#!/bin/bash
#
# .---.                  .              .
# |                      |              |
# |--- .--. .-.  .-.  .-.|  .-. .--.--. |.-.  .-. .--.  .-.
# |    |   (.-' (.-' (   | (   )|  |  | |   )(   )|  | (.-'
# '    '     --'  --'  -' -  -' '  '   -' -'   -' '   -  --'
#
#                    Freedom in the Cloud
#
# Backup functions
#
# License
# =======
#
# Copyright (C) 2014-2016 Bob Mottram <bob@robotics.uk.to>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# whether a given site is being suspended during backup
SUSPENDED_SITE=

function suspend_site {
	# suspends a given website
	SUSPENDED_SITE="$1"
	nginx_dissite $SUSPENDED_SITE
	service nginx reload
}

function restart_site {
	# restarts a given website
	if [ ! $SUSPENDED_SITE ]; then
		return
	fi
	nginx_ensite $SUSPENDED_SITE
	service nginx reload
	SUSPENDED_SITE=
}

function configure_backup_key {
	if grep -Fxq "configure_backup_key" $COMPLETION_FILE; then
		return
	fi
	apt-get -y install gnupg

	BACKUP_KEY_EXISTS=$(gpg_key_exists "root" "$MY_NAME (backup key)")
	if [[ $BACKUP_KEY_EXISTS == "yes" ]]; then
		return
	fi

	# Generate a GPG key for backups
	BACKUP_KEY_EXISTS=$(gpg_key_exists "$MY_USERNAME" "$MY_NAME (backup key)")
	if [[ $BACKUP_KEY_EXISTS == "no" ]]; then
		echo 'Key-Type: 1' > /home/$MY_USERNAME/gpg-genkey.conf
		echo 'Key-Length: 4096' >> /home/$MY_USERNAME/gpg-genkey.conf
		echo 'Subkey-Type: 1' >> /home/$MY_USERNAME/gpg-genkey.conf
		echo 'Subkey-Length: 4096' >> /home/$MY_USERNAME/gpg-genkey.conf
		echo "Name-Real:  $MY_NAME" >> /home/$MY_USERNAME/gpg-genkey.conf
		echo "Name-Email: $MY_EMAIL_ADDRESS" >> /home/$MY_USERNAME/gpg-genkey.conf
		echo "Name-Comment: backup key" >> /home/$MY_USERNAME/gpg-genkey.conf
		echo 'Expire-Date: 0' >> /home/$MY_USERNAME/gpg-genkey.conf
		chown $MY_USERNAME:$MY_USERNAME /home/$MY_USERNAME/gpg-genkey.conf
		echo $'Backup key does not exist. Creating it.'
		su -c "gpg --batch --gen-key /home/$MY_USERNAME/gpg-genkey.conf" - $MY_USERNAME
		shred -zu /home/$MY_USERNAME/gpg-genkey.conf
		echo $'Checking that the Backup key was created'
		BACKUP_KEY_EXISTS=$(gpg_key_exists "$MY_USERNAME" "$MY_NAME (backup key)")
		if [[ $BACKUP_KEY_EXISTS == "no" ]]; then
			echo $'Backup key could not be created'
			exit 43382
		fi
	fi
	MY_BACKUP_KEY_ID=$(su -c "gpg --list-keys \"$MY_NAME (backup key)\" | grep 'pub '" - $MY_USERNAME | awk -F ' ' '{print $2}' | awk -F '/' '{print $2}')
	echo "Backup key: $MY_BACKUP_KEY_ID"
	MY_BACKUP_KEY=/home/$MY_USERNAME/backup_key
	su -c "gpg --output ${MY_BACKUP_KEY}_public.asc --armor --export $MY_BACKUP_KEY_ID" - $MY_USERNAME
	su -c "gpg --output ${MY_BACKUP_KEY}_private.asc --armor --export-secret-key $MY_BACKUP_KEY_ID" - $MY_USERNAME
	if [ ! -f ${MY_BACKUP_KEY}_public.asc ]; then
		echo 'Public backup key could not be exported'
		exit 36829
	fi
	if [ ! -f ${MY_BACKUP_KEY}_private.asc ]; then
		echo 'Private backup key could not be exported'
		exit 29235
	fi

