#!/usr/bin/env zsh

setopt ERR_EXIT
tmp=`mktemp`
trap "rm -f $tmp.pnm $tmp.jxl" HUP PIPE INT QUIT TERM EXIT
case $1:e in
pnm) cp $1 $tmp.pnm ;;
gif) giftopnm < $1 > $tmp.pnm ;;
png) pngtopnm < $1 > $tmp.pnm ;;
webp) dwebp -mt -quiet -o $tmp.pnm $1 ;;
*)
    print unknown extension >&2
    exit 1
esac

common=(--quiet --distance=0 --effort=9 --brotli_effort=11)
prev=$(( 1 << 62 ))
best=""
zmodload -F zsh/stat b:zstat
for g (0 1 2 3) {
    opts=(--modular_group_size=$g)
    cjxl $common $opts $tmp.pnm $tmp.jxl
    zstat -A cur +size $tmp.jxl
    [[ $cur -gt $prev ]] || {
        prev=$cur
        best=($opts)
    }
}
zstat -A cur +size $1
[[ $cur -lt $prev ]] && {
    print $1 is smaller : $cur vs $prev
    exit 2
}
cjxl $common $best $tmp.pnm $1:r.jxl