/*
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 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 (
	"fmt"
	"strconv"
	"strings"

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

// Route defines routes related information used within a RouteProfile
type Route struct {
	ID              string // RouteID
	FilterIDs       []string
	AccountIDs      []string
	RateProfileIDs  []string // used when computing price
	ResourceIDs     []string // queried in some strategies
	StatIDs         []string // queried in some strategies
	Weights         utils.DynamicWeights
	Blocker         bool // do not process further route after this one
	RouteParameters string

	cacheRoute map[string]interface{} // cache["*ratio"]=ratio
}

// RouteProfile represents the configuration of a Route profile
type RouteProfile struct {
	Tenant            string
	ID                string // LCR Profile ID
	FilterIDs         []string
	Sorting           string // Sorting strategy
	SortingParameters []string
	Routes            []*Route
	Weights           utils.DynamicWeights
}

// RouteProfileWithAPIOpts is used in replicatorV1 for dispatcher
type RouteProfileWithAPIOpts struct {
	*RouteProfile
	APIOpts map[string]interface{}
}

func (rp *RouteProfile) compileCacheParameters() error {
	if rp.Sorting == utils.MetaLoad {
		// construct the map for ratio
		ratioMap := make(map[string]int)
		// []string{"routeID:Ratio"}
		for _, splIDWithRatio := range rp.SortingParameters {
			splitted := strings.Split(splIDWithRatio, utils.ConcatenatedKeySep)
			ratioVal, err := strconv.Atoi(splitted[1])
			if err != nil {
				return err
			}
			ratioMap[splitted[0]] = ratioVal
		}
		// add the ratio for each route
		for _, route := range rp.Routes {
			route.cacheRoute = make(map[string]interface{})
			if ratioRoute, has := ratioMap[route.ID]; !has { // in case that ratio isn't defined for specific routes check for default
				if ratioDefault, has := ratioMap[utils.MetaDefault]; !has { // in case that *default ratio isn't defined take it from config
					route.cacheRoute[utils.MetaRatio] = config.CgrConfig().RouteSCfg().DefaultRatio
				} else {
					route.cacheRoute[utils.MetaRatio] = ratioDefault
				}
			} else {
				route.cacheRoute[utils.MetaRatio] = ratioRoute
			}
		}
	}
	return nil
}

// Compile is a wrapper for convenience setting up the RouteProfile
func (rp *RouteProfile) Compile() error {
	return rp.compileCacheParameters()
}

// TenantID returns unique identifier of the LCRProfile in a multi-tenant environment
func (rp *RouteProfile) TenantID() string {
	return utils.ConcatenatedKey(rp.Tenant, rp.ID)
}

// NewRouteService initializes the Route Service
func NewRouteService(dm *DataManager,
	filterS *FilterS, cfg *config.CGRConfig, connMgr *ConnManager) (rS *RouteService) {
	rS = &RouteService{
		dm:      dm,
		filterS: filterS,
		cfg:     cfg,
		connMgr: connMgr,
		sorter: RouteSortDispatcher{
			utils.MetaWeight: NewWeightSorter(cfg),
			utils.MetaLC:     NewLeastCostSorter(cfg, connMgr),
			utils.MetaHC:     NewHighestCostSorter(cfg, connMgr),
			utils.MetaQOS:    NewQOSRouteSorter(cfg, connMgr),
			utils.MetaReas:   NewResourceAscendetSorter(cfg, connMgr),
			utils.MetaReds:   NewResourceDescendentSorter(cfg, connMgr),
			utils.MetaLoad:   NewLoadDistributionSorter(cfg, connMgr),
		},
	}
	return
}

// RouteService is the service computing route queries
type RouteService struct {
	dm      *DataManager
	filterS *FilterS
	cfg     *config.CGRConfig
	sorter  RouteSortDispatcher
	connMgr *ConnManager
}

// Shutdown is called to shutdown the service
func (rpS *RouteService) Shutdown() {
	utils.Logger.Info(fmt.Sprintf("<%s> service shutdown initialized", utils.RouteS))
	utils.Logger.Info(fmt.Sprintf("<%s> service shutdown complete", utils.RouteS))
}

