aprs.me/lib/aprs_web/live/packets_live/callsign_view.ex

defmodule AprsWeb.PacketsLive.CallsignView do
  @moduledoc """
  LiveView for displaying packets specific to a single callsign.

  Shows up to 100 packets total (stored + live) for the specified callsign.
  Includes both stored packets from the database (last hour) and live incoming packets.
  """
  use AprsWeb, :live_view

  import Ecto.Query

  alias Aprs.EncodingUtils
  alias Aprs.Packet
  alias Aprs.Repo
  alias AprsWeb.Endpoint

  @impl true
  def mount(%{"callsign" => callsign}, _session, socket) do
    # Validate and normalize callsign
    normalized_callsign = String.upcase(String.trim(callsign))

    if valid_callsign?(normalized_callsign) do
      # Subscribe to live packet updates if connected
      if connected?(socket) do
        Endpoint.subscribe("aprs_messages")
      end

      # Get stored packets for this callsign (up to 100)
      stored_packets = get_stored_packets(normalized_callsign, 100)

      socket =
        socket
        |> assign(:callsign, normalized_callsign)
        |> assign(:packets, stored_packets)
        |> assign(:live_packets, [])
        |> assign(:all_packets, stored_packets)
        |> assign(:error, nil)

      {:ok, socket}
    else
      socket =
        socket
        |> assign(:callsign, normalized_callsign)
        |> assign(:packets, [])
        |> assign(:live_packets, [])
        |> assign(:all_packets, [])
        |> assign(:error, "Invalid callsign format")

      {:ok, socket}
    end
  end

  @impl true
  def handle_info(%{event: "packet", payload: payload}, socket) do
    # Handle incoming live packets - only process if they match our callsign
    # Only process packets for this specific callsign
    if packet_matches_callsign?(payload, socket.assigns.callsign) do
      # Sanitize the packet to prevent JSON encoding errors
      sanitized_payload = EncodingUtils.sanitize_packet(payload)

      # Add to live packets and maintain combined limit of 100
      current_live = socket.assigns.live_packets
      current_stored = socket.assigns.packets

      # Calculate how many total packets we have
      total_count = length(current_live) + length(current_stored)

      # If we're at or over the limit, remove the oldest stored packet
      {updated_stored, updated_live} =
        if total_count >= 100 do
          # Remove the oldest stored packet if we have any, otherwise remove oldest live
          case current_stored do
            [] ->
              # No stored packets, remove oldest live packet
              live_without_oldest = Enum.drop(current_live, -1)
              {current_stored, [sanitized_payload | live_without_oldest]}

            _ ->
              # Remove oldest stored packet
              stored_without_oldest = Enum.drop(current_stored, -1)
              {stored_without_oldest, [sanitized_payload | current_live]}
          end
        else
          # Under limit, just add the new packet
          {current_stored, [sanitized_payload | current_live]}
        end

      # Calculate combined packets for display
      all_packets = get_all_packets_list(updated_stored, updated_live)

      socket =
        socket
        |> assign(:packets, updated_stored)
        |> assign(:live_packets, updated_live)
        |> assign(:all_packets, all_packets)

      {:noreply, socket}
    else
      {:noreply, socket}
    end
  end

  @impl true
  def handle_info(_message, socket) do
    {:noreply, socket}
  end

  # Private helper functions

  # Get recent packets for this callsign from the database (all packets, not just position)
  # Returns packets from the last hour, filtered by callsign
  defp get_stored_packets(callsign, limit) do
    one_hour_ago = DateTime.add(DateTime.utc_now(), -3600, :second)

    # Create query for all packets (not just position packets) for this callsign
    query =
      from p in Packet,
        where: p.received_at >= ^one_hour_ago,
        order_by: [desc: p.received_at],
        limit: ^limit

    # Apply callsign filter
    filtered_query =
      if String.contains?(callsign, "-") do
        # Exact match for callsign with SSID
        [base_call, ssid] = String.split(callsign, "-", parts: 2)

        from p in query,
          where:
            ilike(p.base_callsign, ^base_call) and
              ((is_nil(p.ssid) and ^ssid == "0") or p.ssid == ^ssid)
      else
        # Match base callsign exactly, regardless of SSID
        from p in query, where: ilike(p.base_callsign, ^callsign)
      end

    filtered_query
    |> Repo.all()
    |> Enum.map(&EncodingUtils.sanitize_packet/1)
  rescue
    error ->
      require Logger

      Logger.error("Failed to fetch stored packets for callsign #{callsign}: #{inspect(error)}")
      []
  end

  defp packet_matches_callsign?(packet, target_callsign) do
    # Check if packet sender or base_callsign matches the target callsign
    # Supports both exact matches and SSID variants (e.g., "N0CALL" matches "N0CALL-1")
    sender = packet.sender || ""
    base_callsign = packet.base_callsign || ""

    # Convert to uppercase for case-insensitive comparison
    sender_upper = String.upcase(sender)
    base_upper = String.upcase(base_callsign)
    target_upper = String.upcase(target_callsign)

    # Check exact match for sender or base_callsign
    # Also check if the sender starts with the target callsign (for SSID variants)
    sender_upper == target_upper || base_upper == target_upper ||
      String.starts_with?(sender_upper, target_upper <> "-")
  end

  # Helper to get all packets (stored + live) in chronological order
  # Combines stored and live packets, sorts by timestamp (newest first), and limits to 100
  defp get_all_packets_list(stored, live) do
    # Combine and sort by received_at timestamp (newest first)
    (live ++ stored)
    |> Enum.sort_by(
      fn packet ->
        case packet.received_at do
          %DateTime{} = dt ->
            DateTime.to_unix(dt, :microsecond)

          dt when is_binary(dt) ->
            case DateTime.from_iso8601(dt) do
              {:ok, parsed_dt, _} -> DateTime.to_unix(parsed_dt, :microsecond)
              _ -> 0
            end

          _ ->
            0
        end
      end,
      :desc
    )
    # Ensure we never exceed 100 total
    |> Enum.take(100)
  end

  # Validates if the callsign format is reasonable
  defp valid_callsign?(callsign) do
    # Basic validation for amateur radio callsign format
    # Should be 3-8 characters, can contain letters, numbers, and one hyphen for SSID
    case String.trim(callsign) do
      "" -> false
      cs when byte_size(cs) < 3 or byte_size(cs) > 15 -> false
      cs -> Regex.match?(~r/^[A-Z0-9]+(-[A-Z0-9]{1,2})?$/i, cs)
    end
  end
end