#!/bin/bash

# bcterm
# starts or activates wcalc calculator in urxvt window in the middle of the screen
# patch to your wbar button, openbox menu ...

# configurable variables
sleep="0.01"             # sleep before it gets active
ww="300"                 # window width
wh="300"                 # window height

# checks
command -v xdpyinfo >/dev/null 2>&1 ||    { >&2 echo "I need xdpyinfo." ; exit 1; }
command -v xdotool >/dev/null 2>&1 ||   { >&2 echo "I need xdotool." ; exit 1; }
command -v awk >/dev/null 2>&1 ||   { >&2 echo "I need awk." ; exit 1; }
#command -v bc >/dev/null 2>&1 ||   { >&2 echo "I need bc." ; exit 1; }
command -v wcalc >/dev/null 2>&1 ||   { >&2 echo "I need wcalc." ; exit 1; }

# get screen resolution width/height and halve it
read -r w h <<<$(xdpyinfo | awk -F'[ x]+' '/dimensions:/{print $3, $4}')
halfw=$((w / 2))
halfh=$((h / 2))

# calc stuff
centerw=$((halfw - ww / 2))
centerh=$((halfh - wh / 2))

# action

# check if one is allready active and select and exit
xdotool search -name 'calculus' windowactivate && { echo "allready running" ; exit; }

# if not launch one
(urxvt -bg black -title calculus -e wcalc & sleep "$sleep") && xdotool search --sync --name 'calculus' windowactivate windowsize "$ww" "$wh" windowmove "$centerw" "$centerh"
# replace 'wcalc -q' with 'bc -l' if you wish.