/*
Rating system designed to be used in VoIP Carriers World
Copyright (C) 2012-2015 ITsysCOM

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

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

package engine

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
	"path"
	"reflect"
	"strings"
	"time"

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

var cdrServer *CdrServer // Share the server so we can use it in http handlers

type CallCostLog struct {
	CgrId          string
	Source         string
	RunId          string
	Usage          float64 // real usage (not increment rounded)
	CallCost       *CallCost
	CheckDuplicate bool
}

// Handler for generic cgr cdr http
func cgrCdrHandler(w http.ResponseWriter, r *http.Request) {
	cgrCdr, err := NewCgrCdrFromHttpReq(r, cdrServer.cgrCfg.DefaultTimezone)
	if err != nil {
		utils.Logger.Err(fmt.Sprintf("<CDRS> Could not create CDR entry: %s", err.Error()))
		return
	}
	if err := cdrServer.processCdr(cgrCdr.AsStoredCdr(cdrServer.cgrCfg.DefaultTimezone)); err != nil {
		utils.Logger.Err(fmt.Sprintf("<CDRS> Errors when storing CDR entry: %s", err.Error()))
	}
}

// Handler for fs http
func fsCdrHandler(w http.ResponseWriter, r *http.Request) {
	body, _ := ioutil.ReadAll(r.Body)
	fsCdr, err := NewFSCdr(body, cdrServer.cgrCfg)
	if err != nil {
		utils.Logger.Err(fmt.Sprintf("<CDRS> Could not create CDR entry: %s", err.Error()))
		return
	}
	if err := cdrServer.processCdr(fsCdr.AsStoredCdr(cdrServer.Timezone())); err != nil {
		utils.Logger.Err(fmt.Sprintf("<CDRS> Errors when storing CDR entry: %s", err.Error()))
	}
}

func NewCdrServer(cgrCfg *config.CGRConfig, cdrDb CdrStorage, rater, pubsub, users, aliases, stats rpcclient.RpcClientConnection) (*CdrServer, error) {
	if rater == nil || reflect.ValueOf(rater).IsNil() { // Work around so we store actual nil instead of nil interface value, faster to check here than in CdrServer code
		rater = nil
	}
	if pubsub == nil || reflect.ValueOf(pubsub).IsNil() {
		pubsub = nil
	}
	if users == nil || reflect.ValueOf(users).IsNil() {
		users = nil
	}
	if aliases == nil || reflect.ValueOf(aliases).IsNil() {
		aliases = nil
	}
	if stats == nil || reflect.ValueOf(stats).IsNil() {
		stats = nil
	}
	return &CdrServer{cgrCfg: cgrCfg, cdrDb: cdrDb, rals: rater, pubsub: pubsub, users: users, aliases: aliases, stats: stats, guard: Guardian}, nil
}

type CdrServer struct {
	cgrCfg        *config.CGRConfig
	cdrDb         CdrStorage
	rals          rpcclient.RpcClientConnection
	pubsub        rpcclient.RpcClientConnection
	users         rpcclient.RpcClientConnection
	aliases       rpcclient.RpcClientConnection
	stats         rpcclient.RpcClientConnection
	guard         *GuardianLock
	responseCache *ResponseCache
}

func (self *CdrServer) Timezone() string {
	return self.cgrCfg.DefaultTimezone
}
func (self *CdrServer) SetTimeToLive(timeToLive time.Duration, out *int) error {
	self.responseCache = NewResponseCache(timeToLive)
	return nil
}

func (self *CdrServer) getCache() *ResponseCache {
	if self.responseCache == nil {
		self.responseCache = NewResponseCache(0)
	}
	return self.responseCache
}

func (self *CdrServer) RegisterHandlersToServer(server *utils.Server) {
	cdrServer = self // Share the server object for handlers
	server.RegisterHttpFunc("/cdr_http", cgrCdrHandler)
	server.RegisterHttpFunc("/freeswitch_json", fsCdrHandler)
}

