package com.ruoyi.im.util;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.security.MessageDigest;
import java.util.*;

/**
 * 简化版支付工具类
 */
public class SimplePayUtil {

    private String mchId;        // 商户ID
    private String key;          // 商户密钥
    private String baseUrl;      // 支付系统基础URL

    public SimplePayUtil(String mchId, String key, String baseUrl) {
        this.mchId = mchId;
        this.key = key;
        this.baseUrl = baseUrl;
    }

    /**
     * 统一下单 - 最简单版本
     */
    public String createOrder(String productId, String orderNo, int amount, String notifyUrl) {
        try {
            // 构建参数
            Map<String, Object> params = new HashMap<>();
            params.put("mchId", mchId);
            params.put("productId", productId);
            params.put("mchOrderNo", orderNo);
            params.put("amount", amount);
            params.put("notifyUrl", notifyUrl);

            // 生成签名
            String sign = generateSign(params);
            params.put("sign", sign);

            // 发送请求
            String url = baseUrl + "/api/pay/create_order";
            String result = sendPost(url, params);

            return result;

        } catch (Exception e) {
            return "{\"retCode\":\"FAIL\",\"retMsg\":\"" + e.getMessage() + "\"}";
        }
    }

    /**
     * 查询订单 - 最简单版本
     */
    public String queryOrder(String orderNo) {
        try {
            // 构建参数
            Map<String, Object> params = new HashMap<>();
            params.put("mchId", mchId);
            params.put("mchOrderNo", orderNo);

            // 生成签名
            String sign = generateSign(params);
            params.put("sign", sign);

            // 发送请求
            String url = baseUrl + "/api/pay/query_order";
            String result = sendPost(url, params);

            return result;

        } catch (Exception e) {
            return "{\"retCode\":\"FAIL\",\"retMsg\":\"" + e.getMessage() + "\"}";
        }
    }

    /**
     * 生成签名
     */
    private String generateSign(Map<String, Object> params) throws Exception {
        // 移除sign参数
        Map<String, Object> signParams = new HashMap<>(params);
        signParams.remove("sign");

        // 过滤空值并排序
        List<String> keys = new ArrayList<>();
        for (Map.Entry<String, Object> entry : signParams.entrySet()) {
            if (entry.getValue() != null && !entry.getValue().toString().trim().isEmpty()) {
                keys.add(entry.getKey());
            }
        }

        // ASCII码排序
        Collections.sort(keys);

        // 拼接字符串
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < keys.size(); i++) {
            String key = keys.get(i);
            String value = signParams.get(key).toString();
            if (i > 0) {
                sb.append("&");
            }
            sb.append(key).append("=").append(value);
        }

        // 拼接key并MD5加密
        String stringSignTemp = sb.toString() + "&key=" + key;
        MessageDigest md = MessageDigest.getInstance("MD5");
        byte[] array = md.digest(stringSignTemp.getBytes("UTF-8"));
        StringBuilder result = new StringBuilder();
        for (byte item : array) {
            result.append(String.format("%02x", item));
        }

        return result.toString().toUpperCase();
    }

    /**
     * 发送POST请求
     */
    private String sendPost(String urlStr, Map<String, Object> params) throws Exception {
        // 构建参数字符串
        StringBuilder postData = new StringBuilder();
        for (Map.Entry<String, Object> param : params.entrySet()) {
            if (postData.length() != 0) postData.append('&');
            postData.append(URLEncoder.encode(param.getKey(), "UTF-8"));
            postData.append('=');
            postData.append(URLEncoder.encode(String.valueOf(param.getValue()), "UTF-8"));
        }

        byte[] postDataBytes = postData.toString().getBytes("UTF-8");

        URL url = new URL(urlStr);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        conn.setRequestProperty("Content-Length", String.valueOf(postDataBytes.length));
        conn.setDoOutput(true);

        // 发送数据
        OutputStream os = conn.getOutputStream();
        os.write(postDataBytes);
        os.flush();
        os.close();

        // 读取响应
        BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), "UTF-8"));
        StringBuilder response = new StringBuilder();
        String line;
        while ((line = reader.readLine()) != null) {
            response.append(line);
        }
        reader.close();

        return response.toString();
    }

    /**
     * 验证回调签名
     */
    public boolean verifyNotifySign(Map<String, String> params) {
        try {
            String receivedSign = params.get("sign");
            Map<String, Object> signParams = new HashMap<>(params);
            String calculatedSign = generateSign(signParams);
            return calculatedSign.equals(receivedSign);
        } catch (Exception e) {
            return false;
        }
    }
}