#!/bin/sh

TMPDIR="${TMPDIR:-/tmp}"
tmp="$TMPDIR/nsxiv_rifle_$$"

is_img_extension() {
    grep -iE '\.(jpe?g|png|gif|svg|webp|tiff|heif|avif|ico|bmp)$'
}

listfiles() {
    find -L "///${1%/*}" -maxdepth 1 -type f -print |
        is_img_extension | sort -V | tee "$tmp"
}

open_img() {
    # only go through listfiles() if the file has a valid img extension
    if echo "$1" | is_img_extension >/dev/null 2>&1; then
        trap 'rm -f $tmp' EXIT
        count="$(listfiles "$1" | grep -nF "$1")"
    fi
    if [ -n "$count" ]; then
        nsxiv -i -n "${count%%:*}" -a -p -- < "$tmp"
    else
        # fallback incase file didn't have a valid extension, or we couldn't
        # find it inside the list
        nsxiv -a -p -- "$@"
    fi
}

[ "$1" = '--' ] && shift
case "$1" in
    "") echo "Usage: ${0##*/} PICTURES" >&2; exit 1 ;;
    /*) open_img "$1" ;;
    "~"/*) open_img "$HOME/${1#"~"/}" ;;
    *) open_img "$PWD/$1" ;;
esac