#!/usr/bin/env bash
#
# kvmx-create virtual machine installer
#
# Copyright (C) 2017 Silvio Rhatto - rhatto at riseup.net
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published
# by the Free Software Foundation, either version 3 of the License,
# or 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

# Parameters
BASENAME="`basename $0`"
DIRNAME="`dirname $0`"

# Load configuration
function kvmx_config_load {
  if [ ! -z "$1" ] && [ -e "$1" ]; then
    source $1
  fi
}

# Read a parameter from user
function kvmx_user_input {
  local input
  local param="$1"
  local default="$2"
  shift 2

  if echo $param | grep -q 'passwd'; then
    read -s -rep "$* (defaults to $default): " input
  else
    read -rep "$* (defaults to $default): " input
  fi

  if [ -z "$input" ]; then
    export $param="$default"
  else
    export $param="$input"
  fi
}

# Get a configuration parameter if not previously defined by a sourced file
function kvmx_user_config {
  local param="$1"
  local default="$2"
  shift 2

  if [ -z "`eval echo '$'$param`" ]; then
    kvmx_user_input $param $default $*
  fi
}

# Install a package
function kvmx_install_package {
  if [ -z "$1" ]; then
    return
  fi

  dpkg -s $1 &> /dev/null

  if [ "$?" == "1" ]; then
    echo "Installing package $1..."
    DEBIAN_FRONTEND=noninteractive $SUDO apt-get install $1 -y || exit 1
  fi
}

# Abort on error
function kvmx_exit_on_error {
  if [ "$?" != "0" ]; then
    echo "Error: $*"
    exit 1
  fi
}

# Run a command using sudo and abort on error
function kvmx_sudo_run {
  if [ "`whoami`" != 'root' ]; then
    SUDO="sudo"
  fi

  $SUDO $*
  kvmx_exit_on_error $*
}

# Make sure there is provision config.
function kvmx_config {
  kvmx_user_config   image             /var/cache/qemu/debian/box.img   "Destination image"
  kvmx_user_config   size              3G                               "Image size"
  kvmx_user_config   format            qcow2                            "Image format: raw or qcow2"
  kvmx_user_config   method            custom                           "Bootstrap method: custom or vmdeboostrap"
  kvmx_user_config   hostname          machine                          "Hostname"
  kvmx_user_config   domain            example.org                      "Domain"
  kvmx_user_config   arch              amd64                            "System arch"
  kvmx_user_config   version           stretch                          "Distro version"
  kvmx_user_config   mirror            http://http.debian.net/debian/   "Debian mirror"
  kvmx_user_config   ssh_support       y                                "Administration using passwordless SSH (y/n)"
  kvmx_user_config   ssh_custom        y                                "Setup a custom SSH keypair (y/n)"
}

# Load config file
kvmx_config_load $1

# Get config parameters
kvmx_config

# Check
if [ -e "$image" ]; then
  echo "error: $image already exists."
  exit 1
fi

# Ensure base folder exists
kvmx_sudo_run mkdir -p `dirname $image`

#
# vmdebootstrap version
#
function kvmx_create_vmdebootstrap {
  # Check for requirements
  for req in vmdebootstrap mbr; do
    kvmx_install_package $req
  done

  # Image format
  if [ "$format" == "qcow2" ]; then
    format="--convert-qcow2"
  else
    formt=""
  fi

  # Run
  kvmx_sudo_run vmdebootstrap --verbose --image=$image --size=$size --distribution=$version \
    --mirror=$mirror --arch=$arch --hostname=$hostname.$domain    \
    --grub $format

  # Fix permissions
  kvmx_sudo_run chown -R `whoami`. `dirname $image`

  # Cleanup
  kvmx_sudo_run rm debootstrap.log
  kvmx_sudo_run rm ${image}.raw
}

#
# Custom version
#
function kvmx_create_custom {
  WORK="`mktemp -d`"

  # Check for requirements.
  for req in debootstrap grub-pc parted; do
    kvmx_install_package $req
  done

  echo "Creating image..."
  #kvmx_sudo_run dd if=/dev/zero of=$image bs=$size count=1
  kvmx_sudo_run qemu-img create -f raw $image $size
  device="`sudo losetup --find --show $image`"

  echo "Partitioning image at $device..."
  kvmx_sudo_run parted -s -- $device mklabel gpt
  kvmx_sudo_run parted -s -- $device unit    MB mkpart    non-fs 2  3
  kvmx_sudo_run parted -s -- $device set     1  bios_grub on
  kvmx_sudo_run parted -s -- $device unit    MB mkpart    ext2   3 -1
  kvmx_sudo_run parted -s -- $device set     2  boot on
  kvmx_sudo_run mkfs.ext4 ${device}p2
  kvmx_sudo_run mount ${device}p2 $WORK/

  # Non-interactive installation
  APT_INSTALL="kvmx_sudo_run LC_ALL=C DEBIAN_FRONTEND=noninteractive chroot $WORK/ apt-get install -y"

