#!/bin/bash

if [[ $# -lt 2 ]]; then
    echo "Usage: $0 <dir1> <dir2> [del]"
    exit 1
fi

dir1="$1"
dir2="$2"

find "$dir1" -mindepth 2 -maxdepth 2 -type d -printf '%P\n' |
while IFS= read -r rel; do
    if [[ -d "$dir2/$rel" ]]; then
        # Exists in both
        if [[ "$3" == "del" ]]; then
            echo "Deleting: $dir1/$rel"
            rm -rf -- "$dir1/$rel"

            # Remove empty author directory
            author="${rel%%/*}"
            rmdir --ignore-fail-on-non-empty "$dir1/$author" 2>/dev/null
        fi
    else
        # Only exists in $1
        echo "$rel"
    fi
done