package com.its.api.utils;

import io.netty.channel.Channel;

import java.net.*;
import java.util.ArrayList;
import java.util.Enumeration;

public final class NettyUtils {

    public static String getTcpAddress(Channel ch) {
        String localIp = "local-unknown";
        String remoteIp = "remote-unknown";
        int localPort = 0;
        int remotePort = 0;
        InetSocketAddress localAddr = (InetSocketAddress)ch.localAddress();
        if (localAddr != null) {
            localIp = localAddr.getAddress().getHostAddress();
            localPort = localAddr.getPort();
        }

        InetSocketAddress remoteAddr = (InetSocketAddress)ch.remoteAddress();
        if (remoteAddr != null) {
            remoteIp = remoteAddr.getAddress().getHostAddress();
            remotePort = remoteAddr.getPort();
        }
        return "[Local #(" + localIp + ":" + localPort + ") Remote #(" + remoteIp + ":" + remotePort + ")]";
    }
    public static String getRemoteAddress(Channel ch) {
        String ip = getRemoteIpAddress(ch);
        int  port = getRemotePort(ch);
        return "[Remote #(" + ip + ":" + port + ")]";
    }

    public static String getLocalAddress(Channel ch) {
        String ip = getLocalIpAddress(ch);
        int  port = getLocalPort(ch);
        return "[Local #(" + ip + ":" + port + ")]";
    }

    public static String getRemoteIpAddress(Channel ch) {
        String ip = "unknown";
        InetSocketAddress inetAddr = (InetSocketAddress)ch.remoteAddress();
        if (inetAddr != null) {
            ip = inetAddr.getAddress().getHostAddress();
        }
        return ip;
    }

    public static int getRemotePort(Channel ch) {
        int port = 0;
        InetSocketAddress inetAddr = (InetSocketAddress)ch.remoteAddress();
        if (inetAddr != null)
            port = inetAddr.getPort();
        return port;
    }

    public static String getLocalIpAddress(Channel ch) {
        String ip = "unknown";
        InetSocketAddress inetAddr = (InetSocketAddress)ch.localAddress();
        if (inetAddr != null) {
            ip = inetAddr.getAddress().getHostAddress();
        }
        return ip;
    }

    public static int getLocalPort(Channel ch) {
        int port = 0;
        InetSocketAddress inetAddr = (InetSocketAddress)ch.localAddress();
        if (inetAddr != null)
            port = inetAddr.getPort();
        return port;
    }

    public static final String OS_NAME = System.getProperty("os.name");
    private static boolean isLinuxPlatform = false;
    private static boolean isWindowsPlatform = false;

    static {
        if (OS_NAME != null && OS_NAME.toLowerCase().contains("linux")) {
            isLinuxPlatform = true;
        }

        if (OS_NAME != null && OS_NAME.toLowerCase().contains("windows")) {
            isWindowsPlatform = true;
        }
    }

    public static String getLocalAddress() {
        try {
            // Traversal Network interface to get the first non-loopback and non-private address
            Enumeration<NetworkInterface> enumeration = NetworkInterface.getNetworkInterfaces();
            ArrayList<String> ipv4Result = new ArrayList<String>();
            ArrayList<String> ipv6Result = new ArrayList<String>();
            while (enumeration.hasMoreElements()) {
                final NetworkInterface networkInterface = enumeration.nextElement();
                final Enumeration<InetAddress> en = networkInterface.getInetAddresses();
                while (en.hasMoreElements()) {
                    final InetAddress address = en.nextElement();
                    if (!address.isLoopbackAddress()) {
                        if (address instanceof Inet6Address) {
                            ipv6Result.add(normalizeHostAddress(address));
                        } else {
                            ipv4Result.add(normalizeHostAddress(address));
                        }
                    }
                }
            }

            // prefer ipv4
            if (!ipv4Result.isEmpty()) {
                for (String ip : ipv4Result) {
                    if (ip.startsWith("127.0") || ip.startsWith("192.168")) {
                        continue;
                    }

                    return ip;
                }

                return ipv4Result.get(ipv4Result.size() - 1);
            } else if (!ipv6Result.isEmpty()) {
                return ipv6Result.get(0);
            }
            //If failed to find,fall back to localhost
            final InetAddress localHost = InetAddress.getLocalHost();
            return normalizeHostAddress(localHost);
        } catch (Exception e) {
        }

        return null;
    }

    public static String normalizeHostAddress(final InetAddress localHost) {
        if (localHost instanceof Inet6Address) {
            return "[" + localHost.getHostAddress() + "]";
        } else {
            return localHost.getHostAddress();
        }
    }

    public static SocketAddress string2SocketAddress(final String addr) {
        String[] s = addr.split(":");
        InetSocketAddress isa = new InetSocketAddress(s[0], Integer.parseInt(s[1]));
        return isa;
    }

    public static String socketAddress2String(final SocketAddress addr) {
        StringBuilder sb = new StringBuilder();
        InetSocketAddress inetSocketAddress = (InetSocketAddress) addr;
        sb.append(inetSocketAddress.getAddress().getHostAddress());
        sb.append(":");
        sb.append(inetSocketAddress.getPort());
        return sb.toString();
    }

    public static String parseChannelRemoteAddr(final Channel channel) {
        if (null == channel) {
            return "";
        }
        SocketAddress remote = channel.remoteAddress();
        final String addr = remote != null ? remote.toString() : "";

        if (addr.length() > 0) {
            int index = addr.lastIndexOf("/");
            if (index >= 0) {
                return addr.substring(index + 1);
            }

            return addr;
        }

        return "";
    }

    public static String parseSocketAddressAddr(SocketAddress socketAddress) {
        if (socketAddress != null) {
            final String addr = socketAddress.toString();

            if (addr.length() > 0) {
                return addr.startsWith("/") ? addr.substring(1) : addr;
            }
        }
        return "";
    }
}