package com.its.vms.xnettcp.vms.protocol.impl.dle;

import com.google.common.primitives.Bytes;
import com.its.vms.xnettcp.vms.protocol.VmsFrameHead;
import com.its.vms.xnettcp.vms.protocol.VmsFramePacket;
import com.its.vms.xnettcp.vms.protocol.VmsFrameTail;
import com.its.vms.xnettcp.vms.protocol.VmsProtocolConst;
import com.its.vms.xnettcp.vms.protocol.enums.eVmsOpCode;
import lombok.extern.slf4j.Slf4j;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.ArrayList;
import java.util.List;

@Slf4j
public class VmsDleFramePacket implements VmsFramePacket {
    public static final ByteOrder BYTE_ORDER = ByteOrder.BIG_ENDIAN;

    /**
     * Protocol CRC16
     */
    private final static int[] crc16_arc = {
            0x0000, 0xc0c1, 0xc181, 0x0140, 0xc301, 0x03c0, 0x0280, 0xc241,
            0xc601, 0x06c0, 0x0780, 0xc741, 0x0500, 0xc5c1, 0xc481, 0x0440,
            0xcc01, 0x0cc0, 0x0d80, 0xcd41, 0x0f00, 0xcfc1, 0xce81, 0x0e40,
            0x0a00, 0xcac1, 0xcb81, 0x0b40, 0xc901, 0x09c0, 0x0880, 0xc841,
            0xd801, 0x18c0, 0x1980, 0xd941, 0x1b00, 0xdbc1, 0xda81, 0x1a40,
            0x1e00, 0xdec1, 0xdf81, 0x1f40, 0xdd01, 0x1dc0, 0x1c80, 0xdc41,
            0x1400, 0xd4c1, 0xd581, 0x1540, 0xd701, 0x17c0, 0x1680, 0xd641,
            0xd201, 0x12c0, 0x1380, 0xd341, 0x1100, 0xd1c1, 0xd081, 0x1040,
            0xf001, 0x30c0, 0x3180, 0xf141, 0x3300, 0xf3c1, 0xf281, 0x3240,
            0x3600, 0xf6c1, 0xf781, 0x3740, 0xf501, 0x35c0, 0x3480, 0xf441,
            0x3c00, 0xfcc1, 0xfd81, 0x3d40, 0xff01, 0x3fc0, 0x3e80, 0xfe41,
            0xfa01, 0x3ac0, 0x3b80, 0xfb41, 0x3900, 0xf9c1, 0xf881, 0x3840,
            0x2800, 0xe8c1, 0xe981, 0x2940, 0xeb01, 0x2bc0, 0x2a80, 0xea41,
            0xee01, 0x2ec0, 0x2f80, 0xef41, 0x2d00, 0xedc1, 0xec81, 0x2c40,
            0xe401, 0x24c0, 0x2580, 0xe541, 0x2700, 0xe7c1, 0xe681, 0x2640,
            0x2200, 0xe2c1, 0xe381, 0x2340, 0xe101, 0x21c0, 0x2080, 0xe041,
            0xa001, 0x60c0, 0x6180, 0xa141, 0x6300, 0xa3c1, 0xa281, 0x6240,
            0x6600, 0xa6c1, 0xa781, 0x6740, 0xa501, 0x65c0, 0x6480, 0xa441,
            0x6c00, 0xacc1, 0xad81, 0x6d40, 0xaf01, 0x6fc0, 0x6e80, 0xae41,
            0xaa01, 0x6ac0, 0x6b80, 0xab41, 0x6900, 0xa9c1, 0xa881, 0x6840,
            0x7800, 0xb8c1, 0xb981, 0x7940, 0xbb01, 0x7bc0, 0x7a80, 0xba41,
            0xbe01, 0x7ec0, 0x7f80, 0xbf41, 0x7d00, 0xbdc1, 0xbc81, 0x7c40,
            0xb401, 0x74c0, 0x7580, 0xb541, 0x7700, 0xb7c1, 0xb681, 0x7640,
            0x7200, 0xb2c1, 0xb381, 0x7340, 0xb101, 0x71c0, 0x7080, 0xb041,
            0x5000, 0x90c1, 0x9181, 0x5140, 0x9301, 0x53c0, 0x5280, 0x9241,
            0x9601, 0x56c0, 0x5780, 0x9741, 0x5500, 0x95c1, 0x9481, 0x5440,
            0x9c01, 0x5cc0, 0x5d80, 0x9d41, 0x5f00, 0x9fc1, 0x9e81, 0x5e40,
            0x5a00, 0x9ac1, 0x9b81, 0x5b40, 0x9901, 0x59c0, 0x5880, 0x9841,
            0x8801, 0x48c0, 0x4980, 0x8941, 0x4b00, 0x8bc1, 0x8a81, 0x4a40,
            0x4e00, 0x8ec1, 0x8f81, 0x4f40, 0x8d01, 0x4dc0, 0x4c80, 0x8c41,
            0x4400, 0x84c1, 0x8581, 0x4540, 0x8701, 0x47c0, 0x4680, 0x8641,
            0x8201, 0x42c0, 0x4380, 0x8341, 0x4100, 0x81c1, 0x8081, 0x4040
    };

