# by joevt Dec 30, 2020

checkkext () {
	local thekextpath="$1"
	if [[ -d "$thekextpath" ]]; then
		if [[ -f "$thekextpath/Contents/Info.plist" ]]; then
			local kextname="$(basename "$thekextpath")"
			if [[ "$kextname" =~ ".*\.kext" ]]; then
				local kextidentifier=""
				kextidentifier="$(/usr/libexec/PlistBuddy -c 'Print :CFBundleIdentifier' "$thekextpath/Contents/Info.plist" 2> /dev/null)"
				local theerr=$?
				if (( theerr == 0 )); then
					return 0
				else
					echo "# Missing CFBundleIdentifier" 1>&2
					return 1
				fi
			else
				echo "# That's not a kext" 1>&2
				return 1
			fi
		else
			echo "# Missing Info.plist" 1>&2
			return 1
		fi
	else
		echo "# Expected a kext folder" 1>&2
		return 1
	fi
}


unloadkext () {
	local thekextpath="$1"
	checkkext "$thekextpath" || return 1
	
	local kextname="$(basename "$thekextpath")"
	local kextsrcdir="$(dirname "$thekextpath")"
	local kexttmpdir="$(mktemp -d)"
	local kextinstalldir="/Library/Extensions"
	local kextidentifier="$(/usr/libexec/PlistBuddy -c 'Print :CFBundleIdentifier' "$thekextpath/Contents/Info.plist")"

	echo "# kextname: $kextname"
	echo "# kextidentifier: $kextidentifier"
	if ( kextstat | grep -q "$kextidentifier" ); then
		while ( kextstat | grep -q "$kextidentifier" ); do
			echo "# Unloading $kextname"
			sleep 1
			sudo kextunload -b "$kextidentifier"
		done
		echo "# $kextname is unloaded"
	else
		echo "# $kextname is not loaded"
	fi
}


installkext () {
	local doload=0
	if [[ "$1" == "-l" ]]; then
		doload=1
		shift 1
	fi
	local thekextpath="$1"
	checkkext "$thekextpath" || return 1
	
	local kextname="$(basename "$thekextpath")"
	local kextsrcdir="$(dirname "$thekextpath")"
	local kexttmpdir="$(mktemp -d)"
	local kextinstalldir="/Library/Extensions"
	local kextidentifier="$(/usr/libexec/PlistBuddy -c 'Print :CFBundleIdentifier' "$thekextpath/Contents/Info.plist")"

	if ((doload)); then
		unloadkext "$thekextpath"
	else
		echo "# kextname: $kextname"
		echo "# kextidentifier: $kextidentifier"
	fi

	mount | grep ' on / ' | grep -q 'read-only' && sudo mount -uw /

	sudo cp -R "$thekextpath" "$kexttmpdir/$kextname"
	sudo chown -R root:wheel "$kexttmpdir/$kextname"
	sudo find "$kexttmpdir/$kextname" -type d -exec /bin/chmod 0755 {} \;
	sudo find "$kexttmpdir/$kextname" -type f -exec /bin/chmod 0644 {} \;
	if [[ -n "$kextinstalldir" ]]; then
		[[ -d "/System/Library/Extensions/$kextname" ]] && sudo rm -R "/System/Library/Extensions/$kextname"
		[[ -d "/Library/Extensions/$kextname" ]] && sudo rm -R "/Library/Extensions/$kextname"
		sudo mv "$kexttmpdir/$kextname" "$kextinstalldir"
		if ((doload)); then
			sudo kextutil "$kextinstalldir/$kextname"
		fi
	else
		if ((doload)); then
			sudo kextutil "$kexttmpdir/$kextname"
		fi
	fi
	if ((doload)); then
		kextstat | grep "$kextidentifier"
	fi
}


removekext () {
	local thekextpath="$1"
	[[ -d "$thekextpath" ]] && sudo rm -R "$thekextpath"
}


rebuildkextcache () {
	sudo kextcache -i /
}