#!/bin/bash
# example: I=10 radar=00004 bomsnarf
# defaults to Melbourne 512km and 6 minute interval

mkdir -p imgs ; cd imgs

: ${I:=6}
: ${radar:=021}
: ${count:=10}
: ${site:=http://www.bom.gov.au}
: ${path:=/radar/IDR${radar}.T.}
: ${pre:="$site$path"}
: ${ext:=.png}

Z=$[$I * 60 - 60]
w=${pre##*/}
w=${w%.}

D=`dtu`
S=`date2secs "$D"`
get() {
	N=`secs2ndate "$S"`
	D=`secs2date "$S"`
	U="$pre$N$ext"
	F=${U##*/}
	already=0
#	printf "%-10s  %-s  $U  " "$w" "$D"
	printf "%-10s  %-s  " "$w" "$D"
	[ -e "$F" ] && { echo got; already=1; return 0; }
	wget -c -q "$U" && { echo "^_^"; return 0; }
	echo "0_o"
	return 1
}
while true; do
	get && break
	S=$[$S-60]
done
# TODO detect I if not specified?
if [ $already = 0 ]; then
	S0="$S"
	while true; do
		S=$[$S-$I*60]
		get || break
		[ $already = 1 ] && break
	done
	S="$S0"
fi
while true; do
	S=$[$S+$[$I*60]]
	while true; do
		get "$N" && break
		sleep $Z
	done
	sleep $Z
done