/*
==================================================================================
  Copyright (c) 2019 AT&T Intellectual Property.
  Copyright (c) 2019 Nokia

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
==================================================================================
*/

package control

import (
	"fmt"
	"gerrit.o-ran-sc.org/r/ric-plt/e2ap/pkg/e2ap"
	rtmgrclient "gerrit.o-ran-sc.org/r/ric-plt/submgr/pkg/rtmgr_client"
	"gerrit.o-ran-sc.org/r/ric-plt/submgr/pkg/xapptweaks"
	"gerrit.o-ran-sc.org/r/ric-plt/xapp-frame/pkg/models"
	"gerrit.o-ran-sc.org/r/ric-plt/xapp-frame/pkg/xapp"
	httptransport "github.com/go-openapi/runtime/client"
	"github.com/go-openapi/strfmt"
	"github.com/spf13/viper"
	"time"
)

//-----------------------------------------------------------------------------
//
//-----------------------------------------------------------------------------

func idstring(err error, entries ...fmt.Stringer) string {
	var retval string = ""
	var filler string = ""
	for _, entry := range entries {
		retval += filler + entry.String()
		filler = " "
	}
	if err != nil {
		retval += filler + "err(" + err.Error() + ")"
		filler = " "

	}
	return retval
}

//-----------------------------------------------------------------------------
//
//-----------------------------------------------------------------------------

var e2tSubReqTimeout time.Duration = 5 * time.Second
var e2tSubDelReqTime time.Duration = 5 * time.Second
var e2tMaxSubReqTryCount uint64 = 2    // Initial try + retry
var e2tMaxSubDelReqTryCount uint64 = 2 // Initial try + retry

var e2tRecvMsgTimeout time.Duration = 5 * time.Second

type Control struct {
	xapptweaks.XappWrapper
	e2ap     *E2ap
	registry *Registry
	tracker  *Tracker
	//subscriber *xapp.Subscriber
}

type RMRMeid struct {
	PlmnID  string
	EnbID   string
	RanName string
}

func init() {
	xapp.Logger.Info("SUBMGR")
	viper.AutomaticEnv()
	viper.SetEnvPrefix("submgr")
	viper.AllowEmptyEnv(true)
}

func NewControl() *Control {

	transport := httptransport.New(viper.GetString("rtmgr.HostAddr")+":"+viper.GetString("rtmgr.port"), viper.GetString("rtmgr.baseUrl"), []string{"http"})
	rtmgrClient := RtmgrClient{rtClient: rtmgrclient.New(transport, strfmt.Default)}

	registry := new(Registry)
	registry.Initialize()
	registry.rtmgrClient = &rtmgrClient

	tracker := new(Tracker)
	tracker.Init()

	//subscriber := xapp.NewSubscriber(viper.GetString("subscription.host"), viper.GetInt("subscription.timeout"))

	c := &Control{e2ap: new(E2ap),
		registry: registry,
		tracker:  tracker,
		//subscriber: subscriber,
	}
	c.XappWrapper.Init("")
	go xapp.Subscription.Listen(c.SubscriptionHandler, c.QueryHandler)
	//go c.subscriber.Listen(c.SubscriptionHandler, c.QueryHandler)
	return c
}

func (c *Control) ReadyCB(data interface{}) {
	if c.Rmr == nil {
		c.Rmr = xapp.Rmr
	}
}

func (c *Control) Run() {
	xapp.SetReadyCB(c.ReadyCB, nil)
	xapp.Run(c)
}

//-------------------------------------------------------------------
//
//-------------------------------------------------------------------
func (c *Control) SubscriptionHandler(stype models.SubscriptionType, params interface{}) (models.SubscriptionResult, error) {
	/*
	   switch p := params.(type) {
	   case *models.ReportParams:
	       trans := c.tracker.NewXappTransaction(NewRmrEndpoint(p.ClientEndpoint),"" , 0, &xapp.RMRMeid{RanName: p.Meid})
	       if trans == nil {
	             xapp.Logger.Error("XAPP-SubReq: %s", idstring(fmt.Errorf("transaction not created"), params))
	             return
	       }
	       defer trans.Release()
	   case *models.ControlParams:
	   case *models.PolicyParams:
	   }
	*/
	return models.SubscriptionResult{}, fmt.Errorf("Subscription rest interface not implemented")
}

func (c *Control) QueryHandler() (models.SubscriptionList, error) {
	return c.registry.QueryHandler()
}