// matchingRouteProfilesForEvent returns ordered list of matching resources which are active by the time of the call
func (rpS *RouteService) matchingRouteProfilesForEvent(ctx *context.Context, tnt string, ev *utils.CGREvent) (matchingRPrf RouteProfilesWithWeight, err error) {
	evNm := utils.MapStorage{
		utils.MetaReq:  ev.Event,
		utils.MetaOpts: ev.APIOpts,
	}
	rPrfIDs, err := MatchingItemIDsForEvent(ctx, evNm,
		rpS.cfg.RouteSCfg().StringIndexedFields,
		rpS.cfg.RouteSCfg().PrefixIndexedFields,
		rpS.cfg.RouteSCfg().SuffixIndexedFields,
		rpS.dm, utils.CacheRouteFilterIndexes, tnt,
		rpS.cfg.RouteSCfg().IndexedSelects,
		rpS.cfg.RouteSCfg().NestedFields,
	)
	if err != nil {
		return nil, err
	}
	matchingRPrf = make(RouteProfilesWithWeight, 0, len(rPrfIDs))
	for lpID := range rPrfIDs {
		var rPrf *RouteProfile
		if rPrf, err = rpS.dm.GetRouteProfile(ctx, tnt, lpID, true, true, utils.NonTransactional); err != nil {
			if err == utils.ErrNotFound {
				continue
			}
			return
		}
		var pass bool
		if pass, err = rpS.filterS.Pass(ctx, tnt, rPrf.FilterIDs,
			evNm); err != nil {
			return
		} else if !pass {
			continue
		}
		var weight float64
		if weight, err = WeightFromDynamics(ctx, rPrf.Weights,
			rpS.filterS, ev.Tenant, evNm); err != nil {
			return
		}
		matchingRPrf = append(matchingRPrf, &RouteProfileWithWeight{RouteProfile: rPrf, Weight: weight})
	}
	if len(matchingRPrf) == 0 {
		return nil, utils.ErrNotFound
	}
	matchingRPrf.Sort()
	return
}

func newOptsGetRoutes(ctx *context.Context, ev *utils.CGREvent, fS *FilterS, cfgOpts *config.RoutesOpts) (opts *optsGetRoutes, err error) {
	var ignoreErrors bool
	if ignoreErrors, err = GetBoolOpts(ctx, ev.Tenant, ev, fS, cfgOpts.IgnoreErrors,
		config.RoutesIgnoreErrorsDftOpt, utils.OptsRoutesIgnoreErrors); err != nil {
		return
	}
	opts = &optsGetRoutes{
		ignoreErrors: ignoreErrors,
		paginator:    &utils.Paginator{},
	}
	var limit *int
	if limit, err = GetIntPointerOpts(ctx, ev.Tenant, ev, fS, cfgOpts.Limit,
		utils.OptsRoutesLimit); err != nil {
		if err != utils.ErrNotFound {
			return
		}
	} else {
		opts.paginator.Limit = limit
	}
	var offset *int
	if offset, err = GetIntPointerOpts(ctx, ev.Tenant, ev, fS, cfgOpts.Offset,
		utils.OptsRoutesOffset); err != nil {
		if err != utils.ErrNotFound {
			return
		}
	} else {
		opts.paginator.Offset = offset
	}

	var maxCost interface{}
	if maxCost, err = GetInterfaceOpts(ctx, ev.Tenant, ev, fS, cfgOpts.MaxCost, config.RoutesMaxCostDftOpt,
		utils.OptsRoutesMaxCost); err != nil {
		return
	}

	switch maxCost {
	case utils.EmptyString, nil:
	case utils.MetaEventCost:
		if err = ev.CheckMandatoryFields([]string{utils.AccountField,
			utils.Destination, utils.SetupTime, utils.Usage}); err != nil {
			return
		}
	// ToDoNext: rates.V1CostForEvent
	// cd, err := NewCallDescriptorFromCGREvent(attr.CGREvent,
	// 	config.CgrConfig().GeneralCfg().DefaultTimezone)
	// if err != nil {
	// 	return nil, err
	// }
	// cc, err := cd.GetCost()
	// if err != nil {
	// 	return nil, err
	// }
	// opts.maxCost = cc.Cost
	default:
		if opts.maxCost, err = utils.IfaceAsFloat64(maxCost); err != nil {
			return nil, err
		}
	}

	return
}

type optsGetRoutes struct {
	ignoreErrors      bool
	maxCost           float64
	paginator         *utils.Paginator
	sortingParameters []string //used for QOS strategy
	sortingStragety   string
}

