#!/bin/bash

set -e

###############################################################################
# Script to create a virtual machine for testing NetworkManager.
#
# Commands:
#  - build: build a new VM, named "$VM" ("nm").
#  - run: start the VM.
#  - exec: run bash inside the VM, connecting via ssh (this is the default).
#  - stop: stop the VM.
#  - reexec: stop and exec.
#  - clean: stop the VM and delete the image.
#
#   Commands exec and reexec accepts extra arguments, which are the command to
#   execute in the VM instead of opening an ssh session.
#
# NetworkManager directories:
#
#   The NetworkManager root directory is mounted in the VM as a filesystem share.
#   You can run `make install` and run tests.
#
#   Create a symlink ./.git/NetworkManager-ci, to share the CI directory too.
#
# Required packages:
#
#   Your host needs libvirt, libvirt-nss and guestfs-tools. To access the VM with
#   `ssh root@$VM`, configure /etc/nsswitch.conf as explained in
#   https://libvirt.org/nss.html (otherwise, `nm-in-vm exec` won't work, either).
#
# Prepare for testing:
#
#   There is a script nm-env-prepare.sh to generate a net1 interface for testing.
#   Currently NM-ci requires a working eth1, so use this before running a CI test:
#   `nm-env-prepare.sh --prefix eth -i 1 && sleep 1 && nmcli device connect eth1`
#
# Additional VMs:
#
#   By default, the VM named 'nm' is created, but additional ones can be created:
#   $ VM=nm2 nm-in-vm build
#   $ VM=nm2 nm-in-vm exec
#   $ VM=nm2 nm-in-vm stop
#
# Choosing a different OS:
#
#   By default Fedora is used, but you can choose a different OS. Most from the
#   list `virt-builder --list` will work.
#   $ OS_VERSION=debian-12 nm-in-vm build
#   $ nm-in-vm exec
#   $ nm-in-vm stop
###############################################################################

# Check for libvirt
if ! (command -v virsh && command -v virt-builder && command -v virt-install) &>/dev/null; then
    echo "libvirt and guestfs-tools are required" >&2
    exit 1
fi

# set defaults if user didn't define these values
VM=${VM:="nm"}
OS_VERSION=${OS_VERSION:=}
RAM=${RAM:=2048}
IMAGE_SIZE=${IMAGE_SIZE:=10G}
ROOT_PASSWORD=${ROOT_PASSWORD:=nm}
LIBVIRT_POOL=${LIBVIRT_POOL:=default}  # only useful if BASEDIR_VM_IMAGE is empty
BASEDIR_VM_IMAGE=${BASEDIR_VM_IMAGE:=}
BASEDIR_NM=${BASEDIR_NM:=}
BASEDIR_NM_CI=${BASEDIR_NM_CI:=}
HOST_BRIDGE=${HOST_BRIDGE:=virbr0}
SSH_LOG_LEVEL=${SSH_LOG_LEVEL:=ERROR}

if [[ -z $OS_VERSION ]]; then
    # if running Fedora, select same version, else select latest Fedora
    if grep -q "^ID=fedora$" /etc/os-release 2>/dev/null ; then
        OS_VERSION="$(sed -n 's/^VERSION_ID=\([0-9]\+\)$/fedora-\1/p' /etc/os-release)"
    else
        OS_VERSION=$(virt-builder --list | grep '^fedora' | sort | tail -n 1 | cut -d" " -f 1)
    fi
fi

if [[ -z $BASEDIR_NM ]]; then
    BASEDIR_NM="$(readlink -f "$(dirname -- "$BASH_SOURCE")/..")"
fi

if [[ -z $BASEDIR_NM_CI && -d "$BASEDIR_NM/.git/NetworkManager-ci" ]]; then
    BASEDIR_NM_CI="$(readlink -f "$BASEDIR_NM/.git/NetworkManager-ci")"
fi

if [[ -z $BASEDIR_VM_IMAGE ]]; then
    libvirt_pool_path_xml=$(virsh pool-dumpxml $LIBVIRT_POOL | grep -F '<path>')
    if [[ $libvirt_pool_path_xml =~ \<path\>(.*)\</path\> ]]; then
        BASEDIR_VM_IMAGE=${BASH_REMATCH[1]}
    else
        BASEDIR_VM_IMAGE=$BASEDIR_NM
    fi
fi

# compute some values that depends on user selectable variables
basedir_vm_image=$(readlink -f "$BASEDIR_VM_IMAGE")
vm_image_file="$VM.qcow2"
os_variant=${OS_VERSION//-/}  # virt-install --os-variant value, deduced from OS_VERSION
os_variant=${os_variant/centosstream/centos-stream}

