package home;
import java.util.Arrays;

public class Dell55AA1FParser {
    // ³£Á¿¶¨Òå
    private static final String EXPECTED_HEADER = "55AA1F"; // ЭÒéÍ·
    private static final int FIXED_FIELDS_LENGTH = 11; // ´Ó±êÇ©IDµ½±£Áô×ֶεĹ̶¨³¤¶È(×Ö½Ú)
    private static final ThreadLocal<ParseResult> RESULT_CACHE = 
            ThreadLocal.withInitial(ParseResult::new);

    // ½âÎö½á¹ûÀà
    public static class ParseResult {
        public int dataLength;    // Êý¾Ý³¤¶È
        public int messageType;    // ÏûÏ¢ÀàÐÍ
        public String tagId;       // ±êÇ©ID(2×Ö½Ú)
        public int distance;       // ¾àÀë(ÀåÃ×)
        public int angle;          // ½Ç¶È(¶È)
        public int signalQuality;  // ÐźÅÖÊÁ¿(0-255)
        public int buttonPressed;  // °´Å¥×´Ì¬
        public int power;          // µçÁ¿
        public String reserved;    // ±£Áô×Ö¶Î
        public String userData;    // Óû§Êý¾Ý
        public String checksum;    // УÑéºÍ
        
        public void reset() {
            dataLength = 0;
            messageType = 0;
            tagId = "";
            distance = 0;
            angle = 0;
            signalQuality = 0;
            buttonPressed = 0;
            power = 0;
            reserved = "";
            userData = "";
            checksum = "";
        }
    }

    /**
     * ½âÎö55AA1FЭÒéÊý¾Ý
     * @param message Ê®Áù½øÖÆ×Ö·û´®
     * @return ½âÎö½á¹û(´íÎóʱ·µ»Ønull)
     */
    public static ParseResult parse(String message, String ip, int port) {
        if (message == null || message.isEmpty()) {
            return null;
        }

        // ÇåÏ´Êý¾Ý£ºÒƳýËùÓзÇÊ®Áù½øÖÆ×Ö·û
        char[] cleanedMessage = cleanMessage(message);

        if (cleanedMessage == null) {
            return null;
        }

        // ЭÒéͷУÑé (55AA1F)
        if (cleanedMessage.length < 6 || 
            !new String(cleanedMessage, 0, 6).equals(EXPECTED_HEADER)) {
            return null;
        }

        ParseResult result = RESULT_CACHE.get();
        result.reset();

        try {
            // ½âÎöÊý¾Ý³¤¶È (λÖÃ6-7)
            result.dataLength = HexUtils.fastHexToByte(cleanedMessage[6], cleanedMessage[7]);
            
            // ¼ÆËãÆÚÍûµÄ×Ü×Ö·û³¤¶È
            int expectedCharLength = 8 + // °üÍ·(4×Ö·û) + ÏûÏ¢ÀàÐÍ(2×Ö·û) + Êý¾Ý³¤¶È(2×Ö·û)
                                    result.dataLength * 2 + // Êý¾Ý²¿·Ö
                                    4; // УÑéºÍ(4×Ö·û)

//            if (cleanedMessage.length != expectedCharLength) {
//                System.err.println("Data length mismatch: expected " + expectedCharLength + 
//                                 ", got " + cleanedMessage.length);
//                return null;
//            }

            // ½âÎöÏûÏ¢ÀàÐÍ (λÖÃ4-5)
            result.messageType = HexUtils.fastHexToByte(cleanedMessage[4], cleanedMessage[5]);

            // ½âÎö±êÇ©ID (λÖÃ8-11)£¬Ö±½ÓÈ¡×Ö·û´®
            result.tagId = new String(cleanedMessage, 8, 4);

            // ½âÎö¾àÀë (λÖÃ12-15, 2×Ö½ÚС¶ËÕûÊý)
            int distLow = HexUtils.fastHexToByte(cleanedMessage[12], cleanedMessage[13]);
            int distHigh = HexUtils.fastHexToByte(cleanedMessage[14], cleanedMessage[15]);
            result.distance = (distHigh << 8) | distLow;