// V1GetRoutes returns the list of valid routes
func (rpS *RouteService) V1GetRoutes(ctx *context.Context, args *utils.CGREvent, reply *SortedRoutesList) (err error) {
	if missing := utils.MissingStructFields(args, []string{utils.ID}); len(missing) != 0 {
		return utils.NewErrMandatoryIeMissing(missing...)
	} else if args.Event == nil {
		return utils.NewErrMandatoryIeMissing(utils.Event)
	}
	tnt := args.Tenant
	if tnt == utils.EmptyString {
		tnt = rpS.cfg.GeneralCfg().DefaultTenant
	}
	if len(rpS.cfg.RouteSCfg().AttributeSConns) != 0 {
		if args.APIOpts == nil {
			args.APIOpts = make(map[string]interface{})
		}
		args.APIOpts[utils.Subsys] = utils.MetaRoutes
		var context string
		if context, err = GetStringOpts(ctx, tnt, args, rpS.filterS, rpS.cfg.RouteSCfg().Opts.Context,
			config.RoutesContextDftOpt, utils.OptsContext); err != nil {
			return
		}
		args.APIOpts[utils.OptsContext] = context
		var rplyEv AttrSProcessEventReply
		if err := rpS.connMgr.Call(ctx, rpS.cfg.RouteSCfg().AttributeSConns,
			utils.AttributeSv1ProcessEvent, args, &rplyEv); err == nil && len(rplyEv.AlteredFields) != 0 {
			args = rplyEv.CGREvent
			args.APIOpts = rplyEv.APIOpts
		} else if err.Error() != utils.ErrNotFound.Error() {
			return utils.NewErrRouteS(err)
		}
	}
	var sSps SortedRoutesList
	if sSps, err = rpS.sortedRoutesForEvent(ctx, tnt, args); err != nil {
		if err != utils.ErrNotFound {
			err = utils.NewErrServerError(err)
		}
		return
	}
	*reply = sSps
	return
}

// V1GetRouteProfilesForEvent returns the list of valid route profiles
func (rpS *RouteService) V1GetRouteProfilesForEvent(ctx *context.Context, args *utils.CGREvent, reply *[]*RouteProfile) (_ error) {
	if missing := utils.MissingStructFields(args, []string{utils.ID}); len(missing) != 0 {
		return utils.NewErrMandatoryIeMissing(missing...)
	} else if args.Event == nil {
		return utils.NewErrMandatoryIeMissing(utils.Event)
	}
	tnt := args.Tenant
	if tnt == utils.EmptyString {
		tnt = rpS.cfg.GeneralCfg().DefaultTenant
	}
	sPs, err := rpS.matchingRouteProfilesForEvent(ctx, tnt, args)
	if err != nil {
		if err != utils.ErrNotFound {
			err = utils.NewErrServerError(err)
		}
		return err
	}
	*reply = make([]*RouteProfile, len(sPs))
	for i, sP := range sPs {
		(*reply)[i] = sP.RouteProfile
	}
	return
}

var lazyRouteFltrPrfxs = []string{utils.DynamicDataPrefix + utils.MetaReq,
	utils.DynamicDataPrefix + utils.MetaAccounts,
	utils.DynamicDataPrefix + utils.MetaResources,
	utils.DynamicDataPrefix + utils.MetaStats}

// sortedRoutesForEvent will return the list of valid route IDs
// for event based on filters and sorting algorithms
func (rpS *RouteService) sortedRoutesForProfile(ctx *context.Context, tnt string, rPrfl *RouteProfile, ev *utils.CGREvent,
	pag utils.Paginator, extraOpts *optsGetRoutes) (sortedRoutes *SortedRoutes, err error) {
	extraOpts.sortingParameters = rPrfl.SortingParameters // populate sortingParameters in extraOpts
	extraOpts.sortingStragety = rPrfl.Sorting             // populate sortingStrategy in extraOpts
	//construct the DP and pass it to filterS
	nM := utils.MapStorage{
		utils.MetaReq:  ev.Event,
		utils.MetaOpts: ev.APIOpts,
	}
	passedRoutes := make(map[string]*RouteWithWeight)
	// apply filters for event
	for _, route := range rPrfl.Routes {
		var pass bool
		var lazyCheckRules []*FilterRule
		if pass, lazyCheckRules, err = rpS.filterS.LazyPass(ctx, tnt,
			route.FilterIDs, nM, lazyRouteFltrPrfxs); err != nil {
			return
		} else if !pass {
			continue
		}
		var weight float64
		if weight, err = WeightFromDynamics(ctx, route.Weights,
			rpS.filterS, ev.Tenant, nM); err != nil {
			return
		}
		if prev, has := passedRoutes[route.ID]; !has || prev.Weight < weight {
			passedRoutes[route.ID] = &RouteWithWeight{
				Route:          route,
				lazyCheckRules: lazyCheckRules,
				Weight:         weight,
			}
		}
	}