// Used to process external CDRs
func (self *CdrServer) ProcessExternalCdr(eCDR *ExternalCDR) error {
	cdr, err := NewCDRFromExternalCDR(eCDR, self.cgrCfg.DefaultTimezone)
	if err != nil {
		return err
	}
	return self.processCdr(cdr)
}

func (self *CdrServer) storeSMCost(smCost *SMCost, checkDuplicate bool) error {
	smCost.CostDetails.UpdateCost()                                              // make sure the total cost reflect the increments
	smCost.CostDetails.UpdateRatedUsage()                                        // make sure rated usage is updated
	lockKey := utils.CDRS_SOURCE + smCost.CGRID + smCost.RunID + smCost.OriginID // Will lock on this ID
	if checkDuplicate {
		_, err := self.guard.Guard(func() (interface{}, error) {
			smCosts, err := self.cdrDb.GetSMCosts(smCost.CGRID, smCost.RunID, "", "")
			if err != nil {
				return nil, err
			}
			if len(smCosts) != 0 {
				return nil, utils.ErrExists
			}
			return nil, self.cdrDb.SetSMCost(smCost)
		}, time.Duration(2*time.Second), lockKey) // FixMe: Possible deadlock with Guard from SMG session close()
		return err
	}
	return self.cdrDb.SetSMCost(smCost)
}

// Returns error if not able to properly store the CDR, mediation is async since we can always recover offline
func (self *CdrServer) processCdr(cdr *CDR) (err error) {
	if cdr.Direction == "" {
		cdr.Direction = utils.OUT
	}
	if cdr.RequestType == "" {
		cdr.RequestType = self.cgrCfg.DefaultReqType
	}
	if cdr.Tenant == "" {
		cdr.Tenant = self.cgrCfg.DefaultTenant
	}
	if cdr.Category == "" {
		cdr.Category = self.cgrCfg.DefaultCategory
	}
	if cdr.Subject == "" { // Use account information as rating subject if missing
		cdr.Subject = cdr.Account
	}
	if !cdr.Rated { // Enforce the RunID if CDR is not rated
		cdr.RunID = utils.MetaRaw
	}
	if self.cgrCfg.CDRSStoreCdrs { // Store RawCDRs, this we do sync so we can reply with the status
		if cdr.CostDetails != nil {
			cdr.CostDetails.UpdateCost()
			cdr.CostDetails.UpdateRatedUsage()
		}
		if err := self.cdrDb.SetCDR(cdr, false); err != nil {
			utils.Logger.Err(fmt.Sprintf("<CDRS> Storing primary CDR %+v, got error: %s", cdr, err.Error()))
			return err // Error is propagated back and we don't continue processing the CDR if we cannot store it
		}
	}
	// Attach raw CDR to stats
	if self.stats != nil { // Send raw CDR to stats
		var out int
		go self.stats.Call("CDRStatsV1.AppendCDR", cdr, &out)
	}
	if len(self.cgrCfg.CDRSCdrReplication) != 0 { // Replicate raw CDR
		go self.replicateCdr(cdr)
	}

	if self.rals != nil && !cdr.Rated { // CDRs not rated will be processed by Rating
		go self.deriveRateStoreStatsReplicate(cdr, self.cgrCfg.CDRSStoreCdrs, self.stats != nil, len(self.cgrCfg.CDRSCdrReplication) != 0)
	}
	return nil
}

