package com.ruoyi.im.util;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.math.BigDecimal;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.*;

@Component
public class PayService {

    @Value("${pay.mch-id}")
    private String mchId;

    @Value("${pay.key}")
    private String key;

    @Value("${pay.channelCode}")
    private String channelCode;

    @Value("${pay.base-url}")
    private String baseUrl;

    /**
     * 创建支付订单 - 适配新支付系统（修正版）
     */
    public String createOrder(BigDecimal amount, String orderNo,String payProductId,String callBackUrl) {
        try {
            Map<String, Object> params = new HashMap<>();

            // 必需参数
            params.put("userCode", mchId); // 商户号
            params.put("channelCode", payProductId); // 通道码
            params.put("orderId", orderNo); // 订单号
            params.put("orderMoney", amount); // 金额（格式化金额）
            params.put("callbackUrl", callBackUrl+"/userPolicy/notify"); // 回调地址

            // 可选参数（根据业务需要添加）
            // params.put("returnUrl", returnUrl);
            // params.put("clientIp", clientIp);
            // params.put("currency", currency);
            // params.put("gameId", gameId);
            // params.put("gameIp", gameIp);

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

            // 构建GET请求URL
            String url = buildGetUrl(baseUrl, params);

            // 发送GET请求，设置正确的Content-Type和可能的token
            return sendGet(url);

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

    /**
     * 发送GET请求 - 修正版
     */
    private String sendGet(String url) {
        try {
            HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
            connection.setRequestMethod("GET");
            connection.setConnectTimeout(10000); // 10秒连接超时
            connection.setReadTimeout(10000); // 10秒读取超时

            // 设置请求头
            connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            connection.setRequestProperty("Accept", "*/*");

            int responseCode = connection.getResponseCode();
            if (responseCode == HttpURLConnection.HTTP_OK) {
                BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
                String inputLine;
                StringBuilder response = new StringBuilder();

                while ((inputLine = in.readLine()) != null) {
                    response.append(inputLine);
                }
                in.close();

                return response.toString();
            } else {
                return "{\"retCode\":\"FAIL\",\"retMsg\":\"HTTP error code: " + responseCode + "\"}";
            }
        } catch (Exception e) {
            return "{\"retCode\":\"FAIL\",\"retMsg\":\"" + e.getMessage() + "\"}";
        }
    }

    /**
     * 新支付系统签名生成 - 最终修正版
     */
    private String generateNewSign(Map<String, Object> params) {
        try {
            // 1. 参数名ASCII码从小到大排序（字典序）
            List<String> keys = new ArrayList<>(params.keySet());
            Collections.sort(keys);

            // 2. 如果参数的值为空不参与签名
            StringBuilder stringA = new StringBuilder();
            for (String key : keys) {
                Object value = params.get(key);
                // 值为空不参与签名，且sign参数不参与签名
                if (value != null && !"".equals(value.toString().trim()) && !"sign".equals(key)) {
                    if (stringA.length() > 0) {
                        stringA.append("&");
                    }
                    stringA.append(key).append("=").append(value.toString());
                }
            }

            // 3. 在stringA最后拼接上key（根据示例，应该是直接拼接key值，没有key=前缀）
            // 示例：callbackUrl=http://baidu.com&channelCode=0000&orderId=P12312321123&orderMoney=2.01&userCode=10008&key=8c1511c3413106ac529f6ec9ad095c08
            // 注意：示例中实际上是有"&key="的，但文档描述是"在stringA最后拼接上key"
            // 按照示例，应该是：stringA + "&key=" + key
            String stringSignTemp = stringA.toString() + "&key=" + key;

            // 4. 对stringSignTemp进行MD5运算，再将得到的字符串所有字符转换为小写
            String md5Result = md5(stringSignTemp);
            return md5Result.toLowerCase();

        } catch (Exception e) {
            throw new RuntimeException("生成签名失败: " + e.getMessage());
        }
    }

    /**
     * 金额格式化（确保金额格式正确）
     */
    private String formatAmount(BigDecimal amount) {
        // 根据接口描述：金额,单位元,小数点的0可随意设置,比如100.10或100.00或100都可以
        // 这里我们统一格式化为2位小数
        return String.format("%.2f", amount);
    }

    /**
     * 构建GET请求URL
     */
    private String buildGetUrl(String baseUrl, Map<String, Object> params) {
        try {
            StringBuilder urlBuilder = new StringBuilder(baseUrl);
            boolean firstParam = true;

            for (Map.Entry<String, Object> entry : params.entrySet()) {
                if (entry.getValue() != null && !"".equals(entry.getValue().toString().trim())) {
                    if (firstParam) {
                        urlBuilder.append("?");
                        firstParam = false;
                    } else {
                        urlBuilder.append("&");
                    }
                    urlBuilder.append(URLEncoder.encode(entry.getKey(), "UTF-8"))
                            .append("=")
                            .append(URLEncoder.encode(entry.getValue().toString(), "UTF-8"));
                }
            }

            return urlBuilder.toString();
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException("构建URL失败: " + e.getMessage());
        }
    }

    /**
     * MD5加密工具方法
     */
    private String md5(String input) {
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            byte[] messageDigest = md.digest(input.getBytes(StandardCharsets.UTF_8));

            StringBuilder hexString = new StringBuilder();
            for (byte b : messageDigest) {
                String hex = Integer.toHexString(0xff & b);
                if (hex.length() == 1) {
                    hexString.append('0');
                }
                hexString.append(hex);
            }
            return hexString.toString();
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException("MD5加密失败", e);
        }
    }
    /**
     * 验证回调签名
     */
    public boolean verifySign(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;
        }
    }

    /**
     * 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());
            }
        }
        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);
        }

        // 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);
        conn.getOutputStream().write(postDataBytes);

        // 读取响应
        Scanner scanner = new Scanner(conn.getInputStream(), "UTF-8");
        String response = scanner.useDelimiter("\\A").next();
        scanner.close();
        return response;
    }
}