/*
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"
	"sort"
	"strings"

	"github.com/cgrates/birpc/context"

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

// SortedRoute represents one route in SortedRoutes
type SortedRoute struct {
	RouteID         string
	RouteParameters string
	SortingData     map[string]interface{} // store here extra info like cost or stats (can contain the data that we do not use to sort after)
	sortingDataF64  map[string]float64     // only the data we sort after
}

// SortedRoutes represents all viable routes inside one routing profile
type SortedRoutes struct {
	ProfileID string         // Profile matched
	Sorting   string         // Sorting algorithm
	Routes    []*SortedRoute // list of route IDs and SortingData data
}

// RouteIDs returns a list of route IDs
func (sRoutes *SortedRoutes) RouteIDs() (rIDs []string) {
	rIDs = make([]string, len(sRoutes.Routes))
	for i, sRoute := range sRoutes.Routes {
		rIDs[i] = sRoute.RouteID
	}
	return
}

// RoutesWithParams returns a list of routes IDs with Parameters
func (sRoutes *SortedRoutes) RoutesWithParams() (sPs []string) {
	sPs = make([]string, len(sRoutes.Routes))
	for i, spl := range sRoutes.Routes {
		sPs[i] = spl.RouteID
		if spl.RouteParameters != "" {
			sPs[i] += utils.InInFieldSep + spl.RouteParameters
		}
	}
	return
}

// SortWeight is part of sort interface, sort based on Weight
func (sRoutes *SortedRoutes) SortWeight() {
	sort.Slice(sRoutes.Routes, func(i, j int) bool {
		if sRoutes.Routes[i].sortingDataF64[utils.Weight] == sRoutes.Routes[j].sortingDataF64[utils.Weight] {
			return utils.BoolGenerator().RandomBool()
		}
		return sRoutes.Routes[i].sortingDataF64[utils.Weight] > sRoutes.Routes[j].sortingDataF64[utils.Weight]
	})
}

// SortLeastCost is part of sort interface,
// sort ascendent based on Cost with fallback on Weight
func (sRoutes *SortedRoutes) SortLeastCost() {
	sort.Slice(sRoutes.Routes, func(i, j int) bool {
		if sRoutes.Routes[i].sortingDataF64[utils.Cost] == sRoutes.Routes[j].sortingDataF64[utils.Cost] {
			if sRoutes.Routes[i].sortingDataF64[utils.Weight] == sRoutes.Routes[j].sortingDataF64[utils.Weight] {
				return utils.BoolGenerator().RandomBool()
			}
			return sRoutes.Routes[i].sortingDataF64[utils.Weight] > sRoutes.Routes[j].sortingDataF64[utils.Weight]
		}
		return sRoutes.Routes[i].sortingDataF64[utils.Cost] < sRoutes.Routes[j].sortingDataF64[utils.Cost]
	})
}

// SortHighestCost is part of sort interface,
// sort descendent based on Cost with fallback on Weight
func (sRoutes *SortedRoutes) SortHighestCost() {
	sort.Slice(sRoutes.Routes, func(i, j int) bool {
		if sRoutes.Routes[i].sortingDataF64[utils.Cost] == sRoutes.Routes[j].sortingDataF64[utils.Cost] {
			if sRoutes.Routes[i].sortingDataF64[utils.Weight] == sRoutes.Routes[j].sortingDataF64[utils.Weight] {
				return utils.BoolGenerator().RandomBool()
			}
			return sRoutes.Routes[i].sortingDataF64[utils.Weight] > sRoutes.Routes[j].sortingDataF64[utils.Weight]
		}
		return sRoutes.Routes[i].sortingDataF64[utils.Cost] > sRoutes.Routes[j].sortingDataF64[utils.Cost]
	})
}

// SortQOS is part of sort interface,
// sort based on Stats
func (sRoutes *SortedRoutes) SortQOS(params []string) {
	//sort routes
	sort.Slice(sRoutes.Routes, func(i, j int) bool {
		for _, param := range params {
			//in case we have the same value for the current param we skip to the next one
			if sRoutes.Routes[i].sortingDataF64[param] == sRoutes.Routes[j].sortingDataF64[param] {
				continue
			}
			switch param {
			default:
				if sRoutes.Routes[i].sortingDataF64[param] > sRoutes.Routes[j].sortingDataF64[param] {
					return true
				}
				return false
			case utils.MetaPDD: //in case of pdd the smallest value if the best
				if sRoutes.Routes[i].sortingDataF64[param] < sRoutes.Routes[j].sortingDataF64[param] {
					return true
				}
				return false
			}

