defmodule ToweropsWeb.MobileChannel do
  @moduledoc """
  Phoenix channel for real-time mobile app communication.

  Supports two topic patterns:
  - `mobile:org:<org_id>` — org-level alerts and device status events
  - `mobile:device:<device_id>` — device-level sensor and interface events
  """

  use ToweropsWeb, :channel

  alias Towerops.Devices
  alias Towerops.Organizations

  @impl true
  def join("mobile:org:" <> org_id, _params, socket) do
    user_id = socket.assigns.user_id

    if Organizations.user_has_access?(user_id, org_id) do
      _ = Phoenix.PubSub.subscribe(Towerops.PubSub, "organization:#{org_id}:alerts")
      _ = Phoenix.PubSub.subscribe(Towerops.PubSub, "devices:org:#{org_id}")

      {:ok, socket}
    else
      {:error, %{reason: "unauthorized"}}
    end
  end

  def join("mobile:device:" <> device_id, _params, socket) do
    user_id = socket.assigns.user_id

    case Devices.get_device(device_id) do
      nil ->
        {:error, %{reason: "not_found"}}

      device ->
        if Organizations.user_has_access?(user_id, device.organization_id) do
          _ = Phoenix.PubSub.subscribe(Towerops.PubSub, "device:#{device_id}")
          {:ok, socket}
        else
          {:error, %{reason: "unauthorized"}}
        end
    end
  end

  # Org-level: alert changed
  @impl true
  def handle_info({:alert_changed, org_id}, socket) do
    push(socket, "alert:changed", %{organization_id: org_id})
    {:noreply, socket}
  end

  # Org-level: device events
  def handle_info({event, org_id}, socket)
      when event in [:device_created, :device_updated, :device_status_changed, :device_deleted] do
    push(socket, "device:changed", %{
      event: to_string(event),
      organization_id: org_id
    })

    {:noreply, socket}
  end

  # Device-level: sensor and interface events from SensorChangeDetector/DevicePollerWorker
  def handle_info({:device_event, event}, socket) when is_map(event) do
    push(socket, "device:event", %{
      device_id: event.device_id,
      event_type: event.event_type,
      severity: event.severity,
      message: event.message,
      metadata: event.metadata,
      occurred_at: format_datetime(event.occurred_at)
    })

    {:noreply, socket}
  end

  # Device-level: bulk data updates
  def handle_info({update_type, device_id}, socket)
      when update_type in [:sensors_updated, :state_sensors_updated, :interfaces_updated, :neighbors_updated] and
             is_binary(device_id) do
    push(socket, "device:updated", %{
      device_id: device_id,
      update_type: to_string(update_type)
    })

    {:noreply, socket}
  end

  # Catch-all for unhandled PubSub messages
  def handle_info(_msg, socket) do
    {:noreply, socket}
  end

  defp format_datetime(%DateTime{} = dt), do: DateTime.to_iso8601(dt)
  defp format_datetime(other), do: to_string(other)
end