defmodule ToweropsWeb.GraphLive.Show do
  @moduledoc false
  use ToweropsWeb, :live_view

  alias Towerops.Agents
  alias Towerops.Devices
  alias Towerops.Devices.DeviceSchema
  alias Towerops.Monitoring
  alias Towerops.Snmp
  alias ToweropsWeb.GraphLive.Polling

  require Logger

  @impl true
  def mount(_params, _session, socket) do
    {:ok, socket}
  end

  @impl true
  def handle_params(%{"id" => device_id, "check_id" => check_id} = params, _, socket) do
    organization = socket.assigns.current_scope.organization

    with {:ok, device} <- find_device(device_id),
         :ok <- verify_device_access(device, organization),
         {:ok, check} <- find_check(check_id),
         :ok <- verify_check_device(check, device_id) do
      socket = initialize_check_graph_view(socket, device, check, params)
      {:noreply, socket}
    else
      {:error, :not_found} ->
        {:noreply,
         socket
         |> put_flash(:error, t("Device not found"))
         |> push_navigate(to: ~p"/devices")}

      {:error, :check_not_found} ->
        {:noreply,
         socket
         |> put_flash(:error, t("Check not found"))
         |> push_navigate(to: ~p"/devices/#{device_id}?tab=checks")}

      {:error, :check_device_mismatch} ->
        {:noreply,
         socket
         |> put_flash(:error, t("Check does not belong to this device"))
         |> push_navigate(to: ~p"/devices/#{device_id}?tab=checks")}

      {:error, :access_denied} ->
        {:noreply,
         socket
         |> put_flash(:error, t("You don't have access to this device"))
         |> push_navigate(to: ~p"/devices")}
    end
  end

  @impl true
  def handle_params(%{"id" => device_id, "sensor_type" => sensor_type} = params, _, socket) do
    organization = socket.assigns.current_scope.organization

    with {:ok, device} <- find_device(device_id),
         :ok <- verify_device_access(device, organization) do
      socket = initialize_graph_view(socket, device_id, sensor_type, params)
      {:noreply, socket}
    else
      {:error, :not_found} ->
        {:noreply,
         socket
         |> put_flash(:error, t("Device not found"))
         |> push_navigate(to: ~p"/devices")}

      {:error, :access_denied} ->
        {:noreply,
         socket
         |> put_flash(:error, t("You don't have access to this device"))
         |> push_navigate(to: ~p"/devices")}
    end
  end

  defp find_device(device_id) do
    case Devices.get_device(device_id) do
      nil -> {:error, :not_found}
      device -> {:ok, device}
    end
  end

  defp verify_device_access(device, organization) do
    if device.organization_id == organization.id do
      :ok
    else
      {:error, :access_denied}
    end
  end

  defp find_check(check_id) do
    case Monitoring.get_check(check_id) do
      nil -> {:error, :check_not_found}
      check -> {:ok, check}
    end
  end

  defp verify_check_device(check, device_id) do
    if check.device_id == device_id do
      :ok
    else
      {:error, :check_device_mismatch}
    end
  end

  defp initialize_check_graph_view(socket, device, check, params) do
    range = Map.get(params, "range", "24h")
    {from_time, to_time} = get_time_range_for_graph(range)

    {chart_data, unit, auto_scale, dual_axis} = build_check_chart_data(check, from_time, to_time)
    {max_value, min_value} = calculate_chart_stats(chart_data)

    socket
    |> assign(:device, device)
    |> assign(:device_id, device.id)
    |> assign(:check_id, check.id)
    |> assign(:range, range)
    |> assign(:page_title, "#{device.name} - #{check.name}")
    |> assign(:chart_title, check.name)
    |> assign(:chart_data, chart_data)
    |> assign(:unit, unit)
    |> assign(:auto_scale, auto_scale)
    |> assign(:dual_axis, dual_axis)
    |> assign(:show_zero_line, false)
    |> assign(:max_value, max_value)
    |> assign(:min_value, min_value)
    |> assign(:is_live_mode, false)
  end

  defp build_check_chart_data(%{check_type: "dns"} = check, from_time, to_time) do
    points = Monitoring.get_check_graph_data_with_status(check.id, from_time, to_time)

    if Enum.empty?(points) do
      {nil, "ms", true, false}
    else
      response_time_dataset = %{
        label: "Response Time (ms)",
        yAxisID: "y",
        data:
          points
          |> Enum.filter(fn p -> p.value != nil end)
          |> Enum.map(fn p ->
            %{x: DateTime.to_unix(p.timestamp, :millisecond), y: Float.round(p.value, 1)}
          end)
      }

      status_dataset = %{
        label: "Status",
        yAxisID: "y1",
        data:
          Enum.map(points, fn p ->
            %{
              x: DateTime.to_unix(p.timestamp, :millisecond),
              y: if(p.status == 0, do: 1, else: 0)
            }
          end)
      }

