#!/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 $0`"
GLOBAL_USER_CONFIG_FILE="$HOME/.config/kvmxconfig"

# Load basic functions
export APP_BASE="`$DIRNAME/kvmx app_base`"
source $APP_BASE/lib/kvmx/functions || exit 1

# 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 {
  if [ -e "$GLOBAL_USER_CONFIG_FILE" ]; then
    source $GLOBAL_USER_CONFIG_FILE
  fi

  local default_password="`head -c ${1:-20} /dev/urandom | base64`"

  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)"
  kvmx_user_config   user              user                             "Initial user name"
  kvmx_user_config   password          $RANDOM                          "Initial user password"

  if [ ! -z "$image_base" ]; then
    image="$image_base/$hostname/box.img"
  else
    image_base="$HOME/.local/share/kvmx"
    kvmx_user_config image             $image_base/debian/box.img       "Destination image (ending in .img)"
  fi

  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   bootloader        grub                             "Bootloader: grub or extlinux"
}

# 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; do
    kvmx_install_package $req
  done

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

  if [ "$booloader" == "grub" ]; then
    boot_option="--grub"
  fi

  # Run
  kvmx_sudo_run vmdebootstrap --verbose --image=$image --size=$size --distribution=$version \
                              --mirror=$mirror --arch=$arch --hostname=$hostname.$domain $boot_option $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`"

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

  # Check for requirements.
  for req in debootstrap 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=$arch --include linux-image-$kernel_arch $version $WORK/ $mirror

  # Initial configuration.
  echo "Applying initial configuration..."

  # 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

  # Mount auxiliary filesystems needed by the bootloader
  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

  if [ "$bootloader" == "grub" ]; then
    $APT_INSTALL grub-pc
    kvmx_sudo_run chroot $WORK/ update-grub
    kvmx_sudo_run chroot $WORK/ grub-install $device
    # Possible alternatives:
    # https://packages.debian.org/jessie/grub-firmware-qemu
    # https://superuser.com/questions/130955/how-to-install-grub-into-an-img-file
    #kvmx_sudo_run grub-install --boot-directory=$WORK/boot $image
  elif [ "$bootloader" == "extlinux" ]; then
    # http://www.grulic.org.ar/~mdione/glob/posts/create-a-disk-image-with-a-booting-running-debian/
    # http://www.syslinux.org/wiki/index.php?title=EXTLINUX
    # http://www.syslinux.org/wiki/index.php?title=Mbr
    $APT_INSTALL extlinux
    kvmx_sudo_run chroot $WORK/ extlinux --install /boot
    kvmx_sudo_run dd bs=440 count=1 conv=notrunc if=$WORK/usr/lib/EXTLINUX/gptmbr.bin of=$device
    cat <<-EOF | $SUDO tee $WORK/boot/syslinux.cfg > /dev/null
default linux
timeout 1

label   linux
say     Booting linux...
linux   /vmlinuz
append  root=/dev/vda1 ro
initrd  /initrd.img
EOF
  fi

  # Umount auxiliary filesystems
  kvmx_sudo_run umount $WORK/proc
  kvmx_sudo_run umount $WORK/sys
  kvmx_sudo_run umount $WORK/dev

  # Run basic provision
  __kvmx_create_custom_second_stage

  # Umount image
  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`
}

# Second stage procedure
function __kvmx_create_custom_second_stage {
  # Networking: eth0
  cat <<-EOF | $SUDO tee $WORK/etc/network/interfaces.d/eth0 > /dev/null
allow-hotplug eth0
iface eth0 inet dhcp
EOF

  # Networking: ens3
  # See #799253 - virtio ens3 network interface
  #     https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=799253
  cat <<-EOF | $SUDO tee $WORK/etc/network/interfaces.d/ens3 > /dev/null
allow-hotplug ens3
iface ens3 inet dhcp
EOF

  # 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 "Updating list of packages..."
  #kvmx_sudo_run chroot $WORK/ apt-get update
  #kvmx_sudo_run chroot $WORK/ apt-get dist-upgrade -y

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

  # 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
  if ! grep -q "^$user:" $WORK/etc/passwd; then
    kvmx_sudo_run chroot $WORK/ useradd $user -G sudo -s /bin/bash
  fi

  if [ "$ssh_support" == "y" ]; then
    if [ "$ssh_custom" == "y" ]; then
      privkey="`dirname $image`/ssh/$hostname.key"
      pubkey="${privkey}.pub"
      mkdir -p "`dirname $privkey`"
      __kvmx_ssh_keygen $privkey "$user@$hostname"
    else
      pubkey="$DIRNAME/share/ssh/insecure_private_key.pub"
    fi

    kvmx_sudo_run chroot $WORK/ mkdir -p /home/$user/.ssh
    kvmx_sudo_run chroot $WORK/ chmod 700 /home/$user/.ssh
    kvmx_sudo_run cp $pubkey $WORK/home/$user/.ssh/authorized_keys
    kvmx_sudo_run chroot $WORK/ chmod 600 /home/$user/.ssh/authorized_keys
    kvmx_sudo_run touch  $WORK/home/$user/.hushlogin
  fi

  kvmx_sudo_run chroot $WORK/ chown -R $user.$user /home/$user
  echo "$user:$password" | kvmx_sudo_run chroot $WORK/ chpasswd
}

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