package com.tongran.agent.client.utils;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Enumeration;

public class MachineFingerprint {

    /**
     * 获取服务器硬件指纹：MD5( MAC + CPU信息 )
     */
    public static String getHardwareFingerprint() {
        StringBuilder data = new StringBuilder();

        // 1. 获取第一个非回环网卡的 MAC 地址
        String mac = getFirstValidMacAddress();
        if (mac != null) {
            data.append(mac);
            System.out.println("MAC 信息="+mac);
        } else {
            System.err.println("无法获取 MAC 地址");
        }

        // 2. 获取 CPU 信息（如 CPU 型号、序列号）
        String cpuInfo = getCpuInfo();
        if (cpuInfo != null) {
            System.out.println("CPU 信息="+cpuInfo);
            data.append(cpuInfo);
        } else {
            System.err.println("无法获取 CPU 信息");
        }
        data.append(System.currentTimeMillis());
        if (data.length() == 0) {
            return "unknown";
        }

        // 3. 生成 MD5
        return md5(data.toString());
    }

    /**
     * 获取第一个非回环、UP 状态网卡的 MAC 地址
     */
    private static String getFirstValidMacAddress() {
        try {
            Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
            while (interfaces.hasMoreElements()) {
                NetworkInterface ni = interfaces.nextElement();
                if (ni.isLoopback() || !ni.isUp()) continue;
                byte[] mac = ni.getHardwareAddress();
                if (mac != null && mac.length > 0) {
                    StringBuilder sb = new StringBuilder();
                    for (int i = 0; i < mac.length; i++) {
                        sb.append(String.format("%02X", mac[i]));
                        if (i < mac.length - 1) sb.append(":");
                    }
                    return sb.toString();
                }
            }
        } catch (SocketException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 读取 CPU 信息（CPU 型号 + 序列号，如果存在）
     */
    private static String getCpuInfo() {
        StringBuilder cpuInfo = new StringBuilder();
        try {
            Process process = Runtime.getRuntime().exec("cat /proc/cpuinfo");
            BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
            String line;
            boolean found = false;
            while ((line = reader.readLine()) != null) {
                if (line.contains("model name")) {
                    cpuInfo.append(line.split(":")[1].trim()).append(";");
                    found = true;
                }
                // 树莓派等设备有 cpu serial
                if (line.contains("Serial")) {
                    cpuInfo.append("Serial=").append(line.split(":")[1].trim());
                    found = true;
                }
                // 多数 x86 服务器没有 serial，可用 processor 数量做补充
                if (line.startsWith("processor")) {
                    // 可选：记录核心数
                }
            }
            reader.close();
            return found ? cpuInfo.toString() : null;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 生成 MD5 哈希
     */
    private static String md5(String input) {
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            byte[] digest = md.digest(input.getBytes());
            StringBuilder sb = new StringBuilder();
            for (byte b : digest) {
                sb.append(String.format("%02x", b & 0xff));
            }
            return sb.toString();
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException("MD5 算法不可用", e);
        }
    }

    // ================== 测试 ==================
    public static void main(String[] args) {
        String fingerprint = getHardwareFingerprint();
        System.out.println("服务器硬件指纹 (MD5): " + fingerprint);
    }
}