package com.stylefeng.guns.core.util;

import ch.qos.logback.core.encoder.Encoder;
import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.lang.StringUtils;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.util.*;


public class NotifyDemo {
    /**
     * md5秘钥
     */
    static final String md5key = "impARTxrQcfwmRijpDNCw6hPxaWCddKEpYxjaKXDhCaTCXJ6";


    /**
     * 支付通知模块，用于：在支付成功后 接受银商平台发送的支付结果通知
     */
//    @RequestMapping(value = "/notify.do", method = RequestMethod.POST)
    public String getNotify(HttpServletRequest request, HttpServletResponse response) throws Exception {

        /*接收参数*/
        Map<String, String> params = getRequestParams(request);
        System.out.println("params:" + params);
        String sign = params.get("sign");
        System.out.println(sign);

        /*验签*/
        //对通知内容生成sign
        String strSign = makeSign(md5key, params);
        //System.out.println("strSign="+strSign);
        //判断签名是否相等
        if (sign.equals(strSign)) {
            // 收到通知后记得返回SUCCESS
            System.out.println("验签通过");
            PrintWriter writer = response.getWriter();
            writer.print("SUCCESS");
            writer.flush();
        } else {
            System.out.println("验签未通过");
        }

        //更新商户系统的订单

        //跳转支付完成页面
        return "/WEB-INF/views/jsp/payResult.jsp";
    }


    // 获取HttpServletRequest里面的参数
    public static Map<String, String> getRequestParams(HttpServletRequest request) {
        Map<String, String[]> params = request.getParameterMap();
        Map<String, String> params2 = new HashMap<>();
        for (String key : params.keySet()) {
            String[] values = params.get(key);
            if (values.length > 0) {
                params2.put(key, request.getParameter(key));
            }
        }
        return params2;
    }


    public static String makeSign(String md5Key, Map<String, String> params) {

        String preStr = buildSignString(params); // 把数组所有元素，按照“参数=参数值”的模式用“&”字符拼接成字符串
        String text = preStr + md5Key;
        System.out.println("待签名字符串：" + text);
        return DigestUtils.sha256Hex(getContentBytes(text)).toUpperCase();
    }

    /**
     * 生成签名. 注意，若含有sign_type字段，必须和signType参数保持一致。
     *
     * @param data     待签名数据
     * @param key      API密钥
     * @param signType 签名方式
     * @return 签名
     */
    public static String generateSignature(final Map<String, String> data, String key, String signType) throws Exception {
        Set<String> keySet = data.keySet();
        String[] keyArray = keySet.toArray(new String[keySet.size()]);
        Arrays.sort(keyArray);
        StringBuilder sb = new StringBuilder();
        for (String k : keyArray) {
            if (k.equals("sign")) {
                continue;
            }
            if (data.get(k).trim().length() > 0) {
                // 参数值为空，则不参与签名
                sb.append(k).append("=").append(data.get(k).trim()).append("&");
            }
        }
        sb.append("key=").append(key);
        if ("HMAC-SHA256".equals(signType)) {
            return HMACSHA256(sb.toString(), key);
        } else {
            throw new Exception(String.format("Invalid sign_type: %s", signType));
        }
    }

    /**
     * 生成 HMACSHA256
     *
     * @param data 待处理数据
     * @param key  密钥
     * @return 加密结果
     * @throws Exception
     */
    public static String HMACSHA256(String data, String key) throws Exception {
        Mac sha256_HMAC = Mac.getInstance("HmacSHA256");
        SecretKeySpec secret_key = new SecretKeySpec(key.getBytes("UTF-8"), "HmacSHA256");
        sha256_HMAC.init(secret_key);
        byte[] array = sha256_HMAC.doFinal(data.getBytes("UTF-8"));
        StringBuilder sb = new StringBuilder();
        for (byte item : array) {
            sb.append(Integer.toHexString((item & 0xFF) | 0x100).substring(1, 3));
        }
        return sb.toString().toUpperCase();
    }

    // 构建签名字符串
    public static String buildSignString(Map<String, String> params) {

        // params.put("Zm","test_test");

        if (params == null || params.size() == 0) {
            return "";
        }

        List<String> keys = new ArrayList<>(params.size());

        for (String key : params.keySet()) {
            if ("sign".equals(key))
                continue;
            if (StringUtils.isEmpty(params.get(key)))
                continue;
            keys.add(key);
        }
        //System.out.println(listToString(keys));

        Collections.sort(keys);

        StringBuilder buf = new StringBuilder();

        for (int i = 0; i < keys.size(); i++) {
            String key = keys.get(i);
            String value = params.get(key);

            if (i == keys.size() - 1) {// 拼接时，不包括最后一个&字符
                buf.append(key + "=" + value);
            } else {
                buf.append(key + "=" + value + "&");
            }
        }

        return buf.toString();
    }

    // 根据编码类型获得签名内容byte[]
    public static byte[] getContentBytes(String content) {
        try {
            return content.getBytes("UTF-8");
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException("签名过程中出现错误");
        }
    }
}