package publicsWay;

import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;

// ÖØÃüÃûΪPacketParser£¬±íʾÊý¾Ý°ü½âÎöÆ÷
public class PacketParser {
	// Ìí¼ÓÊ®Áù½øÖÆ×Ö·ûÊý×é³£Á¿
	private static final char[] HEX_ARRAY = "0123456789ABCDEF".toCharArray();
	// »º³åÇø×Ö½ÚÊý×é
	private byte[] buffer = new byte[4096];
	// µ±Ç°»º³åÇøÓÐЧÊý¾Ý³¤¶È
	private int bufferLength = 0;

	// ×·¼ÓÐÂÊý¾Ýµ½»º³åÇø
	public void appendData(byte[] newData, int length) {
		// ¼ì²é»º³åÇøÊÇ·ñ×ã¹»
		if (bufferLength + length > buffer.length) {
			// ´´½¨Ðµĸü´ó»º³åÇø
			byte[] newBuffer = new byte[bufferLength + length];
			// ¸´ÖÆÔ­ÓÐÊý¾Ý
			System.arraycopy(buffer, 0, newBuffer, 0, bufferLength);
			buffer = newBuffer;
		}
		// ×·¼ÓÐÂÊý¾Ý
		System.arraycopy(newData, 0, buffer, bufferLength, length);
		// ¸üлº³åÇø³¤¶È
		bufferLength += length;
	}

	// ÐÂÔö·½·¨£º×Ö½ÚÊý×éתʮÁù½øÖÆ×Ö·û´®
	public static String bytesToHexString(byte[] bytes) {
		if (bytes == null) return "";
		char[] hexChars = new char[bytes.length * 2];
		for (int j = 0; j < bytes.length; j++) {
			int v = bytes[j] & 0xFF;
			hexChars[j * 2] = HEX_ARRAY[v >>> 4];
			hexChars[j * 2 + 1] = HEX_ARRAY[v & 0x0F];
		}
		return new String(hexChars);
	}

	// ½âÎö»º³åÇøÖеÄËùÓÐÍêÕûÊý¾Ý°ü
	public List<DataPacket> parsePackets() {
		List<DataPacket> packets = new ArrayList<>();
		int index = 0;  // µ±Ç°½âÎöλÖÃË÷Òý

		// ±éÀú»º³åÇø²éÕÒÍêÕûÊý¾Ý°ü
		while (index <= bufferLength - 4) { // È·±£ÓÐ×ã¹»Êý¾Ý¼ì²é°üÍ·
			// ¼ì²é°üÍ·±êʶ 0x55 0xAA
			if (buffer[index] == 0x55 && (buffer[index + 1] & 0xFF) == 0xAA) {
				// »ñÈ¡°üÀàÐÍ£¨µÚ3×Ö½Ú£©
				int packetType = buffer[index + 2] & 0xFF;
				// »ñÈ¡Êý¾Ý³¤¶È£¨µÚ4×Ö½Ú£©
				int dataLenField = buffer[index + 3] & 0xFF;
				// ¼ÆËãÍêÕû°ü³¤¶È£¨°üÍ·+Êý¾Ý+УÑ飩
				int totalPacketLen = 2 + dataLenField + 2;  // Ôö¼Ó2×Ö½ÚУÑéλ

				// ¼ì²éÊÇ·ñÓÐ×ã¹»Êý¾Ý¹¹³ÉÍêÕû°ü
				if (index + totalPacketLen > bufferLength) {
					break; // Êý¾Ý²»×㣬µÈ´ý¸ü¶àÊý¾Ý
				}

				// ÌáÈ¡ÍêÕûÊý¾Ý°ü
				byte[] packetData = new byte[totalPacketLen];
				System.arraycopy(buffer, index, packetData, 0, totalPacketLen);

				// Ñé֤УÑéºÍ
				if (verifyChecksum(packetData)) {
					// ½âÎöµ¥¸öÊý¾Ý°ü
					DataPacket packet = parseSinglePacket(packetType, packetData);
					if (packet != null) {
						packets.add(packet); // Ìí¼Óµ½½á¹ûÁбí
					}
					index += totalPacketLen; // Òƶ¯µ½ÏÂÒ»¸ö°ü
				} else {
					index++; // УÑéʧ°Ü£¬Ìø¹ýµ±Ç°×Ö½Ú
				}
			} else {
				index++; // ·Ç°üÍ·±êʶ£¬¼ÌÐø²éÕÒ
			}
		}

		// ÇåÀíÒÑ´¦ÀíÊý¾Ý
		if (index > 0) {
			int remaining = bufferLength - index;
			if (remaining > 0) {
				// Òƶ¯Ê£ÓàÊý¾Ýµ½»º³åÇø¿ªÍ·
				System.arraycopy(buffer, index, buffer, 0, remaining);
			}
			bufferLength = remaining; // ¸üлº³åÇø³¤¶È
		}

		return packets;
	}

	// УÑéÊý¾Ý°ü
	private boolean verifyChecksum(byte[] packet) {
	    int len = packet.length;
	    if (len < 4) return false;

	    int sum = 0;
	    // ´ÓÊý¾ÝÀàÐÍ¿ªÊ¼µ½Ð£ÑéÂëÇ°½áÊø (°üÍ·2×Ö½ÚÒÑÌø¹ý)
	    for (int i = 2; i < len - 2; i++) {
	        sum += packet[i] & 0xFF;
	    }
	    sum = ~sum & 0xFFFF; // È¡·´²¢±£Áô16λ

