#!/bin/bash -u

	# shellcheck disable=SC1091
	# Load configuration parameter
	source ./config.sh

	# Load common functions
	source ./lib.sh

function main() {

	# This is the mount point of the install target. 
	export TARGETMOUNTPOINT="/target"


	# ******************************************************************************* 
	#                                Confirmation before installation 
	# ******************************************************************************* 

	# parameters for distribution check
	export DISTRIBUTIONSIGNATURE="ubuntu"
	export DISTRIBUTIONNAME="Ubuntu"

	# Check whetehr given signature exist or not
	if ! distribution_check ; then
		return 1 # with error status
	fi

	# Common part of the parameter confirmation
	if ! confirmation ; then
		return 1 # with error status
	fi

	# ******************************************************************************* 
	#                                Pre-install stage 
	# ******************************************************************************* 

	# Common part of the pre-install stage
	if ! pre_install ; then
		return 1 # with error status
	fi


	# ******************************************************************************* 
	#                                Para-install stage 
	# ******************************************************************************* 

	# Start the GUI installer and modify the target /etc/default/grub in parallel
	if ! para_install_local ; then
		return 1 # with error status
	fi

	# ******************************************************************************* 
	#                                Post-install stage 
	# ******************************************************************************* 

	# Distribution dependent finalizing. Embedd encryption key into the ramfs image. 
	post_install_local

	# Normal end
	return 0

}	# End of main()


# ******************************************************************************* 
# Ubuntu dependent para-installation process
function para_install_local() {
	# Show common message to let the operator focus on the critical part
	para_install_msg

	# Distrobution dependent message
	cat <<- HEREDOC

	************************ CAUTION! CAUTION! CAUTION! ****************************
	
	Make sure to click "Continue Testing",  at the end of the Ubiquity installer.
	Just exit the installer without rebooting. Other wise, your system
	is unable to boot. 

	Type return key to start Ubiquity.
	HEREDOC

	# waitfor a console input
	read -r

	# Start Ubiquity installer 
	ubiquity &

	# Record the PID of the installer. 
	export INSTALLER_PID=$!


	# Record the install PID, modify the /etc/default/grub of the target, 
	# and then, wait for the end of the intaller. 
	if ! grub_check_and_modify_local ; then
		return 1 # with error status
	fi

	return 0
}

# ******************************************************************************* 
# Ubuntu dependent post-installation process
function post_install_local() {
	## Mount the target file system
	# ${TARGETMOUNTPOINT} is created by the GUI/TUI installer
	echo "...Mounting /dev/mapper/${VGNAME}-${LVROOTNAME} on ${TARGETMOUNTPOINT}."
	mount /dev/mapper/"${VGNAME}"-"${LVROOTNAME}" ${TARGETMOUNTPOINT}

	# And mount other directories
	echo "...Mounting all other dirs."
	for n in proc sys dev etc/resolv.conf; do mount --rbind "/$n" "${TARGETMOUNTPOINT}/$n"; done

	# Change root and create the keyfile and ramfs image for Linux kernel. 
	echo "...Chroot to ${TARGETMOUNTPOINT}."
	# shellcheck disable=SC2086
	cat <<- HEREDOC | chroot ${TARGETMOUNTPOINT} /bin/bash
	# Mount the rest of partitions by target /etc/fstab
	mount -a

	# Set up the kernel hook of encryption
	echo "...Installing cryptsetup-initramfs package."
	apt -qq install -y cryptsetup-initramfs

	# Prepare a key file to embed in to the ramfs.
	echo "...Prepairing key file."
	mkdir /etc/luks
	dd if=/dev/urandom of=/etc/luks/boot_os.keyfile bs=4096 count=1 status=none
	chmod u=rx,go-rwx /etc/luks
	chmod u=r,go-rwx /etc/luks/boot_os.keyfile

	# Add a key to the key file. Use the passphrase in the environment variable. 
	echo "...Adding a key to the key file."
	printf %s "${PASSPHRASE}" | cryptsetup luksAddKey -d - "${DEV}${CRYPTPARTITION}" /etc/luks/boot_os.keyfile

	# Add the LUKS volume information to /etc/crypttab to decrypt by kernel.  
	echo "...Adding LUKS volume info to /etc/crypttab."
	echo "${CRYPTPARTNAME} UUID=$(blkid -s UUID -o value ${DEV}${CRYPTPARTITION}) /etc/luks/boot_os.keyfile luks,discard" >> /etc/crypttab

	# Putting key file into the ramfs initial image
	echo "...Registering key file to the ramfs"
	echo "KEYFILE_PATTERN=/etc/luks/*.keyfile" >> /etc/cryptsetup-initramfs/conf-hook
	echo "UMASK=0077" >> /etc/initramfs-tools/initramfs.conf

	# Finally, update the ramfs initial image with the key file. 
	echo "...Upadting initramfs."
	update-initramfs -uk all

	# Leave chroot
	HEREDOC

	# Unmount all
	echo "...Unmounting all."
	umount -R ${TARGETMOUNTPOINT}

	# Finishing message
	cat <<- HEREDOC
	****************** Post-install process finished ******************

	...Ready to reboot.
	HEREDOC

	retrun 0

} # End of post_install_local()


# ******************************************************************************* 
# This function will be executed in the foreguround context, to watch the GUI installer. 
function grub_check_and_modify_local() {

	# While the /etc/default/grub in the install target is NOT existing, keep sleeping.
	# If installer terminated without file copy, this script also terminates.
	while [ ! -e ${TARGETMOUNTPOINT}/etc/default/grub ]
	do
		sleep 1 # 1sec.

		# Check if installer quit unexpectedly
		if ! ps $INSTALLER_PID  > /dev/null ; then	# If not exists
			# Delete the nwe volume if overwrite install, and close all
			on_unexpected_installer_quit
			return 1 # with error status
		fi
	done # while

	# Perhaps, too neuvous. Wait 1 more sectond to avoid the rece condition.
	sleep 1 # 1sec.

	# Make target GRUB aware to the crypt partition
	# This must do it after start of the file copy by installer, but before the end of the file copy.
	echo "...Adding GRUB_ENABLE_CRYPTODISK entry to ${TARGETMOUNTPOINT}/etc/default/grub "
	echo "GRUB_ENABLE_CRYPTODISK=y" >> ${TARGETMOUNTPOINT}/etc/default/grub

	# And then, wait for the end of installer process
	echo "...Waiting for the end of GUI/TUI installer."
	echo "...Again, DO NOT reboot/restart here. Just exit the GUI/TUI installer."
	wait $INSTALLER_PID

	# succesfull return
	return 0

} # grub_check_and_modify_local()

# ******************************************************************************* 
# Execute
main