      chart_data = safe_encode_chart_data(%{datasets: [response_time_dataset, status_dataset]})
      {chart_data, "ms", true, true}
    end
  end

  defp build_check_chart_data(check, from_time, to_time) do
    graph_data_points = Monitoring.get_check_graph_data(check.id, from_time, to_time)
    {unit, auto_scale} = get_check_unit_and_scale(check)

    chart_data =
      if Enum.empty?(graph_data_points) do
        nil
      else
        dataset = %{
          label: check.name,
          data:
            Enum.map(graph_data_points, fn point ->
              %{
                x: DateTime.to_unix(point.timestamp, :millisecond),
                y: Float.round(point.value, 1)
              }
            end)
        }

        safe_encode_chart_data(%{datasets: [dataset]})
      end

    {chart_data, unit, auto_scale, false}
  end

  @doc false
  def get_time_range_for_graph("1h"), do: {DateTime.add(DateTime.utc_now(), -1, :hour), DateTime.utc_now()}
  def get_time_range_for_graph("6h"), do: {DateTime.add(DateTime.utc_now(), -6, :hour), DateTime.utc_now()}
  def get_time_range_for_graph("12h"), do: {DateTime.add(DateTime.utc_now(), -12, :hour), DateTime.utc_now()}
  def get_time_range_for_graph("24h"), do: {DateTime.add(DateTime.utc_now(), -24, :hour), DateTime.utc_now()}
  def get_time_range_for_graph("7d"), do: {DateTime.add(DateTime.utc_now(), -7, :day), DateTime.utc_now()}
  def get_time_range_for_graph("30d"), do: {DateTime.add(DateTime.utc_now(), -30, :day), DateTime.utc_now()}
  def get_time_range_for_graph(_), do: {DateTime.add(DateTime.utc_now(), -24, :hour), DateTime.utc_now()}

  @doc false
  def get_check_unit_and_scale(%{check_type: "snmp_sensor", config: config}) do
    unit = config["sensor_unit"] || ""
    {unit, true}
  end

  def get_check_unit_and_scale(%{check_type: "snmp_processor"}), do: {"%", false}
  def get_check_unit_and_scale(%{check_type: "snmp_storage"}), do: {"%", false}
  def get_check_unit_and_scale(%{check_type: "http"}), do: {"ms", true}
  def get_check_unit_and_scale(%{check_type: "tcp"}), do: {"ms", true}
  def get_check_unit_and_scale(%{check_type: "dns"}), do: {"ms", true}
  def get_check_unit_and_scale(_), do: {"", true}

  defp initialize_graph_view(socket, device_id, sensor_type, params) do
    maybe_subscribe_to_device(socket, device_id)

    range = Map.get(params, "range", "24h")
    interface_id = Map.get(params, "interface_id")
    sensor_id = Map.get(params, "sensor_id")
    storage_id = Map.get(params, "storage_id")

    socket
    |> assign(:device_id, device_id)
    |> assign(:sensor_type, sensor_type)
    |> assign(:range, range)
    |> assign(:interface_id, interface_id)
    |> assign(:sensor_id, sensor_id)
    |> assign(:storage_id, storage_id)
    |> assign(:is_live_mode, range == "live")
    |> maybe_start_live_polling()
    |> load_graph_data()
  end

  defp maybe_subscribe_to_device(socket, device_id) do
    _ =
      if connected?(socket) do
        Phoenix.PubSub.subscribe(Towerops.PubSub, "device:#{device_id}")
      end

    :ok
  end

  @impl true
  def handle_event("change_range", %{"range" => range}, socket) do
    # Check if this is a check-based graph or sensor-based graph
    if Map.has_key?(socket.assigns, :check_id) do
      # Check-based graph
      params = %{"range" => range, "check_id" => socket.assigns.check_id}

      {:noreply,
       push_patch(socket,
         to: ~p"/devices/#{socket.assigns.device_id}/graph/check?#{params}"
       )}
    else
      # Sensor-based graph (existing behavior)
      params = build_graph_params(socket.assigns, range)

      {:noreply,
       push_patch(socket,
         to: ~p"/devices/#{socket.assigns.device_id}/graph/#{socket.assigns.sensor_type}?#{params}"
       )}
    end
  end

  @doc false
  def build_graph_params(assigns, range) do
    base_params = %{"range" => range}

    base_params =
      if assigns.interface_id do
        Map.put(base_params, "interface_id", assigns.interface_id)
      else
        base_params
      end

    base_params =
      if assigns.sensor_id do
        Map.put(base_params, "sensor_id", assigns.sensor_id)
      else
        base_params
      end

    if assigns.storage_id do
      Map.put(base_params, "storage_id", assigns.storage_id)
    else
      base_params
    end
  end