	# import backup key to root user
	gpg --import --import ${MY_BACKUP_KEY}_public.asc
	gpg --allow-secret-key-import --import ${MY_BACKUP_KEY}_private.asc

	shred -zu ${MY_BACKUP_KEY}_public.asc
	shred -zu ${MY_BACKUP_KEY}_private.asc

	echo 'configure_backup_key' >> $COMPLETION_FILE
}

function backup_to_friends_servers {
	# update crontab
	echo '#!/bin/bash' > /etc/cron.daily/backuptofriends
	echo "if [ -f /usr/local/bin/${PROJECT_NAME}-backup-remote ]; then" >> /etc/cron.daily/backuptofriends
	echo "    /usr/local/bin/${PROJECT_NAME}-backup-remote" >> /etc/cron.daily/backuptofriends
	echo 'else' >> /etc/cron.daily/backuptofriends
	echo "    /usr/bin/${PROJECT_NAME}-backup-remote" >> /etc/cron.daily/backuptofriends
	echo 'fi' >> /etc/cron.daily/backuptofriends
	chmod +x /etc/cron.daily/backuptofriends
}

function backup_mount_drive {
	if [ $1 ]; then
		USB_DRIVE=/dev/${1}1
	fi

	# get the admin user
	ADMIN_USERNAME=$(cat $COMPLETION_FILE | grep "Admin user" | awk -F ':' '{print $2}')
	if [ $2 ]; then
		ADMIN_USERNAME=$2
	fi
	ADMIN_NAME=$(getent passwd $ADMIN_USERNAME | cut -d: -f5 | cut -d, -f1)

	if [ $3 ]; then
		RESTORE_APP=$3
	fi

	# check that the backup destination is available
	if [ ! -b $USB_DRIVE ]; then
		echo $"Please attach a USB drive"
		exit 1
	fi

	# unmount if already mounted
	umount -f $USB_MOUNT
	if [ ! -d $USB_MOUNT ]; then
		mkdir $USB_MOUNT
	fi
	if [ -f /dev/mapper/encrypted_usb ]; then
		rm -rf /dev/mapper/encrypted_usb
	fi
	cryptsetup luksClose encrypted_usb

	# mount the encrypted backup drive
	cryptsetup luksOpen $USB_DRIVE encrypted_usb
	if [ "$?" = "0" ]; then
		USB_DRIVE=/dev/mapper/encrypted_usb
	fi
	mount $USB_DRIVE $USB_MOUNT
	if [ ! "$?" = "0" ]; then
		echo $"There was a problem mounting the USB drive to $USB_MOUNT"
		rm -rf $USB_MOUNT
		exit 783452
	fi
}

function backup_unmount_drive {
	if [ $1 ]; then
		USB_DRIVE=${1}
		if [ $2 ]; then
			USB_MOUNT=${2}
		fi
	fi
	sync
	umount $USB_MOUNT
	if [ ! "$?" = "0" ]; then
		echo $"Unable to unmount the drive."
		rm -rf $USB_MOUNT
		exit 9
	fi
	rm -rf $USB_MOUNT
	if [[ $USB_DRIVE == /dev/mapper/encrypted_usb ]]; then
		echo $"Unmount encrypted USB"
		cryptsetup luksClose encrypted_usb
	fi
	if [ -f /dev/mapper/encrypted_usb ]; then
		rm -rf /dev/mapper/encrypted_usb
	fi
}

