#! /bin/sh

set -e

case "$1" in
    '')
        current_wallpaper_file=$(
            awk '
                NR == 2 {
                    if (NF > 3) {
                        # XXX Assume feh wrote a N>4-field command line, like:
                        #         feh --no-fehbg --bg-scale $file
                        sub("^" $1 " +" $2 " +" $3 " +", "")
                    } else if (NF < 4) {
                        # XXX Assume feh wrote a N<4-field command line, like:
                        #         feh --bg-scale $file
                        sub("^" $1 " +" $2 " +", "")
                    } else {
                        printf "[error] Unexpected number of fields in ~/.fehbg command: %s\n" $0 > "/dev/stderr"
                        exit 1
                    }
                    print
                    exit 0
                }
                ' \
                ~/.fehbg \
            | xargs  # Unquote the filename, which feh puts in single quotes.
        );;
    *)
        current_wallpaper_file="$1"
esac

sha256sum "$current_wallpaper_file" >> "$FILE_WALLPAPER_FAVS"
sort -u "$FILE_WALLPAPER_FAVS" | sponge "$FILE_WALLPAPER_FAVS"