#!/bin/bash
# Little OCR scan for payments code line in BVR
# With PZ10 check for validity
# Use netpbm, tesseract and xdotool
# Could be freely distributable under term of GPL V3+
# (C) 2020 - F-Hauri.CH
#
# To be linked to special keyboard key shortcut...

# DEVICE="-d net:scanhost:genesys"

checkPz10() {
    if ! [[ "$1" =~ ^[0-9]+$ ]] ; then
        return false
    fi
    local pz=0 i tbl=(0 9 4 6 8 2 7 1 3 5) a=${1:0:-1} b=${1:${#1}-1}
    for ((i=0;i<${#a};i++));do
        pz=${tbl[($pz+${a:i:1})%10]}
    done
    pz=$((pz?10-pz:0))
    [ "$pz" = "$b" ]
}

string=$(
    scanimage $DEVICE --mode Gray --resolution 600 -t 12 -l 1 -y 13 -x 150 |
	pnmscale .33333 2>/dev/null |
	pnmflip -r180 |
	tee /tmp/lastocr.pnm |
	tesseract - - txt  2>/dev/null |
	tr -d $'\r\n\f'
      )

[ "${string// }" ] || exit 121

for check in ${string//[>+]/ };do
    checkPz10 $check || exit 123
done

xdostring=""
for ((i=0;i<${#string};i++)) {
	char=${string:i:1}
	char=${char// /space}
	char=${char//>/greater}
	char=${char//+/plus}
	xdostring+=$char\ 
}

xdotool key $xdostring Return