defmodule Localiser.Web.Controllers.SensorController do
  use Phoenix.Controller, formats: [:json]
  use OpenApiSpex.ControllerSpecs

  alias Localiser.Domain.Sensors
  alias Localiser.Localisation.Sensor.Server, as: SensorServer
  alias Localiser.Web.Schemas

  tags ["Sensors"]
  security [%{"bearerAuth" => []}]

  operation :index,
    summary: "List all sensors",
    responses: [
      ok: {"Sensor list", "application/json", %OpenApiSpex.Schema{type: :array, items: Schemas.Sensor}},
      unauthorized: {"Unauthorized", "application/json", Schemas.Error}
    ]

  operation :unplaced,
    summary: "List sensors not yet assigned to a room",
    responses: [
      ok: {"Sensor list", "application/json", %OpenApiSpex.Schema{type: :array, items: Schemas.Sensor}},
      unauthorized: {"Unauthorized", "application/json", Schemas.Error}
    ]

  operation :show,
    summary: "Get a sensor",
    parameters: [id: [in: :path, type: :integer, required: true]],
    responses: [
      ok: {"Sensor", "application/json", Schemas.Sensor},
      unauthorized: {"Unauthorized", "application/json", Schemas.Error}
    ]

  operation :update,
    summary: "Update sensor metadata",
    parameters: [id: [in: :path, type: :integer, required: true]],
    request_body: {"Sensor params", "application/json", Schemas.SensorUpdateParams},
    responses: [
      ok: {"Updated sensor", "application/json", Schemas.Sensor},
      unauthorized: {"Unauthorized", "application/json", Schemas.Error},
      unprocessable_entity: {"Validation errors", "application/json", Schemas.ValidationErrors}
    ]

  operation :delete,
    summary: "Delete / unenrol a sensor",
    parameters: [id: [in: :path, type: :integer, required: true]],
    responses: [
      no_content: "Deleted",
      unauthorized: {"Unauthorized", "application/json", Schemas.Error}
    ]

  operation :place,
    summary: "Place sensor at a position in a room",
    parameters: [id: [in: :path, type: :integer, required: true]],
    request_body: {"Place params", "application/json", Schemas.SensorPlaceParams, required: true},
    responses: [
      ok: {"Updated sensor", "application/json", Schemas.Sensor},
      bad_request: {"Missing params", "application/json", Schemas.Error},
      unauthorized: {"Unauthorized", "application/json", Schemas.Error},
      unprocessable_entity: {"Validation errors", "application/json", Schemas.ValidationErrors}
    ]

  operation :unplace,
    summary: "Remove sensor from floor layout",
    parameters: [id: [in: :path, type: :integer, required: true]],
    responses: [
      ok: {"Updated sensor", "application/json", Schemas.Sensor},
      unauthorized: {"Unauthorized", "application/json", Schemas.Error}
    ]

  operation :calibration_start,
    summary: "Begin RSSI calibration",
    parameters: [id: [in: :path, type: :integer, required: true]],
    request_body: {"Calibration params", "application/json", Schemas.CalibrationStartParams, required: true},
    responses: [
      ok: {"Calibration started", "application/json", Schemas.CalibrationStatus},
      bad_request: {"Missing reference_distance", "application/json", Schemas.Error},
      unauthorized: {"Unauthorized", "application/json", Schemas.Error}
    ]

  operation :calibration_stop,
    summary: "Abort active calibration",
    parameters: [id: [in: :path, type: :integer, required: true]],
    responses: [
      ok: {"Calibration aborted", "application/json", Schemas.CalibrationStatus},
      unauthorized: {"Unauthorized", "application/json", Schemas.Error}
    ]

  def index(conn, _params) do
    json(conn, Enum.map(Sensors.list_sensors(), &render_sensor/1))
  end

  def unplaced(conn, _params) do
    json(conn, Enum.map(Sensors.list_unplaced(), &render_sensor/1))
  end

  def show(conn, %{"id" => id}) do
    sensor = Sensors.get_sensor!(id)
    json(conn, render_sensor(sensor))
  end

  def update(conn, %{"id" => id} = params) do
    sensor = Sensors.get_sensor!(id)
    attrs  = Map.drop(params, ["id"])

    case Sensors.update_sensor(sensor, attrs) do
      {:ok, updated} ->
        json(conn, render_sensor(updated))

      {:error, changeset} ->
        conn
        |> put_status(:unprocessable_entity)
        |> json(%{errors: format_errors(changeset)})
    end
  end

  def delete(conn, %{"id" => id}) do
    sensor = Sensors.get_sensor!(id)
    {:ok, _} = Sensors.delete_sensor(sensor)
    send_resp(conn, :no_content, "")
  end

  def place(conn, %{"id" => id, "room_id" => room_id, "x" => x, "y" => y}) do
    sensor = Sensors.get_sensor!(id)

    case Sensors.place_sensor(sensor, room_id, {x, y}) do
      {:ok, updated} ->
        json(conn, render_sensor(updated))

      {:error, changeset} ->
        conn
        |> put_status(:unprocessable_entity)
        |> json(%{errors: format_errors(changeset)})
    end
  end

  def place(conn, _params) do
    conn
    |> put_status(:bad_request)
    |> json(%{error: "room_id, x, and y are required"})
  end

  def unplace(conn, %{"id" => id}) do
    sensor = Sensors.get_sensor!(id)

    case Sensors.remove_from_layout(sensor) do
      {:ok, updated} ->
        json(conn, render_sensor(updated))

      {:error, changeset} ->
        conn
        |> put_status(:unprocessable_entity)
        |> json(%{errors: format_errors(changeset)})
    end
  end

  def calibration_start(conn, %{"id" => id, "reference_distance" => ref_dist}) do
    sensor = Sensors.get_sensor!(id)
    :ok = SensorServer.begin_calibration(sensor.sensor_id, ref_dist)
    json(conn, %{status: "calibrating"})
  end

  def calibration_start(conn, _params) do
    conn
    |> put_status(:bad_request)
    |> json(%{error: "reference_distance is required"})
  end

  def calibration_stop(conn, %{"id" => id}) do
    sensor = Sensors.get_sensor!(id)
    :ok = SensorServer.abort_calibration(sensor.sensor_id)
    json(conn, %{status: "idle"})
  end

  defp render_sensor(sensor) do
    %{
      id:        sensor.id,
      sensor_id: sensor.sensor_id,
      room_id:   sensor.room_id,
      floor_x:   sensor.floor_x,
      floor_y:   sensor.floor_y
    }
  end

  defp format_errors(changeset) do
    Ecto.Changeset.traverse_errors(changeset, fn {msg, opts} ->
      Enum.reduce(opts, msg, fn {key, val}, acc ->
        String.replace(acc, "%{#{key}}", to_string(val))
      end)
    end)
  end
end