#!/usr/bin/env bash
set -euC

################################################################################
## Constants

## FIXME: There seems to be a problem with file upload where the task is
## registered to `node051` no matter what node we are actually uploading to? For
## now, let us just use `node051` everywhere.
readonly node=node051

readonly tmpdir=/tmp/proxmox-remove-$RANDOM
mkdir $tmpdir

################################################################################
## Parse arguments

api_url=
username=
password=
vm_ids_or_names=

help () {
  cat <<EOF
Usage: $0 [OPTION...] ID_OR_NAME [ID_OR_NAME...]

Options:
  --api-url STR     Base URL of the Proxmox API (required)
  --username STR    Username, with provider (eg. niols@pve)
  --password STR    Password

  -h|-?|--help      Show this help and exit

Options can also be provided by adding assignments to a '.proxmox' file in the
current working directory. For instance, it could contain:

  api_url=https://192.168.51.81:8006/api2/json
  username=mireille@pve
  debug=true

Command line options take precedence over options found in the '.proxmox' file.
EOF
}

# shellcheck disable=SC2059
die () { printf '\033[31m'; printf "$@"; printf '\033[0m\n'; exit 2; }
# shellcheck disable=SC2059
die_with_help () { printf '\033[31m'; printf "$@"; printf '\033[0m\n'; help; exit 2; }

if [ -f .proxmox ]; then
  # shellcheck disable=SC1091
  . "$PWD"/.proxmox
fi

while [ $# -gt 0 ]; do
  argument=$1
  shift
  case $argument in
    --api-url|--api_url) readonly api_url="$1"; shift ;;
    --username) readonly username=$1; shift ;;
    --password) readonly password=$1; shift ;;

    -h|-\?|--help) help; exit 0 ;;

    -*) die_with_help "Unknown argument: '%s'." "$argument" ;;

    *) vm_ids_or_names="$vm_ids_or_names $argument" ;;
  esac
done

if [ -z "$vm_ids_or_names" ]; then
  die_with_help "Required: at least one VM id or name.\n"
fi

if [ -z "$api_url" ] || [ -z "$username" ] || [ -z "$password" ]; then
  die_with_help "Required: '--api-url', '--username' and '--password'."
fi

################################################################################
## Getting started

printf 'Authenticating...'
response=$(
    http \
        --verify no \
        POST "$api_url"/access/ticket \
        "username=$username" \
        "password=$password"
    )
ticket=$(echo "$response" | jq -r .data.ticket)
readonly ticket
csrf_token=$(echo "$response" | jq -r .data.CSRFPreventionToken)
readonly csrf_token
printf ' done.\n'

acquire_lock () {
  until mkdir "$tmpdir/lock-$1" 2>/dev/null; do sleep 1; done
}
release_lock () {
  rmdir "$tmpdir/lock-$1"
}

proxmox () {
  acquire_lock proxmox
  http \
    --verify no \
    --form \
    "$@" \
    "Cookie:PVEAuthCookie=$ticket" \
    "CSRFPreventionToken:$csrf_token"
  release_lock proxmox
}

## Way to inject different behaviour on unexpected status.
# shellcheck disable=SC2317
default_proxmox_sync_unexpected_status_handler () {
  die "unexpected status: '%s'" "$1"
}
proxmox_sync_unexpected_status_handler=default_proxmox_sync_unexpected_status_handler

## Synchronous variant for when the `proxmox` function would just respond an
## UPID in the `data` JSON field.
proxmox_sync () {
  local response upid status

  response=$(proxmox "$@")
  upid=$(echo "$response" | jq -r .data)

  while :; do
    response=$(proxmox GET "$api_url/nodes/$node/tasks/$upid/status")
    status=$(echo "$response" | jq -r .data.status)

    case $status in
      running) sleep 1 ;;
      stopped) break ;;
      *) "$proxmox_sync_unexpected_status_handler" "$status" ;;
    esac
  done
}

################################################################################
## Grab VM options
##
## Takes the name of the VM, grabs `.#vmOptions.<name>` and gets the id from it.

is_integer () {
  [ "$1" -eq "$1" ] 2>/dev/null
}

grab_vm_options () {
  local options

  if is_integer "$1"; then
    vm_id=$1
    vm_name="#$1"

  else
    vm_name=$1

    printf 'Grabing VM options for VM %s...\n' "$vm_name"

    options=$(
      nix eval \
        --impure --raw --expr "
          builtins.toJSON (builtins.getFlake (builtins.toString ./.)).vmOptions.$vm_name
        " \
      --log-format raw --quiet
    )

    vm_id=$(echo "$options" | jq -r .vmId)

    printf 'done grabing VM options for VM %s. Got id: %d.\n' \
      "$vm_name" "$vm_id"
  fi
}

################################################################################
## Stop VM

stop_vm () {
  printf 'Stopping VM %s...\n' "$vm_name"

  proxmox_sync POST "$api_url/nodes/$node/qemu/$vm_id/status/stop" \
    'overrule-shutdown'==1

  printf 'done stopping VM %s.\n' "$vm_name"
}

################################################################################
## Delete VM

# shellcheck disable=SC2317
proxmox_sync_unexpected_status_handler_ignore_null () {
  case $1 in
    null)
      printf "Attempted to delete VM %s, but got 'null' status. Maybe the VM already does not exist?\n" \
        "$vm_name"
      exit 0
      ;;
    *)
      default_proxmox_sync_unexpected_status_handler "$1"
      ;;
  esac
}

delete_vm () {
  printf 'Deleting VM %s...\n' "$vm_name"

  proxmox_sync_unexpected_status_handler=proxmox_sync_unexpected_status_handler_ignore_null
  proxmox_sync DELETE "$api_url/nodes/$node/qemu/$vm_id" \
    'destroy-unreferenced-disks'==1 \
    'purge'==1
  proxmox_sync_unexpected_status_handler=default_proxmox_sync_unexpected_status_handler

  printf 'done deleting VM %s.\n' "$vm_name"
}

################################################################################
## Main loop

printf 'Removing VMs%s...\n' "$vm_ids_or_names"

remove_vm () (
  grab_vm_options "$1"
  stop_vm
  delete_vm
)

for vm_id_or_name in $vm_ids_or_names; do
  remove_vm "$vm_id_or_name" &
done

nb_errors=0
while :; do
  wait -n && :
  case $? in
    0) ;;
    127) break ;;
    *) nb_errors=$((nb_errors + 1)) ;;
  esac
done
if [ "$nb_errors" != 0 ]; then
  die 'encountered %d errors while removing VMs%s.' "$nb_errors" "$vm_ids_or_names"
fi

printf 'done removing VMs%s.\n' "$vm_ids_or_names"

################################################################################
## Cleanup

rm -Rf $tmpdir
exit 0