#!/bin/bash

# default values
PROGNAME=$(basename $0)
FULLPROG=$0

# usage
function usage () {
    echo "usage: $PROGNAME [-h] [-r] cmd"
    echo " -h: help message"
    echo " -s: set stats"
    echo " -r: reset stats"
    echo "cmd: shell command"
}

# reset
function reset () {
    echo "reseting stats"
    [ -f $resource ] && rm $resource
}

# variables
set=
cmd=
resource=$HOME/.$PROGNAME

# parameter processing
while [ $# -gt 0 ]; do
    if [ "$cmd" ]; then
        cmd="$cmd $1"
    else
        case "$1" in
        -h) usage; exit 0;;
        -s) set="yes";;
        -r) reset; exit 0;;
        *) cmd="$1";;
        esac
    fi
    shift
done

# check arguments
[ "$cmd" ] || { echo "no command specified"; exit 1; }
[ "$(which ${cmd/ *})" ] || { echo "command not found '$cmd'"; exit 1; }
 
# read old values
[ -f $resource ] && source $resource

# main
var=$(echo _$cmd | sed 's/[^A-Za-z0-9]/_/g;s/__*/_/g')
newvar=($(eval $cmd | awk '{ for (i = 1; i <= NF; i++) if ($(i) ~ /^[-+0-9][0-9]*$/) printf " %s", $(i) }'))
eval oldvar=(\${$var[@]})

# compute diff
for ((i=0; i<${#newvar[@]}; i++)); do
    [ "${oldvar[$i]}" ] && v[$i]=$((newvar[i] - oldvar[i])) || v[$i]=${newvar[$i]}
done

# ouput
if [ "$set" = "yes" ]; then
    echo "$var=(${newvar[@]})" >>$resource
    awk -F= '{ a[$1]=$2 } END { for (i in a) print i "=" a[i] }' $resource > $resource.n
    mv -f $resource.n $resource
else
    str=""
    for ((i=0; i<${#v[@]}; i++)); do
        str="$str; v[$i]=${v[$i]}"
    done
    eval $cmd | gawk 'BEGIN { k=0 '"$str"' } { n = 1; for (i=1; i<=NF; i++) if ($(i) ~ /^[-+0-9][0-9]*$/) { if ((i == 1) && ! ($0 ~ /^ /)) $(i) = v[k]; else $0 = gensub(/ [-+0-9][0-9]*/, " " v[k], n); k++; n++ } print }'
fi