#!/bin/bash

########################################################################
#
# This script follows a guide to install Ubuntu on the ZFS filesystem:
# https://github.com/zfsonlinux/pkg-zfs/wiki/HOWTO-install-Ubuntu-18.04-to-a-Whole-Disk-Native-ZFS-Root-Filesystem-using-Ubiquity-GUI-installer
#
########################################################################

. `dirname "$0"`/install-common.sh || exit 1


#this should be executed after the reboot to remove the temporary datasets, create a snapshot, and update the system
if [[ "$1" == "--cleanup" ]]; then
    poolname2=`zpool list | tail -n +2 | cut -d' ' -f1`
    numpools=`echo $poolname2 | wc -l`
    if [[ $numpools != 1 ]]; then
        error "$numpools zfs pools found; expected 1"
    fi
    zfs snapshot $poolname2/ROOT/ubuntu-1@post-reboot || error "Error making snapshot of zfs pool"
    zfs destroy $poolname2/ubuntu-temp || error "Error removing temporary"
    apt update || error "Error with apt update"
    apt dist-upgrade -y || error "Error with dist-upgrade"
    zfs snapshot $poolname2/ROOT/ubuntu-1@post-reboot-updates || error "Error making post-update snapshot"
    color green "Cleanup succeeded! Enjoy your new Ubuntu installation on ZFS :)"
    exit
fi

ubuntu_release=`lsb_release -a|grep "Release:" | awk '{print $2}'`
if [[ "$ubuntu_release" == 16.04 ]]; then
    color green "This script has been tested with Ubuntu \"16.04\""
    zfsutils="zfsutils-linux"
elif [[ "$ubuntu_release" == 18.04 ]]; then
    color green "This script has been tested with Ubuntu \"18.04\""
    zfsutils="zfsutils"
else
    warning "This script has not been tested with Ubuntu \"$ubuntu_release\""
    zfsutils="zfsutils"
fi

apt update || error "Error retrieving latest package lists (apt update)"
apt install -y $zfsutils || error "Error installing zfsutils package"

#ask for the name of the pool and check to make sure it is valid
color green "What do you want to name the pool?"
read poolname
if ( echo "$poolname" | grep -q ' ' ) || [[ -z "$poolname" ]]; then
	error "FAILURE: pool name contains spaces or is empty: \"$poolname\". The convention is lowercase letters only, no spaces."
fi

#show user a choice of disk and get disk info; see function defined above
disk_status
echo "$disks"
color green "Enter which disk(s) you want to use separated by spaces. e.g. \"sdb sdc\""
color orange "WARNING: at this time, the only supported array types are single disks and mirrors with 2 disks. The script needs to be modified for different configurations. (You can add additional disks or mirrors later.) Please enter 1 or 2 disks."
read selected

#TODO add support for configs other than single disks or mirrors of just 2 disks
#make sure only 1 or 2 disks were selected
num_selected=`echo "$selected" | wc -w`
if [[ "$num_selected" -ne 1 ]] && [[ "$num_selected" -ne 2 ]]; then
    error "Only single disks and mirrors of 2 disks are supported, but you entered $num_selected disks."
fi

#loop through the disks the user selected and find them by id
ids=
ids_part1=
for d in $selected; do
    id=`echo "$disks" | grep "${d}$" | head -1 | awk '{print $1}'`
    if [[ -z "$id" ]]; then
        warning "no /dev/disk/by-id found for drive \"$d\"!"
        yes_or_no "Continue with the alternate name for the disk (/dev/$d)? This could cause problems if the name changes in the future. Storage built-in to a system should not change name."
        if [[ "$answer" == y ]]; then
            color yellow "Continuing with the alternate name."
            id="/dev/$d"
            if [[ "$d" == "nvme"* ]]; then
                id_part1="/dev/${d}p1"
            elif [[ "$d" == "sd"? ]]; then
                id_part1="/dev/${d}1"
            else
                id_part1="/dev/${d}1"
                warning "disk name format not recognized: \"${id}\" Assuming \"${id_part1}\" is 1st partition"
            fi
        else
            error "disk not found by ID and user selected not to identify it by the alternate name, so the disk could not be assigned a name"
        fi
    else
        id="/dev/disk/by-id/$id"
        id_part1="/dev/disk/by-id/${id}-part1"
    fi
    ids="$ids $id"
    ids_part1="$ids_part1 $id_part1"
done