  # Private functions

  defp load_graph_data(socket) do
    if socket.assigns.is_live_mode do
      load_live_mode_graph_data(socket)
    else
      # Historical mode - existing logic
      device_id = socket.assigns.device_id
      sensor_type = socket.assigns.sensor_type
      range = socket.assigns.range

      device =
        case Devices.get_device(device_id) do
          nil -> raise Ecto.NoResultsError, queryable: DeviceSchema
          device -> device
        end

      {chart_data, title_suffix} = load_chart_data_for_type(socket.assigns, range)

      {title, unit, auto_scale} = get_chart_config(sensor_type)
      chart_title = if title_suffix, do: "#{title} - #{title_suffix}", else: title
      show_zero_line = sensor_type == "traffic"

      # Calculate max/min values from chart data
      {max_value, min_value} = calculate_chart_stats(chart_data)

      socket
      |> assign(:device, device)
      |> assign(:page_title, "#{device.name} - #{chart_title}")
      |> assign(:chart_title, chart_title)
      |> assign(:chart_data, chart_data)
      |> assign(:unit, unit)
      |> assign(:auto_scale, auto_scale)
      |> assign(:dual_axis, false)
      |> assign(:show_zero_line, show_zero_line)
      |> assign(:max_value, max_value)
      |> assign(:min_value, min_value)
    end
  end

  defp load_live_mode_graph_data(socket) do
    device_id = socket.assigns.device_id
    sensor_type = socket.assigns.sensor_type

    device =
      case Devices.get_device(device_id) do
        nil -> raise Ecto.NoResultsError, queryable: DeviceSchema
        device -> device
      end

    {title, unit, auto_scale} = get_chart_config(sensor_type)

    title_suffix = get_title_suffix(socket.assigns)
    chart_title = if title_suffix, do: "#{title} - #{title_suffix}", else: title

    socket
    |> assign(:device, device)
    |> assign(:page_title, "#{device.name} - #{chart_title} (Live)")
    |> assign(:chart_title, chart_title)
    |> assign(:chart_data, safe_encode_chart_data(%{datasets: []}))
    |> assign(:unit, unit)
    |> assign(:auto_scale, auto_scale)
    |> assign(:dual_axis, false)
    |> assign(:show_zero_line, sensor_type == "traffic")
    |> assign(:max_value, nil)
    |> assign(:min_value, nil)
    |> assign(:previous_interface_stats, nil)
  end

  defp get_title_suffix(assigns) do
    cond do
      assigns[:sensor_id] ->
        get_sensor_name(assigns[:sensor_id])

      assigns[:interface_id] && assigns[:sensor_type] in ["traffic", "interface_errors"] ->
        get_interface_name(assigns[:interface_id])

      assigns[:storage_id] && assigns[:sensor_type] == "storage_volume" ->
        get_storage_name(assigns[:storage_id])

      true ->
        nil
    end
  end

  defp load_chart_data_for_type(%{sensor_type: "latency", device_id: device_id}, range) do
    {load_latency_chart_data(device_id, range), nil}
  end

  defp load_chart_data_for_type(%{sensor_type: "traffic", interface_id: interface_id}, range)
       when not is_nil(interface_id) do
    {load_interface_traffic_chart_data(interface_id, range), get_interface_name(interface_id)}
  end

  defp load_chart_data_for_type(%{sensor_type: "interface_errors", interface_id: interface_id}, range)
       when not is_nil(interface_id) do
    {load_interface_errors_chart_data(interface_id, range), get_interface_name(interface_id)}
  end

  defp load_chart_data_for_type(%{sensor_type: "traffic", device_id: device_id}, range) do
    {load_traffic_chart_data(device_id, range), nil}
  end

  defp load_chart_data_for_type(%{sensor_type: "storage_volume", storage_id: storage_id}, range)
       when not is_nil(storage_id) do
    {load_storage_chart_data(storage_id, range), get_storage_name(storage_id)}
  end

  defp load_chart_data_for_type(%{sensor_id: sensor_id}, range) when not is_nil(sensor_id) do
    {load_single_sensor_chart_data(sensor_id, range), get_sensor_name(sensor_id)}
  end

  defp load_chart_data_for_type(%{sensor_type: sensor_type, device_id: device_id}, range) do
    sensor_types = get_sensor_types_for_chart(sensor_type)
    {load_sensor_chart_data(device_id, sensor_types, range), nil}
  end

  @doc false
  def get_sensor_types_for_chart("processors"), do: ["cpu_load"]
  def get_sensor_types_for_chart("memory"), do: ["memory_usage"]
  def get_sensor_types_for_chart("storage"), do: ["disk_usage"]
  def get_sensor_types_for_chart("temperature"), do: ["temperature", "cpu_temperature", "celsius"]
  def get_sensor_types_for_chart("voltage"), do: ["voltage", "volts"]
  def get_sensor_types_for_chart("traffic"), do: nil
  # For unknown sensor types, use the type directly (supports count, pppoe_sessions, etc.)
  def get_sensor_types_for_chart(sensor_type), do: [sensor_type]