// Returns error if not able to properly store the CDR, mediation is async since we can always recover offline
func (self *CdrServer) deriveRateStoreStatsReplicate(cdr *CDR, store, stats, replicate bool) error {
	cdrRuns, err := self.deriveCdrs(cdr)
	if err != nil {
		return err
	}
	var ratedCDRs []*CDR // Gather all CDRs received from rating subsystem
	for _, cdrRun := range cdrRuns {
		if err := LoadUserProfile(cdrRun, utils.EXTRA_FIELDS); err != nil {
			utils.Logger.Err(fmt.Sprintf("<CDRS> UserS handling for CDR %+v, got error: %s", cdrRun, err.Error()))
			continue
		}
		if err := LoadAlias(&AttrMatchingAlias{
			Destination: cdrRun.Destination,
			Direction:   cdrRun.Direction,
			Tenant:      cdrRun.Tenant,
			Category:    cdrRun.Category,
			Account:     cdrRun.Account,
			Subject:     cdrRun.Subject,
			Context:     utils.ALIAS_CONTEXT_RATING,
		}, cdrRun, utils.EXTRA_FIELDS); err != nil && err != utils.ErrNotFound {
			utils.Logger.Err(fmt.Sprintf("<CDRS> Aliasing CDR %+v, got error: %s", cdrRun, err.Error()))
			continue
		}
		rcvRatedCDRs, err := self.rateCDR(cdrRun)
		if err != nil {
			cdrRun.Cost = -1.0 // If there was an error, mark the CDR
			cdrRun.ExtraInfo = err.Error()
			rcvRatedCDRs = []*CDR{cdrRun}
		}
		ratedCDRs = append(ratedCDRs, rcvRatedCDRs...)
	}
	// Request should be processed by SureTax
	for _, ratedCDR := range ratedCDRs {
		if ratedCDR.RunID == utils.META_SURETAX {
			if err := SureTaxProcessCdr(ratedCDR); err != nil {
				ratedCDR.Cost = -1.0
				ratedCDR.ExtraInfo = err.Error() // Something failed, write the error in the ExtraInfo
			}
		}
	}
	// Store rated CDRs
	if store {
		for _, ratedCDR := range ratedCDRs {
			if ratedCDR.CostDetails != nil {
				ratedCDR.CostDetails.UpdateCost()
				ratedCDR.CostDetails.UpdateRatedUsage()
			}
			if err := self.cdrDb.SetCDR(ratedCDR, true); err != nil {
				utils.Logger.Err(fmt.Sprintf("<CDRS> Storing rated CDR %+v, got error: %s", ratedCDR, err.Error()))
			}
		}
	}
	// Attach CDR to stats
	if stats { // Send CDR to stats
		for _, ratedCDR := range ratedCDRs {
			var out int
			if err := self.stats.Call("CDRStatsV1.AppendCDR", ratedCDR, &out); err != nil {
				utils.Logger.Err(fmt.Sprintf("<CDRS> Could not send CDR to stats: %s", err.Error()))
			}
		}
	}
	if replicate {
		for _, ratedCDR := range ratedCDRs {
			self.replicateCdr(ratedCDR)
		}
	}
	return nil
}

