#!/bin/sh

ERR () {
	printf '[ERROR] %s\n' "$1"
	test -n "$2" && exit "$2"
}

TRY_AND_RETRY () {
	while ! $1
	do
		ERR "$2"
		echo -n 'Want to try again? (Y/n) '
		read choose
		case "$choose" in
			N|n) exit 1 ;;
		esac
	done
}

sudo_prog='sudo --prompt=Sudo_Password:'
cur_uid="$(id -u)"
cur_gid="$(id -g)"

_MOUNT () {
	test -e "${2}" || TRY_AND_RETRY "mkdir ${2}" "Failed to create directory: ${2}"
	echo "Mounting ${1} into ${2}"
	TRY_AND_RETRY "${sudo_prog} mount ${1} ${2}" "Failed to mound ${1} on ${2}."
	echo "Succesfully Mounted ${1} into ${2}"
}

_LUKS_OPEN () {
	echo "Opening Encrypted file: ${1} as ${2}"
	TRY_AND_RETRY "${sudo_prog} cryptsetup luksOpen ${1} ${2}" "Failed to open luks file: ${1}."
	echo "Succesfully Opened Encrypted file: ${1} as ${2}"
}

_CHECK_DIR_PERM () {
	dir_perm="$(stat -c '%u:%g' "${1}")"
	cur_perm="${cur_uid}:${cur_gid}"
	test "$dir_perm" = "$cur_perm" && return 0
	echo -n "Directory ${1} is not owned by current user. Want to change direcory owner? (Y/n) "
	read choose
	case "$choose" in
		N|n) return 0 ;;
	esac
	echo "Changing ownership of ${1} from ${dir_perm} to ${cur_perm}."
	TRY_AND_RETRY "${sudo_prog} chown ${cur_perm} ${1}" || ERR "Failed to change permission of directory ${1} from ${dir_perm} to ${cur_perm}." 1
}

file_path="$1"
test -n "$file_path" || { echo 'No file given'; exit 1; }
file="$(basename "$file_path")"
name="$(echo "$file" | cut -d. -f1)"
_name="__${name}__"
ext="$(echo "$file" | cut -d. -f2)"
block_dev="/dev/mapper/${_name}"

test "$ext" = 'luks' || ERR "File $file_path does not have extencion .luks." 1

if test -e ./"$name"
then
	test -d "./${name}" || ERR "File ${name} already exist in current directory. And is not a directory." 1

	if test -b "$block_dev"
	then
		echo -n "File ${file_path} Already open. Want to close? (Y/n) "
		read choose
		case "$choose" in
			N|n) exit 0 ;;
		esac
		echo "Unmounting ./${name}"
		TRY_AND_RETRY "${sudo_prog} umount ./${name}" "Failed to unmount ./${name}."
		echo "Succesfully Unmounted ./${name}"

		echo "Closing luks block dev ${block_dev}"
		TRY_AND_RETRY "${sudo_prog} cryptsetup close ${block_dev}" "Failed to close luks file: ${file_path}."
		echo "Succesfully Closed ${file_path}."

		echo -n "Delete directory ./${name}? (Y/n) "
		read choose
		case "$choose" in
			N|n) exit 0 ;;
		esac

		TRY_AND_RETRY "rmdir ./${name}" "Failed to remove directory: ./${name}"
		exit 0
	fi
fi

if test -e "$file_path"
then
	test -f "$file_path" || ERR "${file_path} Is not a regular file" 1

	file_type="$(file -b ${file_path} | cut -d' ' -f-2)"
	test "$file_type" = 'LUKS encrypted' || ERR "${file_path} is not a LUKS encrypted file." 1
else
	echo -n "File ${file_path} does not exist. Want to create? (Y/n) "
	read choose
	case "$choose" in
		N|n) exit 1 ;;
	esac

	echo -n "What size? (10G) "
	read _size
	if test "$choose" = ''
	then
		_size='10G'
	fi
	truncate --size="$_size" "$file_path" || ERR "Failed to allocate file: ${file_path}" 1
	echo "Succesfully Allocated file: ${file_path}"

	echo "Encrypting file: ${file_path}"
	TRY_AND_RETRY "cryptsetup luksFormat -c aes-xts-plain64 -s 512 -y ${file_path}" "Failed to format file: ${file_path}"
	echo "Succesfully Encrypted file: ${file_path}"

	_LUKS_OPEN "$file_path" "$_name"

	echo "Formating ${_name} as ext4"
	TRY_AND_RETRY "${sudo_prog} mkfs.ext4 -m0 ${block_dev}" "Failed to format block dev: ${block_dev}"
	echo "Succesfully Formated ${_name} as ext4"

	_MOUNT "$block_dev" "./${name}"

	_CHECK_DIR_PERM "./${name}"

	echo "Succesfully Created and Opened file: ${file_path} into ./${name}"

	exit 0
fi

_LUKS_OPEN "$file_path" "$_name"

_MOUNT "$block_dev" "./${name}"

_CHECK_DIR_PERM "./${name}"

echo "Opened ${file_path} on ./${name}"

exit 0