#!/usr/bin/env bash
# pve-wol-server.sh — Wake-on-LAN → Proxmox VM/LXC starter
#
# Listens for UDP/9 magic packets on a given interface, extracts the
# target MAC from the payload, finds the matching Proxmox guest and
# starts it if it is stopped.

set -Eeuo pipefail

# ===================== Config =====================

# Interface that sees the WOL packets (IP of the node)
# Override via environment: IFACE=mgmt1264 ./pve-wol-server.sh
IFACE="${IFACE:-proxmox}"

QEMU_CFG_DIR="/etc/pve/qemu-server"
LXC_CFG_DIR="/etc/pve/lxc"

DEBUG="${DEBUG:-1}"

# ===================== Helpers ====================

#log()   { printf '%s %s\n' "$(date -Is)" "$*" >&1; }
#debug() { [[ "$DEBUG" = "1" ]] && log "[DEBUG] $*"; }

log() {
  # send logs to stderr so they don’t corrupt command substitutions
  printf '%s %s\n' "$(date -Is)" "$*" >&2
}

debug() {
  [[ "$DEBUG" = "1" ]] && log "[DEBUG] $*"
}

get_wake_mac() {
  # Capture one UDP/9 packet on $IFACE, dump raw bytes,
  # locate 6x 0xff (ffffffffffff) and read the next 6 bytes as MAC.

  tcpdump -i "$IFACE" -c 1 -U -n -w - 'udp port 9' 2>/dev/null \
  | hexdump -ve '1/1 "%02x"' \
  | awk '
      {
        hex = $0
        # 6x ff = 12x "f"
        pos = index(hex, "ffffffffffff")
        if (pos == 0) {
          exit 1
        }
        # Immediately after that comes the 6-byte target MAC (12 hex chars)
        start = pos + 12
        mac   = substr(hex, start, 12)
        printf("%s:%s:%s:%s:%s:%s\n",
               substr(mac, 1,2), substr(mac, 3,2),
               substr(mac, 5,2), substr(mac, 7,2),
               substr(mac, 9,2), substr(mac,11,2))
      }'
}

find_guest_by_mac() {
  local mac="$1"
  local -a matches=()

  debug "Searching configs for MAC $mac"

  if [[ -d "$QEMU_CFG_DIR" ]]; then
    mapfile -t matches < <(grep -iRl -- "$mac" "$QEMU_CFG_DIR" 2>/dev/null || true)
    if (( ${#matches[@]} > 0 )); then
      [[ ${#matches[@]} -gt 1 ]] && log "Multiple QEMU configs match $mac, using ${matches[0]}"
      printf 'qemu|%s\n' "${matches[0]}"
      return 0
    fi
  fi

  if [[ -d "$LXC_CFG_DIR" ]]; then
    mapfile -t matches < <(grep -iRl -- "$mac" "$LXC_CFG_DIR" 2>/dev/null || true)
    if (( ${#matches[@]} > 0 )); then
      [[ ${#matches[@]} -gt 1 ]] && log "Multiple LXC configs match $mac, using ${matches[0]}"
      printf 'lxc|%s\n' "${matches[0]}"
      return 0
    fi
  fi

  return 1
}

start_qemu_vm() {
  local vm_id="$1"
  local status name

  status=$(qm status "$vm_id" --verbose 2>/dev/null | awk -F': *' '/^status:/{print $2; exit}')
  name=$(qm config "$vm_id" 2>/dev/null | awk -F': *' '/^name:/{print $2; exit}')
  [[ -z "$name" ]] && name="<unknown>"

  if [[ -z "$status" ]]; then
    log "VM $vm_id: unable to read status (wrong node or missing config?)"
    return 1
  fi

  log "VM $vm_id ($name) current status: $status"

  if [[ "$status" != "stopped" ]]; then
    log "SKIP   VM $vm_id ($name): already $status"
    return 0
  fi

  log "START  VM $vm_id ($name)"
  qm start "$vm_id"
}

start_lxc_ct() {
  local ct_id="$1"
  local status name

  status=$(pct status "$ct_id" --verbose 2>/dev/null | awk -F': *' '/^status:/{print $2; exit}')
  name=$(pct config "$ct_id" 2>/dev/null | awk -F': *' '/^hostname:/{print $2; exit}')
  [[ -z "$name" ]] && name="<unknown>"

  if [[ -z "$status" ]]; then
    log "CT $ct_id ($name) current status: $status"

    if [[ -z "$status" ]]; then
      log "CT $ct_id: unable to read status (wrong node or missing config?)"
      return 1
    fi
  fi

  if [[ "$status" != "stopped" ]]; then
    log "SKIP   CT $ct_id ($name): already $status"
    return 0
  fi

  log "START  CT $ct_id ($name)"
  pct start "$ct_id"
}

handle_mac() {
  local mac="$1"
  mac="${mac,,}"

  log "Captured magic packet for MAC: $mac"

  local guest_info guest_type cfg_path vm_file vm_id
  if ! guest_info="$(find_guest_by_mac "$mac")"; then
    log "No VM/LXC config contains MAC $mac"
    return 0
  fi

  guest_type="${guest_info%%|*}"
  cfg_path="${guest_info#*|}"
  vm_file="$(basename "$cfg_path")"
  vm_id="${vm_file%%.*}"

  log "Match: type=$guest_type id=$vm_id config=$cfg_path"

  case "$guest_type" in
    qemu) start_qemu_vm "$vm_id" ;;
    lxc)  start_lxc_ct "$vm_id" ;;
    *)    log "Internal error: unknown guest type '$guest_type'" ;;
  esac
}

# Test mode: simulate WOL for a given MAC
if [[ "${1:-}" == "--test" && -n "${2:-}" ]]; then
  handle_mac "${2,,}"
  exit 0
fi

log "WOL listener starting on interface $IFACE (UDP/9)"

while true; do
  debug "Waiting for magic packet on $IFACE ..."
  wake_mac="$(get_wake_mac || true)"

  if [[ -z "${wake_mac:-}" ]]; then
    debug "No MAC parsed from packet, retrying…"
    sleep 1
    continue
  fi

  handle_mac "$wake_mac"
  sleep 5    # simple rate limit
done