  @doc false
  def get_chart_config("latency"), do: {"Ping Latency", "ms", true}
  def get_chart_config("processors"), do: {"Processor Usage", "%", false}
  def get_chart_config("memory"), do: {"Memory Usage", "%", false}
  def get_chart_config("storage"), do: {"Storage Usage", "%", false}
  def get_chart_config("storage_volume"), do: {"Storage Usage", "%", false}
  def get_chart_config("temperature"), do: {"Temperature", "°C", true}
  def get_chart_config("voltage"), do: {"Voltage", "V", true}
  def get_chart_config("traffic"), do: {"Overall Traffic", "bps", true}
  def get_chart_config("interface_errors"), do: {"Interface Errors & Discards", "", true}
  def get_chart_config("count"), do: {"Count", "", true}
  def get_chart_config("pppoe_sessions"), do: {"PPPoE Sessions", "", true}
  def get_chart_config("connections"), do: {"Connections", "", true}
  def get_chart_config("wireless"), do: {"Wireless Metrics", "", true}
  # Humanize unknown sensor types for title
  def get_chart_config(sensor_type), do: {humanize_sensor_type(sensor_type), "", true}

  @doc false
  def humanize_sensor_type(sensor_type) do
    sensor_type
    |> String.replace("_", " ")
    |> String.split()
    |> Enum.map_join(" ", &String.capitalize/1)
  end

  defp load_sensor_chart_data(device_id, sensor_types, range) do
    case Snmp.get_device_with_associations(device_id) do
      nil ->
        nil

      device ->
        build_sensor_chart_json(device, sensor_types, range)
    end
  end

  defp load_single_sensor_chart_data(sensor_id, range) do
    case Snmp.get_sensor(sensor_id) do
      nil ->
        nil

      sensor ->
        since = get_datetime_from_range(range)
        limit = get_limit_for_range(range)
        dataset = sensor_to_dataset(sensor, since, limit)

        # Return nil if no data points (empty readings)
        if Enum.empty?(dataset.data) do
          nil
        else
          safe_encode_chart_data(%{datasets: [dataset]})
        end
    end
  end

  defp get_sensor_name(sensor_id) do
    case Snmp.get_sensor(sensor_id) do
      nil -> nil
      sensor -> sensor.sensor_descr
    end
  end

  defp load_storage_chart_data(storage_id, range) do
    case Snmp.get_storage(storage_id) do
      nil ->
        nil

      storage ->
        since = get_datetime_from_range(range)
        limit = get_limit_for_range(range)
        dataset = storage_to_dataset(storage, since, limit)
        safe_encode_chart_data(%{datasets: [dataset]})
    end
  end

  defp get_storage_name(storage_id) do
    case Snmp.get_storage(storage_id) do
      nil -> nil
      storage -> storage.description || "Storage #{storage.storage_index}"
    end
  end

  defp storage_to_dataset(storage, since, limit) do
    readings =
      storage.id
      |> Snmp.get_storage_readings(since: since, limit: limit)
      |> Enum.reverse()

    %{
      label: storage.description || "Storage #{storage.storage_index}",
      data: Enum.map(readings, &storage_reading_to_chart_point/1)
    }
  end

  defp storage_reading_to_chart_point(reading) do
    %{
      x: DateTime.to_unix(reading.checked_at, :millisecond),
      y: if(reading.usage_percent, do: Float.round(reading.usage_percent, 1))
    }
  end

  defp build_sensor_chart_json(device, sensor_types, range) do
    sensors =
      device.sensors
      |> Enum.filter(&(&1.sensor_type in sensor_types))
      |> Enum.sort_by(& &1.sensor_index)

    if Enum.empty?(sensors) do
      nil
    else
      since = get_datetime_from_range(range)
      limit = get_limit_for_range(range)
      datasets = Enum.map(sensors, &sensor_to_dataset(&1, since, limit))
      safe_encode_chart_data(%{datasets: datasets})
    end
  end

  defp sensor_to_dataset(sensor, since, limit) do
    readings =
      sensor.id
      |> Snmp.get_sensor_readings(since: since, limit: limit)
      |> Enum.reverse()

