#!/bin/bash

# fqt - FLAMP Queue Touch'
#
# Simplify matching queue ID in FLAMP by changing file's date.

Help()
{
   echo 'Usage: fqt \[OPTION\]... TIMESTAMP... FILE...'
   echo 'Update a file'\''s timestamp helping recreate the hash, or queue id, in FLAMP.'
   echo
   echo 'options:'
   echo '  -h             display this help and exit'
   echo '  --help         display longer help and exit'
   echo '  -v, --version  output version information and exit'
   echo
   echo 'fqt is short for FLAMP Queue Touch'
}

LongHelp()
{
   echo 'Example'
   echo '  FLAMP text shown in FLDIGI:'
   echo '/// BEGIN ///'
   echo 'QST DE N0CALL'
   echo
   echo '<PROG 18 588E>{D5C6}FLAMP 2.2.07'
   echo '<FILE 35 EEAC>{D5C6}20230610151423:flamp-file.k2s'
   echo '                    ^^^^^^^^^^^^^^--> --> --> --> Use these numbers -->\'
   echo '<ID 26 6D1A>{D5C6}N0CALL Demonstration'
   echo '<SIZE 13 4B1B>{D5C6}45 1 64                                           |'
   echo '<DATA 53 5A03>{D5C6:1}[b64:start]VGhpcyBpcyBhIHRlc3QuCg==             v'
   echo '[b64:end]'
   echo '<CNTL 10 2CBA>{D5C6:EOF}                                              |'
   echo '<CNTL 10 8CB6>{D5C6:EOT}                                              v'
   echo
   echo 'QST DE N0CALL K                                                       |'
   echo '///  END  ///                                                         v'
   echo '               vvvvvvvvvvvvvv <-- <-- <-- <-- <-- <-- <-- Here <-- <--/'
   echo '  command: fqt 20230607013934 flamp-file.k2s'
   echo
   echo 'Tips'
   echo '  If hash doesn'\''t match, try to'
   echo '    Remove and re-Add the file in FLAMP'
   echo '    Toggle Comp check box (usually compression, unless file is small)'
   echo '    Change base64 (usually base64)'
   echo '    Change Blk size (usually 64)'
   echo
   echo 'Information on hash in documentation'
   echo 'FLAMP Amateur Multicast Protocol (AMP-2) - Version 3.0'
   echo 'available at: <http://www.w1hkj.com/files/flamp/Amp-2.V3.0.Protocol.pdf>'
   echo
   echo '  20130316010524:ShortMessage2.txt0base12896'
   echo
   echo '  Example format:'
   echo
   echo '  |20130316010524:ShortMessage2.txt|0|base128|96|'
   echo '  |     DTS      :       FN        |C|   B   |BS|'
   echo
   echo '  DTS = Date/Time Stamp'
   echo '  FN  = File Name'
   echo '   C  = Compression 1=ON,0=OFF'
   echo '   B  = Base Conversion (base64, base128, or base256)'
   echo '  BS  = Block Size, 1 or more characters'
   echo '   |  = Field separator.'
   echo
   echo 'CRC-16/MODBUS 20230607013934:flamp-file.k2s1base6464 D5C6'
   echo '  needs localtime file dated 20230606213934 America/New_York.'
   echo
   echo 'Usage: fqt [OPTION]... TIMESTAMP... FILE...'
   echo 'Update a file'\''s timestamp helping recreate the hash, or queue id, in FLAMP.'
   echo
   echo 'TIMESTAMP is the string appearing in FLAMP header'
   echo 'and is formatted YYYYmmddHHMMSS '
   echo
   echo 'A FILE argument that does not exist is created empty. (Not helpful.)'
   echo
   echo 'options:'
   echo '  -h             display short help and exit'
   echo '  --help         display this longer help and exit'
   echo '  -v, --version  output version information and exit'
   echo
   echo 'This should work across timezones and across Daylight Savings times.'
   echo
   echo 'fqt is short for FLAMP Queue Touch'
}

Version()
{
   echo 'fqt - FLAMP Queue Touch'
   echo 'Not Copyrighted'
   echo 'No License'
   echo 'This is free software: you are free to change and redistribute it.'
   echo 'There is NO WARRANTY, to the extent permitted by law.'
   echo
   echo 'Use at your own risk!'
   echo
   echo 'Written by a ham.'
}

