#!/bin/bash -u
#   $0 [ type [ word ] ]
# type is 'solid' or 'clearing'
# Draw a circle on the terminal screen using cursor control.
# Put out the word or a "*" if no word.
# -Ian! D. Allen - idallen@idallen.ca - www.idallen.com

PATH=/bin:/usr/bin ; export PATH
LC_ALL=C ; export LC_ALL   # no internationalization in this script
LANG=C ; export LANG
umask 022

type=${1-'solid'}
word=${2-'*'}

ColourSwitch () {
    # this fails if terminal doesn't do colours; let it pass
    tput setaf ${colours[$colour]} # || exit $?
    colour=$(( colour + 1 ))
    if [ $colour -ge ${#colours[*]} ] ; then
        colour=0
    fi
}

el=
el1=
if [ "$type" = "clearing" ] ; then
	el=$( tput el ) || exit $?
	el1=$( tput el1 ) || exit $?
fi

ss=( $(stty size) ) || exit $?
rows=${ss[0]}
cols=${ss[1]}
width=$cols
margin=$(( width - ${#word} ))
or=$(( rows / 2 ))
oc=$(( cols / 2 ))
colours=( $( seq 1 6 | sort -R ) )
colour=0
r=$rows
# echo "colours ${colours[*]}"
while [ $r -gt 0 ] ; do
    for (( x=0 ; x <= r ; x++ )) ; do
	y=$( dc -e "5 k $r $r * $x $x * - v 0.5 + 0 k 2 / p" )
	#echo "x $x y $y"

        ox=$(( oc + x ))
	oy=$(( or + y ))
	(( x % 3 == 0 )) && ColourSwitch
        tput cup $oy $ox || exit $? ;  echo -n "$el1$word"
    done
    for (( x=r ; x >= 0 ; x-- )) ; do
	y=$( dc -e "5 k $r $r * $x $x * - v 0.5 + 0 k 2 / p" )
        ox=$(( oc + x ))
	oy=$(( or - y ))
	(( x % 3 == 0 )) && ColourSwitch
        tput cup $oy $ox || exit $? ;  echo -n "$el1$word"

    done
    for (( x=0 ; x <= r ; x++ )) ; do
	y=$( dc -e "5 k $r $r * $x $x * - v 0.5 + 0 k 2 / p" )
        ox=$(( oc - x  ))
	oy=$(( or - y  ))
	(( x % 3 == 0 )) && ColourSwitch
	if [ "$ox" -lt 0 ] ; then
	    ox=0
	fi
        tput cup $oy $ox || exit $? ;  echo -n "$word$el"
    done
    for (( x=r ; x >= 0 ; x-- )) ; do
	y=$( dc -e "5 k $r $r * $x $x * - v 0.5 + 0 k 2 / p" )
        ox=$(( oc - x  ))
	if [ "$ox" -lt 0 ] ; then
	    ox=0
	fi
	oy=$(( or + y ))
	(( x % 3 == 0 )) && ColourSwitch
        tput cup $oy $ox || exit $? ;  echo -n "$word$el"
    done
    r=$(( r - 5 ))
done
tput sgr0 || exit $?
tput cup 0 0 || exit $?