func (self *CdrServer) deriveCdrs(cdr *CDR) ([]*CDR, error) {
	dfltCDRRun := cdr.Clone()
	cdrRuns := []*CDR{dfltCDRRun}
	if cdr.RunID != utils.MetaRaw { // Only derive *raw CDRs
		return cdrRuns, nil
	}
	dfltCDRRun.RunID = utils.META_DEFAULT // Rewrite *raw with *default since we have it as first run
	if err := LoadUserProfile(cdr, utils.EXTRA_FIELDS); err != nil {
		return nil, err
	}
	if err := LoadAlias(&AttrMatchingAlias{
		Destination: cdr.Destination,
		Direction:   cdr.Direction,
		Tenant:      cdr.Tenant,
		Category:    cdr.Category,
		Account:     cdr.Account,
		Subject:     cdr.Subject,
		Context:     utils.ALIAS_CONTEXT_RATING,
	}, cdr, utils.EXTRA_FIELDS); err != nil && err != utils.ErrNotFound {
		return nil, err
	}
	attrsDC := &utils.AttrDerivedChargers{Tenant: cdr.Tenant, Category: cdr.Category, Direction: cdr.Direction,
		Account: cdr.Account, Subject: cdr.Subject, Destination: cdr.Destination}
	var dcs utils.DerivedChargers
	if err := self.rals.Call("Responder.GetDerivedChargers", attrsDC, &dcs); err != nil {
		utils.Logger.Err(fmt.Sprintf("Could not get derived charging for cgrid %s, error: %s", cdr.CGRID, err.Error()))
		return nil, err
	}
	for _, dc := range dcs.Chargers {
		runFilters, _ := utils.ParseRSRFields(dc.RunFilters, utils.INFIELD_SEP)
		matchingAllFilters := true
		for _, dcRunFilter := range runFilters {
			if !dcRunFilter.FilterPasses(cdr.FieldAsString(dcRunFilter)) {
				matchingAllFilters = false
				break
			}
		}
		if !matchingAllFilters { // Do not process the derived charger further if not all filters were matched
			continue
		}
		dcRequestTypeFld, _ := utils.NewRSRField(dc.RequestTypeField)
		dcDirFld, _ := utils.NewRSRField(dc.DirectionField)
		dcTenantFld, _ := utils.NewRSRField(dc.TenantField)
		dcCategoryFld, _ := utils.NewRSRField(dc.CategoryField)
		dcAcntFld, _ := utils.NewRSRField(dc.AccountField)
		dcSubjFld, _ := utils.NewRSRField(dc.SubjectField)
		dcDstFld, _ := utils.NewRSRField(dc.DestinationField)
		dcSTimeFld, _ := utils.NewRSRField(dc.SetupTimeField)
		dcPddFld, _ := utils.NewRSRField(dc.PDDField)
		dcATimeFld, _ := utils.NewRSRField(dc.AnswerTimeField)
		dcDurFld, _ := utils.NewRSRField(dc.UsageField)
		dcSupplFld, _ := utils.NewRSRField(dc.SupplierField)
		dcDCauseFld, _ := utils.NewRSRField(dc.DisconnectCauseField)
		dcRatedFld, _ := utils.NewRSRField(dc.RatedField)
		dcCostFld, _ := utils.NewRSRField(dc.CostField)
		forkedCdr, err := cdr.ForkCdr(dc.RunID, dcRequestTypeFld, dcDirFld, dcTenantFld, dcCategoryFld, dcAcntFld, dcSubjFld, dcDstFld,
			dcSTimeFld, dcPddFld, dcATimeFld, dcDurFld, dcSupplFld, dcDCauseFld, dcRatedFld, dcCostFld, []*utils.RSRField{}, true, self.cgrCfg.DefaultTimezone)
		if err != nil {
			utils.Logger.Err(fmt.Sprintf("Could not fork CGR with cgrid %s, run: %s, error: %s", cdr.CGRID, dc.RunID, err.Error()))
			continue // do not add it to the forked CDR list
		}
		if !forkedCdr.Rated {
			forkedCdr.Cost = -1.0 // Make sure that un-rated CDRs start with Cost -1
		}
		cdrRuns = append(cdrRuns, forkedCdr)
	}
	return cdrRuns, nil
}

// rateCDR will populate cost field
// Returns more than one rated CDR in case of SMCost retrieved based on prefix
func (self *CdrServer) rateCDR(cdr *CDR) ([]*CDR, error) {
	var qryCC *CallCost
	var err error
	if cdr.RequestType == utils.META_NONE {
		return nil, nil
	}
	var cdrsRated []*CDR
	_, hasLastUsed := cdr.ExtraFields[utils.LastUsed]
	if utils.IsSliceMember([]string{utils.META_PREPAID, utils.PREPAID}, cdr.RequestType) && (cdr.Usage != 0 || hasLastUsed) { // ToDo: Get rid of PREPAID as soon as we don't want to support it backwards
		// Should be previously calculated and stored in DB
		delay := utils.Fib()
		var smCosts []*SMCost
		for i := 0; i < 4; i++ {
			smCosts, err = self.cdrDb.GetSMCosts(cdr.CGRID, cdr.RunID, cdr.OriginHost, cdr.ExtraFields[utils.OriginIDPrefix])
			if err == nil && len(smCosts) != 0 {
				break
			}
			if i != 3 {
				time.Sleep(delay())
			}
		}
		if len(smCosts) != 0 { // Cost retrieved from SMCost table
			for _, smCost := range smCosts {
				cdrClone := cdr.Clone()
				cdrClone.OriginID = smCost.OriginID
				if cdr.Usage == 0 {
					cdrClone.Usage = time.Duration(smCost.Usage * utils.NANO_MULTIPLIER) // Usage is float as seconds, convert back to duration
				}
				cdrClone.Cost = smCost.CostDetails.Cost
				cdrClone.CostDetails = smCost.CostDetails
				cdrsRated = append(cdrsRated, cdrClone)
			}
			return cdrsRated, nil
		}
		if len(smCosts) == 0 { //calculate CDR as for pseudoprepaid
			utils.Logger.Warning(fmt.Sprintf("<Cdrs> WARNING: Could not find CallCostLog for cgrid: %s, source: %s, runid: %s, will recalculate", cdr.CGRID, utils.SESSION_MANAGER_SOURCE, cdr.RunID))
			qryCC, err = self.getCostFromRater(cdr)
		}
	} else {
		qryCC, err = self.getCostFromRater(cdr)
	}
	if err != nil {
		return nil, err
	} else if qryCC != nil {
		cdr.Cost = qryCC.Cost
		cdr.CostDetails = qryCC
	}
	return []*CDR{cdr}, nil
}