	    // »ñÈ¡°üÖеÄУÑéÂë (С¶Ëģʽ)
	    int receivedChecksum = ((packet[len - 1] & 0xFF) << 8) | (packet[len - 2] & 0xFF);

	    return sum == receivedChecksum;
	}



	// ½âÎöµ¥¸öÊý¾Ý°ü
	private DataPacket parseSinglePacket(int packetType, byte[] packet) {        

		// ´´½¨Êý¾Ý°ü¶ÔÏ󣨰üº¬°üÀàÐÍ£©
		return new DataPacket(packetType, packet);
	}

	// Êý¾Ý°üÄÚ²¿Àà
	public static class DataPacket {
		private final int packetType;  // °üÀàÐÍ
		private final byte[] packet;//°üÊý¾Ý


		public DataPacket(int packetType, byte[] packet) {
			this.packetType = packetType;
			this.packet = packet;
		}

		// »ñÈ¡°üÀàÐÍ
		public int getPacketType() {
			return packetType;
		}

		// °üÊý¾Ý
		public byte[] getPacket() {
			return packet;
		}

	}

	// HEX×Ö·û´®×ª×Ö½ÚÊý×é
	public static byte[] hexStringToBytes(String hex) {
		// ÒƳý¿Õ¸ñ
		hex = hex.replaceAll("\\s", "");
		int len = hex.length();
		// ´´½¨½á¹ûÊý×é
		byte[] data = new byte[len / 2];
		// ÿÁ½¸ö×Ö·ûת»»Ò»¸ö×Ö½Ú
		for (int i = 0; i < len; i += 2) {
			// ¸ßλת»»
			int high = Character.digit(hex.charAt(i), 16) << 4;
			// µÍλת»»
			int low = Character.digit(hex.charAt(i + 1), 16);
			data[i / 2] = (byte) (high | low);
		}
		return data;
	}

	
	

	/**Êä³öУÑéÂë*/
	public static String calculateChecksum(String input) {
		// ¼ì²éÊäÈëÊÇ·ñΪ¿Õ
		if (input == null) {
			throw new IllegalArgumentException("ÊäÈë²»ÄÜΪnull");
		}

		// ÒƳýËùÓпոñ
		String cleanInput = input.replaceAll("\\s", "");

		// ÑéÖ¤´¦ÀíºóµÄ×Ö·û´®
		if (cleanInput.length() < 8 || !cleanInput.startsWith("55AA")) {
			throw new IllegalArgumentException("ÊäÈë×Ö·û´®±ØÐëÒÔ55AA¿ªÍ·ÇÒ³¤¶ÈÖÁÉÙΪ8£¨È¥³ý¿Õ¸ñºó£©");
		}

		// È¥µô°üÍ·(55AA)ºÍ×îºó4¸ö×Ö·û
		String dataPart = cleanInput.substring(4, cleanInput.length() - 4);

		// ¼ì²éÖм䲿·Ö³¤¶ÈÊÇ·ñΪżÊý
		if (dataPart.length() % 2 != 0) {
			throw new IllegalArgumentException("Öм䲿·Ö³¤¶È±ØÐëÊÇżÊý£¨È¥³ý¿Õ¸ñºó£©");
		}

		int sum = 0;
		// ÿÁ½¸ö×Ö·û½âÎöΪһ¸ö×Ö½Ú
		for (int i = 0; i < dataPart.length(); i += 2) {
			String byteStr = dataPart.substring(i, i + 2);
			int byteValue = Integer.parseInt(byteStr, 16);
			sum = (sum + byteValue) & 0xFFFF; // ±£³Ö16λ·¶Î§
		}

		// È¡·´²¢±£³Ö16λ
		int checksum = (~sum) & 0xFFFF;

		// ÏÔʽ´¦Àí¸ßλÔÚÇ°¸ñʽ
		int  lowByte= (checksum >>> 8) & 0xFF;  // ¸ß8λ
		int  highByte= checksum & 0xFF;           // µÍ8λ

		// ¸ñʽ»¯Îª4λʮÁù½øÖÆ×Ö·û´®£¨´óд£©£¬¸ßλÔÚÇ°
		System.out.println(String.format("%02X%02X", highByte, lowByte));
		return String.format("%02X%02X", highByte, lowByte);
	}

	/** ½«×Ö½ÚÊý×éתΪʮÁù½øÖÆ×Ö·û´®£¬ÀýÈç [55 AA 01 02 ...] */
	private static String bytesToHex(byte[] bytes) {
		if (bytes == null) return "null";
		StringBuilder sb = new StringBuilder(bytes.length * 3);
		for (byte b : bytes) {
			sb.append(String.format("%02X ", b & 0xFF));
		}
		// È¥µô×îºóÒ»¸ö¿Õ¸ñ
		return sb.substring(0, sb.length() - 1);
	}
}