    %{
      label: sensor.sensor_descr,
      data: Enum.map(readings, &reading_to_chart_point/1)
    }
  end

  defp reading_to_chart_point(reading) do
    %{
      x: DateTime.to_unix(reading.checked_at, :millisecond),
      y: if(reading.value, do: Float.round(reading.value, 1))
    }
  end

  defp get_datetime_from_range("1h"), do: DateTime.add(DateTime.utc_now(), -1, :hour)
  defp get_datetime_from_range("6h"), do: DateTime.add(DateTime.utc_now(), -6, :hour)
  defp get_datetime_from_range("12h"), do: DateTime.add(DateTime.utc_now(), -12, :hour)
  defp get_datetime_from_range("24h"), do: DateTime.add(DateTime.utc_now(), -24, :hour)
  defp get_datetime_from_range("7d"), do: DateTime.add(DateTime.utc_now(), -7, :day)
  defp get_datetime_from_range("30d"), do: DateTime.add(DateTime.utc_now(), -30, :day)
  defp get_datetime_from_range(_), do: DateTime.add(DateTime.utc_now(), -24, :hour)

  defp get_limit_for_range("1h"), do: 360
  defp get_limit_for_range("6h"), do: 720
  defp get_limit_for_range("12h"), do: 1440
  defp get_limit_for_range("24h"), do: 2880
  defp get_limit_for_range("7d"), do: 10_080
  defp get_limit_for_range("30d"), do: 43_200
  defp get_limit_for_range(_), do: 2880

  defp load_traffic_chart_data(device_id, range) do
    case Snmp.get_device_with_associations(device_id) do
      nil -> nil
      device -> build_traffic_chart_json(device, range)
    end
  end

  defp load_interface_traffic_chart_data(interface_id, range) do
    case Snmp.get_interface(interface_id) do
      nil -> nil
      interface -> build_interface_traffic_chart_json(interface, range)
    end
  end

  defp load_interface_errors_chart_data(interface_id, range) do
    case Snmp.get_interface(interface_id) do
      nil -> nil
      interface -> build_interface_errors_chart_json(interface, range)
    end
  end

  defp build_interface_errors_chart_json(interface, range) do
    since = get_datetime_from_range(range)
    limit = get_limit_for_range(range)

    stats =
      interface.id
      |> Snmp.get_interface_stats(since: since, limit: limit)
      |> Enum.reverse()

    if Enum.empty?(stats) do
      nil
    else
      datasets =
        Enum.reject(
          [
            %{label: "In Errors", data: build_error_rate_data(stats, :if_in_errors)},
            %{label: "Out Errors", data: build_error_rate_data(stats, :if_out_errors)},
            %{label: "In Discards", data: build_error_rate_data(stats, :if_in_discards)},
            %{label: "Out Discards", data: build_error_rate_data(stats, :if_out_discards)}
          ],
          fn ds -> Enum.empty?(ds.data) end
        )

      if Enum.empty?(datasets), do: nil, else: safe_encode_chart_data(%{datasets: datasets})
    end
  end

  # Calculates rate-of-change per minute for a cumulative error/discard counter
  defp build_error_rate_data(stats, field) do
    stats
    |> Enum.chunk_every(2, 1, :discard)
    |> Enum.flat_map(fn [stat1, stat2] ->
      v1 = Map.get(stat1, field)
      v2 = Map.get(stat2, field)

      if is_nil(v1) or is_nil(v2) do
        []
      else
        time_diff = stat2.checked_at |> DateTime.diff(stat1.checked_at, :second) |> max(1)
        rate = ((v2 - v1) / time_diff * 60) |> max(0) |> Float.round(2)
        [%{x: DateTime.to_unix(stat2.checked_at, :millisecond), y: rate}]
      end
    end)
  end

  defp get_interface_name(interface_id) do
    case Snmp.get_interface(interface_id) do
      nil -> "Unknown Interface"
      interface -> interface.if_name || interface.if_descr || "Interface #{interface.if_index}"
    end
  end

  defp load_latency_chart_data(device_id, range) do
    since = get_datetime_from_range(range)
    limit = get_limit_for_range(range)

    checks =
      device_id
      |> Monitoring.get_latency_data(since: since, limit: limit)
      |> Enum.reverse()

    if Enum.empty?(checks) do
      nil
    else
      dataset = %{
        label: "Ping Latency",
        data: Enum.map(checks, &latency_check_to_chart_point/1)
      }

      Jason.encode!(%{datasets: [dataset]})
    end
  end

  defp latency_check_to_chart_point(check) do
    %{
      x: DateTime.to_unix(check.checked_at, :millisecond),
      y: Float.round(check.response_time_ms, 1)
    }
  end

  @doc false
  def calculate_chart_stats(nil), do: {nil, nil}

  @doc false
  def calculate_chart_stats(chart_data) when is_binary(chart_data) do
    case Jason.decode(chart_data) do
      {:ok, %{"datasets" => datasets}} ->
        extract_min_max_from_datasets(datasets)

