/*
 * Copyright (c) 2010-2012 Grid Dynamics Consulting Services, Inc, All Rights Reserved
 * http://www.griddynamics.com
 *
 * This library is free software; you can redistribute it and/or modify it under the terms of
 * the Apache License; either
 * version 2.0 of the License, or any later version.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.griddynamics.jagger.agent.impl;

import org.snmp4j.CommunityTarget;
import org.snmp4j.PDU;
import org.snmp4j.Snmp;
import org.snmp4j.Target;
import org.snmp4j.TransportMapping;
import org.snmp4j.event.ResponseEvent;
import org.snmp4j.mp.SnmpConstants;
import org.snmp4j.smi.Address;
import org.snmp4j.smi.GenericAddress;
import org.snmp4j.smi.OID;
import org.snmp4j.smi.OctetString;
import org.snmp4j.smi.VariableBinding;
import org.snmp4j.transport.DefaultUdpTransportMapping;

import java.io.IOException;
import java.util.Arrays;
import java.util.List;

/**
 * User: dkotlyarov
 */
public class SNMPProvider {
    private final String address;
    private final Snmp snmp;

    public SNMPProvider(String address) {
        try {
            this.address = address;
            TransportMapping transport = new DefaultUdpTransportMapping();
            this.snmp = new Snmp(transport);
            transport.listen();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public String getAddress() {
        return address;
    }

    public int getAsInt(OID oid) throws IOException {
        ResponseEvent event = get(Arrays.asList(oid));
        return event.getResponse().get(0).getVariable().toInt();
    }

    public long getAsLong(OID oid) throws IOException {
        ResponseEvent event = get(Arrays.asList(oid));
        return event.getResponse().get(0).getVariable().toLong();
    }

    public String getAsString(OID oid) throws IOException {
        ResponseEvent event = get(Arrays.asList(oid));
        return event.getResponse().get(0).getVariable().toString();
    }

    public ResponseEvent get(List<OID> oids) throws IOException {
        PDU pdu = new PDU();
        for (OID oid : oids) {
            pdu.add(new VariableBinding(oid));
        }
        pdu.setType(PDU.GET);
        ResponseEvent event = snmp.send(pdu, getTarget(), null);
        if(event != null) {
            return event;
        }
        throw new RuntimeException("GET timed out");
    }

    private Target getTarget() {
        Address targetAddress = GenericAddress.parse(address);
        CommunityTarget target = new CommunityTarget();
        target.setCommunity(new OctetString("public"));
        target.setAddress(targetAddress);
        target.setRetries(2);
        target.setTimeout(1500);
        target.setVersion(SnmpConstants.version2c);
        return target;
    }
}