package org.example.ssmico.demos.web.util;

import cn.hutool.core.convert.Convert;
import cn.hutool.json.JSONUtil;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.gson.*;
import org.example.ssmico.demos.web.dto.ResultDto;

import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.security.*;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.*;
import java.util.stream.Collectors;

public class RsaSigner {

    public String genSign(Map<String, Object> data, String priKey) throws NoSuchAlgorithmException, InvalidKeySpecException, SignatureException, InvalidKeyException {
        Map<String, String> stringMap = toStringMap(new GsonBuilder().create().toJson(data));
        return this.sign(this.genSignString(stringMap), priKey);
    }

    public String genSignString(Map<String, String> params) {
        if (null == params || params.size() == 0) {
            return "";
        }

        List<String> sortedKeys = new ArrayList<>(params.keySet());
        sortedKeys.remove("sign");
        sortedKeys.sort(null);
        String sb = sortedKeys.stream().map(s -> s + "=" + params.get(s)).collect(Collectors.joining("&"));

        System.out.println("genSignString = " + sb);

        return sb;
    }

    public String sign(String str, String priKey) throws NoSuchAlgorithmException, InvalidKeySpecException, InvalidKeyException, SignatureException {
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        byte[] decodedKey = Base64.getDecoder().decode(priKey.getBytes(StandardCharsets.UTF_8));
        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(decodedKey);
        PrivateKey pk = keyFactory.generatePrivate(keySpec);

        Signature signature = Signature.getInstance("MD5withRSA");
        signature.initSign(pk);
        signature.update(str.getBytes(StandardCharsets.UTF_8));
        return new String(Base64.getEncoder().encode(signature.sign()), StandardCharsets.UTF_8);
    }

    public boolean verifySign(JsonElement data, String sign, String pubKey) throws NoSuchAlgorithmException, InvalidKeySpecException, InvalidKeyException, SignatureException {
        Map<String, String> resMap = toStringMap(data);
        String signString = this.genSignString(resMap);

        byte[] keyBytes = Base64.getDecoder().decode(pubKey.getBytes(StandardCharsets.UTF_8));
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PublicKey key = keyFactory.generatePublic(keySpec);
        Signature signature = Signature.getInstance("MD5withRSA");
        signature.initVerify(key);
        signature.update(signString.getBytes(StandardCharsets.UTF_8));
        return signature.verify(Base64.getDecoder().decode(sign.getBytes(StandardCharsets.UTF_8)));
    }

    public Map<String, String> toStringMap(String str) {
        JsonParser jp = new JsonParser();
        JsonElement jEle = jp.parse(str);
        return toStringMap(jEle);
    }

    public static Map<String, String> toStringMap(JsonElement jEle) {
        Map<String, String> resMap = new HashMap<>();
        if (null != jEle && jEle.isJsonObject()) {
            for (Map.Entry<String, JsonElement> entry : jEle.getAsJsonObject().entrySet()) {
                resMap.put(entry.getKey(), valueAsString(entry.getValue()));
            }
        }
        return resMap;
    }

    public static String valueAsString(JsonElement element) {
        if (element.isJsonNull()) {
            return "";
        } else if (element.isJsonPrimitive()) {
            return element.getAsJsonPrimitive().getAsString();
        } else if (element.isJsonObject()) {
            StringBuilder sb = new StringBuilder();
            for (Map.Entry<String, JsonElement> entry : element.getAsJsonObject().entrySet()) {
                sb.append(valueAsString(entry.getValue()));
            }
            return sb.toString();
        } else if (element.isJsonArray()) {
            StringBuilder sb = new StringBuilder();
            for (JsonElement vv : element.getAsJsonArray()) {
                sb.append(valueAsString(vv));
            }
            return sb.toString();
        }
        return "";
    }

    public static String doPost(String httpUrl, String param) {
        URL url = null;
        HttpURLConnection connection = null;
        InputStream is = null;
        OutputStream os = null;
        String result = "";

        try {
            url = new URL(httpUrl);
            connection = (HttpURLConnection) url.openConnection();

            if (connection instanceof HttpsURLConnection) {
                SSLContext sc = SSLContext.getInstance("SSL");
                sc.init(null, new TrustManager[]{new X509TrustManager() {
                    @Override
                    public void checkClientTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException {}

                    @Override
                    public void checkServerTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException {}

                    @Override
                    public X509Certificate[] getAcceptedIssuers() {
                        return new X509Certificate[0];
                    }
                }}, new SecureRandom());
                ((HttpsURLConnection) connection).setSSLSocketFactory(sc.getSocketFactory());
                ((HttpsURLConnection) connection).setHostnameVerifier((hostname, session) -> true);
            }

            connection.setRequestMethod("POST");
            connection.setDoOutput(true);
            connection.setDoInput(true);
            connection.setUseCaches(false);
            connection.setRequestProperty("Content-Type", "application/json");

            os = connection.getOutputStream();
            os.write(param.getBytes());
            os.flush();

            if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
                is = connection.getInputStream();
                BufferedReader reader = new BufferedReader(new InputStreamReader(is, "UTF-8"));
                String line = null;
                while ((line = reader.readLine()) != null) {
                    result += line;
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (os != null) {
                    os.close();
                }
                if (is != null) {
                    is.close();
                }
                if (connection != null) {
                    connection.disconnect();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        return result;
    }
}