/*
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 engine

import (
	"fmt"

	"github.com/cgrates/cgrates/config"
	"github.com/cgrates/cgrates/utils"
	"github.com/cgrates/rpcclient"
)

// NewConnManager returns the Connection Manager
func NewConnManager(cfg *config.CGRConfig, rpcInternal map[string]chan rpcclient.ClientConnector) (cM *ConnManager) {
	cM = &ConnManager{cfg: cfg, rpcInternal: rpcInternal}
	SetConnManager(cM)
	return
}

// ConnManager handle the RPC connections
type ConnManager struct {
	cfg         *config.CGRConfig
	rpcInternal map[string]chan rpcclient.ClientConnector
}

// getConn is used to retrieve a connection from cache
// in case this doesn't exist create it and cache it
func (cM *ConnManager) getConn(connID string, biRPCClient rpcclient.ClientConnector) (conn rpcclient.ClientConnector, err error) {
	//try to get the connection from cache
	if x, ok := Cache.Get(utils.CacheRPCConnections, connID); ok {
		if x == nil {
			return nil, utils.ErrNotFound
		}
		return x.(rpcclient.ClientConnector), nil
	}
	// in case we don't find in cache create the connection and add this in cache
	var intChan chan rpcclient.ClientConnector
	var connCfg *config.RPCConn
	isBiRPCCLient := false
	if internalChan, has := cM.rpcInternal[connID]; has {
		connCfg = cM.cfg.RPCConns()[utils.MetaInternal]
		intChan = internalChan
		isBiRPCCLient = true
	} else {
		connCfg = cM.cfg.RPCConns()[connID]
	}
	var conPool *rpcclient.RPCPool
	if conPool, err = NewRPCPool(connCfg.Strategy,
		cM.cfg.TlsCfg().ClientKey,
		cM.cfg.TlsCfg().ClientCerificate, cM.cfg.TlsCfg().CaCertificate,
		cM.cfg.GeneralCfg().ConnectAttempts, cM.cfg.GeneralCfg().Reconnects,
		cM.cfg.GeneralCfg().ConnectTimeout, cM.cfg.GeneralCfg().ReplyTimeout,
		connCfg.Conns, intChan, false); err != nil {
		return
	}
	conn = conPool
	if biRPCClient != nil && isBiRPCCLient { // special handling for SessionS BiJSONRPCClient
		var rply string
		sSIntConn := <-intChan
		intChan <- sSIntConn
		conn = utils.NewBiRPCInternalClient(sSIntConn.(utils.BiRPCServer))
		conn.(*utils.BiRPCInternalClient).SetClientConn(biRPCClient)
		if err = conn.Call(utils.SessionSv1RegisterInternalBiJSONConn,
			utils.EmptyString, &rply); err != nil {
			utils.Logger.Crit(fmt.Sprintf("<%s> Could not register biRPCClient, error: <%s>",
				utils.SessionS, err.Error()))
			return
		}
	}
	Cache.Set(utils.CacheRPCConnections, connID, conn, nil,
		true, utils.NonTransactional)
	return
}

// Call gets the connection calls the method on it
func (cM *ConnManager) Call(connIDs []string, biRPCClient rpcclient.ClientConnector,
	method string, arg, reply interface{}) (err error) {
	if len(connIDs) == 0 {
		return utils.NewErrMandatoryIeMissing("connIDs")
	}
	var conn rpcclient.ClientConnector
	for _, connID := range connIDs {
		if conn, err = cM.getConn(connID, biRPCClient); err != nil {
			continue
		}
		if err = conn.Call(method, arg, reply); rpcclient.IsNetworkError(err) {
			continue
		} else {
			return
		}
	}
	return
}