emcomm-tools-os-community/overlay/opt/emcomm-tools/bin/et-winlink-find

#!/bin/bash
#
# Author  : Gaston
# Date    : 30 November 2025
# Updated : 1 December 2025
# Purpose : Finds Winlink RMS stations by channel near a given location
set -o pipefail

source /opt/emcomm-tools/bin/et-common

# Temporary file to hold location for all supported location types
LOCATION_FILE=/tmp/location.json

[[ -e ${TMP_FILE} ]] && rm ${TMP_FILE}

usage() {
  echo "Usage: $(basename $0) [OPTIONS]"
  echo
  echo "Location options (choose one):"
  echo "  --call CALLSIGN        Search near callsign"
  echo "  --grid GRID            Search near Maidenhead grid"
  echo "  --latlon LAT,LON       Search near coordinates (use decimal degrees)"
  echo
  echo "If no location option is specified, your position will be pulled from a supported"
  echo "ETC GPS unit or fallback to the grid square configured by 'et-user'."
  echo
  echo "Other options (optional):"
  echo "  -b BAND                Band [70cm|2m|6m|10m|12m|15m|17m|20m|30m|40m|80m|160m]"
  echo "  -m MODE                Mode [ardop|vara|packet]"
  echo

  exit 1
}

loc_type=""
loc_value=""
band=""
mode=""

while [[ $# -gt 0 ]]; do
  case "$1" in
    --call)   loc_type="call";   loc_value="$2"; shift 2 ;;
    --grid)   loc_type="grid";   loc_value="$2"; shift 2 ;;
    --latlon) loc_type="latlon"; loc_value="$2"; shift 2 ;;
    -b)          band="$2"; shift 2 ;;
    -m)          mode="$2";  shift 2 ;;
    -*|--*)      echo "Unknown option: $1"; usage ;;
    -h|--help)   usage ;;
    *)           echo "Unexpected argument: $1"; usage ;;
  esac
done

# Use local ETC user position if location is not defined
if [[ -z $loc_type ]]; then
   loc_type="gps"
fi

#echo "$loc_type = $loc_value"

case "$loc_type" in
  gps)
    curl -f -s "http://localhost:1981/api/geo/position" | jq .position > ${LOCATION_FILE}
    if [[ $? -ne 0 ]]; then
      echo -e "${RED}Can't determine your position for use as the transmitting station.${NC}" >&2
      echo "Try specifying your callsign, grid or lat,lon." >&2
      echo "  --call CALLSIGN        Search near callsign" >&2
      echo "  --grid GRID            Search near Maidenhead grid" >&2
      echo "  --latlon LAT,LON       Search near coordinates (use decimal degrees)" >&2
      exit 1
    fi
    ;;
  call)
    curl -f -s "http://localhost:1981/api/license?callsign=${loc_value}" > ${LOCATION_FILE}
    if [[ $? -ne 0 ]]; then
      echo -e "${RED}Location not found for callsign: ${loc_value}.${NC}" >&2
      exit 1
    fi
    ;;
  grid)
    curl -f -s "http://localhost:1981/api/geo/grid?gridSquare=${loc_value}"  | jq '{lat: .position.lat, lon: .position.lon}' > ${LOCATION_FILE}
    if [[ $? -ne 0 ]]; then
      echo -e "${RED}Error converting grid to lat/lon using value: ${loc_value}.${NC}" >&2
      exit 1
    fi
    ;;
  latlon)
    # Write directly to JSON for consistency
    IFS=',' read -r tmpLat tmpLon <<< "$loc_value"
    if [[ -z $tmpLat || -z $tmpLon ]]; then
      echo -e "${RED}Invalid lat,lon format: $value. Expected 'lat,lon'.${NC}" >&2
      exit 1
    fi
    jq -n --arg lat "$tmpLat" --arg lon "$tmpLon" '{lat: ($lat|tonumber), lon: ($lon|tonumber)}' > ${LOCATION_FILE}
    ;;
  *)
    echo -e "${RED}Invalid location type: $loc_type${NC}" >&2
    exit 1 
    ;;
esac

validate_latitude() {
  local lat="$1"

  if [[ -z "$lat" ]]; then
    echo -e "${RED}Latitude can't be an empty value${NC}" >&2
    return 1
  fi

  if ! [[ "$lat" =~ ^-?[0-9]+([.][0-9]+)?$ ]]; then
    echo -e "${RED}Latitude must be a number${NC}" >&2
    return 1
  fi

  local latf
  latf=$(printf "%.10f" "$lat" 2>/dev/null) || {
    echo -e "${RED}Error converting latitude${NC}" >&2
    return 1
  }

  # Check range: -90 <= lat <= 90
  if (( $(echo "$latf < -90" | bc -l) )) || (( $(echo "$latf > 90" | bc -l) )); then
    echo -e "${RED}Latitude must be in range between -90 and 90 degrees${NC}" >&2
    return 1
  fi
}

validate_longitude() {
  local lon="$1"

  if [[ -z "$lon" ]]; then
    echo -e "${RED}Longitude can't be an empty value${NC}" >&2
    return 1
  fi

  if ! [[ "$lon" =~ ^-?[0-9]+([.][0-9]+)?$ ]]; then
    echo -e "${RED}Longitude must be a number${NC}" >&2
    return 1
  fi

  local lonf
  lonf=$(printf "%.10f" "$lon" 2>/dev/null) || {
    echo -e "${RED}Error converting longitude ${NC}" >&2
    return 1
  }

  # Check range: -180 <= lat <= 1800
  if (( $(echo "$lon < -180" | bc -l) )) || (( $(echo "$lon > 180" | bc -l) )); then
    echo -e "${RED}Longitude must be in range between -180 and 180 degrees${NC}" >&2
    return 1
  fi
}

LAT=$(jq .lat $LOCATION_FILE)
LON=$(jq .lon $LOCATION_FILE)

validate_latitude "$LAT" || exit 1
validate_longitude "$LON" || exit 1

QUERY="http://localhost:1981/api/winlink/near?lat=${LAT}&lon=${LON}"
[[ -n "${band}" ]] && QUERY="${QUERY}&band=${band}"
[[ -n "${mode}" ]] && QUERY="${QUERY}&mode=${mode}"

OUT=$(curl -s "${QUERY}")

if [[ -z "${OUT}" ]] || [[ "${OUT}" = "[]" ]]; then
    echo "No Winlink RMS channels found."
    exit 1
fi

echo
echo "Nearby Winlink RMS Channels:"
echo "----------------------------"

echo "${OUT}" | jq -r '
    (["Station","Callsign","Lat","Lon","Mode","Freq","Band"] | @tsv),
    (.[] | [
        .callsign,
        .base_callsign,
        (.lat | tostring),
        (.lon | tostring),
        .mode,
        (.freq | tostring),
        .band
    ] | @tsv)
' | column -t -s $'\t'