// Retrive the cost from engine
func (self *CdrServer) getCostFromRater(cdr *CDR) (*CallCost, error) {
	cc := new(CallCost)
	var err error
	timeStart := cdr.AnswerTime
	if timeStart.IsZero() { // Fix for FreeSWITCH unanswered calls
		timeStart = cdr.SetupTime
	}
	cd := &CallDescriptor{
		TOR:             cdr.ToR,
		Direction:       cdr.Direction,
		Tenant:          cdr.Tenant,
		Category:        cdr.Category,
		Subject:         cdr.Subject,
		Account:         cdr.Account,
		Destination:     cdr.Destination,
		TimeStart:       timeStart,
		TimeEnd:         timeStart.Add(cdr.Usage),
		DurationIndex:   cdr.Usage,
		PerformRounding: true,
	}
	if utils.IsSliceMember([]string{utils.META_PSEUDOPREPAID, utils.META_POSTPAID, utils.META_PREPAID, utils.PSEUDOPREPAID, utils.POSTPAID, utils.PREPAID}, cdr.RequestType) { // Prepaid - Cost can be recalculated in case of missing records from SM
		err = self.rals.Call("Responder.Debit", cd, cc)
	} else {
		err = self.rals.Call("Responder.GetCost", cd, cc)
	}
	if err != nil {
		return cc, err
	}
	return cc, nil
}

// ToDo: Add websocket support
func (self *CdrServer) replicateCdr(cdr *CDR) error {
	for _, rplCfg := range self.cgrCfg.CDRSCdrReplication {
		passesFilters := true
		for _, cdfFltr := range rplCfg.CdrFilter {
			if !cdfFltr.FilterPasses(cdr.FieldAsString(cdfFltr)) {
				passesFilters = false
				break
			}
		}
		if !passesFilters { // Not passes filters, ignore this replication
			continue
		}
		var body interface{}
		var content = ""
		switch rplCfg.Transport {
		case utils.META_HTTP_POST:
			content = utils.CONTENT_FORM
			body = cdr.AsHttpForm()
		case utils.META_HTTP_JSON:
			content = utils.CONTENT_JSON
			jsn, err := json.Marshal(cdr)
			if err != nil {
				return err
			}
			body = jsn
		}
		var errChan chan error
		if rplCfg.Synchronous {
			errChan = make(chan error)
		}
		go func(body interface{}, rplCfg *config.CdrReplicationCfg, content string, errChan chan error) {
			fallbackPath := path.Join(
				self.cgrCfg.HttpFailedDir,
				rplCfg.FallbackFileName())
			_, _, err := utils.HttpPoster(
				rplCfg.Address, self.cgrCfg.HttpSkipTlsVerify, body,
				content, rplCfg.Attempts, fallbackPath, false) // ToDo: Review caching here after we are sure that the connection leak is gone
			if err != nil {
				utils.Logger.Err(fmt.Sprintf(
					"<CDRReplicator> Replicating CDR: %+v, got error: %s", cdr, err.Error()))
				if rplCfg.Synchronous {
					errChan <- err
				}
			}
			if rplCfg.Synchronous {
				errChan <- nil
			}
		}(body, rplCfg, content, errChan)
		if rplCfg.Synchronous { // Synchronize here
			<-errChan
		}
	}
	return nil
}