	if sortedRoutes, err = rpS.sorter.SortRoutes(ctx, rPrfl.ID, rPrfl.Sorting,
		passedRoutes, ev, extraOpts); err != nil {
		return nil, err
	}
	if pag.Offset != nil {
		if *pag.Offset <= len(sortedRoutes.Routes) {
			sortedRoutes.Routes = sortedRoutes.Routes[*pag.Offset:]
		}
	}
	if pag.Limit != nil {
		if *pag.Limit <= len(sortedRoutes.Routes) {
			sortedRoutes.Routes = sortedRoutes.Routes[:*pag.Limit]
		}
	}
	return
}

// sortedRoutesForEvent will return the list of sortedRoutes
// for event based on filters and sorting algorithms
func (rpS *RouteService) sortedRoutesForEvent(ctx *context.Context, tnt string, args *utils.CGREvent) (sortedRoutes SortedRoutesList, err error) {
	var rPrfs RouteProfilesWithWeight
	if rPrfs, err = rpS.matchingRouteProfilesForEvent(ctx, tnt, args); err != nil {
		return
	}
	prfCount := len(rPrfs) // if the option is not present return for all profiles
	var prfCountOpt int
	if prfCountOpt, err = GetIntOpts(ctx, tnt, args, rpS.filterS, rpS.cfg.RouteSCfg().Opts.ProfileCount,
		config.RoutesProfileCountDftOpt, utils.OptsRoutesProfileCount); err != nil {
		return
	}
	if prfCount > prfCountOpt { // it has the option and is smaller that the current number of profiles
		prfCount = prfCountOpt
	}
	var extraOpts *optsGetRoutes
	if extraOpts, err = newOptsGetRoutes(ctx, args, rpS.filterS, rpS.cfg.RouteSCfg().Opts); err != nil { // convert routes arguments into internal options used to limit data
		return
	}

	var startIdx, noSrtRoutes int
	if extraOpts.paginator.Offset != nil { // save the offset in a varible to not duble check if we have offset and is still not 0
		startIdx = *extraOpts.paginator.Offset
	}
	sortedRoutes = make(SortedRoutesList, 0, prfCount)
	for _, rPrfl := range rPrfs {
		var prfPag utils.Paginator
		if extraOpts.paginator.Limit != nil { // we have a limit
			if noSrtRoutes >= *extraOpts.paginator.Limit { // the limit was reached
				break
			}
			if noSrtRoutes+len(rPrfl.Routes) > *extraOpts.paginator.Limit { // the limit will be reached in this profile
				limit := *extraOpts.paginator.Limit - noSrtRoutes // make it relative to current profile
				prfPag.Limit = &limit                             // add the limit to the paginator
			}
		}
		if startIdx > 0 { // we have offest
			if idx := startIdx - len(rPrfl.Routes); idx >= 0 { // we still have offset so try the next profile
				startIdx = idx
				continue
			}
			// we have offset but is in the range of this profile
			offset := startIdx // store in a seoarate var so when startIdx is updated the prfPag.Offset remains the same
			startIdx = 0       // set it to 0 for the following loop
			prfPag.Offset = &offset
		}
		var sr *SortedRoutes
		if sr, err = rpS.sortedRoutesForProfile(ctx, tnt, rPrfl.RouteProfile, args, prfPag, extraOpts); err != nil {
			return
		}
		if len(sr.Routes) != 0 {
			noSrtRoutes += len(sr.Routes)
			sortedRoutes = append(sortedRoutes, sr)
			if len(sortedRoutes) == prfCount { // the profile count was reached
				break
			}
		}
	}
	if len(sortedRoutes) == 0 {
		err = utils.ErrNotFound
	}
	return
}

// V1GetRoutesList returns the list of valid routes
func (rpS *RouteService) V1GetRoutesList(ctx *context.Context, args *utils.CGREvent, reply *[]string) (err error) {
	sR := new(SortedRoutesList)
	if err = rpS.V1GetRoutes(ctx, args, sR); err != nil {
		return
	}
	*reply = sR.RoutesWithParams()
	return
}