#!/bin/bash

# Storage device to install the linux.  
export DEV="/dev/sda"

# Whether you want to erase all contents of the storage device or not.
# 1 : Yes, I want to erase all.
# 0 : No, I don't. I want to add to the existing LUKS volume. 
export ERASEALL=1

# Logical Volume name for your Linux installation. Keep it unique from other distribution.
export LVROOTNAME="void"

# Logical volume size of the Linux installation.
# 30% mean, new logical volume will use 30% of the free space in the LVM volume group.
# For example, assume the free space is 100GB, and LVROOTSIZE is 30%FREE. Script will create 30GB logical volume.  
export LVROOTSIZE="50%FREE"

# Set the size of EFI partition and swap partition. The unit is Byte. you can use M,G... notation.
export EFISIZE="100M"
export LVSWAPSIZE="8G"

# Usually, these names can be left untouched. 
# If you change, keep them consistent through all instllation in your system.
export CRYPTPARTNAME="luks_volume"
export VGNAME="vg1"
export LVSWAPNAME="swap"

# ********************** DO NOT edit following lines ******************************

# Detect firmware type. 1 : EFI, 0 : BIOS
if [ -d /sys/firmware/efi ]; then
export ISEFI=1  # Yes, EFI
else
export ISEFI=0  # No, BIOS
fi # is EFI firmaare? 

# Set partition number based on the firmware type
if [  ${ISEFI} -eq 1  ] ; then 
# EFI firmware
export EFIPARTITION=1
export CRYPTPARTITION=2
else
# BIOS firmware
export CRYPTPARTITION=1
fi  # EFI firmware


# Varidate whether script is executed as sourced or not
(return 0 2>/dev/null) && sourced=1 || sourced=0
if [ $sourced -eq 0 ] ; then
	cat <<HEREDOC 1>&2
***** ERROR : Must execute as source *****
Execute as following : 
source 1-pre-install.sh

Installation terminated.
HEREDOC
	exit    # use "exit" instead of "return", if not "sourced" execusion
fi # "sourced" validation



# ----- Confirmations -----
# Distribution check
uname -a | grep void -i > /dev/null
if [ $? -eq 1  ] ; then	# "Void" is not found in the OS name.
	uname -a
	echo "This system seems to be not Void Linux, while this script is dediated to the Void Linux."
	echo "Are you sure you want to run this script for installation? [Y/N]"
	read YESNO
	if [ ${YESNO} != "Y" -a ${YESNO} != "y" ] ; then
		cat <<HEREDOC 1>&2

Installation terminated.
HEREDOC
		return
	fi	# if YES

fi # "Void" is not found in the OS name.

# For surre ask the config.sh is edited
echo "Did you edit config.sys? Are you ready to install? [Y/N]"
read YESNO
if [ ${YESNO} != "Y" -a ${YESNO} != "y" ] ; then
	cat <<HEREDOC 1>&2

Installation terminated.
HEREDOC
	return
fi	# if YES

# For sure ask ready to erase. 
if [ ${ERASEALL} -eq 1 ] ; then
	echo "Are you sure you want to erase entire ${DEV}? [Y/N]"
	read YESNO
	if [ ${YESNO} != "Y" -a ${YESNO} != "y" ] ; then
		cat <<HEREDOC 1>&2
Check config.sh. The variable ERASEALL is ${ERASEALL}.

Installation terminated.
HEREDOC
		return
	fi	# if YES
fi	# if erase all

# Install essential packages.
xbps-install -y gptfdisk

# ----- Set Passphrase -----
# Input passphrase
echo "Type passphrase for the disk encryption."
read -sr PASSPHRASE
export PASSPHRASE

echo "Type passphrase again, to confirm."
read -sr PASSPHRASE_C

# Validate whether both are indentical or not
if [ ${PASSPHRASE} != ${PASSPHRASE_C} ] ; then
	cat <<HEREDOC 1>&2
***** ERROR : Passphrase doesn't match *****
Installation terminated.
HEREDOC
	return
fi	# passphrase validation


# ----- Erase entire disk, create partitions, format them  and encrypt the LUKS partition -----
if [ ${ERASEALL} -eq 1 ] ; then