# Note that we use "$@" to let each command-line parameter expand to a
# separate word. The quotes around "$@" are essential!
# We need TEMP as the 'eval set --' would nuke the return value of getopt.
if ! TEMP=$(getopt -o '::hv' --long 'help,version' -n 'fqt' -- "$@") ;
then
        echo 'Unexpected input. Terminating...' >&2
        exit 1
fi

# Note the quotes around "$TEMP": they are essential!
eval set -- "$TEMP"
unset TEMP


# getopt -l "help" -a -o "" -- "$@"
while true; do
   case "$1" in
      '-h')
         Help
         exit;;
      '--help')
         LongHelp
         exit;;
      '-v'|'--version')
         Version
         exit;;
      '--') # Useless for this file?
         shift
         break;;
     *) # Invalid option
         echo 'Error: Invalid option'
         exit 1;;
   esac
done

GIVEN="$1"
#echo "$GIVEN"
# YYYYmmddHHMMSS
# 20230607013934

GIVEN_DATE=$(echo "$GIVEN" | sed 's/\(....\)\(..\)\(..\)\(..\)\(..\)\(..\)/\1-\2-\3 \4:\5:\6/')
#echo "$GIVEN_DATE"
# YYYY-mm-dd HH:MM:SS
# 2023-06-07 01:39:34

UTC_TOUCH="$(date -d "$GIVEN_DATE"Z +%Y%m%d%H%M.%S)"
#echo "$UTC_TOUCH"
# YYYYmmddHHMM.SS
# 202306062139.34

echo touch -mt "$UTC_TOUCH" "$2"
touch -mt "$UTC_TOUCH" "$2"


function calc_crc16( )
{
# Modified from
# https://github.com/onslauth/bash_crc16/blob/master/crc16-table.sh

	# poly=0x8005

	declare -a crc_16_table=(     
	  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 
	)

	input="$1"
	# crc=0     # for CRC-16/ARC
   crc=65535 # for CRC-16/MODBUS

	len=${#input}
	for (( i = 0; i<len; i++ ))
	do
		char=${input:$i:1}
		j=$( printf "%02x" "'$char" )
		declare -i buf=0x${j}
		crc=$(( crc_16_table[ ( crc ^ buf ) & 0xff ] ^ ( crc >> 8 ) ))
	done

	printf "%04X" $crc
}

crc16=$( calc_crc16 "123456789" )
echo "crc16 : 123456789 : $crc16"
echo "CRC-16/ARC    BB3D"
echo "CRC-16/MODBUS 4B37" 

DEMO=20230610151423:flamp-file.k2s1base6464
crc16=$( calc_crc16 "$DEMO" )
echo "crc16 : $DEMO : $crc16 "
echo "CRC-16/ARC    D9F6"
echo "CRC-16/MODBUS D5C6" 

echo
# echo UTC_TOUCH "$UTC_TOUCH"
CONVERT_BACK_TO_DATE=$(echo "$UTC_TOUCH" | sed 's/\(....\)\(..\)\(..\)\(..\)\(..\)\.\(..\)/\1-\2-\3 \4:\5:\6/')
echo CONVERT_BACK_TO_DATE "$CONVERT_BACK_TO_DATE"
OFFSET=$(date -d "$CONVERT_BACK_TO_DATE" +%z)
echo "$OFFSET"
FLAMP_DATE=$(TZ=':Zulu' date -d "$CONVERT_BACK_TO_DATE $OFFSET" +%Y%m%d%H%M%S)
echo FLAMP_DATE "$FLAMP_DATE"
CONVERT_BACK_TO_DATE=$(stat -c %y flamp-file.k2s)
echo CONVERT_BACK_TO_DATE "$CONVERT_BACK_TO_DATE"
FLAMP_DATE=$(TZ=':Zulu' date -d "$CONVERT_BACK_TO_DATE" +%Y%m%d%H%M%S)
echo FLAMP_DATE "$FLAMP_DATE"
DEMO1C="$FLAMP_DATE:${2}1base6464"
crc16=$( calc_crc16 "$DEMO1C" )
echo "Compression On : crc16 : $DEMO1C : $crc16"
DEMO1NC="$FLAMP_DATE:${2}0base6464"
crc16=$( calc_crc16 "$DEMO1NC" )
echo "Compression Off : crc16 : $DEMO1NC : $crc16"
echo

DEMO2="${1}:${2}1base6464"
crc16=$( calc_crc16 "$DEMO2" )
echo "crc16 : $DEMO2 : $crc16"