#!/bin/bash

set -u # forbid undefined variables
set -e # forbid command failure

readonly PATH=/bin:/sbin:/usr/bin:/usr/sbin
export PATH

trap "echo -ne '\033[0m'" EXIT
echo -ne '\033[33;40m'

test_mach_o() {
    if $(file -b "$1" | grep 'executable ' | grep -sq 'Mach-O '); then
        # This is Mach-O file.
        exit 0
    fi

    exit 1
}

if [ ! -e "$1" ]; then
    echo "Invalid argument: '$1'"
    exit 1
fi

find "$1" -print0 | while read -d $'\0' filepath; do
    if [ -d "$filepath" ]; then
        chmod -h 755 "$filepath"
    else
        extension=${filepath##*.}
        if [ "$extension" = 'sh' ]; then
            chmod -h 755 "$filepath"
        elif $(test_mach_o "$filepath"); then
            # Preserve the set-user-ID-on-execution bits.
            chmod -h u+rwx,go=rx "$filepath"
        else
            chmod -h 644 "$filepath"
        fi
    fi
done