package com.iflytop.gd.system.models;

import com.iflytop.gd.system.utils.ByteArray;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;

public class DataPacket {
    public static final int PACKET_TYPE_OFFSET = 0;
    public static final int CMDID_OFFSET       = 1;
    public static final int MODULE_ID_OFFSET   = 3;
    public static final int INDEX_OFFSET       = 4;
    public static final int DATA_LEN_OFFSET    = 6;
    public static final int DATA_OFFSET        = 7;

    public static final int PACKET_MIN_LEN = 8;//

    public static final int CMD_OVERTIME = 1500;


    public static final int PACKET_TYPE_CMD       = 0xA0;
    public static final int PACKET_TYPE_ACK       = 0xA1;
    public static final int PACKET_TYPE_ERROR_ACK = 0xA2;
    public static final int PACKET_TYPE_EVENT     = 0xA3;

    byte[] raw;

    public DataPacket(byte[] cmd) {
        raw = new byte[cmd.length];
        System.arraycopy(cmd, 0, raw, 0, cmd.length);
    }

    public String toByteString() {
        return ByteArray.toByteString(raw);
    }

    static public DataPacket createPacket(Integer moduleId, int packetType, Integer cmdId, Integer[] params) {
        int        bufferSize = DataPacket.PACKET_MIN_LEN + 4 * params.length;
        ByteBuffer buffer     = ByteBuffer.allocate(bufferSize);
        buffer.order(ByteOrder.LITTLE_ENDIAN);
        buffer.put((byte) (packetType & 0xff)); // packetType
        buffer.putShort((short) (cmdId & 0xffff)); // cmdid
        buffer.put((byte) (moduleId & 0xFF)); // moduleId
        buffer.put((byte) 0x4C); // index
        buffer.put((byte) 0x00); // index
        buffer.put((byte) (params.length * 4)); // datalen
        for (int value : params) {
            buffer.putInt(value);
        }
        // int8_t  checksum;
        int checksum = 0;
        for (int i = 0; i < bufferSize - 1; i++) {
            checksum += buffer.get(i);
        }
        buffer.put((byte) checksum);
        return new DataPacket(buffer.array());
    }


    public static DataPacket createCommandDataPacket(Integer moduleId, Integer cmdId, Integer... params) {
        return createPacket(moduleId, PACKET_TYPE_CMD, cmdId, params);
    }

    public int getPacketIndex() {
        return ByteArray.readU16bit(raw, INDEX_OFFSET);
    }

    public void setPacketIndex(int packetIndex) {
        ByteArray.setU16bit(raw, INDEX_OFFSET, packetIndex);
        int checkSum = computeCheckSum();
        ByteArray.setU8(raw, raw.length - 1, checkSum);
    }

    public int computeCheckSum() {
        int checkcode = 0;
        for (int i = 0; i < raw.length - 1; i++) {
            checkcode += raw[i];
        }
        return checkcode & 0xFF;
    }

    public int getCmdId() {
        return ByteArray.readU16bit(raw, CMDID_OFFSET);
    }

    public int getPacketType() {
        return ByteArray.readU8bit(raw, PACKET_TYPE_OFFSET);
    }

    public int getModuleId() {
        return ByteArray.readU8bit(raw, MODULE_ID_OFFSET);
    }

    public int getDataLen() {
        return ByteArray.readU8bit(raw, DATA_LEN_OFFSET);
    }
}