import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketTimeoutException;

public class TCPConnectionTester {
    
    private static final int CONNECT_TIMEOUT_MS = 3000;
    
    /**
     * 测试TCP连接
     * @param ip IP地址
     * @param port 端口号
     * @return 如果连接成功，返回true；否则返回false
     */
    public static boolean testTCPConnection(String ip, int port) {
        return testTCPConnection(ip, port, CONNECT_TIMEOUT_MS);
    }
    
    /**
     * 测试TCP连接（可自定义超时时间）
     * @param ip IP地址
     * @param port 端口号
     * @param timeoutMs 超时时间（毫秒）
     * @return 如果连接成功，返回true；否则返回false
     */
    public static boolean testTCPConnection(String ip, int port, int timeoutMs) {
        if (ip == null || ip.trim().isEmpty()) {
            throw new IllegalArgumentException("IP地址不能为空");
        }
        if (port < 1 || port > 65535) {
            throw new IllegalArgumentException("端口号必须在1-65535范围内");
        }
        
        try (Socket socket = new Socket()) {
            socket.connect(new InetSocketAddress(ip, port), timeoutMs);
            return true;
        } catch (SocketTimeoutException e) {
            System.err.println("连接超时: " + ip + ":" + port);
        } catch (IOException e) {
            System.err.println("连接失败 " + ip + ":" + port + ": " + e.getMessage());
        }
        return false;
    }
    
    /**
     * 带详细信息的测试方法
     */
    public static ConnectionResult testWithDetails(String ip, int port) {
        long startTime = System.currentTimeMillis();
        try (Socket socket = new Socket()) {
            socket.connect(new InetSocketAddress(ip, port), CONNECT_TIMEOUT_MS);
            long duration = System.currentTimeMillis() - startTime;
            return new ConnectionResult(true, duration, "连接成功");
        } catch (SocketTimeoutException e) {
            long duration = System.currentTimeMillis() - startTime;
            return new ConnectionResult(false, duration, "连接超时");
        } catch (IOException e) {
            long duration = System.currentTimeMillis() - startTime;
            return new ConnectionResult(false, duration, "连接失败: " + e.getMessage());
        }
    }
    
    // 内部结果类
    public static class ConnectionResult {
        private final boolean success;
        private final long durationMs;
        private final String message;
        
        public ConnectionResult(boolean success, long durationMs, String message) {
            this.success = success;
            this.durationMs = durationMs;
            this.message = message;
        }
        
        // getters...
        public boolean isSuccess() { return success; }
        public long getDurationMs() { return durationMs; }
        public String getMessage() { return message; }
        
        @Override
        public String toString() {
            return String.format("连接%s - 耗时: %dms - %s", 
                success ? "成功" : "失败", durationMs, message);
        }
    }
}