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

  import ToweropsWeb.Api.ErrorHelpers, only: [translate_errors: 1]

  alias Towerops.Monitoring
  alias Towerops.Monitoring.Check
  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", "")

    if check_type in @service_check_types do
      attrs = Map.put(check_params, "organization_id", organization_id)
      create_and_respond(conn, attrs)
    else
      conn
      |> put_status(:bad_request)
      |> json(%{error: "Invalid check type '#{check_type}'. Must be one of: #{Enum.join(@service_check_types, ", ")}"})
    end
  end

  def create(conn, _params) do
    conn
    |> put_status(:bad_request)
    |> json(%{error: "Missing 'check' parameter"})
  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} ->
        conn
        |> put_status(:unprocessable_entity)
        |> json(%{errors: translate_errors(changeset)})
    end
  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

    case ScopedResource.fetch(Check, id, organization_id) do
      {:ok, check} ->
        json(conn, format_check(check))

      {:error, :forbidden} ->
        conn
        |> put_status(:forbidden)
        |> json(%{error: "Access denied to this check"})

      {:error, :not_found} ->
        conn
        |> put_status(:not_found)
        |> json(%{error: "Check not found"})
    end
  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

    case ScopedResource.fetch(Check, id, organization_id) do
      {:ok, check} ->
        case Monitoring.update_check(check, check_params) do
          {:ok, updated_check} ->
            json(conn, format_check(updated_check))

          {:error, %Ecto.Changeset{} = changeset} ->
            conn
            |> put_status(:unprocessable_entity)
            |> json(%{errors: translate_errors(changeset)})
        end

      {:error, :forbidden} ->
        conn
        |> put_status(:forbidden)
        |> json(%{error: "Access denied to this check"})

      {:error, :not_found} ->
        conn
        |> put_status(:not_found)
        |> json(%{error: "Check not found"})
    end
  end

  def update(conn, _params) do
    conn
    |> put_status(:bad_request)
    |> json(%{error: "Missing 'check' parameter"})
  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

    case ScopedResource.fetch(Check, id, organization_id) do
      {:ok, check} ->
        case Monitoring.delete_check(check) do
          {:ok, _check} ->
            json(conn, %{success: true})

          {:error, %Ecto.Changeset{} = changeset} ->
            conn
            |> put_status(:unprocessable_entity)
            |> json(%{errors: translate_errors(changeset)})
        end

      {:error, :forbidden} ->
        conn
        |> put_status(:forbidden)
        |> json(%{error: "Access denied to this check"})

      {:error, :not_found} ->
        conn
        |> put_status(:not_found)
        |> json(%{error: "Check not found"})
    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