defmodule BexioApiClient.Helpers do
  @moduledoc false

  @doc """
  Convert the given string into an Elixir date.

  Examples:
      iex> BexioApiClient.Helpers.to_date(nil)
      nil

      iex> BexioApiClient.Helpers.to_date("2013-02-22")
      ~D[2013-02-22]
  """
  @spec to_date(String.t() | nil) :: Date.t() | nil
  def to_date(nil), do: nil

  def to_date(date) do
    Date.from_iso8601!(date)
  end

  @doc """
  Convert the given string into an Elixir decimal.

  Examples:
      iex> BexioApiClient.Helpers.to_decimal(nil)
      nil

      iex> BexioApiClient.Helpers.to_decimal("2.331")
      #Decimal<2.331>
  """
  @spec to_decimal(String.t() | nil) :: Decimal.t() | nil
  def to_decimal(nil), do: nil
  def to_decimal(decimal), do: Decimal.new(decimal)

  # The format from Bexio is 2022-09-13 09:14:21
  @doc """
  Convert the given string into an Elixir date.

  Examples:
      iex> BexioApiClient.Helpers.to_datetime(nil)
      nil

      iex> BexioApiClient.Helpers.to_datetime("2022-09-13 09:14:21")
      ~N[2022-09-13 09:14:21]
  """
  @spec to_datetime(String.t() | nil) :: DateTime.t() | nil
  def to_datetime(nil), do: nil

  def to_datetime(datetime) do
    [zurich_date, zurich_time] = String.split(datetime, " ")
    date = Date.from_iso8601!(zurich_date)
    time = Time.from_iso8601!(zurich_time)
    NaiveDateTime.new!(date, time)
  end

  def to_iso8601(nil), do: nil
  def to_iso8601(%NaiveDateTime{} = n), do: NaiveDateTime.to_iso8601(n)
  def to_iso8601(%DateTime{} = dt), do: DateTime.to_iso8601(dt)

  def to_naive_string(nil), do: nil
  def to_naive_string(n), do: NaiveDateTime.to_string(n)

  # The format from Bexio 3.0 is 2022-09-13T09:14:21+00:00
  @doc """
  Convert the given string into an elixir date using offsets

  Examples:
      iex> BexioApiClient.Helpers.to_offset_datetime(nil)
      nil

      iex> BexioApiClient.Helpers.to_offset_datetime("2022-09-13T09:14:21+02:00")
      ~U[2022-09-13 07:14:21Z]
  """
  def to_offset_datetime(nil), do: nil

  def to_offset_datetime(datetime) do
    case DateTime.from_iso8601(datetime) do
      {:ok, datetime, _offset} -> datetime
      {:error, error} -> raise ArgumentError, message: error
    end
  end

  @spec string_to_array(String.t() | nil) :: [integer()]
  def string_to_array(nil), do: []

  def string_to_array(string) do
    string
    |> String.split(",")
    |> Enum.map(&String.to_integer/1)
    |> Enum.uniq()
    |> Enum.sort()
  end

  @type handler_callback_result_type :: any()
  @type tesla_body_callback_type :: any()
  @spec bexio_body_handling(call :: (() -> tesla_body_callback_type), callback :: (tesla_body_callback_type, Tesla.Env.t() -> handler_callback_result_type)) ::
          {:ok, handler_callback_result_type}
          | {:error,
             :invalid_access
             | :unauthorized
             | :not_found
             | :length_required
             | :invalid_data
             | :could_not_be_saved
             | :rate_limited
             | :unexpected_api_condition
             | :api_not_available}
  def bexio_body_handling(call, callback) do
    bexio_handling(call, fn body, env ->
      {:ok, callback.(body, env)}
    end)
  end

  @spec bexio_handling(call :: (() -> tesla_body_callback_type), callback :: (tesla_body_callback_type, Tesla.Env.t() -> handler_callback_result_type)) ::
          handler_callback_result_type
          | {:error,
             :invalid_access
             | :unauthorized
             | :not_found
             | :length_required
             | :invalid_data
             | :could_not_be_saved
             | :rate_limited
             | :unexpected_api_condition
             | :api_not_available}
  def bexio_handling(call, callback) do
    case call.() do
      {:ok, %Tesla.Env{status: status, body: body} = env} when status in [200, 201, 301] ->
        callback.(body, env)

      {:ok, %Tesla.Env{status: status}} ->
        {:error, error_code(status)}

      {:error, error} ->
        {:error, error}
    end
  end

  defp error_code(400), do: :bad_request
  defp error_code(401), do: :invalid_access
  defp error_code(403), do: :unauthorized
  defp error_code(404), do: :not_found
  defp error_code(411), do: :length_required
  defp error_code(415), do: :invalid_data
  defp error_code(422), do: :could_not_be_saved
  defp error_code(429), do: :rate_limited
  defp error_code(500), do: :unexpected_api_condition
  defp error_code(503), do: :api_not_available

  @doc """
  converts a list of maps ("id" => id, "name" => name) into a single map with all values converted to %{id: name}

  Examples:

    iex> BexioApiClient.Helpers.body_to_map([%{"id" => 1, "name" => "hello"}, %{"id" => 2, "name" => "world"}], nil)
    %{1 => "hello", 2 => "world"}

  """
  @spec body_to_map(list(%{String.t() => any()}), Tesla.Env.t()) :: %{integer() => String.t()}
  def body_to_map(body, _env) do
    body
    |> Enum.map(fn %{"id" => id, "name" => name} -> {id, name} end)
    |> Enum.into(%{})
  end

  @doc """
  Converts the pattern %{"id" => id, "name" => name} into %{id: id, name: name}

  Examples:

    iex> BexioApiClient.Helpers.id_name(%{"id" => 1, "name" => "hello"}, nil)
    %{id: 1, name: "hello"}

  """
  @spec id_name(%{String.t() => any()}, Tesla.Env.t()) :: %{id: integer(), name: String.t()}
  def id_name(%{"id" => id, "name" => name}, _env), do: %{id: id, name: name}

  @doc """
  Just interprets the delete result into either true or false depending on the success key in the map

  Example:

    iex> BexioApiClient.Helpers.success_response(%{"success" => true}, %Tesla.Env{})
    true

    iex> BexioApiClient.Helpers.success_response(%{"failure" => true}, %Tesla.Env{})
    false

  """
  @spec success_response(map(), Tesla.Env.t()) :: boolean()
  def success_response(%{"success" => true}, _env), do: true
  def success_response(_result, _env), do: false
end