#!/bin/sh
#
# Create a new VM for liw.


set -eu


verbose()
{
    echo "INFO: $@"
}


die()
{
    echo "$@" 1>&2
    exit 1
}


get_ip()
{
    python -c '
import sys, json
leases = json.load(open(sys.argv[1]))
for lease in leases:
    if lease["mac-address"] ==  sys.argv[2]:
        print lease["ip-address"]
' "$1" "$2" || true
}


xz_uncompressed_size()
{
    xz --robot --verbose --list "$1" | awk '/^file/ { print $5 }'
}

raw_uncompressed_size()
{
    stat -c %s "$1"
}


# Check parameters.

if [ "$#" -lt 2 ]
then
    die "Usage: $0 NAME BASE [virt-install-options]"
fi
verbose "Command line args OK"


# Config variables.
. "$HOME/.config/ansibleness/vm.conf"
verbose "Loaded config file"

# Command line parameters: name of VM and base image (no .img.xz suffix).
name="$1"
case "$2" in
    */*) basepath="$2" ;;
    *)   basepath="$imagedir/base-$2.img.xz" ;;
esac
verbose "basepath=$basepath"

shift 2

# Does the base image exist?
if [ ! -e "$basepath" ]
then
    echo "$basepath does not exist" 1>&2
    exit 1
fi
verbose "$basepath exists"

# Is base image compressed?
case "$basepath" in
    *.xz) xz=true ;;
    *) xz=false ;;
esac


# How large is the (uncompressed) image? In bytes.
if $xz
then
    size="$(xz_uncompressed_size "$basepath")"
else
    size="$(raw_uncompressed_size "$basepath")"
fi
verbose "Image is $size bytes"

# Create new LV.
verbose "Creating LV /dev/$vg/$name"
sudo lvcreate --name "$name" --size "${size}b" \
     --zero y --wipesignatures n --activate y "$vg"
lvpath="/dev/$vg/$name"
verbose "lvpath=$lvpath"
#sudo lvchange -ay "$lvpath"

# Copy uncompressed image to LV.
if $xz
then
    verbose "Uncompressing and copying image to LV"
    unxz < "$basepath" |
        pv --size "$size" |
        sudo ionice -c3 tee "$lvpath" > /dev/null
else
    verbose "Copying uncompressed imagew to LV"
    pv "$basepath" |
        sudo ionice -c3 tee "$lvpath" > /dev/null
fi

# Edit /etc/hostname
verbose "Set hostname on new system to $name"
mnt="$(mktemp -d)"
for part in $(sudo kpartx -asv "$lvpath" | awk '/^add map / { print $3 }')
do
    sudo mount "/dev/mapper/$part" "$mnt"
    if [ -e "$mnt/etc/hostname" ]
    then
        echo "$name" | sudo tee "$mnt/etc/hostname"
    fi
    sudo umount "$mnt"
done
sudo kpartx -dsv "$lvpath"

# Create VM.
verbose "Creating VM"
virt-install --connect qemu:///system \
             --quiet \
             --name="$name" \
             --memory=1024 \
             --cpu=host-model-only \
             --import \
             --os-variant=debian9 \
             --disk="path=$lvpath,cache=none" \
             --network="$vmnetwork" \
             --graphics=spice \
             --noautoconsole \
             "$@"

# If we're using the virtual network "default", wait for the VM to get
# a DHCP response and add it to /etc/hosts. We don't do it for other
# types of network (e.g., bridge=br0), since we ... can't.

if [ "$vmnetwork" = "network=default" ]
then
    verbose "Waiting for VM to boot and get IP"

    # Get the MAC address.
    mac="$(virsh -c qemu:///system dumpxml "$name" |
           sed -n "/<mac address=/s/^.*'\(.*\)'.*/\1/p")"
    verbose "MAC: $mac"

    # Get IP address related to the MAC address. Append that to /etc/hosts.
    leases=/var/lib/libvirt/dnsmasq/virbr0.status
    
    ip=""
    while [ "$ip" = "" ]
    do
        sleep 1
        if [ -s "$leases" ]
        then
            ip="$(get_ip "$leases" "$mac")"
        fi
    done
    echo "$ip $name" | sudo tee -a /etc/hosts > /dev/null

    # Done.
    echo "Virtual machine $name ($ip) has been created and started."
else
    echo "Virtual machine $name has been created and started, and may be ready soon."
fi