//-------------------------------------------------------------------
//
//-------------------------------------------------------------------

func (c *Control) rmrSendToE2T(desc string, subs *Subscription, trans *TransactionSubs) (err error) {
	params := xapptweaks.NewParams(nil)
	params.Mtype = trans.GetMtype()
	params.SubId = int(subs.GetReqId().Seq)
	params.Xid = ""
	params.Meid = subs.GetMeid()
	params.Src = ""
	params.PayloadLen = len(trans.Payload.Buf)
	params.Payload = trans.Payload.Buf
	params.Mbuf = nil
	xapp.Logger.Info("MSG to E2T: %s %s %s", desc, trans.String(), params.String())
	return c.RmrSend(params, 5)
}

func (c *Control) rmrSendToXapp(desc string, subs *Subscription, trans *TransactionXapp) (err error) {

	params := xapptweaks.NewParams(nil)
	params.Mtype = trans.GetMtype()
	params.SubId = int(subs.GetReqId().Seq)
	params.Xid = trans.GetXid()
	params.Meid = trans.GetMeid()
	params.Src = ""
	params.PayloadLen = len(trans.Payload.Buf)
	params.Payload = trans.Payload.Buf
	params.Mbuf = nil
	xapp.Logger.Info("MSG to XAPP: %s %s %s", desc, trans.String(), params.String())
	return c.RmrSend(params, 5)
}

func (c *Control) Consume(params *xapp.RMRParams) (err error) {
	msg := xapptweaks.NewParams(params)
	if c.Rmr == nil {
		err = fmt.Errorf("Rmr object nil can handle %s", msg.String())
		xapp.Logger.Error("%s", err.Error())
		return
	}
	c.CntRecvMsg++

	defer c.Rmr.Free(msg.Mbuf)

	switch msg.Mtype {
	case xapp.RIC_SUB_REQ:
		go c.handleXAPPSubscriptionRequest(msg)
	case xapp.RIC_SUB_RESP:
		go c.handleE2TSubscriptionResponse(msg)
	case xapp.RIC_SUB_FAILURE:
		go c.handleE2TSubscriptionFailure(msg)
	case xapp.RIC_SUB_DEL_REQ:
		go c.handleXAPPSubscriptionDeleteRequest(msg)
	case xapp.RIC_SUB_DEL_RESP:
		go c.handleE2TSubscriptionDeleteResponse(msg)
	case xapp.RIC_SUB_DEL_FAILURE:
		go c.handleE2TSubscriptionDeleteFailure(msg)
	default:
		xapp.Logger.Info("Unknown Message Type '%d', discarding", msg.Mtype)
	}
	return
}

//-------------------------------------------------------------------
// handle from XAPP Subscription Request
//------------------------------------------------------------------
func (c *Control) handleXAPPSubscriptionRequest(params *xapptweaks.RMRParams) {
	xapp.Logger.Info("MSG from XAPP: %s", params.String())

	subReqMsg, err := c.e2ap.UnpackSubscriptionRequest(params.Payload)
	if err != nil {
		xapp.Logger.Error("XAPP-SubReq: %s", idstring(err, params))
		return
	}

	trans := c.tracker.NewXappTransaction(NewRmrEndpoint(params.Src), params.Xid, subReqMsg.RequestId.Seq, params.Meid)
	if trans == nil {
		xapp.Logger.Error("XAPP-SubReq: %s", idstring(fmt.Errorf("transaction not created"), params))
		return
	}
	defer trans.Release()

	err = c.tracker.Track(trans)
	if err != nil {
		xapp.Logger.Error("XAPP-SubReq: %s", idstring(err, trans))
		return
	}

	subs, err := c.registry.AssignToSubscription(trans, subReqMsg)
	if err != nil {
		xapp.Logger.Error("XAPP-SubReq: %s", idstring(err, trans))
		return
	}