	# Assign specified space and rest of disk to the EFI and LUKS partition, respectively.
	if [  ${ISEFI} -eq 1 ] ; then
		# Zap existing partition table and create new GPT
		echo "...Initialize ${DEV} with GPT."
		sgdisk --zap-all "${DEV}"
		# Create EFI partition and format it
		echo "...Create an EFI partition on ${DEV}."
		sgdisk --new=${EFIPARTITION}:0:+${EFISIZE} --change-name=${EFIPARTITION}:"EFI System"  --typecode=${EFIPARTITION}:ef00 "${DEV}"  
		echo "...Format the EFI parttion."
		mkfs.vfat -F 32 -n EFI-SP "${DEV}${EFIPARTITION}"
		# Create Linux partition
		echo "...Create a Linux partition on ${DEV}."
		sgdisk --new=${CRYPTPARTITION}:0:0    --change-name=${CRYPTPARTITION}:"Linux LUKS" --typecode=${CRYPTPARTITION}:8309 "${DEV}"
		# Then print them
		sgdisk --print "${DEV}"
	else
		# Zap existing partition table
		echo "...Erase partition table of ${DEV}."
		dd if=/dev/zero of=${DEV} bs=512 count=1
		# Create MBR and allocate max storage for Linux partition
		echo "...Create a Linux partition on ${DEV} with MBR."
		sfdisk ${DEV} <<HEREDOC
2M,,L
HEREDOC
	fi	# if EFI firmware

	# Encrypt the partition to install Linux
	echo "...Initialize ${DEV}${CRYPTPARTITION} as crypt partition"
	printf %s "${PASSPHRASE}" | cryptsetup luksFormat --type=luks1 --key-file - --batch-mode "${DEV}${CRYPTPARTITION}"

fi	# if erase all

# ----- Open the LUKS partition -----
# Open the crypt partition. 
echo "...Open a crypt partition ${DEV}${CRYPTPARTITION} as \"${CRYPTPARTNAME}\""
printf %s "${PASSPHRASE}" | cryptsetup open -d - "${DEV}${CRYPTPARTITION}" ${CRYPTPARTNAME}

# Check whether successful open. If mapped, it is successful. 
if [ ! -e /dev/mapper/${CRYPTPARTNAME} ] ; then 
	cat <<HEREDOC 1>&2
***** ERROR : Cannot open LUKS volume "${CRYPTPARTNAME}" on ${DEV}${CRYPTPARTITION}. *****
Check passphrase and config.txt

Installation terminated.
HEREDOC
	return
fi	# if crypt volume is unable to open

# ----- Configure the LVM in LUKS volume -----
# Check volume group ${VGNAME} exist or not
vgdisplay -s ${VGNAME} &> /dev/null
if  [ $? -eq 0 ] ; then		# is return value 0? ( exist ?)
	echo "...Volume group ${VGNAME} already exist. Skipped to create. No problem."
else
	echo "...Initialize a physical volume on \"${CRYPTPARTNAME}\""
	pvcreate /dev/mapper/${CRYPTPARTNAME}
	echo "...And then create Volume group \"${VGNAME}\"."
	vgcreate ${VGNAME} /dev/mapper/${CRYPTPARTNAME}
fi # if /dev/volume-groupt not exist

# Create a SWAP Logical Volume on VG, if it doesn't exist
if [ -e /dev/mapper/${VGNAME}-${LVSWAPNAME} ] ; then 
	echo "...Swap volume already exist. Skipped to create. No problem."
else
	echo "...Create logical volume \"${LVSWAPNAME}\" on \"${VGNAME}\"."
	lvcreate -L ${LVSWAPSIZE} -n ${LVSWAPNAME} ${VGNAME} 
fi	# if /dev/mapper/swap volume already exit. 

# Create a ROOT Logical Volume on VG. 
if [ -e /dev/mapper/${VGNAME}-${LVROOTNAME} ] ; then 
	cat <<HEREDOC 1>&2
***** ERROR : Logical volume "${VGNAME}-${LVROOTNAME}" already exists. *****
Check LVROOTNAME environment variable in config.txt.

Installation terminated.
HEREDOC
	return
else
	echo "...Create logical volume \"${LVROOTNAME}\" on \"${VGNAME}\"."
	lvcreate -l ${LVROOTSIZE} -n ${LVROOTNAME} ${VGNAME}
fi	# if the root volun already exist

# ADD "rd.auto=1 cryptdevice=/dev/sda2:${LUKS_NAME} root=/dev/mapper/${VGNAME}-${ROOTNAME}" to GRUB.
# This is magical part. I have not understood why this is required. 
# Refer https://wiki.voidlinux.org/Install_LVM_LUKS#Installation_using_void-installer
echo "...Modify /etc/default/grub."
sed -i "s#loglevel=4#loglevel=4 rd.auto=1 cryptdevice=/dev/sda2:${LUKS_NAME} root=/dev/mapper/${VGNAME}-${ROOTNAME}#" /etc/default/grub

# Finishing message
if [ ${ISEFI} -eq 1 ] ; then
	cat <<HEREDOC

****************** Pre-install process finished ******************

...Next, open the void-installer, map the /, swap, EFI partition and start installation.
...And then, execute "source 2-para-install.sh" during the void-installer copies files. 
HEREDOC
else
	cat <<HEREDOC

****************** Pre-install process finished ******************

...Next, open the void-installer installer, map the /, swap volume and start installation.
...And then, execute "source 2-para-install.sh" during the void-installer copies files. 
HEREDOC
fi # Is EFI?