##############################################################################

do_build() {
    local t
    t=$'\t'

    if vm_is_installed; then
        echo "The virtual machine '$VM' is already installed, skiping build" >&2
        return 0
    fi

    if vm_image_exists; then
        echo "The image '$basedir_vm_image/$vm_image_file' already exists, skiping build" >&2
        return 0
    fi

    if [[ -n $BASEDIR_NM_CI ]]; then
        nm_ci_mkdir=("--mkdir" "$BASEDIR_NM_CI")
        nm_ci_fstab=("--append-line" "/etc/fstab:/NM_CI${t}$BASEDIR_NM_CI${t}9p${t}trans=virtio,rw,_netdev${t}0${t}0")
        nm_ci_fs=("--filesystem" "$BASEDIR_NM_CI,/NM_CI")
    fi

    echo "Creating VM"
    echo " - VM NAME: $VM"
    echo " - OS VERSION: $OS_VERSION"
    echo " - SIZE: $IMAGE_SIZE"
    echo " - RAM: $RAM"
    echo " - ROOT PASSWORD: $ROOT_PASSWORD"
    echo " - IMAGE PATH: $basedir_vm_image/$vm_image_file"
    echo " - NM DIR: $BASEDIR_NM"
    echo " - NM CI DIR: $([[ -n $BASEDIR_NM_CI ]] && echo "$BASEDIR_NM_CI" || echo '<none>')"
    echo " - HOST BRIDGE: $HOST_BRIDGE"
    
    virt-builder "$OS_VERSION" \
        --output "$basedir_vm_image/$vm_image_file" \
        --size "$IMAGE_SIZE" \
        --format qcow2 \
        --arch x86_64 \
        --hostname "$VM" \
        --root-password password:nm \
        --ssh-inject root \
        --mkdir "$BASEDIR_NM" \
        --append-line "/etc/fstab:/NM${t}$BASEDIR_NM${t}9p${t}trans=virtio,rw,_netdev${t}0${t}0" \
        "${nm_ci_mkdir[@]}" \
        "${nm_ci_fstab[@]}" \
        --update

    virt-install \
        --name "$VM" \
        --ram "$RAM" \
        --disk "path=$basedir_vm_image/$vm_image_file,format=qcow2" \
        --os-variant "$os_variant" \
        --filesystem "$BASEDIR_NM,/NM" \
        "${nm_ci_fs[@]}" \
        --network "bridge=$HOST_BRIDGE" \
        --import \
        --autoconsole none \
        --noreboot
}

do_clean() {
    vm_is_running && virsh shutdown "$VM" &>/dev/null
    vm_is_installed && virsh undefine "$VM" &>/dev/null
    rm -f "$basedir_vm_image/$vm_image_file"
}

do_run() {
    vm_is_installed || do_build
    vm_is_running && return 0
    virsh start "$VM" >&2
}

do_exec() {
    do_run

    local failed=0
    while ! ping -c 1 "$VM" &>/dev/null; do
        failed=$((failed + 1))
        (( failed < 15 )) || die "Timeout trying to ping the VM"
        sleep 1
    done

    ssh \
        -o StrictHostKeyChecking=no \
        -o UserKnownHostsFile=/dev/null \
        -o LogLevel="$SSH_LOG_LEVEL" \
        "root@$VM" "$@"
}

do_reexec() {
    vm_is_running && do_stop

    local waited=0
    while vm_is_running; do
        waited=$((waited + 1))
        (( waited < 30 )) || die "Timeout waiting for VM shutdown"
        sleep 1
    done

    do_exec "$@"
}

do_stop() {
    vm_is_running && virsh shutdown "$VM" >&2
}

###############################################################################

vm_image_exists() {
    [[ -f "$basedir_vm_image/$vm_image_file" ]] || return 1
}

vm_is_installed() {
    virsh list --all --name | grep --fixed-strings --line-regexp "$VM" &>/dev/null || return 1
}

vm_is_running() {
    virsh list --name | grep --fixed-strings --line-regexp "$VM" &>/dev/null || return 1
}

usage() {
    echo "nm-in-vm [-h|--help] build|run|exec|stop|reexec|clean"
}

help() {
    usage
    echo
    awk '/^####*$/ { if (on) exit; on=-1; } !/^####*$/ { if (on) print(substr($0,3)) }' "$BASH_SOURCE"
    echo
}

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

###############################################################################

cmd=

while (( $# > 0 )); do
    case "$1" in
        build|run|exec|reexec|stop|clean)
            cmd="$1"
            shift
            ;;
        -h|--help)
            help
            exit 0
            ;;
        --)
            shift
            break
            ;;
        *)
            [[ $cmd != "" ]] && break
            echo "Invalid argument '$1'" >&2
            echo $(usage) >&2
            exit 1
            ;;
    esac
done

if [[ $cmd == "" ]]; then
    cmd=exec
fi

if [[ $UID == 0 ]]; then
    die "cannot run as root"
fi

if [[ $cmd != exec && $cmd != reexec && $# != 0 ]]; then
    die "Extra arguments are only allowed with exec|reexec command"
fi

do_$cmd "$@"