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 java.util.concurrent.atomic.AtomicInteger;

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 final AtomicInteger RECEIVED_PACKET_COUNTER = new AtomicInteger(0);

	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();
		}
	}

	public static void processIncomingMessage(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;
		}
		int sequence = incrementReceivedPacketCounter();
		System.out.println("收到了差分数据(" + sequence + ")：" + message);
		Coordinate.parseGNGGAToCoordinateList(message);
		int count = Coordinate.coordinates.size();
		System.out.println("savenum:" + count);

		Device.updateFromGNGGA(message, fields[15]);
	}
	
	/**处理串口接收到的数据*/
	public static void processSerialData(String message) {
		String[] fields = message.split(",");
		// 检查字段数量是否完整
		if (fields.length < 15) {
			System.err.println("Invalid serial GNGGA format, expected at least 15 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;
		}
		int sequence = incrementReceivedPacketCounter();
		System.out.println("收到了串口数据(" + sequence + ")：" + message);
		Coordinate.dellchuankougngga(message);
		int count = Coordinate.coordinates.size();
		System.out.println("savenum:" + count);

		Device.updateFromSerialGNGGA(message);
	}

	private static int incrementReceivedPacketCounter() {
		return RECEIVED_PACKET_COUNTER.updateAndGet(current -> {
			int next = current + 1;
			if (next > 10000 || next <= 0) {
				next = 1;
			}
			return next;
		});
	}

	public static int getReceivedPacketCount() {
		return RECEIVED_PACKET_COUNTER.get();
	}

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

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

		@Override
		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;
				processIncomingMessage(fullMessage);
			}
		}
	}
}