// UwbDataParser.java
package publicsWay;
import java.util.ArrayList;
import java.util.List;

public class UwbDataParser {
    private byte[] buffer = new byte[4096];
    private int bufferLength = 0;
 // Ìí¼ÓеÄparse·½·¨
    public String parse(byte[] data) {
        // Ìí¼ÓÊý¾Ýµ½»º³åÇø
        appendData(data, data.length);
        
        // ½âÎöÊý¾Ý°ü
        List<DataPacket> packets = parsePackets();
        
        if (packets.isEmpty()) {
            return "No complete packet found in data";
        }
        
        StringBuilder result = new StringBuilder();
        for (DataPacket packet : packets) {
            result.append(packet.toString()).append("\n");
        }
        return result.toString();
    }
    
    public void appendData(byte[] newData, int length) {
        if (bufferLength + length > buffer.length) {
            byte[] newBuffer = new byte[bufferLength + length];
            System.arraycopy(buffer, 0, newBuffer, 0, bufferLength);
            buffer = newBuffer;
        }
        System.arraycopy(newData, 0, buffer, bufferLength, length);
        bufferLength += length;
    }

    public void clearBuffer() {
        bufferLength = 0;
    }

    public List<DataPacket> parsePackets() {
        List<DataPacket> packets = new ArrayList<>();
        int index = 0;
        
        while (index <= bufferLength - 4) {
            if (buffer[index] == 0x55 && (buffer[index + 1] & 0xFF) == 0xAA) {
                int dataType = buffer[index + 2] & 0xFF;
                int dataLenField = buffer[index + 3] & 0xFF;
                int totalPacketLen = 4 + dataLenField;
                
                if (index + totalPacketLen > bufferLength) {
                    break;
                }
                
                byte[] packetData = new byte[totalPacketLen];
                System.arraycopy(buffer, index, packetData, 0, totalPacketLen);
                
                if (verifyChecksum(packetData)) {
                    DataPacket packet = parseSinglePacket(packetData);
                    if (packet != null) {
                        packets.add(packet);
                    }
                    index += totalPacketLen;
                } else {
                    index++;
                }
            } else {
                index++;
            }
        }
        
        if (index > 0) {
            int remaining = bufferLength - index;
            System.arraycopy(buffer, index, buffer, 0, remaining);
            bufferLength = remaining;
        }
        
        return packets;
    }

    private boolean verifyChecksum(byte[] packet) {
        int len = packet.length;
        if (len < 4) return false;
        
        int sum = 0;
        for (int i = 2; i < len - 2; i++) {
            sum += packet[i] & 0xFF;
        }
        sum = ~sum & 0xFFFF;
        
        int receivedChecksum = ((packet[len - 1] & 0xFF) << 8) | (packet[len - 2] & 0xFF);
        
        return sum == receivedChecksum;
    }

    private DataPacket parseSinglePacket(byte[] packet) {
        int sequence = packet[4] & 0xFF;
        int tagId = ((packet[6] & 0xFF) << 8) | (packet[5] & 0xFF);
        int baseId = ((packet[8] & 0xFF) << 8) | (packet[7] & 0xFF);
        
        int distance = (packet[12] << 24) | 
                     ((packet[11] & 0xFF) << 16) | 
                     ((packet[10] & 0xFF) << 8) | 
                     (packet[9] & 0xFF);
        
        int battery = packet[13] & 0xFF;
        int buttonStatus = packet[14] & 0xFF;
        
        return new DataPacket(sequence, 
                            String.format("%04X", tagId),
                            String.format("%04X", baseId),
                            distance, battery, buttonStatus);
    }

    public static class DataPacket {
        private final int sequence;
        private final String tagId;
        private final String baseId;
        private final int distance;
        private final int battery;
        private final int buttonStatus;

        public DataPacket(int sequence, String tagId, String baseId, 
                          int distance, int battery, int buttonStatus) {
            this.sequence = sequence;
            this.tagId = tagId;
            this.baseId = baseId;
            this.distance = distance;
            this.battery = battery;
            this.buttonStatus = buttonStatus;
        }
      
    }
}