  # Initial system install.
  echo "Installing base system..."
  kvmx_sudo_run LC_ALL=C DEBIAN_FRONTEND=noninteractive debootstrap --arch=$arch $version $WORK/ $mirror

  # Initial configuration.
  echo "Applying initial configuration..."
  kvmx_sudo_run mount none -t proc  $WORK/proc
  kvmx_sudo_run mount none -t sysfs $WORK/sys
  kvmx_sudo_run mount -o bind /dev/ $WORK/dev

  # Hostname configuration.
  echo $hostname.$domain     | $SUDO tee    $WORK/etc/hostname > /dev/null
  echo "127.0.0.1 localhost" | $SUDO tee -a $WORK/etc/hosts    > /dev/null

  # This ordering is important for facter correctly guess the domain name
  echo "127.0.0.1 $hostname.$domain $hostname" | $SUDO tee -a $WORK/etc/hosts > /dev/null

  # Invert hostname contents to avoid http://projects.puppetlabs.com/issues/2533
  tac $WORK/etc/hosts | $SUDO tee $WORK/etc/hosts.new > /dev/null
  kvmx_sudo_run mv $WORK/etc/hosts.new $WORK/etc/hosts

  # Fstab
  echo "/dev/vda2 / ext4 errors=remount-ro 0 1" | $SUDO tee $WORK/etc/fstab > /dev/null

  # Locale
  $APT_INSTALL locales
  echo "LANG=$LANG"  | $SUDO tee    $WORK/etc/default/locale > /dev/null
  echo "$LANG UTF-8" | $SUDO tee -a $WORK/etc/locale.gen     > /dev/null
  kvmx_sudo_run chroot $WORK/ locale-gen

  # Initial upgrade
  echo "Applying initial upgrades..."
  kvmx_sudo_run chroot $WORK/ apt-get update
  kvmx_sudo_run chroot $WORK/ apt-get upgrade -y

  if [ "$arch" == "i386" ]; then
    kernel_arch="686"
  else
    kernel_arch="$arch"
  fi

  # Basic packages
  $APT_INSTALL screen cron lsb-release openssl rsync -y
  $APT_INSTALL spice-vdagent qemu-guest-agent

  # Kernel
  $APT_INSTALL linux-image-$kernel_arch -y

  # OpenSSH
  $APT_INSTALL openssh-server -y
  kvmx_sudo_run chroot $WORK/ service ssh stop

  # Sudo
  echo "Installing sudo..."
  $APT_INSTALL sudo -y
  echo "%sudo ALL=NOPASSWD: ALL" | $SUDO tee $WORK/etc/sudoers.d/local > /dev/null

  # Root password
  echo 'root:root' | kvmx_sudo_run chroot $WORK/ chpasswd

  # Initial user
  kvmx_sudo_run chroot $WORK/ useradd user -G sudo -s /bin/bash
  kvmx_sudo_run chroot $WORK/ mkdir -p /home/user/.ssh
  kvmx_sudo_run chroot $WORK/ chmod 700 /home/user/.ssh
  kvmx_sudo_run cp $DIRNAME/share/ssh/insecure_private_key.pub $WORK/home/user/.ssh/authorized_keys
  kvmx_sudo_run chroot $WORK/ chmod 600 /home/user/.ssh/authorized_keys
  kvmx_sudo_run touch  $WORK/home/user/.hushlogin
  kvmx_sudo_run chroot $WORK/ chown -R user.user /home/user
  echo 'user:user' | kvmx_sudo_run chroot $WORK/ chpasswd

  # Networking
  cat <<-EOF | $SUDO tee $WORK/etc/network/interfaces.d/ens3 > /dev/null
allow-hotplug ens3
iface ens3 inet dhcp
EOF

  # Grub
  $APT_INSTALL grub-pc -y
  kvmx_sudo_run chroot $WORK/ update-grub
  kvmx_sudo_run chroot $WORK/ grub-install $device

  # Teardown
  kvmx_sudo_run umount $WORK/proc
  kvmx_sudo_run umount $WORK/sys
  kvmx_sudo_run umount $WORK/dev
  kvmx_sudo_run umount $WORK
  kvmx_sudo_run rmdir  $WORK
  kvmx_sudo_run losetup -d $device

  # Image conversion
  if [ "$format" == "qcow2" ]; then
    echo "Converting raw image to qcow2..."
    kvmx_sudo_run mv $image $image.raw
    kvmx_sudo_run qemu-img convert -O qcow2 ${image}.raw $image
    kvmx_sudo_run rm ${image}.raw
  fi

  # Fix permissions
  kvmx_sudo_run chown -R `whoami`. `dirname $image`
}

# Dispatch
if [ "$method" == "custom" ]; then
  kvmx_create_custom
elif [ "$method" == "vmdebootstrap" ]; then
  kvmx_create_vmdebootstrap
else
  echo "$BASENAME: invalid method $method"
  exit 1
fi