#!/bin/ash

# Allow further customization via ENV variables
: ${MQTT_BASETOPIC:="owrtwifi"}
: ${MQTT_STATUS_TOPIC:="${MQTT_BASETOPIC}/status/mac-"}
: ${MQTT_MAINTENANCE_TOPIC:="${MQTT_BASETOPIC}/maintenance"}
: ${MQTT_USER:=""}
: ${MQTT_PASSWORD:=""}
: ${MQTT_ID:="${MQTT_BASETOPIC}"}

DEFAULT_MODE="event"
DEFAULT_MQTT_SERVER="10.1.1.50"
DEFAULT_LAST_SEEN_UPDATE_PERIOD_S=120

MODE=$DEFAULT_MODE
MQTT_SERVER=$DEFAULT_MQTT_SERVER
LAST_SEEN_UPDATE_PERIOD_S=$DEFAULT_LAST_SEEN_UPDATE_PERIOD_S

SCRIPT_NAME="$(basename "$(test -L "$0" && readlink "$0" || echo "$0")")"


# Parse command line args
test_for_mode() {
  param_mode=$1
  if [ "${param_mode}" == "event" -o "${param_mode}" == "lastseen" ]; then
    MODE=$param_mode
    return 0
  fi
  return 1
}

test_for_ipv4() {
  param_ip=$1
  echo $param_ip | grep -E '\b((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)(\.|$)){4}\b' > /dev/null
  if [ $? -eq 0 ]; then
    MQTT_SERVER=$param_ip
    return 0
  fi
  return 1
}

test_for_update_periode_s() {
  param_up=$1
  expr $param_up : '[0-9][0-9]*$'
  if [ $? -eq 0 ]; then
    LAST_SEEN_UPDATE_PERIOD_S=$param_up
    return 0
  fi
  return 1
}

print_usage() {
cat << EOF
Supported optional parameters:
  mode: "event" or "lastseen" (default: ${DEFAULT_MODE})
    In event mode changes of registered mac addresses are imediately pushed to the MQTT server
    In lastseen mode the registered mac addresses are periodically pushed to the MQTT server
  MQTT server IP: the IPv4 address of the MQTT server (default ${DEFAULT_MQTT_SERVER})
  Udate periode [s]: only relevant for lastseen mode  (default ${LAST_SEEN_UPDATE_PERIOD_S})
Examples:
  ${SCRIPT_NAME}
  ${SCRIPT_NAME} 192.168.1.2
  ${SCRIPT_NAME} lastseen 300
EOF
}

get_dhcp_name() {
  MAC=$1
  DHCP_NAME=$(grep ${MAC} /tmp/dhcp.leases | awk '{print $4}')
  if [ "$DHCP_NAME" = "*" ]; then
    return 1
  else
    echo ${DHCP_NAME}
    return 0
  fi
}

for param in "$@"; do
  test_for_mode $param || \
  test_for_ipv4 $param || \
  test_for_update_periode_s $param || \
  { print_usage; exit 1; }
done


if [ "${MODE}" == "event" ]; then
  echo "${SCRIPT_NAME}, mode: ${MODE}, MQTT server: ${MQTT_SERVER}"
  iw event | \
  while read LINE; do
    if echo $LINE | grep -q -E "(new|del) station"; then
      EVENT=$(echo ${LINE} | awk '/(new|del) station/ {print $2}')
      MAC=$(echo ${LINE} | awk '/(new|del) station/ {print $4}')

      echo "Mac: ${MAC} did ${EVENT}"
      mosquitto_pub \
        -h ${MQTT_SERVER} \
        -u ${MQTT_USER} -P ${MQTT_PASSWORD} -i ${MQTT_ID} \
        -t "${MQTT_STATUS_TOPIC}${MAC//:/-}/event" \
        -m $EVENT

      DHCP_NAME=$(get_dhcp_name ${MAC}) && mosquitto_pub \
          -h ${MQTT_SERVER} \
          -u ${MQTT_USER} -P ${MQTT_PASSWORD} -i ${MQTT_ID} \
          -t "${MQTT_STATUS_TOPIC}${MAC//:/-}/dhcp-name" \
          -m ${DHCP_NAME} \
          -r
    fi
  done
elif [ "${MODE}" == "lastseen" ]; then
  echo "${SCRIPT_NAME}, mode: ${MODE}, MQTT server: ${MQTT_SERVER}, period: ${LAST_SEEN_UPDATE_PERIOD_S}"
  while true; do
    CURRENT_TIMESTAMP=$(date "+%Y-%m-%d %H:%M:%S")
    CURRENT_TIMESTAMP_EPOCH=$(date -d "${CURRENT_TIMESTAMP}" +%s)
    CURRENT_TIMESTAMP_ISO8601=$(date -d "${CURRENT_TIMESTAMP}" -Iseconds)

    # Publish own lastseen state
    mosquitto_pub \
      -h ${MQTT_SERVER} \
      -u ${MQTT_USER} -P ${MQTT_PASSWORD} -i ${MQTT_ID} \
      -t "${MQTT_MAINTENANCE_TOPIC}/lastseen/epoch" \
      -m ${CURRENT_TIMESTAMP_EPOCH} \
      -r

    # Publish lastseen state of wifi devices
    for INTERFACE in $(iw dev | grep Interface | cut -f 2 -s -d" "); do
      # for each interface, get mac addresses of connected stations/clients
      MAC_LIST=$(iw dev ${INTERFACE} station dump | grep Station | cut -f 2 -s -d" ")
      for MAC in ${MAC_LIST}; do
        echo "lastseen epoch   ${MAC//:/-} ${CURRENT_TIMESTAMP_EPOCH}"
        mosquitto_pub \
          -h ${MQTT_SERVER} \
          -u ${MQTT_USER} -P ${MQTT_PASSWORD} -i ${MQTT_ID} \
          -t "${MQTT_STATUS_TOPIC}${MAC//:/-}/lastseen/epoch" \
          -m ${CURRENT_TIMESTAMP_EPOCH} \
          -r
        echo "lastseen iso8601 ${MAC//:/-} ${CURRENT_TIMESTAMP_ISO8601}"
        mosquitto_pub \
          -h ${MQTT_SERVER} \
          -u ${MQTT_USER} -P ${MQTT_PASSWORD} -i ${MQTT_ID} \
          -t "${MQTT_STATUS_TOPIC}${MAC//:/-}/lastseen/iso8601" \
          -m ${CURRENT_TIMESTAMP_ISO8601} \
          -r

        DHCP_NAME=$(get_dhcp_name ${MAC}) && mosquitto_pub \
          -h ${MQTT_SERVER} \
          -u ${MQTT_USER} -P ${MQTT_PASSWORD} -i ${MQTT_ID} \
          -t "${MQTT_STATUS_TOPIC}${MAC//:/-}/dhcp-name" \
          -m ${DHCP_NAME} \
          -r
      done
    done
    sleep $LAST_SEEN_UPDATE_PERIOD_S
  done
fi