#!/run/current-system/sw/bin/bash
set -euo pipefail

WALLPAPER_DIR="$HOME/Wallpapers/pictures"
echo "Wallpaper dir = $WALLPAPER_DIR"

randomize_and_rename_wallpapers() {
    echo "Randomizing JPG filenames..."

    shopt -s nullglob

    # Grab all jpg/JPG files
    files=("$WALLPAPER_DIR"/*.[jJ][pP][gG])

    if [ ${#files[@]} -eq 0 ]; then
        echo "No JPG files found in $WALLPAPER_DIR"
        return
    fi

    # Shuffle the array
    mapfile -t files < <(printf "%s\n" "${files[@]}" | shuf)

    tmp_names=()

    for file in "${files[@]}"; do
        ext="${file##*.}"

        # generate a random 16-character alphanumeric name
        while : ; do
            rand_name=$(head /dev/urandom | tr -dc 'a-zA-Z0-9' | head -c16)
            new_path="$WALLPAPER_DIR/$rand_name.$ext"
            if [[ ! -e "$new_path" ]]; then
                mv "$file" "$new_path"
                tmp_names+=("$new_path")
                echo "Renamed $file -> $new_path"
                break
            fi
        done
    done

    # Sequentially rename to 01.jpg ... 99.jpg
    counter=1
    for file in "${tmp_names[@]}"; do
        new_name=$(printf "%02d.jpg" "$counter")
        mv "$file" "$WALLPAPER_DIR/$new_name"
        echo "Final rename $file -> $WALLPAPER_DIR/$new_name"
        ((counter++))
        [[ $counter -gt 99 ]] && break
    done

    echo "Randomization complete."
}

randomize_and_rename_wallpapers