      _ ->
        {nil, nil}
    end
  end

  defp extract_min_max_from_datasets(datasets) do
    values = Enum.flat_map(datasets, &extract_values_from_dataset/1)

    case values do
      [] -> {nil, nil}
      _ -> {Enum.max(values), Enum.min(values)}
    end
  end

  defp extract_values_from_dataset(%{"data" => data}) when is_list(data) do
    Enum.flat_map(data, &extract_y_value/1)
  end

  defp extract_values_from_dataset(_), do: []

  defp extract_y_value(%{"y" => y}) when is_number(y), do: [y]
  defp extract_y_value(_), do: []

  defp build_traffic_chart_json(device, range) do
    if Enum.empty?(device.interfaces), do: nil, else: build_traffic_datasets(device, range)
  end

  defp build_traffic_datasets(device, range) do
    since = get_datetime_from_range(range)
    limit = get_limit_for_range(range)

    # Process all interfaces (regardless of operational status) to show total device traffic
    if Enum.empty?(device.interfaces), do: nil, else: encode_interface_datasets(device.interfaces, since, limit, device)
  end

  # Get device for adding capacity lines to full-page traffic view
  defp encode_interface_datasets(interfaces, since, limit, device) do
    datasets = build_per_interface_datasets(interfaces, since, limit)

    # Add capacity datasets for backhaul devices
    datasets =
      if device.device.device_role == "backhaul" && !Enum.empty?(datasets) do
        add_capacity_to_full_graph(datasets, interfaces, since, limit, device.sensors)
      else
        datasets
      end

    if Enum.empty?(datasets), do: nil, else: safe_encode_chart_data(%{datasets: datasets})
  end

  defp build_per_interface_datasets(interfaces, since, limit) do
    Enum.flat_map(interfaces, fn interface ->
      stats =
        interface.id
        |> Snmp.get_interface_stats(since: since, limit: limit)
        |> Enum.reverse()

      if Enum.empty?(stats) do
        []
      else
        interface_name = interface.if_name || interface.if_descr
        in_data = calculate_interface_traffic_data(stats, :inbound)
        out_data = calculate_interface_traffic_data(stats, :outbound)

        [
          %{label: "#{interface_name} Out", data: out_data},
          %{label: "#{interface_name} In", data: in_data}
        ]
      end
    end)
  end

  # Add capacity reference lines for backhaul devices on full-page graph.
  # Uses Rx/Tx Capacity sensors when available (e.g. AirFiber adaptive modulation),
  # otherwise falls back to interface configured_capacity_bps or if_speed.
  defp add_capacity_to_full_graph(datasets, interfaces, since, _limit, sensors) do
    rx_sensor = Enum.find(sensors, &(&1.sensor_descr == "Rx Capacity"))
    tx_sensor = Enum.find(sensors, &(&1.sensor_descr == "Tx Capacity"))

    capacity_data = resolve_capacity_data(datasets, interfaces, since, rx_sensor, tx_sensor)

    max_capacity = capacity_data |> Enum.map(fn {_, rx, _} -> rx end) |> Enum.max(fn -> 0 end)

    if max_capacity > 0 do
      datasets ++
        [
          %{
            label: "Capacity (In)",
            data: Enum.map(capacity_data, fn {ts, rx, _} -> %{x: ts, y: Float.round(rx * 1.0, 2)} end),
            borderDash: [5, 5],
            borderWidth: 2,
            pointRadius: 0,
            fill: false
          },
          %{
            label: "Capacity (Out)",
            data: Enum.map(capacity_data, fn {ts, _, tx} -> %{x: ts, y: -Float.round(tx * 1.0, 2)} end),
            borderDash: [5, 5],
            borderWidth: 2,
            pointRadius: 0,
            fill: false
          }
        ]
    else
      datasets
    end
  end

  defp resolve_capacity_data(datasets, interfaces, since, rx_sensor, tx_sensor)
       when rx_sensor != nil or tx_sensor != nil do
    rx_readings = load_capacity_sensor_readings_for_graph(rx_sensor, since)
    tx_readings = load_capacity_sensor_readings_for_graph(tx_sensor, since)

    if map_size(rx_readings) > 0 || map_size(tx_readings) > 0 do
      all_ts =
        (Map.keys(rx_readings) ++ Map.keys(tx_readings))
        |> MapSet.new()
        |> Enum.sort()

      Enum.map(all_ts, fn ts ->
        rx = Map.get(rx_readings, ts, capacity_sensor_fallback_bps(rx_sensor))
        tx = Map.get(tx_readings, ts, capacity_sensor_fallback_bps(tx_sensor))
        {ts, rx, tx}
      end)
    else
      build_interface_speed_capacity(datasets, interfaces, since)
    end
  end

  defp resolve_capacity_data(datasets, interfaces, since, _rx_sensor, _tx_sensor) do
    build_interface_speed_capacity(datasets, interfaces, since)
  end

  defp load_capacity_sensor_readings_for_graph(nil, _since), do: %{}

  defp load_capacity_sensor_readings_for_graph(sensor, since) do
    sensor.id
    |> Snmp.get_sensor_readings(since: since, limit: 1000)
    |> Map.new(fn r ->
      bps = if r.value, do: round(r.value * 1_000_000), else: 0
      {DateTime.to_unix(r.checked_at, :millisecond), bps}
    end)
  end

  defp capacity_sensor_fallback_bps(nil), do: 0
  defp capacity_sensor_fallback_bps(sensor), do: if(sensor.last_value, do: round(sensor.last_value * 1_000_000), else: 0)