// Called by rate/re-rate API, FixMe: deprecate it once new APIer structure is operational
func (self *CdrServer) RateCDRs(cdrFltr *utils.CDRsFilter, sendToStats bool) error {
	cdrs, _, err := self.cdrDb.GetCDRs(cdrFltr, false)
	if err != nil {
		return err
	}
	for _, cdr := range cdrs {
		if err := self.deriveRateStoreStatsReplicate(cdr, self.cgrCfg.CDRSStoreCdrs, sendToStats, len(self.cgrCfg.CDRSCdrReplication) != 0); err != nil {
			utils.Logger.Err(fmt.Sprintf("<CDRS> Processing CDR %+v, got error: %s", cdr, err.Error()))
		}
	}
	return nil
}

// Internally used and called from CDRSv1
// Cached requests for HA setups
func (self *CdrServer) V1ProcessCDR(cdr *CDR, reply *string) error {
	cacheKey := "V1ProcessCDR" + cdr.CGRID + cdr.RunID
	if item, err := self.getCache().Get(cacheKey); err == nil && item != nil {
		if item.Value != nil {
			*reply = item.Value.(string)
		}
		return item.Err
	}
	if err := self.processCdr(cdr); err != nil {
		self.getCache().Cache(cacheKey, &CacheItem{Err: err})
		return utils.NewErrServerError(err)
	}
	self.getCache().Cache(cacheKey, &CacheItem{Value: utils.OK})
	*reply = utils.OK
	return nil
}

// RPC method, differs from storeSMCost through it's signature
func (self *CdrServer) V1StoreSMCost(attr AttrCDRSStoreSMCost, reply *string) error {
	cacheKey := "V1StoreSMCost" + attr.Cost.CGRID + attr.Cost.RunID + attr.Cost.OriginID
	if item, err := self.getCache().Get(cacheKey); err == nil && item != nil {
		if item.Value != nil {
			*reply = item.Value.(string)
		}
		return item.Err
	}
	if err := self.storeSMCost(attr.Cost, attr.CheckDuplicate); err != nil {
		self.getCache().Cache(cacheKey, &CacheItem{Err: err})
		return utils.NewErrServerError(err)
	}
	self.getCache().Cache(cacheKey, &CacheItem{Value: utils.OK})
	*reply = utils.OK
	return nil
}

// Called by rate/re-rate API, RPC method
func (self *CdrServer) V1RateCDRs(attrs utils.AttrRateCDRs, reply *string) error {
	cdrFltr, err := attrs.RPCCDRsFilter.AsCDRsFilter(self.cgrCfg.DefaultTimezone)
	if err != nil {
		return utils.NewErrServerError(err)
	}
	cdrs, _, err := self.cdrDb.GetCDRs(cdrFltr, false)
	if err != nil {
		return err
	}
	storeCDRs := self.cgrCfg.CDRSStoreCdrs
	if attrs.StoreCDRs != nil {
		storeCDRs = *attrs.StoreCDRs
	}
	sendToStats := self.stats != nil
	if attrs.SendToStatS != nil {
		sendToStats = *attrs.SendToStatS
	}
	replicate := len(self.cgrCfg.CDRSCdrReplication) != 0
	if attrs.ReplicateCDRs != nil {
		replicate = *attrs.ReplicateCDRs
	}
	for _, cdr := range cdrs {
		if err := self.deriveRateStoreStatsReplicate(cdr, storeCDRs, sendToStats, replicate); err != nil {
			utils.Logger.Err(fmt.Sprintf("<CDRS> Processing CDR %+v, got error: %s", cdr, err.Error()))
		}
	}
	return nil
}

func (cdrsrv *CdrServer) Call(serviceMethod string, args interface{}, reply interface{}) error {
	parts := strings.Split(serviceMethod, ".")
	if len(parts) != 2 {
		return utils.ErrNotImplemented
	}
	// get method
	method := reflect.ValueOf(cdrsrv).MethodByName(parts[0][len(parts[0])-2:] + parts[1]) // Inherit the version in the method
	if !method.IsValid() {
		return utils.ErrNotImplemented
	}

	// construct the params
	params := []reflect.Value{reflect.ValueOf(args), reflect.ValueOf(reply)}
	ret := method.Call(params)
	if len(ret) != 1 {
		return utils.ErrServerError
	}
	if ret[0].Interface() == nil {
		return nil
	}
	err, ok := ret[0].Interface().(error)
	if !ok {
		return utils.ErrServerError
	}
	return err
}