#!/usr/bin/env bash
# Shared mosquitto_pub/mosquitto_sub argument construction.
# Passwords are read from a protected file rather than placed in .env or Git.

mqtt_common_args() {
  MQTT_ARGS=(-h "$MQTT_HOST" -p "$MQTT_PORT")
  [[ -n "$MQTT_USERNAME" ]] && MQTT_ARGS+=(-u "$MQTT_USERNAME")
  if [[ -n "$MQTT_PASSWORD_FILE" ]]; then
    [[ -r "$MQTT_PASSWORD_FILE" ]] || die "MQTT password file is not readable: $MQTT_PASSWORD_FILE"
    MQTT_ARGS+=(-P "$(<"$MQTT_PASSWORD_FILE")")
  fi
}

mqtt_publish() {
  local topic="$1" payload="$2" retain="${3:-0}"
  [[ -n "$MQTT_HOST" ]] || die "MQTT_HOST is not configured"
  require_command mosquitto_pub
  mqtt_common_args
  # Backup state is retained so Home Assistant receives the latest result after
  # reconnecting. Command messages are handled separately and are never kept.
  (( retain )) && MQTT_ARGS+=(-r)
  mosquitto_pub "${MQTT_ARGS[@]}" -t "$topic" -m "$payload"
}