import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class WapiClient {
    private final String method; // "GET" or "POST"
    private final String secretType; // "MD5" or "Hash"
    private final String apiUrl;
    private final String appId;
    private final String secret;

    public WapiClient(String method, String secretType, String apiUrl, String appId, String secret) {
        this.method = method;
        this.secretType = secretType;
        this.apiUrl = apiUrl;
        this.appId = appId;
        this.secret = secret;
    }

    public String makeRequest(Map<String, String> params) throws Exception {
        // Add required parameters
        Map<String, String> data = new HashMap<>(params);
        data.put("appid", appId);
        data.put("time", String.valueOf(System.currentTimeMillis() / 1000));

        // Generate signature
        String sign;
        if ("MD5".equalsIgnoreCase(secretType)) {
            sign = generateMd5Signature(data);
        } else {
            // Default to MD5 if secretType is not recognized
            sign = this.secret;
        }
        data.put("sign", sign);

        if ("GET".equalsIgnoreCase(method)) {
            return sendGetRequest(data);
        } else {
            return sendPostRequest(data);
        }
    }

    private String generateMd5Signature(Map<String, String> data) throws Exception {
        // Sort keys alphabetically
        List<String> keys = new ArrayList<>(data.keySet());
        Collections.sort(keys);

        // Build the string to hash
        StringBuilder sb = new StringBuilder();
        for (String key : keys) {
            String value = data.get(key);
            if (value != null && !value.isEmpty()) {
                sb.append(key).append(value);
            }
        }
        sb.append(secret);

        // Calculate MD5 hash
        MessageDigest md = MessageDigest.getInstance("MD5");
        byte[] hashBytes = md.digest(sb.toString().getBytes(StandardCharsets.UTF_8));

        // Convert byte array to hex string
        StringBuilder hexString = new StringBuilder();
        for (byte b : hashBytes) {
            String hex = Integer.toHexString(0xff & b);
            if (hex.length() == 1) {
                hexString.append('0');
            }
            hexString.append(hex);
        }

        return hexString.toString();
    }

    private String sendGetRequest(Map<String, String> data) throws Exception {
        // Build query string
        StringBuilder queryString = new StringBuilder();
        for (Map.Entry<String, String> entry : data.entrySet()) {
            if (queryString.length() > 0) {
                queryString.append("&");
            }
            queryString.append(URLEncoder.encode(entry.getKey(), "UTF-8"))
                      .append("=")
                      .append(URLEncoder.encode(entry.getValue(), "UTF-8"));
        }

        URL url = new URL(apiUrl + "?" + queryString);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("GET");

        // Read response
        try (BufferedReader reader = new BufferedReader(
                new InputStreamReader(conn.getInputStream(), StandardCharsets.UTF_8))) {
            StringBuilder response = new StringBuilder();
            String line;
            while ((line = reader.readLine()) != null) {
                response.append(line);
            }
            return response.toString();
        }
    }

    private String sendPostRequest(Map<String, String> data) throws Exception {
        // Build form data
        StringBuilder formData = new StringBuilder();
        for (Map.Entry<String, String> entry : data.entrySet()) {
            if (formData.length() > 0) {
                formData.append("&");
            }
            formData.append(URLEncoder.encode(entry.getKey(), "UTF-8"))
                   .append("=")
                   .append(URLEncoder.encode(entry.getValue(), "UTF-8"));
        }

        URL url = new URL(apiUrl);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=utf-8");
        conn.setDoOutput(true);

        // Write form data
        conn.getOutputStream().write(formData.toString().getBytes(StandardCharsets.UTF_8));

        // Read response
        try (BufferedReader reader = new BufferedReader(
                new InputStreamReader(conn.getInputStream(), StandardCharsets.UTF_8))) {
            StringBuilder response = new StringBuilder();
            String line;
            while ((line = reader.readLine()) != null) {
                response.append(line);
            }
            return response.toString();
        }
    }

    public static void main(String[] args) {
        // Configuration - replace with your actual values
        String method = "GET"; // "GET" or "POST"
        String secretType = "MD5"; // 验证方式MD5,Hash 通过后台我的应用(https://www.wapi.cn/member/my_apply.html)去修改
        String apiUrl = "https://登录后显示/api/22/128";
        String appId = "应用id"; // 通过后台我的应用(https://www.wapi.cn/member/my_apply.html)
        String secret = "应用密钥"; // Replace with your secret key

        // Request parameters
        Map<String, String> params = new HashMap<>();
                            params.put("appid", "1");
                            params.put("date", "2021-08-17");
                            params.put("format", "json");
                            params.put("time", "1545829466")

        WapiClient client = new WapiClient(method, secretType, apiUrl, appId, secret);
        
        try {
            String result = client.makeRequest(params);
            System.out.println("API Response:");
            System.out.println(result);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}