/*
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 services

import (
	"fmt"
	"sync"

	"github.com/cgrates/birpc"
	"github.com/cgrates/birpc/context"
	"github.com/cgrates/cgrates/commonlisteners"
	"github.com/cgrates/cgrates/config"
	"github.com/cgrates/cgrates/ees"
	"github.com/cgrates/cgrates/engine"
	"github.com/cgrates/cgrates/servmanager"
	"github.com/cgrates/cgrates/utils"
)

// NewEventExporterService constructs EventExporterService
func NewEventExporterService(cfg *config.CGRConfig, filterSChan chan *engine.FilterS,
	connMgr *engine.ConnManager, clSChan chan *commonlisteners.CommonListenerS, intConnChan chan birpc.ClientConnector,
	anzChan chan *AnalyzerService, srvDep map[string]*sync.WaitGroup,
	srvIndexer *servmanager.ServiceIndexer) servmanager.Service {
	return &EventExporterService{
		cfg:         cfg,
		filterSChan: filterSChan,
		connMgr:     connMgr,
		clSChan:     clSChan,
		intConnChan: intConnChan,
		anzChan:     anzChan,
		srvDep:      srvDep,
		srvIndexer:  srvIndexer,
		stateDeps:   NewStateDependencies([]string{utils.StateServiceUP}),
	}
}

// EventExporterService is the service structure for EventExporterS
type EventExporterService struct {
	mu sync.RWMutex

	clSChan     chan *commonlisteners.CommonListenerS
	anzChan     chan *AnalyzerService
	filterSChan chan *engine.FilterS

	eeS *ees.EeS
	cl  *commonlisteners.CommonListenerS

	intConnChan chan birpc.ClientConnector
	connMgr     *engine.ConnManager
	cfg         *config.CGRConfig
	srvDep      map[string]*sync.WaitGroup

	intRPCconn birpc.ClientConnector       // expose API methods over internal connection
	srvIndexer *servmanager.ServiceIndexer // access directly services from here
	stateDeps  *StateDependencies          // channel subscriptions for state changes
}

// ServiceName returns the service name
func (es *EventExporterService) ServiceName() string {
	return utils.EEs
}

// ShouldRun returns if the service should be running
func (es *EventExporterService) ShouldRun() (should bool) {
	return es.cfg.EEsCfg().Enabled
}

// IsRunning returns if the service is running
func (es *EventExporterService) IsRunning() bool {
	es.mu.RLock()
	defer es.mu.RUnlock()
	return es.eeS != nil
}

// Reload handles the change of config
func (es *EventExporterService) Reload(*context.Context, context.CancelFunc) error {
	es.mu.Lock()
	defer es.mu.Unlock()
	es.eeS.ClearExporterCache()
	return es.eeS.SetupExporterCache()
}

// Shutdown stops the service
func (es *EventExporterService) Shutdown() error {
	es.mu.Lock()
	defer es.mu.Unlock()
	utils.Logger.Info(fmt.Sprintf("<%s> shutdown <%s>", utils.CoreS, utils.EEs))
	es.eeS.ClearExporterCache()
	es.eeS = nil
	<-es.intConnChan
	es.cl.RpcUnregisterName(utils.EeSv1)
	return nil
}

// Start should handle the service start
func (es *EventExporterService) Start(ctx *context.Context, _ context.CancelFunc) error {
	if es.IsRunning() {
		return utils.ErrServiceAlreadyRunning
	}

	es.cl = <-es.clSChan
	es.clSChan <- es.cl
	fltrS, err := waitForFilterS(ctx, es.filterSChan)
	if err != nil {
		return err
	}
	anz := <-es.anzChan
	es.anzChan <- anz

	utils.Logger.Info(fmt.Sprintf("<%s> starting <%s> subsystem", utils.CoreS, utils.EEs))

	es.mu.Lock()
	defer es.mu.Unlock()

	es.eeS, err = ees.NewEventExporterS(es.cfg, fltrS, es.connMgr)
	if err != nil {
		return err
	}

	srv, _ := engine.NewServiceWithPing(es.eeS, utils.EeSv1, utils.V1Prfx)
	// srv, _ := birpc.NewService(es.rpc, "", false)
	if !es.cfg.DispatcherSCfg().Enabled {
		es.cl.RpcRegister(srv)
	}

	es.intRPCconn = anz.GetInternalCodec(srv, utils.EEs)
	es.intConnChan <- es.intRPCconn
	close(es.stateDeps.StateChan(utils.StateServiceUP))
	return nil
}

// StateChan returns signaling channel of specific state
func (es *EventExporterService) StateChan(stateID string) chan struct{} {
	return es.stateDeps.StateChan(stateID)
}

// IntRPCConn returns the internal connection used by RPCClient
func (es *EventExporterService) IntRPCConn() birpc.ClientConnector {
	return es.intRPCconn
}