	//
	// Wake subs request
	//
	go c.handleSubscriptionCreate(subs, trans)
	event, _ := trans.WaitEvent(0) //blocked wait as timeout is handled in subs side

	err = nil
	if event != nil {
		switch themsg := event.(type) {
		case *e2ap.E2APSubscriptionResponse:
			trans.Mtype, trans.Payload, err = c.e2ap.PackSubscriptionResponse(themsg)
			if err == nil {
				trans.Release()
				c.rmrSendToXapp("", subs, trans)
				return
			}
		case *e2ap.E2APSubscriptionFailure:
			trans.Mtype, trans.Payload, err = c.e2ap.PackSubscriptionFailure(themsg)
			if err == nil {
				c.rmrSendToXapp("", subs, trans)
			}
		default:
			break
		}
	}
	xapp.Logger.Info("XAPP-SubReq: failed %s", idstring(err, trans, subs))
	c.registry.RemoveFromSubscription(subs, trans, 5*time.Second)
}

//-------------------------------------------------------------------
// handle from XAPP Subscription Delete Request
//------------------------------------------------------------------
func (c *Control) handleXAPPSubscriptionDeleteRequest(params *xapptweaks.RMRParams) {
	xapp.Logger.Info("MSG from XAPP: %s", params.String())

	subDelReqMsg, err := c.e2ap.UnpackSubscriptionDeleteRequest(params.Payload)
	if err != nil {
		xapp.Logger.Error("XAPP-SubDelReq %s", idstring(err, params))
		return
	}

	trans := c.tracker.NewXappTransaction(NewRmrEndpoint(params.Src), params.Xid, subDelReqMsg.RequestId.Seq, params.Meid)
	if trans == nil {
		xapp.Logger.Error("XAPP-SubDelReq: %s", idstring(fmt.Errorf("transaction not created"), params))
		return
	}
	defer trans.Release()

	err = c.tracker.Track(trans)
	if err != nil {
		xapp.Logger.Error("XAPP-SubReq: %s", idstring(err, trans))
		return
	}

	subs, err := c.registry.GetSubscriptionFirstMatch([]uint32{trans.GetSubId()})
	if err != nil {
		xapp.Logger.Error("XAPP-SubDelReq: %s", idstring(err, trans))
		return
	}

	//
	// Wake subs delete
	//
	go c.handleSubscriptionDelete(subs, trans)
	trans.WaitEvent(0) //blocked wait as timeout is handled in subs side

	xapp.Logger.Debug("XAPP-SubDelReq: Handling event %s ", idstring(nil, trans, subs))

	// Whatever is received send ok delete response
	subDelRespMsg := &e2ap.E2APSubscriptionDeleteResponse{}
	subDelRespMsg.RequestId = subs.GetReqId().RequestId
	subDelRespMsg.FunctionId = subs.SubReqMsg.FunctionId
	trans.Mtype, trans.Payload, err = c.e2ap.PackSubscriptionDeleteResponse(subDelRespMsg)
	if err == nil {
		c.rmrSendToXapp("", subs, trans)
	}

	c.registry.RemoveFromSubscription(subs, trans, 5*time.Second)
}

//-------------------------------------------------------------------
// SUBS CREATE Handling
//-------------------------------------------------------------------
func (c *Control) handleSubscriptionCreate(subs *Subscription, parentTrans *TransactionXapp) {

	trans := c.tracker.NewSubsTransaction(subs)
	subs.WaitTransactionTurn(trans)
	defer subs.ReleaseTransactionTurn(trans)
	defer trans.Release()

	xapp.Logger.Debug("SUBS-SubReq: Handling %s ", idstring(nil, trans, subs, parentTrans))

	subRfMsg, valid := subs.GetCachedResponse()
	if subRfMsg == nil && valid == true {

