/*
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/engine"
	"github.com/cgrates/cgrates/servmanager"
	"github.com/cgrates/cgrates/utils"
)

// NewStatService returns the Stat Service
func NewStatService(cfg *config.CGRConfig, dm *DataDBService,
	cacheS *CacheService, filterSChan chan *engine.FilterS,
	clSChan chan *commonlisteners.CommonListenerS, internalStatSChan chan birpc.ClientConnector,
	connMgr *engine.ConnManager, anzChan chan *AnalyzerService,
	srvDep map[string]*sync.WaitGroup,
	srvIndexer *servmanager.ServiceIndexer) servmanager.Service {
	return &StatService{
		connChan:    internalStatSChan,
		cfg:         cfg,
		dm:          dm,
		cacheS:      cacheS,
		filterSChan: filterSChan,
		clSChan:     clSChan,
		connMgr:     connMgr,
		anzChan:     anzChan,
		srvDep:      srvDep,
		srvIndexer:  srvIndexer,
		stateDeps:   NewStateDependencies([]string{utils.StateServiceUP}),
	}
}

// StatService implements Service interface
type StatService struct {
	sync.RWMutex

	clSChan     chan *commonlisteners.CommonListenerS
	dm          *DataDBService
	anzChan     chan *AnalyzerService
	cacheS      *CacheService
	filterSChan chan *engine.FilterS

	sts *engine.StatS
	cl  *commonlisteners.CommonListenerS

	connChan 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
}

// Start should handle the sercive start
func (sts *StatService) Start(ctx *context.Context, _ context.CancelFunc) (err error) {
	if sts.IsRunning() {
		return utils.ErrServiceAlreadyRunning
	}

	sts.srvDep[utils.DataDB].Add(1)
	sts.cl = <-sts.clSChan
	sts.clSChan <- sts.cl
	if err = sts.cacheS.WaitToPrecache(ctx,
		utils.CacheStatQueueProfiles,
		utils.CacheStatQueues,
		utils.CacheStatFilterIndexes); err != nil {
		return
	}
	var filterS *engine.FilterS
	if filterS, err = waitForFilterS(ctx, sts.filterSChan); err != nil {
		return
	}
	var datadb *engine.DataManager
	if datadb, err = sts.dm.WaitForDM(ctx); err != nil {
		return
	}
	anz := <-sts.anzChan
	sts.anzChan <- anz

	sts.Lock()
	defer sts.Unlock()
	sts.sts = engine.NewStatService(datadb, sts.cfg, filterS, sts.connMgr)

	utils.Logger.Info(fmt.Sprintf("<%s> starting <%s> subsystem",
		utils.CoreS, utils.StatS))
	sts.sts.StartLoop(ctx)
	srv, _ := engine.NewService(sts.sts)
	// srv, _ := birpc.NewService(apis.NewStatSv1(sts.sts), "", false)
	if !sts.cfg.DispatcherSCfg().Enabled {
		for _, s := range srv {
			sts.cl.RpcRegister(s)
		}
	}
	sts.intRPCconn = anz.GetInternalCodec(srv, utils.StatS)
	sts.connChan <- sts.intRPCconn
	close(sts.stateDeps.StateChan(utils.StateServiceUP))
	return
}

// Reload handles the change of config
func (sts *StatService) Reload(ctx *context.Context, _ context.CancelFunc) (err error) {
	sts.Lock()
	sts.sts.Reload(ctx)
	sts.Unlock()
	return
}

// Shutdown stops the service
func (sts *StatService) Shutdown() (err error) {
	defer sts.srvDep[utils.DataDB].Done()
	sts.Lock()
	defer sts.Unlock()
	sts.sts.Shutdown(context.TODO())
	sts.sts = nil
	<-sts.connChan
	sts.cl.RpcUnregisterName(utils.StatSv1)
	return
}

// IsRunning returns if the service is running
func (sts *StatService) IsRunning() bool {
	sts.RLock()
	defer sts.RUnlock()
	return sts.sts != nil
}

// ServiceName returns the service name
func (sts *StatService) ServiceName() string {
	return utils.StatS
}

// ShouldRun returns if the service should be running
func (sts *StatService) ShouldRun() bool {
	return sts.cfg.StatSCfg().Enabled
}

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

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