/**
 * Copyright (C) 2010-2017 Gordon Fraser, Andrea Arcuri and EvoSuite
 * contributors
 *
 * This file is part of EvoSuite.
 *
 * EvoSuite is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3.0 of the License, or
 * (at your option) any later version.
 *
 * EvoSuite 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
 * Lesser Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with EvoSuite. If not, see <http://www.gnu.org/licenses/>.
 */
package org.evosuite.runtime.vnet;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.util.Collections;
import java.util.List;
import java.lang.reflect.Constructor;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/**
 * Class used to store the state of a NetworkInterface.
 * Note: we cannot override NetworkInterface, and some of
 * its state is anyway not stored in its Java class (ie
 * it depends on the actual hardware, queried with native code).
 * 
 * @author arcuri
 *
 */
public class NetworkInterfaceState {

	private static final Logger logger = LoggerFactory.getLogger(NetworkInterfaceState.class);

	private final static Constructor<NetworkInterface> constructor;
	private final static Field nameField;
	private final static Field indexField;

	static{
		try {
			constructor = NetworkInterface.class.getDeclaredConstructor();
			constructor.setAccessible(true);
			nameField = NetworkInterface.class.getDeclaredField("name");
			nameField.setAccessible(true);
			indexField = NetworkInterface.class.getDeclaredField("index");
			indexField.setAccessible(true);
		} catch (NoSuchMethodException | NoSuchFieldException e) {
			//shouldn't really happen
			throw new RuntimeException("Bug: failed to init "+NetworkInterfaceState.class+": "+e.getMessage());
		}
	}
	
	private NetworkInterface ni;	
	private final List<InetAddress> localAddresses;
	private final byte[] mac;
	private final int mtu;
	private final boolean loopback;
	
	public NetworkInterfaceState(
			String name,
			int index,
			byte[] mac,
			int mtu,
			boolean loopback,
			InetAddress anAddress) {
		
		this.mtu = mtu;
		this.loopback = loopback;		
		this.mac = mac!=null ? mac.clone() : null;
		// for now, we just consider one (IPv4) address per interface
		localAddresses = Collections.singletonList(anAddress);
		
		try {
			ni = constructor.newInstance();
			nameField.set(ni, name);
			indexField.set(ni, index);
		} catch (IllegalArgumentException | InvocationTargetException | InstantiationException | IllegalAccessException | SecurityException e) {
			//shouldn't really happen
			logger.error("Reflection problems: "+e.getMessage());
		}
	}
	
	public NetworkInterface getNetworkInterface() {
		return ni;
	}

	
	public List<InetAddress> getLocalAddresses(){
		return localAddresses; 
	}

	public byte[] getMacAddr(){
		return mac!=null ? mac.clone() : null;
	}
	
	public int getMTU(){
		return mtu; 
	}

	public boolean isLoopback(){
		return loopback; 
	}

	/*
	 * For following methods we return constants.
	 * We could mock them, but not particularly important/useful
	 * for testing purposes
	 */
	
	public boolean isVirtual(){
		return false;
	}
	
	public boolean supportsMulticast(){
		return true;
	}
	
	public boolean isPointToPoint(){
		return false;
	}
	
	
	public boolean isUp(){
		return true;
	}
	
	public NetworkInterface getParent(){
		return null;
	}
}