package net.curisit.securis.utils;

import java.io.InputStream;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import net.curisit.securis.SeCurisException;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

/**
 * Retrieve HW info
 * 
 * @author cesarcalvo
 * 
 */
public class HWInfo {

	private static final Logger log = LogManager.getLogger(HWInfo.class);

	public static String getOsName() {
		return System.getProperty("os.name");
	}

	public static String getArch() {
		return System.getProperty("os.arch");
	}

	public static int getNumCpus() {
		return Runtime.getRuntime().availableProcessors();
	}

	/**
	 * Gets MAC address using Java. Java does not show information about down interfaces
	 * 
	 * @return
	 */
	public static List<String> getMACAddress() throws SeCurisException {
		log.info("Retrieving HW info with Java VM");
		List<byte[]> macs = new ArrayList<byte[]>();
		try {
			for (NetworkInterface network : Collections.list(NetworkInterface.getNetworkInterfaces())) {
				if (!network.isLoopback() && !network.isVirtual() && !network.isPointToPoint() && network.getHardwareAddress() != null) {
					macs.add(network.getHardwareAddress());
					log.debug("Interface added {}, MAC: {}", network.getName(), network.getHardwareAddress());
					logInterface(network);
				}
			}

			if (macs.isEmpty()) {
				throw new SeCurisException("Unable to get MAC address");
			}

			List<String> macAddresses = new ArrayList<String>();
			for (byte[] mac : macs) {
				macAddresses.add(printMacAddress(mac));
			}
			log.info("MAC Addresses: {}", macAddresses);
			return macAddresses;

		} catch (Exception e) {
			throw new SeCurisException("Unable to get MAC address", e);
		} 
	}

	/**
	 * Gets MAC address natively using ipconfig or ifconfig.
	 * @return
	 * @throws CurisException
	 */
	public static List<String> getMACAddressNatively() throws SeCurisException {
		try {
			log.info("Retrieving HW info natively");
			String output;
			if (isWindows()) {
				output = executeCommand(new String[] {"ipconfig", "/all"});
			} else {
				output = executeCommand(new String[] {"ifconfig", "-a"});
			}
			//String output = FileUtils.readFileToString(new File("/Users/cesar/Downloads/ipconfig_no_mac.txt"), "UTF-8");
			log.debug("Command output {}", output);
			List<String> macs = extractMacs(output);
			log.debug("Macs found: {}", macs);
			return macs;
		} catch (SeCurisException ce) {
			throw ce;
		}
	}
	
	/**
	 * Tries to retrieve MAC address natively, if it fails then it tries to retrieve it using Java
	 * @return
	 * @throws CurisException
	 */
	public static List<String> getMACAddressNativelyFailback() throws SeCurisException {
		try {
			return getMACAddressNatively();
		} catch (SeCurisException e) {
			log.info("Error getting HW info natively" .concat(e.getMessage()));			
			return getMACAddress();
		}
	}	
	
	/**
	 * Finds MAC in a string.  Match string like this:
	 * Unix: 60:03:08:95:ae:d0
	 * Windows: 0A-00-27-00-00-00
	 * 
	 * @param line
	 * @return
	 * @throws CurisException
	 */
	private static List<String> extractMacs(String line) throws SeCurisException {
		Pattern pattern = Pattern.compile("(?m)( )([0-9a-fA-F][0-9a-fA-F][:-]){5}([0-9a-fA-F][0-9a-fA-F])($| )");

		
		List<String> macs = new ArrayList<>();
		Matcher matcher = pattern.matcher(line);
		while(matcher.find()){
			String mac = matcher.group().trim().replaceAll(":", "-").toUpperCase();
			if (!mac.equals("00-00-00-00-00-00")) {
				macs.add(mac);
			}
		}
		
		if (macs.isEmpty()) {
			throw new SeCurisException("Mac is not found");
		}
		
		return macs;
	}	

	/**
	 * Executes the given command and return the standard output.
	 * @param command
	 * @return
	 * @throws Exception
	 */
	private static String executeCommand(String[] command) throws SeCurisException {
		try {
			Process process = new ProcessBuilder(command).start();
			InputStream is = process.getInputStream();
					
			String output = IOUtils.toString(is, "UTF-8"); 

			if (process == null || process.exitValue() != 0) {
				throw new SeCurisException(String.format("Error executing command %s", StringUtils.join(command, " ")));
			}		
			return output;
		} catch (Exception e) {
			throw new SeCurisException(String.format("Error executing command %s", StringUtils.join(command, " ")), e);
		}
	}
	
	/**
	 * Returns true is OOSS is windows
	 * @return
	 */
	public static boolean isWindows() {
		String os = System.getProperty("os.name").toLowerCase();
		return (os.indexOf("win") >= 0);
	}	

	/**
	 * Get microprocessor name
	 * 
	 * @return
	 */
	public static String getCPUName() throws SeCurisException {
		return System.getenv("PROCESSOR_IDENTIFIER");
	}

	private static void logInterface(NetworkInterface network) {
		log.debug("Interface name: {}", network.getName());
		log.debug("Interface display name: {}", network.getDisplayName());
		try {
			log.debug("Interface mac: {}", printMacAddress(network.getHardwareAddress()));
		} catch (SocketException e) {
			// Silent
		}
	}

	private static String printMacAddress(byte[] mac) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < mac.length; i++) {
			sb.append(String.format("%s%02X", (i > 0) ? "-" : "", mac[i]));
		}
		return sb.toString();

	}

}