package snmp

import (
	"fmt"

	omd "git.loafle.net/overflow/model/discovery"
	"github.com/k-sone/snmpgo"
)

var defaultPort = 161
var defaultOIDs = []string{
	"1.3.6.1.2.1.1.5.0", //sysName
}

type SNMPResponse struct {
	Host  *omd.Host
	Value map[string]string
	Error error
}

func ScanSNMP(host *omd.Host, community string, ch chan *SNMPResponse) {
	go func() {
		getV2(host, defaultPort, community, defaultOIDs, ch)
	}()
}

func getV2(host *omd.Host, port int, community string, _oids []string, ch chan *SNMPResponse) {
	address := fmt.Sprintf("%s:%d", host.Address, port)
	snmp, err := snmpgo.NewSNMP(snmpgo.SNMPArguments{
		Version:   snmpgo.V2c,
		Address:   address,
		Retries:   1,
		Community: community,
	})
	if err != nil {
		ch <- &SNMPResponse{host, nil, err}
		return
	}
	defer snmp.Close()

	oids, err := snmpgo.NewOids(_oids)
	if err != nil {
		ch <- &SNMPResponse{host, nil, err}
		return
	}

	pdu, err := snmp.GetRequest(oids)
	if err != nil {
		ch <- &SNMPResponse{host, nil, err}
		return
	}

	if pdu.ErrorStatus() != snmpgo.NoError {
		ch <- &SNMPResponse{host, nil, fmt.Errorf("%s", pdu.ErrorStatus().String())}
		return
	}

	if pdu == nil {
		ch <- &SNMPResponse{host, nil, fmt.Errorf("%s", "Empty PDU")}
		return
	}

	resMap := make(map[string]string)
	for _, val := range pdu.VarBinds() {
		resMap[val.Oid.String()] = val.Variable.String()
	}
	ch <- &SNMPResponse{host, resMap, nil}
	return
}