function backup_database_local {
	if [ ${#DATABASE_PASSWORD} -lt 2 ]; then
		echo $"No MariaDB password was given"
		function_check restart_site
		restart_site
		exit 10
	fi
	if [ ! -d $USB_MOUNT/backup/${1} ]; then
		mkdir -p $USB_MOUNT/backup/${1}
	fi
	if [ ! -d $USB_MOUNT/backup/${1}data ]; then
		mkdir -p $USB_MOUNT/backup/${1}data
	fi
	if [ ! -d /root/temp${1}data ]; then
		mkdir -p /root/temp${1}data
	fi
	echo $"Obtaining ${1} database backup"
	mysqldump --lock-tables --password="$DATABASE_PASSWORD" ${1} > /root/temp${1}data/${1}.sql
	if [ ! -s /root/temp${1}data/${1}.sql ]; then
		echo $"${1} database could not be saved"
		shred -zu /root/temp${1}data/*
		rm -rf /root/temp${1}data
		umount $USB_MOUNT
		rm -rf $USB_MOUNT
		restart_site
		exit 6835872
	fi
}

function backup_directory_to_usb {
	if [ ! -d ${1} ]; then
		echo $"WARNING: directory does not exist: ${1}"
	else
		BACKUP_KEY_EXISTS=$(gpg --list-keys "$ADMIN_NAME (backup key)")
		if [ ! "$?" = "0" ]; then
			echo $"Backup key could not be found"
			function_check restart_site
			restart_site
			exit 6
		fi
		MY_BACKUP_KEY_ID=$(gpg --list-keys "$ADMIN_NAME (backup key)" | grep 'pub ' | awk -F ' ' '{print $2}' | awk -F '/' '{print $2}')
		if [ ! -d $USB_MOUNT/backup/${2} ]; then
			mkdir -p $USB_MOUNT/backup/${2}
		fi
		obnam force-lock -r $USB_MOUNT/backup/${2} --encrypt-with $MY_BACKUP_KEY_ID ${1}
		obnam backup -r $USB_MOUNT/backup/${2} --encrypt-with $MY_BACKUP_KEY_ID ${1}
		if [[ $ENABLE_BACKUP_VERIFICATION == "yes" ]]; then
			obnam verify -r $USB_MOUNT/backup/${2} --encrypt-with $MY_BACKUP_KEY_ID ${1}
			if [ ! "$?" = "0" ]; then
				umount $USB_MOUNT
				rm -rf $USB_MOUNT
				if [[ ${1} == "/root/temp"* || ${1} == *"tempbackup" ]]; then
					shred -zu ${1}/*
					rm -rf ${1}
				fi
				function_check restart_site
				restart_site
				exit 683252
			fi
		fi
		obnam forget --keep=30d -r $USB_MOUNT/backup/${2} --encrypt-with $MY_BACKUP_KEY_ID
		if [ ! "$?" = "0" ]; then
			umount $USB_MOUNT
			rm -rf $USB_MOUNT
			if [[ ${1} == "/root/temp"* || ${1} == *"tempbackup" ]]; then
				shred -zu ${1}/*
				rm -rf ${1}
			fi
			function_check restart_site
			restart_site
			exit 7
		fi
		if [[ ${1} == "/root/temp"* || ${1} == *"tempbackup" ]]; then
			shred -zu ${1}/*
			rm -rf ${1}
		fi
	fi
}

function backup_database_to_usb {
	database_name=$1
	backup_database_local $database_name
	backup_directory_to_usb /root/temp${database_name}data ${database_name}data
}

# after user files have been restored permissions may need to be set
function set_user_permissions {
	echo $"Setting permissions"
	for d in /home/*/ ; do
		USERNAME=$(echo "$d" | awk -F '/' '{print $3}')
		if [[ $USERNAME != "git" && $USERNAME != "mirrors" && $USERNAME != "sync" ]]; then
			chown -R $USERNAME:$USERNAME /home/$USERNAME
		fi
	done
}

# NOTE: deliberately no exit 0