/*********************************************************************************
 *      Copyright:  (C) 2020 LingYun IoT System Studio
 *                  All rights reserved.
 *
 *       Filename:  tlv_pack.h
 *    Description:  This head file is for TLV packet
 *                 
 *        Version:  1.0.0(2020年04月14日)
 *         Author:  Guo Wenxue <guowenxue@gmail.com>
 *      ChangeLog:  1, Release initial version on "2020年04月14日 00时52分56秒"
 *                 
 ********************************************************************************/

#include <stdio.h>
#include <string.h>

#include "tlv_pack.h"
#include "crc-itu-t.h"


int packtlv_ack(char *buf, int size, int ack)
{
	unsigned short      crc16 = 0;
	int                 pack_len = 0;
	int                 ofset = 0; /* index position for the buf */

	if(!buf || size<TLV_MIN_SIZE )
	{
		printf("Invalid input arguments\n");
		return 0;
	}

	/*+-------------------------+
     *|   1.fill packet Header  | 
	 *+-------------------------+*/

	buf[ofset] = PACK_HEADER;
	ofset += 1;

	/*+-------------------------+
     *|   2.fill packet Tag     | 
	 *+-------------------------+*/

	buf[ofset] = TAG_ACK;
	ofset += 1;

	/*+-------------------------+
     *|   3.fill packet Length  | 
	 *+-------------------------+*/

    /* ACK message only get 1B payload data */
	pack_len = TLV_FIXED_SIZE + 1;
	buf[ofset] = pack_len;
	ofset += 1;

	/*+-------------------------+
     *|   4.fill packet Value   | 
	 *+-------------------------+*/

    if( ack )
        buf[ofset++] = 1; /* 1 for ACK */
    else
        buf[ofset++] = 0; /* 0 for NAK */

	/*+-------------------------+
     *|   5.fill packet CRC     | 
	 *+-------------------------+*/

	/* Calc CRC16 checksum value from Packet Head(buf[0]) ~ Value(buf[ofset]) */
	crc16 = crc_itu_t(MAGIC_CRC, buf, ofset);

	/* Append the 2 Bytes CRC16 checksum value into the last two bytes in packet buffer */
	ushort_to_bytes(&buf[ofset], crc16);
	ofset += 2;

    /* ofset value is the TLV packet length  */
	return ofset;
}


int packtlv_sn(char *buf, int size, char *sn)
{
	unsigned short      crc16 = 0;
    int                 payload_len = 0;
	int                 pack_len = 0;
	int                 ofset = 0; /* index position for the buf */

	if(!buf || size<TLV_MIN_SIZE )
	{
		printf("Invalid input arguments\n");
		return 0;
	}

	/*+-------------------------+
     *|   1.fill packet Header  | 
	 *+-------------------------+*/
	buf[ofset] = PACK_HEADER;
	ofset += 1;

	/*+-------------------------+
     *|   2.fill packet Tag     | 
	 *+-------------------------+*/
	buf[ofset] = TAG_SN;
	ofset += 1;

	/*+-------------------------+
     *|   3.fill packet Length  | 
	 *+-------------------------+*/

    /* $sn too long maybe result buffer overflow, so we need check the buffer 
     * is large enuf or not. If not enuf we will truncate $sn string 
     */
    if( strlen(sn) <= size-TLV_FIXED_SIZE )
        payload_len = strlen(sn);
    else
        payload_len = size-TLV_FIXED_SIZE;

    /*  TLV packet length is SN length+5Byte () */ 
    pack_len = payload_len + TLV_FIXED_SIZE;

	buf[ofset] = pack_len;
	ofset += 1;

	/*+-------------------------+
     *|   4.fill packet Value   | 
	 *+-------------------------+*/
    memcpy(&buf[ofset], sn, payload_len);
    ofset += payload_len;

	/*+-------------------------+
     *|   5.fill packet CRC     | 
	 *+-------------------------+*/

	/* Calc CRC16 checksum value from Packet Head(buf[0]) ~ Value(buf[ofset]) */
	crc16 = crc_itu_t(MAGIC_CRC, buf, ofset);

	/* Append the 2 Bytes CRC16 checksum value into the last two bytes in packet buffer */
	ushort_to_bytes(&buf[ofset], crc16);
	ofset += 2;

    /* ofset value is the TLV packet length  */
	return ofset;
}


int packtlv_temp(char *buf, int size, uint16_t temp)
{
	unsigned short      crc16 = 0;
	int                 pack_len = 0;
	int                 ofset = 0; /* index position for the buf */

	if(!buf || size<TLV_FIXED_SIZE+2 )
	{
		printf("Invalid input arguments\n");
		return 0;
	}

	/*+-------------------------+
     *|   1.fill packet Header  | 
	 *+-------------------------+*/

	buf[ofset] = PACK_HEADER;
	ofset += 1;

	/*+-------------------------+
     *|   2.fill packet Tag     | 
	 *+-------------------------+*/

	buf[ofset] = TAG_TEMP;
	ofset += 1;