		//
		// In case of failure
		// - make internal delete
		// - in case duplicate cause, retry (currently max 1 retry)
		//
		maxRetries := uint64(1)
		doRetry := true
		for retries := uint64(0); retries <= maxRetries && doRetry; retries++ {
			doRetry = false

			event := c.sendE2TSubscriptionRequest(subs, trans, parentTrans)
			switch themsg := event.(type) {
			case *e2ap.E2APSubscriptionResponse:
				subRfMsg, valid = subs.SetCachedResponse(event, true)
			case *e2ap.E2APSubscriptionFailure:
				subRfMsg, valid = subs.SetCachedResponse(event, false)
				doRetry = true
				for _, item := range themsg.ActionNotAdmittedList.Items {
					if item.Cause.Content != e2ap.E2AP_CauseContent_Ric || (item.Cause.Value != e2ap.E2AP_CauseValue_Ric_duplicate_action && item.Cause.Value != e2ap.E2AP_CauseValue_Ric_duplicate_event) {
						doRetry = false
						break
					}
				}
				xapp.Logger.Info("SUBS-SubReq: internal delete and possible retry due event(%s) retry(%t,%d/%d) %s", typeofSubsMessage(event), doRetry, retries, maxRetries, idstring(nil, trans, subs, parentTrans))
				c.sendE2TSubscriptionDeleteRequest(subs, trans, parentTrans)
			default:
				xapp.Logger.Info("SUBS-SubReq: internal delete due event(%s) %s", typeofSubsMessage(event), idstring(nil, trans, subs, parentTrans))
				subRfMsg, valid = subs.SetCachedResponse(nil, false)
				c.sendE2TSubscriptionDeleteRequest(subs, trans, parentTrans)
			}
		}

		xapp.Logger.Debug("SUBS-SubReq: Handling (e2t response %s) %s", typeofSubsMessage(subRfMsg), idstring(nil, trans, subs, parentTrans))
	} else {
		xapp.Logger.Debug("SUBS-SubReq: Handling (cached response %s) %s", typeofSubsMessage(subRfMsg), idstring(nil, trans, subs, parentTrans))
	}

	parentTrans.SendEvent(subRfMsg, 0)
}

//-------------------------------------------------------------------
// SUBS DELETE Handling
//-------------------------------------------------------------------

func (c *Control) handleSubscriptionDelete(subs *Subscription, parentTrans *TransactionXapp) {

	trans := c.tracker.NewSubsTransaction(subs)
	subs.WaitTransactionTurn(trans)
	defer subs.ReleaseTransactionTurn(trans)
	defer trans.Release()

	xapp.Logger.Debug("SUBS-SubDelReq: Handling %s", idstring(nil, trans, subs, parentTrans))

	subs.mutex.Lock()
	if subs.valid && subs.EpList.HasEndpoint(parentTrans.GetEndpoint()) && subs.EpList.Size() == 1 {
		subs.valid = false
		subs.mutex.Unlock()
		c.sendE2TSubscriptionDeleteRequest(subs, trans, parentTrans)
	} else {
		subs.mutex.Unlock()
	}

	parentTrans.SendEvent(nil, 0)
}

//-------------------------------------------------------------------
// send to E2T Subscription Request
//-------------------------------------------------------------------
func (c *Control) sendE2TSubscriptionRequest(subs *Subscription, trans *TransactionSubs, parentTrans *TransactionXapp) interface{} {
	var err error
	var event interface{} = nil
	var timedOut bool = false

	subReqMsg := subs.SubReqMsg
	subReqMsg.RequestId = subs.GetReqId().RequestId
	trans.Mtype, trans.Payload, err = c.e2ap.PackSubscriptionRequest(subReqMsg)
	if err != nil {
		xapp.Logger.Error("SUBS-SubReq: %s", idstring(err, trans, subs, parentTrans))
		return event
	}

	for retries := uint64(0); retries < e2tMaxSubReqTryCount; retries++ {
		desc := fmt.Sprintf("(retry %d)", retries)
		c.rmrSendToE2T(desc, subs, trans)
		event, timedOut = trans.WaitEvent(e2tSubReqTimeout)
		if timedOut {
			continue
		}
		break
	}
	xapp.Logger.Debug("SUBS-SubReq: Response handling event(%s) %s", typeofSubsMessage(event), idstring(nil, trans, subs, parentTrans))
	return event
}

