/*
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 PURPOev.  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 utils

import (
	"fmt"
	"reflect"
	"strconv"
	"strings"
	"time"
)

// CGREvent is a generic event processed by CGR services
type CGREvent struct {
	Tenant string
	ID     string
	Time   *time.Time // event time
	Event  map[string]interface{}
}

func (ev *CGREvent) HasField(fldName string) (has bool) {
	_, has = ev.Event[fldName]
	return
}

func (ev *CGREvent) CheckMandatoryFields(fldNames []string) error {
	for _, fldName := range fldNames {
		if _, has := ev.Event[fldName]; !has {
			return NewErrMandatoryIeMissing(fldName)
		}
	}
	return nil
}

// AnswerTime returns a field as string instance
func (ev *CGREvent) FieldAsString(fldName string) (val string, err error) {
	iface, has := ev.Event[fldName]
	if !has {
		return "", ErrNotFound
	}
	val, err = IfaceAsString(iface)
	if err != nil {
		return "", fmt.Errorf("cannot cast %s to string", fldName)
	}
	return val, nil
}

// FieldAsTime returns a field as Time instance
func (ev *CGREvent) FieldAsTime(fldName string, timezone string) (t time.Time, err error) {
	iface, has := ev.Event[fldName]
	if !has {
		err = ErrNotFound
		return
	}
	var canCast bool
	if t, canCast = iface.(time.Time); canCast {
		return
	}
	s, canCast := iface.(string)
	if !canCast {
		err = fmt.Errorf("cannot cast %s to string", fldName)
		return
	}
	return ParseTimeDetectLayout(s, timezone)
}

// FieldAsDuration returns a field as Duration instance
func (ev *CGREvent) FieldAsDuration(fldName string) (d time.Duration, err error) {
	iface, has := ev.Event[fldName]
	if !has {
		err = ErrNotFound
		return
	}
	var canCast bool
	if d, canCast = iface.(time.Duration); canCast {
		return
	}
	if f, canCast := iface.(float64); canCast {
		return time.Duration(int64(f)), nil
	}
	s, canCast := iface.(string)
	if !canCast {
		err = fmt.Errorf("cannot cast %s to string", fldName)
		return
	}
	return ParseDurationWithNanosecs(s)
}

// FieldAsFloat64 returns a field as float64 instance
func (ev *CGREvent) FieldAsFloat64(fldName string) (f float64, err error) {
	iface, has := ev.Event[fldName]
	if !has {
		return f, ErrNotFound
	}
	if val, canCast := iface.(float64); canCast {
		return val, nil
	}
	csStr, canCast := iface.(string)
	if !canCast {
		err = fmt.Errorf("cannot cast %s to string", fldName)
		return
	}
	return strconv.ParseFloat(csStr, 64)
}

func (ev *CGREvent) TenantID() string {
	return ConcatenatedKey(ev.Tenant, ev.ID)
}

func (ev *CGREvent) FilterableEvent(fltredFields []string) (fEv map[string]interface{}) {
	fEv = make(map[string]interface{})
	if len(fltredFields) == 0 {
		i := 0
		fltredFields = make([]string, len(ev.Event))
		for k := range ev.Event {
			fltredFields[i] = k
			i++
		}
	}
	for _, fltrFld := range fltredFields {
		fldVal, has := ev.Event[fltrFld]
		if !has {
			continue // the field does not exist in map, ignore it
		}
		valOf := reflect.ValueOf(fldVal)
		if valOf.Kind() == reflect.String {
			fEv[fltrFld] = StringToInterface(valOf.String()) // attempt converting from string to comparable interface
		} else {
			fEv[fltrFld] = fldVal
		}
	}
	return
}

func (ev *CGREvent) Clone() (clned *CGREvent) {
	clned = &CGREvent{
		Tenant: ev.Tenant,
		ID:     ev.ID,
		Event:  make(map[string]interface{}), // a bit forced but safe
	}
	if ev.Time != nil {
		clned.Time = TimePointer(*ev.Time)
	}
	for k, v := range ev.Event {
		clned.Event[k] = v
	}
	return
}

// RemFldsWithPrefix will remove fields starting with prefix from event
func (ev *CGREvent) RemFldsWithPrefix(prfx string) {
	for fldName := range ev.Event {
		if strings.HasPrefix(fldName, prfx) {
			delete(ev.Event, fldName)
		}
	}
}

// RemFldsWithPrefix will remove fields starting with prefix from event
func (ev *CGREvent) ConsumeArgDispatcher() (arg *ArgDispatcher) {
	if ev == nil {
		return
	}
	//check if we have APIKey in event and in case it has add it in ArgDispatcher
	apiKeyIface, hasApiKey := ev.Event[MetaApiKey]
	if hasApiKey {
		delete(ev.Event, MetaApiKey)
		arg = &ArgDispatcher{
			APIKey: StringPointer(apiKeyIface.(string)),
		}
	}
	//check if we have RouteID in event and in case it has add it in ArgDispatcher
	routeIDIface, hasRouteID := ev.Event[MetaRouteID]
	if !hasRouteID {
		return
	}
	delete(ev.Event, MetaRouteID)
	if !hasApiKey { //in case we don't have APIKey, but we have RouteID we need to initialize the struct
		return &ArgDispatcher{
			RouteID: StringPointer(routeIDIface.(string)),
		}
	}
	arg.RouteID = StringPointer(routeIDIface.(string))
	return
}

// CGREvents is a group of generic events processed by CGR services
// ie: derived CDRs
type CGREvents struct {
	Tenant string
	ID     string
	Time   *time.Time // event time
	Events []map[string]interface{}
}

type CGREventWithArgDispatcher struct {
	*CGREvent
	*ArgDispatcher
}

func (ev *CGREventWithArgDispatcher) Clone() (clned *CGREventWithArgDispatcher) {
	clned = &CGREventWithArgDispatcher{
		CGREvent: &CGREvent{
			Tenant: ev.Tenant,
			ID:     ev.ID,
			Event:  make(map[string]interface{}), // a bit forced but safe
		},
	}
	if ev.Time != nil {
		clned.Time = TimePointer(*ev.Time)
	}
	for k, v := range ev.Event {
		clned.Event[k] = v
	}
	if ev.ArgDispatcher != nil {
		clned.ArgDispatcher = new(ArgDispatcher)
		*clned.ArgDispatcher = *ev.ArgDispatcher
	}
	return
}