package com.dky.security;

import org.bouncycastle.jce.provider.BouncyCastleProvider;

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.nio.charset.StandardCharsets;
import java.security.Security;
import java.util.*;

public class SM4Utils {
    static {
        Security.addProvider(new BouncyCastleProvider());
    }

    private static final String SM4_KEY = "mxhXSDiPYFjYgzRb"; // 16 bytes key
    private static final String ALGORITHM = "AES/ECB/PKCS5Padding";

    public static String encrypt(Map<String, String> map) throws Exception {

        Cipher cipher = Cipher.getInstance(ALGORITHM, "BC");
        SecretKeySpec secretKey = new SecretKeySpec(SM4_KEY.getBytes(StandardCharsets.UTF_8), "AES");
        cipher.init(Cipher.ENCRYPT_MODE, secretKey);
        byte[] encrypted = cipher.doFinal(mapToString(map).getBytes(StandardCharsets.UTF_8));
        return Base64.getEncoder().encodeToString(encrypted);
    }

    public static List<Map<String, String>> decrypt(String encrypted) throws Exception {
        List<Map<String, String>> ary = new ArrayList<>();

        File file = new File("file.txt");
        FileReader fileReader = new FileReader(file);
        BufferedReader reader = new BufferedReader(fileReader);
        String line;
        while ((line = reader.readLine()) != null) {
            Cipher cipher = Cipher.getInstance(ALGORITHM, "BC");
            SecretKeySpec secretKey = new SecretKeySpec(line.getBytes(StandardCharsets.UTF_8), "AES");
            cipher.init(Cipher.DECRYPT_MODE, secretKey);
            byte[] decoded = Base64.getDecoder().decode(encrypted);
            try {
                byte[] decrypted = cipher.doFinal(decoded);
                ary.add(stringToMap(new String(decrypted, StandardCharsets.UTF_8)));
            } catch (Exception e) {
                // e.printStackTrace();
            }
        }

        return ary;
    }

    private static String mapToString(Map<String, String> map) {
        StringBuilder sb = new StringBuilder();
        for (Map.Entry<String, String> entry : map.entrySet()) {
            sb.append(entry.getKey()).append('=').append(entry.getValue()).append('&');
        }
        return sb.toString();
    }

    private static Map<String, String> stringToMap(String str) {
        Map<String, String> map = new HashMap<>();
        String[] entries = str.split("&");
        for (String entry : entries) {
            String[] keyValue = entry.split("=", 2);
            if (keyValue.length == 2) {
                map.put(keyValue[0], keyValue[1]);
            }
        }
        return map;
    }

    public static void main(String[] args) throws Exception {
        String s =
                "GWnQ4RqqTc8n1Uj59xLoUtv975fmQsRWuvsk1zRmQu9TwIvlc6FTekndKMh+vMuRbI2bxdmuIxyZndYcg9u5xVa+HaiBZRP8OZFYIAo+66vDVlkBf47Nh2srjFyIXlLH";
        List<Map<String, String>> decryptList = decrypt(s);
        decryptList.forEach(System.out::println);

        /*
        File file = new File("file.txt");
        try {
            FileReader fileReader = new FileReader(file);
            BufferedReader reader = new BufferedReader(fileReader);
            String line;
            while ((line = reader.readLine()) != null) {
                // 处理每一行的数据
                System.out.println(line);
            }
            reader.close();
        } catch (IOException e) {
            e.printStackTrace();
        }*/



    }
}