteriskEvent) V1InitSessionArgs(cgrEvDisp utils.CGREvent) (args *sessions.V1InitSessionArgs) {
	args = &sessions.V1InitSessionArgs{ // defaults
		CGREvent: &cgrEvDisp,
	}
	subsystems, err := cgrEvDisp.FieldAsString(utils.CGRFlags)
	if err != nil {
		utils.Logger.Warning(fmt.Sprintf("<%s> event: %s don't have %s variable",
			utils.AsteriskAgent, utils.ToJSON(cgrEvDisp), utils.CGRFlags))
		args.InitSession = true
		return
	}
	args.ParseFlags(subsystems, utils.PlusChar)
	return
}

func (smaEv *SMAsteriskEvent) V1TerminateSessionArgs(cgrEvDisp utils.CGREvent) (args *sessions.V1TerminateSessionArgs) {
	args = &sessions.V1TerminateSessionArgs{ // defaults
		CGREvent: &cgrEvDisp,
	}
	subsystems, err := cgrEvDisp.FieldAsString(utils.CGRFlags)
	if err != nil {
		utils.Logger.Warning(fmt.Sprintf("<%s> event: %s don't have %s variable",
			utils.AsteriskAgent, utils.ToJSON(cgrEvDisp), utils.CGRFlags))
		args.TerminateSession = true
		return
	}
	args.ParseFlags(subsystems, utils.PlusChar)
	return
}