#!/bin/bash -eu
# Make a directory with content case-insensitive using chattr +F

NEWFLAGS="+F"

usage() {
    echo "Usage: $1 [-c] <directory>"
    echo
    echo "    Make an existing directory case-folding (chattr +F)"
    echo
    echo "Options:"
    echo "  -c    Clear the case-folding flag instead of setting it"
    exit $2
}

while getopts hc opt; do
    case "$opt" in
        h) usage "$0" 0;;
        c) NEWFLAGS="-F";;
        ?) usage "$0" 255;;
    esac
done

shift $((OPTIND - 1))

if [ ! -d "$1" ]; then
    echo -e "\e[31m'$1' is not a directory\e[0m"
    exit 1
fi

# Make sure it doesn't end in /
d="${1%/}"

set -x
# Create new directory with appropriate attributes
mkdir "$d.$$"
chattr $NEWFLAGS "$d.$$"
# Need to re-create the whole subtree, so the flag propagates
# Try to save space by making a recursive hardlink copy
cp -Tldr "$d" "$d.$$"
# Just to be on the safe side, fail if there are any files with a single reference left
find "$d" -type f,l -links +1 -delete
find "$d" -type d -empty -delete
[ ! -d "$d" ]
# Rename to old name
mv "$d.$$" "$d"