  # Fallback: derive capacity from interface configured_capacity_bps or if_speed
  defp build_interface_speed_capacity(datasets, interfaces, since) do
    interface_capacity_map =
      Map.new(interfaces, fn interface ->
        capacity = interface.configured_capacity_bps || interface.if_speed || 0
        {interface.id, capacity}
      end)

    interface_activity_by_timestamp =
      interfaces
      |> Enum.flat_map(fn interface ->
        interface.id
        |> Snmp.get_interface_stats(since: since, limit: 1000)
        |> Enum.map(fn stat ->
          ts_ms = DateTime.to_unix(stat.checked_at, :millisecond)
          {ts_ms, interface.id}
        end)
      end)
      |> Enum.group_by(fn {ts, _} -> ts end, fn {_, iface_id} -> iface_id end)

    all_timestamps =
      datasets
      |> Enum.flat_map(fn dataset ->
        case dataset.data do
          nil -> []
          data -> Enum.map(data, & &1.x)
        end
      end)
      |> Enum.uniq()
      |> Enum.sort()

    Enum.map(all_timestamps, fn ts ->
      active_interfaces =
        interface_activity_by_timestamp
        |> Enum.filter(fn {stat_ts, _} -> abs(stat_ts - ts) < 60_000 end)
        |> Enum.flat_map(fn {_, iface_ids} -> iface_ids end)
        |> Enum.uniq()

      total_capacity =
        Enum.reduce(active_interfaces, 0, fn iface_id, acc ->
          acc + Map.get(interface_capacity_map, iface_id, 0)
        end)

      {ts, total_capacity, total_capacity}
    end)
  end

  defp build_interface_traffic_chart_json(interface, range) do
    since = get_datetime_from_range(range)
    limit = get_limit_for_range(range)

    stats =
      interface.id
      |> Snmp.get_interface_stats(since: since, limit: limit)
      |> Enum.reverse()

    if Enum.empty?(stats) do
      nil
    else
      in_data = calculate_interface_traffic_data(stats, :inbound)
      out_data = calculate_interface_traffic_data(stats, :outbound)

      datasets = [
        %{label: "Outbound", data: out_data},
        %{label: "Inbound", data: in_data}
      ]

      safe_encode_chart_data(%{datasets: datasets})
    end
  end

  defp calculate_interface_traffic_data(stats, :inbound) do
    stats
    |> Enum.chunk_every(2, 1, :discard)
    |> Enum.map(fn [stat1, stat2] ->
      if is_nil(stat1.if_in_octets) or is_nil(stat2.if_in_octets) do
        nil
      else
        time_diff = stat2.checked_at |> DateTime.diff(stat1.checked_at, :second) |> max(1)
        bps = Towerops.Capacity.calculate_bps(stat1.if_in_octets, stat2.if_in_octets, time_diff)

        %{
          x: DateTime.to_unix(stat2.checked_at, :millisecond),
          y: Float.round(bps, 2)
        }
      end
    end)
    |> Enum.reject(&is_nil/1)
  end

  defp calculate_interface_traffic_data(stats, :outbound) do
    stats
    |> Enum.chunk_every(2, 1, :discard)
    |> Enum.map(fn [stat1, stat2] ->
      if is_nil(stat1.if_out_octets) or is_nil(stat2.if_out_octets) do
        nil
      else
        time_diff = stat2.checked_at |> DateTime.diff(stat1.checked_at, :second) |> max(1)
        bps = Towerops.Capacity.calculate_bps(stat1.if_out_octets, stat2.if_out_octets, time_diff)

        %{
          x: DateTime.to_unix(stat2.checked_at, :millisecond),
          y: -Float.round(bps, 2)
        }
      end
    end)
    |> Enum.reject(&is_nil/1)
  end

  @doc false
  def format_value(value, "bps") do
    abs_value = abs(value)

    cond do
      abs_value >= 1_000_000_000 ->
        "#{Float.round(abs_value / 1_000_000_000, 2)} Gbps"

      abs_value >= 1_000_000 ->
        "#{Float.round(abs_value / 1_000_000, 2)} Mbps"

      abs_value >= 1_000 ->
        "#{Float.round(abs_value / 1_000, 2)} Kbps"

      true ->
        "#{Float.round(abs_value, 2)} bps"
    end
  end

  def format_value(value, "") do
    "#{round(value)}"
  end

  def format_value(value, unit) when is_float(value) do
    "#{Float.round(value, 1)} #{unit}"
  end

  def format_value(value, unit) when is_integer(value) do
    "#{Float.round(value / 1, 1)} #{unit}"
  end