//-------------------------------------------------------------------
// send to E2T Subscription Delete Request
//-------------------------------------------------------------------

func (c *Control) sendE2TSubscriptionDeleteRequest(subs *Subscription, trans *TransactionSubs, parentTrans *TransactionXapp) interface{} {
	var err error
	var event interface{}
	var timedOut bool

	subDelReqMsg := &e2ap.E2APSubscriptionDeleteRequest{}
	subDelReqMsg.RequestId = subs.GetReqId().RequestId
	subDelReqMsg.FunctionId = subs.SubReqMsg.FunctionId
	trans.Mtype, trans.Payload, err = c.e2ap.PackSubscriptionDeleteRequest(subDelReqMsg)
	if err != nil {
		xapp.Logger.Error("SUBS-SubDelReq: %s", idstring(err, trans, subs, parentTrans))
		return event
	}

	for retries := uint64(0); retries < e2tMaxSubDelReqTryCount; retries++ {
		desc := fmt.Sprintf("(retry %d)", retries)
		c.rmrSendToE2T(desc, subs, trans)
		event, timedOut = trans.WaitEvent(e2tSubDelReqTime)
		if timedOut {
			continue
		}
		break
	}
	xapp.Logger.Debug("SUBS-SubDelReq: Response handling event(%s) %s", typeofSubsMessage(event), idstring(nil, trans, subs, parentTrans))
	return event
}

//-------------------------------------------------------------------
// handle from E2T Subscription Reponse
//-------------------------------------------------------------------
func (c *Control) handleE2TSubscriptionResponse(params *xapptweaks.RMRParams) {
	xapp.Logger.Info("MSG from E2T: %s", params.String())
	subRespMsg, err := c.e2ap.UnpackSubscriptionResponse(params.Payload)
	if err != nil {
		xapp.Logger.Error("MSG-SubResp %s", idstring(err, params))
		return
	}
	subs, err := c.registry.GetSubscriptionFirstMatch([]uint32{subRespMsg.RequestId.Seq})
	if err != nil {
		xapp.Logger.Error("MSG-SubResp: %s", idstring(err, params))
		return
	}
	trans := subs.GetTransaction()
	if trans == nil {
		err = fmt.Errorf("Ongoing transaction not found")
		xapp.Logger.Error("MSG-SubResp: %s", idstring(err, params, subs))
		return
	}
	sendOk, timedOut := trans.SendEvent(subRespMsg, e2tRecvMsgTimeout)
	if sendOk == false {
		err = fmt.Errorf("Passing event to transaction failed: sendOk(%t) timedOut(%t)", sendOk, timedOut)
		xapp.Logger.Error("MSG-SubResp: %s", idstring(err, trans, subs))
	}
	return
}

//-------------------------------------------------------------------
// handle from E2T Subscription Failure
//-------------------------------------------------------------------
func (c *Control) handleE2TSubscriptionFailure(params *xapptweaks.RMRParams) {
	xapp.Logger.Info("MSG from E2T: %s", params.String())
	subFailMsg, err := c.e2ap.UnpackSubscriptionFailure(params.Payload)
	if err != nil {
		xapp.Logger.Error("MSG-SubFail %s", idstring(err, params))
		return
	}
	subs, err := c.registry.GetSubscriptionFirstMatch([]uint32{subFailMsg.RequestId.Seq})
	if err != nil {
		xapp.Logger.Error("MSG-SubFail: %s", idstring(err, params))
		return
	}
	trans := subs.GetTransaction()
	if trans == nil {
		err = fmt.Errorf("Ongoing transaction not found")
		xapp.Logger.Error("MSG-SubFail: %s", idstring(err, params, subs))
		return
	}
	sendOk, timedOut := trans.SendEvent(subFailMsg, e2tRecvMsgTimeout)
	if sendOk == false {
		err = fmt.Errorf("Passing event to transaction failed: sendOk(%t) timedOut(%t)", sendOk, timedOut)
		xapp.Logger.Error("MSG-SubFail: %s", idstring(err, trans, subs))
	}
	return
}