		}
		//in case that we have the same value for all params we sort base on weight
		if sRoutes.Routes[i].sortingDataF64[utils.Weight] == sRoutes.Routes[j].sortingDataF64[utils.Weight] {
			return utils.BoolGenerator().RandomBool()
		}
		return sRoutes.Routes[i].sortingDataF64[utils.Weight] > sRoutes.Routes[j].sortingDataF64[utils.Weight]
	})
}

// SortResourceAscendent is part of sort interface,
// sort ascendent based on ResourceUsage with fallback on Weight
func (sRoutes *SortedRoutes) SortResourceAscendent() {
	sort.Slice(sRoutes.Routes, func(i, j int) bool {
		if sRoutes.Routes[i].sortingDataF64[utils.ResourceUsage] == sRoutes.Routes[j].sortingDataF64[utils.ResourceUsage] {
			if sRoutes.Routes[i].sortingDataF64[utils.Weight] == sRoutes.Routes[j].sortingDataF64[utils.Weight] {
				return utils.BoolGenerator().RandomBool()
			}
			return sRoutes.Routes[i].sortingDataF64[utils.Weight] > sRoutes.Routes[j].sortingDataF64[utils.Weight]
		}
		return sRoutes.Routes[i].sortingDataF64[utils.ResourceUsage] < sRoutes.Routes[j].sortingDataF64[utils.ResourceUsage]
	})
}

// SortResourceDescendent is part of sort interface,
// sort descendent based on ResourceUsage with fallback on Weight
func (sRoutes *SortedRoutes) SortResourceDescendent() {
	sort.Slice(sRoutes.Routes, func(i, j int) bool {
		if sRoutes.Routes[i].sortingDataF64[utils.ResourceUsage] == sRoutes.Routes[j].sortingDataF64[utils.ResourceUsage] {
			if sRoutes.Routes[i].sortingDataF64[utils.Weight] == sRoutes.Routes[j].sortingDataF64[utils.Weight] {
				return utils.BoolGenerator().RandomBool()
			}
			return sRoutes.Routes[i].sortingDataF64[utils.Weight] > sRoutes.Routes[j].sortingDataF64[utils.Weight]
		}
		return sRoutes.Routes[i].sortingDataF64[utils.ResourceUsage] > sRoutes.Routes[j].sortingDataF64[utils.ResourceUsage]
	})
}

// SortLoadDistribution is part of sort interface,
// sort based on the following formula float64(metricVal/ratio) with fallback on Weight
func (sRoutes *SortedRoutes) SortLoadDistribution() {
	sort.Slice(sRoutes.Routes, func(i, j int) bool {
		// ((ratio + metricVal) / (ratio)) -1 = ((ratio+metricVal)/ratio) - (ratio/ratio) = (ratio+metricVal-ratio)/ratio = metricVal/ratio
		splIVal := sRoutes.Routes[i].sortingDataF64[utils.Load] / sRoutes.Routes[i].sortingDataF64[utils.Ratio]
		splJVal := sRoutes.Routes[j].sortingDataF64[utils.Load] / sRoutes.Routes[j].sortingDataF64[utils.Ratio]
		if splIVal == splJVal {
			if sRoutes.Routes[i].sortingDataF64[utils.Weight] == sRoutes.Routes[j].sortingDataF64[utils.Weight] {
				return utils.BoolGenerator().RandomBool()
			}
			return sRoutes.Routes[i].sortingDataF64[utils.Weight] > sRoutes.Routes[j].sortingDataF64[utils.Weight]
		}
		return splIVal < splJVal
	})
}

