/*
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/cgrates/ers"
	"github.com/cgrates/cgrates/servmanager"
	"github.com/cgrates/cgrates/utils"
	"github.com/cgrates/rpcclient"
)

// NewEventReaderService returns the EventReader Service
func NewEventReaderService() servmanager.Service {
	return &EventReaderService{
		connChan: make(chan rpcclient.RpcClientConnection, 1),
		rldChan:  make(chan struct{}, 1),
	}
}

// EventReaderService implements Service interface
type EventReaderService struct {
	sync.RWMutex
	ers      *ers.ERService
	rldChan  chan struct{}
	stopChan chan struct{}
	connChan chan rpcclient.RpcClientConnection
}

// Start should handle the sercive start
func (erS *EventReaderService) Start(sp servmanager.ServiceProvider, waitCache bool) (err error) {
	if erS.IsRunning() {
		return fmt.Errorf("service aleady running")
	}

	erS.Lock()
	defer erS.Unlock()

	// remake tht stop chan
	erS.stopChan = make(chan struct{}, 1)

	utils.Logger.Info(fmt.Sprintf("<%s> starting <%s> subsystem", utils.CoreS, utils.ERs))
	var sS rpcclient.RpcClientConnection
	if sS, err = sp.GetConnection(utils.SessionS, sp.GetConfig().ERsCfg().SessionSConns); err != nil {
		utils.Logger.Crit(fmt.Sprintf("<%s> failed connecting to <%s>, error: <%s>",
			utils.ERs, utils.SessionS, err.Error()))
		return
	}
	// build the service
	erS.ers = ers.NewERService(sp.GetConfig(), sp.GetFilterS(), sS, erS.stopChan)
	go func(erS *ers.ERService, rldChan chan struct{}) {
		if err := erS.ListenAndServe(rldChan); err != nil {
			utils.Logger.Err(fmt.Sprintf("<%s> error: <%s>", utils.ERs, err.Error()))
			sp.GetExitChan() <- true
		}
	}(erS.ers, erS.rldChan)
	return
}

// GetIntenternalChan returns the internal connection chanel
func (erS *EventReaderService) GetIntenternalChan() (conn chan rpcclient.RpcClientConnection) {
	return erS.connChan
}

// Reload handles the change of config
func (erS *EventReaderService) Reload(sp servmanager.ServiceProvider) (err error) {
	var sS rpcclient.RpcClientConnection
	if sS, err = sp.GetConnection(utils.SessionS, sp.GetConfig().ERsCfg().SessionSConns); err != nil {
		utils.Logger.Crit(fmt.Sprintf("<%s> failed connecting to <%s>, error: <%s>",
			utils.ERs, utils.SessionS, err.Error()))
		return
	}
	erS.RLock()
	erS.ers.SetSessionSConnection(sS)
	erS.rldChan <- struct{}{}
	erS.RUnlock()
	return
}

// Shutdown stops the service
func (erS *EventReaderService) Shutdown() (err error) {
	erS.Lock()
	close(erS.stopChan)
	erS.ers = nil
	erS.Unlock()
	return
}

// GetRPCInterface returns the interface to register for server
func (erS *EventReaderService) GetRPCInterface() interface{} {
	return erS.ers
}

// IsRunning returns if the service is running
func (erS *EventReaderService) IsRunning() bool {
	erS.RLock()
	defer erS.RUnlock()
	return erS != nil && erS.ers != nil
}

// ServiceName returns the service name
func (erS *EventReaderService) ServiceName() string {
	return utils.ERs
}
