/*
==================================================================================
  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"
	"gerrit.o-ran-sc.org/r/ric-plt/xapp-frame/pkg/xapp"
	"sync"
	"time"
)

//-----------------------------------------------------------------------------
//
//-----------------------------------------------------------------------------
type Registry struct {
	mutex       sync.Mutex
	register    map[uint16]*Subscription
	subIds      []uint16
	rtmgrClient *RtmgrClient
}

func (r *Registry) Initialize() {
	r.register = make(map[uint16]*Subscription)
	var i uint16
	for i = 0; i < 65535; i++ {
		r.subIds = append(r.subIds, i+1)
	}
}

func (r *Registry) AssignToSubscription(trans *Transaction, subReqMsg *e2ap.E2APSubscriptionRequest) (*Subscription, error) {
	r.mutex.Lock()
	defer r.mutex.Unlock()

	var sequenceNumber uint16

	//
	// Allocate subscription
	//
	if len(r.subIds) > 0 {
		sequenceNumber = r.subIds[0]
		r.subIds = r.subIds[1:]
		if _, ok := r.register[sequenceNumber]; ok == true {
			r.subIds = append(r.subIds, sequenceNumber)
			return nil, fmt.Errorf("Registry: Failed to reserves subscription")
		}
	} else {
		return nil, fmt.Errorf("Registry: Failed to reserves subscription no free ids")
	}
	subs := &Subscription{
		registry: r,
		Seq:      sequenceNumber,
		Meid:     trans.Meid,
	}

	//
	// Add to subscription
	//
	subs.mutex.Lock()
	defer subs.mutex.Unlock()

	if subs.EpList.AddEndpoint(trans.GetEndpoint()) == false {
		r.subIds = append(r.subIds, sequenceNumber)
		return nil, fmt.Errorf("Registry: Endpoint existing already in subscription")
	}
	epamount := subs.EpList.Size()

	r.mutex.Unlock()
	//
	// Subscription route updates
	//
	var err error
	if epamount == 1 {
		subRouteAction := SubRouteInfo{CREATE, subs.EpList, subs.Seq}
		err = r.rtmgrClient.SubscriptionRequestUpdate(subRouteAction)
	} else {
		subRouteAction := SubRouteInfo{UPDATE, subs.EpList, subs.Seq}
		err = r.rtmgrClient.SubscriptionRequestUpdate(subRouteAction)
	}
	r.mutex.Lock()

	if err != nil {
		r.subIds = append(r.subIds, sequenceNumber)
		return nil, err
	}
	subs.SubReqMsg = subReqMsg

	r.register[sequenceNumber] = subs
	xapp.Logger.Debug("Registry: Create %s", subs.String())
	xapp.Logger.Debug("Registry: substable=%v", r.register)
	return subs, nil
}

func (r *Registry) RemoveFromSubscription(subs *Subscription, trans *Transaction, waitRouteClean time.Duration) error {
	r.mutex.Lock()
	defer r.mutex.Unlock()
	subs.mutex.Lock()
	defer subs.mutex.Unlock()

	delStatus := subs.EpList.DelEndpoint(trans.GetEndpoint())
	epamount := subs.EpList.Size()

	//
	// If last endpoint remove from register map
	//
	if epamount == 0 {
		if _, ok := r.register[subs.Seq]; ok {
			xapp.Logger.Debug("Registry: Delete %s", subs.String())
			delete(r.register, subs.Seq)
			xapp.Logger.Debug("Registry: substable=%v", r.register)
		}
	}
	r.mutex.Unlock()

	//
	// Wait some time before really do route updates
	//
	if waitRouteClean > 0 {
		subs.mutex.Unlock()
		time.Sleep(waitRouteClean)
		subs.mutex.Lock()
	}

	xapp.Logger.Info("Registry: Cleaning %s", subs.String())

	//
	// Subscription route updates
	//
	if delStatus {
		if epamount == 0 {
			tmpList := RmrEndpointList{}
			tmpList.AddEndpoint(trans.GetEndpoint())
			subRouteAction := SubRouteInfo{DELETE, tmpList, subs.Seq}
			r.rtmgrClient.SubscriptionRequestUpdate(subRouteAction)
		} else {
			subRouteAction := SubRouteInfo{UPDATE, subs.EpList, subs.Seq}
			r.rtmgrClient.SubscriptionRequestUpdate(subRouteAction)
		}
	}

	r.mutex.Lock()
	//
	// If last endpoint free seq nro
	//
	if epamount == 0 {
		r.subIds = append(r.subIds, subs.Seq)
	}

	return nil
}

func (r *Registry) GetSubscription(sn uint16) *Subscription {
	r.mutex.Lock()
	defer r.mutex.Unlock()
	if _, ok := r.register[sn]; ok {
		return r.register[sn]
	}
	return nil
}

func (r *Registry) GetSubscriptionFirstMatch(ids []uint16) (*Subscription, error) {
	r.mutex.Lock()
	defer r.mutex.Unlock()
	for _, id := range ids {
		if _, ok := r.register[id]; ok {
			return r.register[id], nil
		}
	}
	return nil, fmt.Errorf("No valid subscription found with ids %v", ids)
}