// Digest returns list of routeIDs + parameters for easier outside access
// format route1:route1params,route2:route2params
func (sRoutes *SortedRoutes) Digest() string {
	return strings.Join(sRoutes.RoutesWithParams(), utils.FieldsSep)
}

func (ss *SortedRoute) AsNavigableMap() (nm *utils.DataNode) {
	nm = &utils.DataNode{
		Type: utils.NMMapType,
		Map: map[string]*utils.DataNode{
			utils.RouteID:         utils.NewLeafNode(ss.RouteID),
			utils.RouteParameters: utils.NewLeafNode(ss.RouteParameters),
		},
	}
	sd := &utils.DataNode{Type: utils.NMMapType, Map: map[string]*utils.DataNode{}}
	for k, d := range ss.SortingData {
		sd.Map[k] = utils.NewLeafNode(d)
	}
	nm.Map[utils.SortingData] = sd
	return
}

func (sRoutes *SortedRoutes) AsNavigableMap() (nm *utils.DataNode) {
	nm = &utils.DataNode{
		Type: utils.NMMapType,
		Map: map[string]*utils.DataNode{
			utils.ProfileID: utils.NewLeafNode(sRoutes.ProfileID),
			utils.Sorting:   utils.NewLeafNode(sRoutes.Sorting),
		},
	}
	sr := make([]*utils.DataNode, len(sRoutes.Routes))
	for i, ss := range sRoutes.Routes {
		sr[i] = ss.AsNavigableMap()
	}
	nm.Map[utils.CapRoutes] = &utils.DataNode{Type: utils.NMSliceType, Slice: sr}
	return
}

// RoutesSorter is the interface which needs to be implemented by routes sorters
type RoutesSorter interface {
	SortRoutes(*context.Context, string, map[string]*RouteWithWeight, *utils.CGREvent, *optsGetRoutes) (*SortedRoutes, error)
}

// RouteSortDispatcher will initialize strategies
// and dispatch requests to them
type RouteSortDispatcher map[string]RoutesSorter

func (ssd RouteSortDispatcher) SortRoutes(ctx *context.Context, prflID, strategy string,
	suppls map[string]*RouteWithWeight, suplEv *utils.CGREvent, extraOpts *optsGetRoutes) (_ *SortedRoutes, err error) {
	sd, has := ssd[strategy]
	if !has {
		err = fmt.Errorf("unsupported sorting strategy: %s", strategy)
		return
	}
	return sd.SortRoutes(ctx, prflID, suppls, suplEv, extraOpts)
}

// SortedRoutesList represents the list of matched routes grouped based of profile
type SortedRoutesList []*SortedRoutes

// RouteIDs returns a list of route IDs
func (sRs SortedRoutesList) RouteIDs() (rIDs []string) {
	for _, sR := range sRs {
		for _, r := range sR.Routes {
			rIDs = append(rIDs, r.RouteID)
		}
	}
	return
}

// RoutesWithParams returns a list of routes IDs with Parameters
func (sRs SortedRoutesList) RoutesWithParams() (sPs []string) {
	for _, sR := range sRs {
		for _, spl := range sR.Routes {
			route := spl.RouteID
			if spl.RouteParameters != "" {
				route += utils.InInFieldSep + spl.RouteParameters
			}
			sPs = append(sPs, route)
		}
	}
	return
}

// Digest returns list of routeIDs + parameters for easier outside access
// format route1:route1params,route2:route2params
func (sRs SortedRoutesList) Digest() string {
	return strings.Join(sRs.RoutesWithParams(), utils.FieldsSep)
}

// AsNavigableMap returns the SortedRoutesSet as NMInterface object
func (sRs SortedRoutesList) AsNavigableMap() (nm *utils.DataNode) {
	nm = &utils.DataNode{Type: utils.NMSliceType, Slice: make([]*utils.DataNode, len(sRs))}
	for i, ss := range sRs {
		nm.Slice[i] = ss.AsNavigableMap()
	}
	return
}

// RouteProfileWithWeight attaches static weight to RouteProfile
type RouteProfileWithWeight struct {
	*RouteProfile
	Weight float64
}

// RouteProfiles is a sortable list of RouteProfile
type RouteProfilesWithWeight []*RouteProfileWithWeight

// Sort is part of sort interface, sort based on Weight
func (lps RouteProfilesWithWeight) Sort() {
	sort.Slice(lps, func(i, j int) bool { return lps[i].Weight > lps[j].Weight })
}