  # Live polling functions

  # Start/stop live polling based on mode
  defp maybe_start_live_polling(socket) do
    if socket.assigns[:is_live_mode] && connected?(socket) do
      cancel_live_polling_timer(socket)

      socket
      |> assign(:live_data_buffer, %{})
      |> assign(:live_data_points, 0)
      |> schedule_live_poll()
    else
      cancel_live_polling_timer(socket)
    end
  end

  # Schedule next poll in 1 second
  defp schedule_live_poll(socket) do
    timer_ref = Process.send_after(self(), :live_poll, 1_000)
    assign(socket, :live_poll_timer, timer_ref)
  end

  # Cancel existing timer
  defp cancel_live_polling_timer(socket) do
    case Map.get(socket.assigns, :live_poll_timer) do
      nil ->
        socket

      timer_ref ->
        _ = Process.cancel_timer(timer_ref)
        assign(socket, :live_poll_timer, nil)
    end
  end

  # Handle device status changes from PubSub
  @impl true
  def handle_info({:device_status_changed, _device_id, _new_status, _response_time}, socket) do
    # Reload device to get updated status
    device = Devices.get_device(socket.assigns.device_id)
    {:noreply, assign(socket, :device, device)}
  end

  # Handle sensor updates from PubSub
  @impl true
  def handle_info({:state_sensors_updated, _device_id}, socket) do
    {:noreply, load_graph_data(socket)}
  end

  # Handle neighbor updates from PubSub (ignored - not relevant to graphs)
  @impl true
  def handle_info({:neighbors_updated, _device_id}, socket) do
    {:noreply, socket}
  end

  # Handle live poll event
  @impl true
  def handle_info(:live_poll, socket) do
    if socket.assigns[:is_live_mode] do
      socket = perform_live_poll(socket)
      {:noreply, schedule_live_poll(socket)}
    else
      {:noreply, socket}
    end
  end

  # Catch-all for unexpected messages
  @impl true
  def handle_info(_msg, socket), do: {:noreply, socket}

  # Perform SNMP polling and update buffer
  defp perform_live_poll(socket) do
    device_id = socket.assigns.device_id

    # Verify device still exists and access is valid
    case Devices.get_device(device_id) do
      nil ->
        socket
        |> put_flash(:error, t("Device no longer exists"))
        |> push_navigate(to: ~p"/devices")

      device ->
        organization = socket.assigns.current_scope.organization

        if device.organization_id == organization.id do
          poll_and_update_buffer(socket, device)
        else
          socket
          |> put_flash(:error, t("Access to device revoked"))
          |> push_navigate(to: ~p"/devices")
        end
    end
  end

  # Poll sensors and update buffer
  defp poll_and_update_buffer(socket, device) do
    now = DateTime.utc_now()
    timestamp_ms = DateTime.to_unix(now, :millisecond)

    agent_token_id = Agents.get_effective_agent_token(device)

    {new_points, updated_stats} =
      if agent_token_id do
        points = Polling.request_agent_live_poll(device.id, agent_token_id, socket.assigns)
        {points, nil}
      else
        client_opts = Polling.build_snmp_client_opts(device)

        if socket.assigns.sensor_type == "traffic" do
          {points, stats} = Polling.poll_traffic_with_state(socket.assigns, client_opts, timestamp_ms)
          {points, stats}
        else
          points = Polling.poll_sensors(socket.assigns, client_opts, timestamp_ms)
          {points, nil}
        end
      end

    {updated_buffer, point_count} =
      Polling.update_buffer(
        socket.assigns.live_data_buffer,
        socket.assigns.live_data_points,
        new_points
      )

    socket
    |> assign(:live_data_buffer, updated_buffer)
    |> assign(:live_data_points, point_count)
    |> assign_previous_stats(updated_stats)
    |> push_event("live_data_update", %{
      timestamp: timestamp_ms,
      points: new_points
    })
  end

  defp assign_previous_stats(socket, nil), do: socket
  defp assign_previous_stats(socket, stats), do: assign(socket, :previous_interface_stats, stats)

  # Cleanup on LiveView termination
  @impl true
  def terminate(_reason, socket) do
    cancel_live_polling_timer(socket)
    :ok
  end

  defp safe_encode_chart_data(data) do
    case Jason.encode(data) do
      {:ok, encoded} ->
        encoded

      {:error, reason} ->
        Logger.error("Failed to encode chart data: #{inspect(reason)}")
        Jason.encode!(%{datasets: []})
    end
  end
end