package udpdell;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import gecaoji.Device;
import zhuye.Coordinate;

public class UDPServer {
	private static final int PORT = 7000; // 默认UDP监听端口
	private static final int BUFFER_SIZE = 65507; // UDP最大包大小
	private static final int THREAD_POOL_SIZE = 100; // 线程池大小

	private static volatile Thread serverThread;

	/**
	 * 启动 UDP 服务端监听线程，线程会常驻运行直至进程结束或手动中断。
	 *
	 * @return 正在运行的监听线程
	 */
	public static synchronized Thread startAsync() {
		if (serverThread != null && serverThread.isAlive()) {
			return serverThread;
		}

		Thread thread = new Thread(UDPServer::runServerLoop, "UDPServer-Listener");
		thread.setDaemon(false); // 保持 JVM 持续存活
		thread.start();
		serverThread = thread;
		return thread;
	}

	/**
	 * 在当前线程中直接运行 UDP 服务端监听。
	 */
	public static void startSync() {
		runServerLoop();
	}

	/**
	 * 监听并处理 UDP 数据包。
	 */
	private static void runServerLoop() {
		ExecutorService executor = Executors.newFixedThreadPool(THREAD_POOL_SIZE);

		try (DatagramSocket socket = new DatagramSocket(PORT)) {
			System.out.println("UDPServer started on port " + PORT);

			while (!Thread.currentThread().isInterrupted()) {
				byte[] buffer = new byte[BUFFER_SIZE];
				DatagramPacket packet = new DatagramPacket(buffer, buffer.length);

				try {
					socket.receive(packet);
					executor.submit(new PacketProcessor(packet));
				} catch (IOException e) {
					if (!socket.isClosed()) {
						System.err.println("Error receiving packet: " + e.getMessage());
					}
				}
			}
		} catch (SocketException e) {
			System.err.println("Could not start server: " + e.getMessage());
		} finally {
			executor.shutdownNow();
		}
	}



	private static class PacketProcessor implements Runnable {
		private final DatagramPacket packet;

		public PacketProcessor(DatagramPacket packet) {
			this.packet = packet;
		}

		public void run() {
			String receivedData = new String(packet.getData(), 0, packet.getLength());
			// 处理可能的连包情况
			String[] messages = receivedData.split("\\$");

			for (String message : messages) {
				if (message.isEmpty()) continue;
				// 重新添加$符号以便统一处理
				String fullMessage = "$" + message;
				processMessage(fullMessage);
			}
		}

		private void processMessage(String message) {
			String[] fields = message.split(",");
			// 检查字段数量是否完整
			if (fields.length != 21) {
				System.err.println("Invalid message format, expected 21 fields but got " + fields.length);
				return;
			}

			// 检查包头是否正确
			if (!fields[0].equals("$GNGGA")) {
				System.err.println("Invalid message header: " + fields[0]);
				return;
			}
			System.out.println("收到了差分数据："+message);
			Coordinate.parseGNGGAToCoordinateList(message);
			int count= Coordinate.coordinates.size();
			System.out.println("savenum:"+count);

			Device.updateFromGNGGA(message, fields[15]);            
			// 打印解析后的数据
			//System.out.println("UTC时间: " + fields[1].toUpperCase());
			//System.out.println("纬度: " + fields[2].toUpperCase());
			//System.out.println("纬度半球: " + fields[3].toUpperCase());
			//System.out.println("经度: " + fields[4].toUpperCase());
			//System.out.println("经度半球: " + fields[5].toUpperCase());
			//System.out.println("定位质量指示: " + fields[6].toUpperCase());
			//System.out.println("卫星数量: " + fields[7].toUpperCase());
			//System.out.println("水平精度因子: " + fields[8].toUpperCase());
			//System.out.println("海拔高度: " + fields[9].toUpperCase());
			//System.out.println("海拔高度单位: " + fields[10].toUpperCase());
			//System.out.println("大地水准面高度: " + fields[11].toUpperCase());
			//System.out.println("大地水准面高度单位: " + fields[12].toUpperCase());
			//System.out.println("差分时间: " + fields[13].toUpperCase());
			//System.out.println("校验和: " + fields[14].toUpperCase());
			//System.out.println("设备编号: " + fields[15].toUpperCase());
			//System.out.println("设备电量: " + fields[16].toUpperCase());
			//System.out.println("卫星信号强度: " + fields[17].toUpperCase());
			//System.out.println("保留位1: " + fields[18].toUpperCase());
			//System.out.println("保留位2: " + fields[19].toUpperCase());
			//System.out.println("保留位3: " + fields[20].toUpperCase());
			//System.out.println("----------------------------------------");
		}
	}
}