//routeLazyPass filters the route based on
func routeLazyPass(ctx *context.Context, filters []*FilterRule, ev *utils.CGREvent, data utils.MapStorage,
	resConns, statConns, acntConns []string) (pass bool, err error) {
	if len(filters) == 0 {
		return true, nil
	}

	dynDP := newDynamicDP(ctx, resConns, statConns, acntConns, //construct the DP and pass it to filterS
		ev.Tenant, utils.MapStorage{
			utils.MetaReq:  ev.Event,
			utils.MetaOpts: ev.APIOpts,
			utils.MetaVars: data,
		})

	for _, rule := range filters { // verify the rules remaining from PartialPass
		if pass, err = rule.Pass(ctx, dynDP); err != nil || !pass {
			return
		}
	}
	return true, nil
}

// RouteWithWeight attaches static weight to Route
type RouteWithWeight struct {
	*Route
	Weight         float64
	lazyCheckRules []*FilterRule
}

// ExternalRoute the attribute for external profile
type ExternalRoute 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         string
	Blocker         bool // do not process further route after this one
	RouteParameters string
}

// APIRouteProfile used by APIs
type APIRouteProfile struct {
	Tenant            string
	ID                string // LCR Profile ID
	FilterIDs         []string
	Sorting           string // Sorting strategy
	SortingParameters []string
	Routes            []*ExternalRoute
	Weights           string
}

type APIRouteProfileWithAPIOpts struct {
	*APIRouteProfile
	APIOpts map[string]interface{}
}

func NewAPIRouteProfile(attr *RouteProfile) (ext *APIRouteProfile) {
	ext = &APIRouteProfile{
		Tenant:            attr.Tenant,
		ID:                attr.ID,
		FilterIDs:         attr.FilterIDs,
		Sorting:           attr.Sorting,
		SortingParameters: attr.SortingParameters,
		Routes:            make([]*ExternalRoute, len(attr.Routes)),
		Weights:           attr.Weights.String(utils.InfieldSep, utils.ANDSep),
	}
	for i, r := range attr.Routes {
		ext.Routes[i] = &ExternalRoute{
			ID:              r.ID,
			FilterIDs:       r.FilterIDs,
			AccountIDs:      r.AccountIDs,
			RateProfileIDs:  r.RateProfileIDs,
			ResourceIDs:     r.ResourceIDs,
			StatIDs:         r.StatIDs,
			Weights:         r.Weights.String(utils.InfieldSep, utils.ANDSep),
			Blocker:         r.Blocker,
			RouteParameters: r.RouteParameters,
		}
	}
	return
}

// AsAttributeProfile converts the external attribute format to the actual AttributeProfile
func (ext *APIRouteProfile) AsRouteProfile() (rp *RouteProfile, err error) {
	if len(ext.Routes) == 0 {
		return nil, utils.NewErrMandatoryIeMissing("Routes")
	}
	rp = &RouteProfile{
		Tenant:            ext.Tenant,
		ID:                ext.ID,
		FilterIDs:         ext.FilterIDs,
		Sorting:           ext.Sorting,
		SortingParameters: ext.SortingParameters,
		Routes:            make([]*Route, len(ext.Routes)),
	}
	if ext.Weights != utils.EmptyString {
		if rp.Weights, err = utils.NewDynamicWeightsFromString(ext.Weights, utils.InfieldSep, utils.ANDSep); err != nil {
			return
		}
	}
	for i, extR := range ext.Routes {
		rp.Routes[i] = &Route{
			ID:              extR.ID,
			FilterIDs:       extR.FilterIDs,
			AccountIDs:      extR.AccountIDs,
			RateProfileIDs:  extR.RateProfileIDs,
			ResourceIDs:     extR.ResourceIDs,
			StatIDs:         extR.StatIDs,
			Blocker:         extR.Blocker,
			RouteParameters: extR.RouteParameters,
		}
		if extR.Weights != utils.EmptyString {
			if rp.Routes[i].Weights, err = utils.NewDynamicWeightsFromString(extR.Weights, utils.InfieldSep, utils.ANDSep); err != nil {
				return
			}
		}
	}
	err = rp.Compile()
	return
}