#!/usr/bin/env bash
set -euo pipefail

BASE_DIR="${BASE_DIR:-/mnt/user/services/posture-check}"
WATCHER_SCRIPT="${WATCHER_SCRIPT:-/mnt/user/services/homelab-infra/services/posture-check/docker-critical-events.sh}"
PID_FILE="${PID_FILE:-$BASE_DIR/docker-critical-events.pid}"
OUT_FILE="${OUT_FILE:-$BASE_DIR/docker-critical-events.out}"
EVENT_LOG="${EVENT_LOG:-$BASE_DIR/docker-critical-events-last.log}"
NTFY_SCRIPT="${NTFY_SCRIPT:-/mnt/user/services/homelab-infra/ops/restore-tests/send-ntfy.sh}"
NTFY_TOPIC="${NTFY_TOPIC:-homelab-alerts}"

usage() {
  cat >&2 <<EOF
Usage: $0 start|stop|restart|status|smoke

start    Start Docker critical-events watcher in the background.
stop     Stop the watcher by pidfile.
restart  Stop and start the watcher.
status   Print watcher status and recent log tail.
smoke    Send one ntfy test message through the same alert path.
EOF
}

is_running() {
  [ -s "$PID_FILE" ] || return 1
  local pid
  pid="$(cat "$PID_FILE")"
  [ -n "$pid" ] || return 1
  kill -0 "$pid" >/dev/null 2>&1
}

start_watcher() {
  mkdir -p "$BASE_DIR"

  if is_running; then
    echo "docker-critical-events watcher already running (pid $(cat "$PID_FILE"))"
    return 0
  fi

  if [ ! -r "$WATCHER_SCRIPT" ]; then
    echo "Watcher script not readable: $WATCHER_SCRIPT" >&2
    return 1
  fi

  NTFY_SCRIPT="$NTFY_SCRIPT" \
  NTFY_TOPIC="$NTFY_TOPIC" \
  OUTPUT_PATH="$EVENT_LOG" \
  nohup bash "$WATCHER_SCRIPT" >"$OUT_FILE" 2>&1 </dev/null &

  echo "$!" > "$PID_FILE"
  sleep 1

  if is_running; then
    echo "docker-critical-events watcher started (pid $(cat "$PID_FILE"))"
  else
    echo "docker-critical-events watcher failed to stay running; see $OUT_FILE" >&2
    return 1
  fi
}

stop_watcher() {
  if ! is_running; then
    rm -f "$PID_FILE"
    echo "docker-critical-events watcher is not running"
    return 0
  fi

  local pid
  pid="$(cat "$PID_FILE")"
  kill "$pid" >/dev/null 2>&1 || true
  sleep 1

  if kill -0 "$pid" >/dev/null 2>&1; then
    echo "watcher still running after SIGTERM; sending SIGKILL"
    kill -9 "$pid" >/dev/null 2>&1 || true
  fi

  rm -f "$PID_FILE"
  echo "docker-critical-events watcher stopped"
}

status_watcher() {
  if is_running; then
    echo "status=running pid=$(cat "$PID_FILE")"
  else
    echo "status=stopped"
    [ -e "$PID_FILE" ] && echo "stale_pidfile=$PID_FILE"
  fi

  echo "watcher_script=$WATCHER_SCRIPT"
  echo "event_log=$EVENT_LOG"
  echo "out_file=$OUT_FILE"

  if [ -s "$EVENT_LOG" ]; then
    echo
    echo "Recent critical events:"
    tail -n 20 "$EVENT_LOG"
  fi

  if [ -s "$OUT_FILE" ]; then
    echo
    echo "Recent watcher output:"
    tail -n 20 "$OUT_FILE"
  fi
}

smoke_ntfy() {
  if [ ! -r "$NTFY_SCRIPT" ]; then
    echo "ntfy helper not readable: $NTFY_SCRIPT" >&2
    return 1
  fi

  bash "$NTFY_SCRIPT" \
    "$NTFY_TOPIC" \
    "Docker critical watcher smoke" \
    "Smoke test from $(hostname) at $(date -Iseconds). No container was stopped." \
    default
  echo "smoke notification sent to $NTFY_TOPIC"
}

case "${1:-}" in
  start)
    start_watcher
    ;;
  stop)
    stop_watcher
    ;;
  restart)
    stop_watcher
    start_watcher
    ;;
  status)
    status_watcher
    ;;
  smoke)
    smoke_ntfy
    ;;
  *)
    usage
    exit 2
    ;;
esac