defmodule ToweropsWeb.Api.V1.ChecksController do
  @moduledoc """
  API controller for managing service checks (HTTP, TCP, DNS, ping).

  All endpoints require API token authentication and operations are scoped
  to the organization associated with the token. Only service check types
  (http, tcp, dns, ping) are exposed — SNMP checks are managed internally.
  """
  use ToweropsWeb, :controller

  alias Towerops.Devices.Device
  alias Towerops.Monitoring
  alias Towerops.Monitoring.Check
  alias ToweropsWeb.Api.ParamFilter
  alias ToweropsWeb.Api.V1.ResourceController, as: Resources
  alias ToweropsWeb.ScopedResource

  @service_check_types ~w(http tcp dns ping)

  @doc """
  GET /api/v1/checks

  Lists service checks for the authenticated organization.
  Optional query params: `check_type`, `device_id`.
  """
  def index(conn, params) do
    organization_id = conn.assigns.current_organization_id

    opts =
      []
      |> maybe_add_opt(:device_id, params["device_id"])
      |> maybe_add_opt(:check_type, params["check_type"])

    checks =
      organization_id
      |> Monitoring.list_checks(opts)
      |> Enum.filter(&(&1.check_type in @service_check_types))
      |> Enum.map(&format_check/1)

    json(conn, %{checks: checks})
  end

  @doc """
  POST /api/v1/checks

  Creates a new service check for the authenticated organization.
  """
  def create(conn, %{"check" => check_params}) do
    organization_id = conn.assigns.current_organization_id

    check_type = Map.get(check_params, "check_type", "")

    cond do
      check_type not in @service_check_types ->
        conn
        |> put_status(:bad_request)
        |> json(%{
          error: "Invalid check type '#{check_type}'. Must be one of: #{Enum.join(@service_check_types, ", ")}"
        })

      not device_in_org?(check_params["device_id"], organization_id) ->
        conn
        |> put_status(:forbidden)
        |> json(%{error: "Access denied to the referenced device"})

      true ->
        attrs =
          check_params
          |> ParamFilter.strip_sensitive()
          |> Map.put("organization_id", organization_id)

        create_and_respond(conn, attrs)
    end
  end

  def create(conn, _params) do
    Resources.missing_param(conn, "check")
  end

  @doc """
  GET /api/v1/checks/:id

  Gets a single check by ID.
  """
  def show(conn, %{"id" => id}) do
    organization_id = conn.assigns.current_organization_id

    Resources.fetch_and_render(conn, Check, id, organization_id, &format_check/1, "Check not found")
  end

  @doc """
  PATCH /api/v1/checks/:id

  Updates a check.
  """
  def update(conn, %{"id" => id, "check" => check_params}) do
    organization_id = conn.assigns.current_organization_id

    Resources.update_and_render(
      conn,
      Check,
      id,
      organization_id,
      %{
        context: Monitoring,
        update_fn: :update_check,
        params: ParamFilter.strip_sensitive(check_params),
        format_fn: &format_check/1,
        not_found_msg: "Check not found"
      }
    )
  end

  def update(conn, _params) do
    Resources.missing_param(conn, "check")
  end

  @doc """
  DELETE /api/v1/checks/:id

  Deletes a check and cancels any scheduled jobs.
  """
  def delete(conn, %{"id" => id}) do
    organization_id = conn.assigns.current_organization_id

    Resources.delete_and_render(conn, Check, id, organization_id, Monitoring, :delete_check, "Check not found")
  end

  defp create_and_respond(conn, attrs) do
    case Monitoring.create_check(attrs) do
      {:ok, check} ->
        _ = if check.enabled, do: Monitoring.schedule_check(check)

        conn
        |> put_status(:created)
        |> json(format_check(check))

      {:error, %Ecto.Changeset{} = changeset} ->
        Resources.unprocessable_entity(conn, changeset)
    end
  end

  defp device_in_org?(nil, _organization_id), do: true

  defp device_in_org?(device_id, organization_id) do
    case ScopedResource.fetch(Device, device_id, organization_id) do
      {:ok, _device} -> true
      _ -> false
    end
  end

  defp format_check(check) do
    %{
      id: check.id,
      name: check.name,
      check_type: check.check_type,
      description: check.description,
      enabled: check.enabled,
      device_id: check.device_id,
      agent_token_id: check.agent_token_id,
      interval_seconds: check.interval_seconds,
      timeout_ms: check.timeout_ms,
      retry_interval_seconds: check.retry_interval_seconds,
      max_check_attempts: check.max_check_attempts,
      config: check.config,
      current_state: check.current_state,
      current_state_type: check.current_state_type,
      last_check_at: check.last_check_at,
      inserted_at: check.inserted_at
    }
  end

  defp maybe_add_opt(opts, _key, nil), do: opts
  defp maybe_add_opt(opts, _key, ""), do: opts
  defp maybe_add_opt(opts, key, value), do: Keyword.put(opts, key, value)
end