if [[ "$num_selected" == 1 ]]; then
    yes_or_no "Do you want to store 2 copies of each file for redundancy and fault tolerance?"
    if [[ "$answer" == y ]]; then
        #this creates a zfs pool with a single disk with 2 copies of each file
        command="zpool create -f -o ashift=12 -O atime=off -O compression=lz4 -O normalization=formD -O recordsize=1M -O xattr=sa -O copies=2 $poolname $ids"
    else
        #this creates a zfs pool with a single disk and only 1 copy of each file
        command="zpool create -f -o ashift=12 -O atime=off -O compression=lz4 -O normalization=formD -O recordsize=1M -O xattr=sa $poolname $ids"
    fi
elif [[ "$num_selected" == 2 ]]; then
    #this command creates a mirror of the 2 disks with certain properties and optimizations enabled
    command="sudo zpool create -d -o feature@async_destroy=enabled -o feature@empty_bpobj=enabled -o feature@lz4_compress=enabled -o ashift=12 -O compression=lz4 -O atime=off $poolname mirror -f $ids" #$ids_part1"
else
    error "Invalid number of disks: $num_selected"
fi


disk_status
color orange "$command"
yes_or_no "Is this OK?"
if [[ "$answer" != "y" ]]; then
	error "ABORTED: user cancelled zfs pool creation"
fi

#run the command to create the zpool
if $command; then
	color green "SUCCESS: zfs pool creation succeeded!"
else
    #retrieve the name of the offending pool(s)
    poolname2=`zpool list | tail -n +2 | cut -d' ' -f1`
	error "FAILURE: zfs pool creation failed! This may have been caused by an already exsisting pool. Unmount it with \"sudo umount -R /$poolname2/; sudo zpool export $poolname2\" and re-run the script to continue."
fi

#upgrade and view the status of the pool
sudo zpool upgrade "$poolname" || error "Error upgrading $poolname"
sudo zpool status -v "$poolname" || error "Error getting status for $poolname"
sudo udevadm trigger || error "Error triggering the udev rule"


#create a temporary pool to install to
zfs create -V 10G $poolname/ubuntu-temp || error "Error creating temporary dataset in $poolname"

#show the user some steps to take manually
color green "Follow the steps below manually:"
cat << EOF
1. Choose any options you wish until you get to the 'Installation Type' screen. (For server applications, you may want to select the minimal installation)
2. Select 'Erase disk and install Ubuntu' and click 'Continue'.
3. Change the 'Select drive:' dropdown to '/dev/zd0 - 10.7 GB Unknown' and click 'Install Now'.
4. A popup summarizes your choices and asks 'Write the changes to disks?". Click 'Continue'.
5. At this point continue through the installer normally.
EOF

if [[ "$ubuntu_release" == 16.04 ]]; then
    echo "6. Finally, a message comes up 'Installation Complete'. DO NOT CLICK ON ANYTHING -- Leave the pop-up window open and continue this script"
    ubiquity --no-bootloader || error "Error with graphical installer &"
else
    echo "6. Finally, a message comes up 'Installation Complete'. Click the 'Continue Testing'."
    ubiquity --no-bootloader || error "Error with graphical installer"
fi

color green "Press ENTER after you have completed the above steps to continue"
read a

zfs create $poolname/ROOT || error "Error creating ROOT dataset in $poolname"
zfs create $poolname/ROOT/ubuntu-1 || error "Error creating ROOT/ubuntu-1 dataset in $poolname"
rsync -avPX /target/. /$poolname/ROOT/ubuntu-1/. || error "Error copying files to new dataset"

#mount important directories to the chroot environment
for d in proc sys dev
do
    mount --bind /$d /$poolname/ROOT/ubuntu-1/$d || error "Error mounting $d to the zfs filesystem for chroot"
done

#running commands inside the chroot
mych="chroot /$poolname/ROOT/ubuntu-1"

cp /etc/resolv.conf /$poolname/ROOT/ubuntu-1/etc/resolv.conf 
$mych apt update || error "Error retrieving package lists (in chroot)"
$mych apt install -y zfs-initramfs || error "Error installing zfs-initramfs (in chroot)"

#comment everything out in /etc/fstab
fstab_file="/$poolname/ROOT/ubuntu-1/etc/fstab"
fstab_contents=`cat $fstab_file`
echo "$fstab_contents" | awk '{print "#" $0}' | sudo tee "$fstab_file" || error "Error updating \"$fstab_file\""

$mych rm /swapfile || warning "Error removing swapfile (in chroot)"

$mych update-grub || error "Error updating grub (in chroot)"

#format the disks and install grub to them so all of them are bootable
for disk in $ids
do
    $mych sgdisk -a1 -n2:512:2047 -t2:EF02 $disk || error "Error formatting $disk"
    $mych grub-install $disk || error "Error installing grub to $disk"
done

umount -R /$poolname/ROOT/ubuntu-1 || error "Error unmounting dataset"
zfs set mountpoint=/ $poolname/ROOT/ubuntu-1 || error "Error setting mountpoint"
zfs snapshot $poolname/ROOT/ubuntu-1@pre-reboot || error "Error making zfs snapshot"
swapoff -a || error "Error unmounting swapfile"
umount /target    || error "Error unmounting /target"
zpool export $poolname   || error "Error exporting zfs pool"
#shutdown -r 0 || error "Error shutting down"

color green "Installation was successful! REBOOT NOW, then run this script with the --cleanup flag to remove the temporary files: '$0 --cleanup'"