//-------------------------------------------------------------------
// handle from E2T Subscription Delete Response
//-------------------------------------------------------------------
func (c *Control) handleE2TSubscriptionDeleteResponse(params *xapptweaks.RMRParams) (err error) {
	xapp.Logger.Info("MSG from E2T: %s", params.String())
	subDelRespMsg, err := c.e2ap.UnpackSubscriptionDeleteResponse(params.Payload)
	if err != nil {
		xapp.Logger.Error("MSG-SubDelResp: %s", idstring(err, params))
		return
	}
	subs, err := c.registry.GetSubscriptionFirstMatch([]uint32{subDelRespMsg.RequestId.Seq})
	if err != nil {
		xapp.Logger.Error("MSG-SubDelResp: %s", idstring(err, params))
		return
	}
	trans := subs.GetTransaction()
	if trans == nil {
		err = fmt.Errorf("Ongoing transaction not found")
		xapp.Logger.Error("MSG-SubDelResp: %s", idstring(err, params, subs))
		return
	}
	sendOk, timedOut := trans.SendEvent(subDelRespMsg, e2tRecvMsgTimeout)
	if sendOk == false {
		err = fmt.Errorf("Passing event to transaction failed: sendOk(%t) timedOut(%t)", sendOk, timedOut)
		xapp.Logger.Error("MSG-SubDelResp: %s", idstring(err, trans, subs))
	}
	return
}

//-------------------------------------------------------------------
// handle from E2T Subscription Delete Failure
//-------------------------------------------------------------------
func (c *Control) handleE2TSubscriptionDeleteFailure(params *xapptweaks.RMRParams) {
	xapp.Logger.Info("MSG from E2T: %s", params.String())
	subDelFailMsg, err := c.e2ap.UnpackSubscriptionDeleteFailure(params.Payload)
	if err != nil {
		xapp.Logger.Error("MSG-SubDelFail: %s", idstring(err, params))
		return
	}
	subs, err := c.registry.GetSubscriptionFirstMatch([]uint32{subDelFailMsg.RequestId.Seq})
	if err != nil {
		xapp.Logger.Error("MSG-SubDelFail: %s", idstring(err, params))
		return
	}
	trans := subs.GetTransaction()
	if trans == nil {
		err = fmt.Errorf("Ongoing transaction not found")
		xapp.Logger.Error("MSG-SubDelFail: %s", idstring(err, params, subs))
		return
	}
	sendOk, timedOut := trans.SendEvent(subDelFailMsg, e2tRecvMsgTimeout)
	if sendOk == false {
		err = fmt.Errorf("Passing event to transaction failed: sendOk(%t) timedOut(%t)", sendOk, timedOut)
		xapp.Logger.Error("MSG-SubDelFail: %s", idstring(err, trans, subs))
	}
	return
}

//-------------------------------------------------------------------
//
//-------------------------------------------------------------------
func typeofSubsMessage(v interface{}) string {
	if v == nil {
		return "NIL"
	}
	switch v.(type) {
	case *e2ap.E2APSubscriptionRequest:
		return "SubReq"
	case *e2ap.E2APSubscriptionResponse:
		return "SubResp"
	case *e2ap.E2APSubscriptionFailure:
		return "SubFail"
	case *e2ap.E2APSubscriptionDeleteRequest:
		return "SubDelReq"
	case *e2ap.E2APSubscriptionDeleteResponse:
		return "SubDelResp"
	case *e2ap.E2APSubscriptionDeleteFailure:
		return "SubDelFail"
	default:
		return "Unknown"
	}
}