	/*+-------------------------+
     *|   3.fill packet Length  | 
	 *+-------------------------+*/

    /* termperature message get 2B payload data */
	pack_len = TLV_FIXED_SIZE + 2;
	buf[ofset] = pack_len;
	ofset += 1;

	/*+-------------------------+
     *|   4.fill packet Value   | 
	 *+-------------------------+*/

    /* temperature get 2 bytes, byte[0]:integer part, byte[1]:fractional part  */
    memcpy(&buf[ofset], &temp, 2);
    ofset += 2;

	/*+-------------------------+
     *|   5.fill packet CRC     | 
	 *+-------------------------+*/

	/* Calc CRC16 checksum value from Packet Head(buf[0]) ~ Value(buf[ofset]) */
	crc16 = crc_itu_t(MAGIC_CRC, buf, ofset);

	/* Append the 2 Bytes CRC16 checksum value into the last two bytes in packet buffer */
	ushort_to_bytes(&buf[ofset], crc16);
	ofset += 2;

    /* ofset value is the TLV packet length  */
	return ofset;
}

int packtlv_time(char *buf, int size, struct tm *tm)
{
	unsigned short      crc16 = 0;
	int                 pack_len = 0;
	int                 ofset = 0; /* index position for the buf */

	if(!buf || size<TLV_FIXED_SIZE+6 )
	{
		printf("Invalid input arguments\n");
		return 0;
	}

	/*+-------------------------+
     *|   1.fill packet Header  | 
	 *+-------------------------+*/

	buf[ofset] = PACK_HEADER;
	ofset += 1;

	/*+-------------------------+
     *|   2.fill packet Tag     | 
	 *+-------------------------+*/

	buf[ofset] = TAG_TIME;
	ofset += 1;

	/*+-------------------------+
     *|   3.fill packet Length  | 
	 *+-------------------------+*/

    /* date time message get 6B payload data */
	pack_len = TLV_FIXED_SIZE + 6;
	buf[ofset] = pack_len;
	ofset += 1;

	/*+-------------------------+
     *|   4.fill packet Value   | 
	 *+-------------------------+*/ 

    buf[ofset++] = tm->tm_year-100; /* tm_year is since 1900, we change it it to 2000 */
    buf[ofset++] = tm->tm_mon+1;    /* tm_mon is from 0~11  */
    buf[ofset++] = tm->tm_mday;
    buf[ofset++] = tm->tm_hour;
    buf[ofset++] = tm->tm_min;
    buf[ofset++] = tm->tm_sec;

	/*+-------------------------+
     *|   5.fill packet CRC     | 
	 *+-------------------------+*/

	/* Calc CRC16 checksum value from Packet Head(buf[0]) ~ Value(buf[ofset]) */
	crc16 = crc_itu_t(MAGIC_CRC, buf, ofset);

	/* Append the 2 Bytes CRC16 checksum value into the last two bytes in packet buffer */
	ushort_to_bytes(&buf[ofset], crc16);
	ofset += 2;

    /* ofset value is the TLV packet length  */
	return ofset;
}



/*+------------------------------+
 *|  dump_buf() implement code   |
 *+------------------------------+*/

#define LINELEN 81
#define CHARS_PER_LINE 16

static char *print_char =
    "                "
    "                "
    " !\"#$%&'()*+,-./"
    "0123456789:;<=>?"
    "@ABCDEFGHIJKLMNO"
    "PQRSTUVWXYZ[\\]^_"
    "`abcdefghijklmno"
    "pqrstuvwxyz{|}~ "
    "                "
    "                "
    " ???????????????"
    "????????????????"
    "????????????????"
    "????????????????"
    "????????????????"
    "????????????????";

/* print every byte in the buffer as HEX and corresponding charactor, which is not printable charactor will be instead as '?' */
void dump_buf(char *data, int len)
{
    int rc;
    int idx;
    char prn[LINELEN];
    char lit[CHARS_PER_LINE + 1];
    char hc[4];
    short line_done = 1;

    rc = len;
    idx = 0;
    lit[CHARS_PER_LINE] = '\0';

    while (rc > 0)
    {
        if (line_done)
            snprintf(prn, LINELEN, "%08X: ", idx);
        do
        {
            unsigned char c = data[idx];
            snprintf(hc, 4, "%02X ", c);
            strncat(prn, hc, 4);
            lit[idx % CHARS_PER_LINE] = print_char[c];
            ++idx;
        } while (--rc > 0 && (idx % CHARS_PER_LINE != 0));

        line_done = (idx % CHARS_PER_LINE) == 0;

        if (line_done)
            printf("%s  %s\n", prn, lit);
        else if (rc == 0)
            strncat(prn, "   ", LINELEN);
    }

    if (!line_done)
    {
        lit[(idx % CHARS_PER_LINE)] = '\0';

        while ((++idx % CHARS_PER_LINE) != 0)
            strncat(prn, "   ", LINELEN);

        printf("%s  %s\n", prn, lit);

    }
}