    //public static AlgoParams Crc16Arc = new AlgoParams("CRC-16/ARC", 16, 0x8005, 0x0, true, true, 0x0, 0xBB3D);

    protected VmsDleFrameHead head;
    protected byte[]          body;
    protected VmsDleFrameTail tail;

    public VmsDleFramePacket(int group, int controller, byte opCode) {
        this.head = new VmsDleFrameHead(group, controller, opCode, 1, 1);
        this.body = null;
        this.tail = new VmsDleFrameTail();
    }

    public VmsDleFramePacket(byte[] packet, int msgLen) {
        this.body = null;
        if (packet == null || msgLen == 0) {
            this.head = new VmsDleFrameHead(0, 0, 0, 1, 1);
            this.tail = new VmsDleFrameTail();
            return;
        }

        this.head = new VmsDleFrameHead(packet);
        this.tail = new VmsDleFrameTail(packet);

        int bodySize = msgLen - VmsDleFrameHead.HEAD_SIZE - VmsDleFrameTail.TAIL_SIZE;
        if (bodySize > 0) {
            this.body = new byte[bodySize];
            System.arraycopy(packet, VmsDleFrameHead.HEAD_SIZE, this.body, 0, bodySize);
        }
    }

    @Override
    public void setBody(byte[] body) {
        this.body = body;
    }

    @Override
    public VmsFrameHead getHead() {
        return this.head;
    }

    /**
     * 요청 패킷을 ByteBuffer 로 변경하여 리턴
     * @return
     */
    @Override
    public ByteBuffer getByteBuffer() {
        makeCRC();
        return getDleBuffer();
    }

    @Override
    public String getOpCodeDesc() {
        eVmsOpCode opCode = eVmsOpCode.getValue((byte)(this.head.getOpCode() & 0xFF));
        if (opCode != null) {
            return opCode.toString();
        }
        return String.format("0x%02X.Unknown OpCode.", (byte)(this.head.getOpCode() & 0xFF));
    }

    @Override
    public int getOpCode() {
        return this.head != null ? this.head.getOpCode() : 0x00;
    }

    @Override
    public byte[] getBody() {
        return this.body;
    }

    @Override
    public VmsFrameTail getTail() {
        return this.tail;
    }

    private ByteBuffer getDleBuffer() {
        List<Byte> list = new ArrayList<Byte>();
        int bodySize = 0;
        if (this.body != null) {
            bodySize = this.body.length;
        }

        // HEAD (패킷 분석결과 DLE Stuffing 하지 않음)
        list.add(this.head.getDle());
        list.add(this.head.getStx());
        byte[] headArr = this.head.getBuffer();
        for (int ii = 2; ii < headArr.length; ii++) {
            byte hb = headArr[ii];
            list.add(hb);
            if (hb == VmsProtocolConst.VMS_DLE) {
                list.add(hb);
            }
        }

        // BODY
        if (bodySize > 0) {
            for (byte b: this.body) {
                list.add(b);
                if (b == VmsProtocolConst.VMS_DLE) {
                    list.add(b);
                }
            }
        }

        // TAIL
        list.add(this.tail.getDle());
        list.add(this.tail.getEtx());
        list.add((byte)(((this.tail.getCrc() & 0xFF00) >> 8) & 0xFF));
        list.add((byte)(((this.tail.getCrc() & 0x00FF)     ) & 0xFF));

        byte[] arr = Bytes.toArray(list);
        ByteBuffer byteBuffer = ByteBuffer.allocate(arr.length);
        byteBuffer.order(VmsDleFramePacket.BYTE_ORDER);
        byteBuffer.put(arr);
        return byteBuffer;
    }

    public ByteBuffer getBuffer() {
        int bodySize = 0;
        if (this.body != null) {
            bodySize = this.body.length;
        }

        this.head.setLength(bodySize);

        ByteBuffer byteBuffer = ByteBuffer.allocate(VmsDleFrameHead.HEAD_SIZE + bodySize + VmsDleFrameTail.TAIL_SIZE);
        byteBuffer.order(VmsDleFramePacket.BYTE_ORDER);

        // HEAD
        byteBuffer.put(this.head.getBuffer());
        // BODY
        if (bodySize > 0) {
            byteBuffer.put(this.body);
        }
        // TAIL
        byteBuffer.put(this.tail.getBuffer());
        return byteBuffer;
    }

    public void makeCRC() {
        // DLE Stuffing 이전 데이터에 대하여 CRC 수행
        ByteBuffer byteBuffer = getBuffer();
        short crc = getCRC16ARC(byteBuffer.array(), 2, byteBuffer.array().length - 6);
        this.tail.setCrc(crc);
    }

    /**
     * CRC16-ARC(https://crccalc.com/)
     * https://github.com/NordicSemiconductor/Android-BLE-Common-Library/blob/master/ble-common/src/main/java/no/nordicsemi/android/ble/common/util/CRC16.java
     * @param data
     * @param start
     * @param length
     * @return
     */
    public short getCRC16ARC(byte[] data, int start, int length) {
        int crc = 0;
        for (int ii = start; ii < (start+length); ii++) {
            crc = (crc >> 8) ^ crc16_arc[(crc ^ data[ii]) & 0xff];
        }
        return (short)(crc & 0x0000FFFF);
    }
}
