#!/bin/bash -eu

XARGS=(xargs -0 -P"$(nproc --ignore=4)" -I'{}' bash -c)
function compress() {
    local cmd files total newdir progress=0

    files=("$1"/*)
    total="${#files[@]}"
    newdir="$(basename "$1")_1080p"
    cmd=(magick '{}' -resize x1080 "$newdir/\$(basename '{}')" '>&2;' echo)
    mkdir -p "$newdir"
    while read -r; do
        echo $((++progress * 100 / total))
    done < <(printf '%s\0' "${files[@]}" | "${XARGS[@]}" "${cmd[*]}")
}

if [ $# = 0 ]; then
    mapfile -t < <(zenity --file-selection --multiple --directory --separator='//' | sed 's // \n g')
    set -- "${MAPFILE[@]}"
fi

for DIR in "$@"; do
    if [ -d "$DIR" ] && [ -x "$DIR" ]; then
        compress "$DIR" | zenity --progress --title="$DIR" --auto-close --time-remaining
    fi
done
zenity --info --text=DONE