            // ½âÎö½Ç¶È (λÖÃ16-19, 2×Ö½ÚС¶ËÓзûºÅÕûÊý)
            int angleLow = HexUtils.fastHexToByte(cleanedMessage[16], cleanedMessage[17]);
            int angleHigh = HexUtils.fastHexToByte(cleanedMessage[18], cleanedMessage[19]);
            short angleShort = (short) ((angleHigh << 8) | angleLow);
            result.angle = angleShort;

            // ½âÎöÐźÅÖÊÁ¿ (λÖÃ20-21)
            result.signalQuality = HexUtils.fastHexToByte(cleanedMessage[20], cleanedMessage[21]);

            // ½âÎö°´Å¥×´Ì¬ (λÖÃ22-23)
            result.buttonPressed = HexUtils.fastHexToByte(cleanedMessage[22], cleanedMessage[23]);

            // ½âÎöµçÁ¿ (λÖÃ24-25)
            result.power = HexUtils.fastHexToByte(cleanedMessage[24], cleanedMessage[25]);

            // ½âÎö±£Áô×ֶΠ(λÖÃ26-29)
            result.reserved = new String(cleanedMessage, 26, 4);

            // ½âÎöÓû§Êý¾Ý
//            int userDataStart = 30;
//            int userDataCharLength = (result.dataLength - FIXED_FIELDS_LENGTH) * 2;
//            if (userDataCharLength > 0) {
//                result.userData = new String(cleanedMessage, userDataStart, userDataCharLength);
//            } else {
//                result.userData = "";
//            }

            // ½âÎöУÑéºÍ (×îºó4¸ö×Ö·û)
            result.checksum = new String(cleanedMessage, cleanedMessage.length - 4, 4);

            // Ñé֤УÑéºÍ
//            byte[] packetBytes = hexStringToByteArray(new String(cleanedMessage));
//            if (!verifyChecksum(packetBytes)) {
//                System.err.println("Checksum verification failed for packet from " + ip + ":" + port);
//                return null;
//            }

        } catch (IndexOutOfBoundsException | NumberFormatException e) {
            System.err.println("Parsing error in 55AA1F packet from " + ip + ":" + port);
            e.printStackTrace();
            return null;
        }

        return result;
    }

    /**
     * ½«Ê®Áù½øÖÆ×Ö·û´®×ª»»Îª×Ö½ÚÊý×é
     */
    private static byte[] hexStringToByteArray(String s) {
        int len = s.length();
        byte[] data = new byte[len / 2];
        for (int i = 0; i < len; i += 2) {
            data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
                                 + Character.digit(s.charAt(i+1), 16));
        }
        return data;
    }

    /**
     * УÑéÊý¾Ý°ü
     * È¥µô°üÍ·ÇóºÍÈ¡·´£¬Ð£ÑéÂëΪС¶Ëģʽ
     */
    private static boolean verifyChecksum(byte[] packet) {
        int len = packet.length;
        if (len < 4) return false;

        int sum = 0;
        // ´ÓÏûÏ¢ÀàÐÍ¿ªÊ¼µ½Ð£ÑéÂëÇ°½áÊø (Ìø¹ý°üÍ·2×Ö½Ú)
        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 - 2] & 0xFF) << 8) | (packet[len - 1] & 0xFF);

        return sum == receivedChecksum;
    }

    private static char[] cleanMessage(String message) {
        char[] cleaned = new char[message.length()];
        int j = 0;
        for (char c : message.toCharArray()) {
            if (Character.isDigit(c) || (c >= 'A' && c <= 'F') || (c >= 'a' && c <= 'f')) {
                cleaned[j++] = Character.toUpperCase(c);
            }
        }
        if (j == 0) return null;
        return Arrays.copyOf(cleaned, j);
    }
   
}