appwrite

defmodule Appwrite.Utils.Service do
  @moduledoc """

  A service utility module for operations like chunked uploads and payload flattening.

  """

  alias Appwrite.Types.Client.Payload

  @chunk_size 5 * 1024 * 1024
  @doc """

  Returns the size for chunked uploads in bytes.



  ## Examples



      iex> Appwrite.Service.chunk_size()

      5242880

  """
  @spec chunk_size() :: non_neg_integer()
  def chunk_size, do: @chunk_size

  @doc """

  Flattens a nested map or list structure into a key-value map with prefixed keys.



  ## Parameters



    - `data` (`Payload.t`): The nested map or list to flatten.

    - `prefix` (`String.t`): The prefix for keys (default: `""`).



  ## Returns



    - A flattened map with keys prefixed appropriately.



  ## Examples



      iex> Appwrite.Service.flatten(%{"key1" => %{"key2" => "value"}}, "prefix")

      %{"prefix[key1][key2]" => "value"}



      iex> Appwrite.Service.flatten(%{"key1" => ["value1", "value2"]})

      %{"key1[0]" => "value1", "key1[1]" => "value2"}

  """
  @spec flatten(Payload.t(), String.t()) :: Payload.t()
  def flatten(data, prefix \\ "") when is_map(data) or is_list(data) do
    try do
      data
      |> Enum.reduce(%{}, fn {key, value}, acc ->
        final_key =
          if prefix == "" do
            key
          else
            "#{prefix}[#{key}]"
          end

        if is_map(value) or is_list(value) do
          Map.merge(acc, flatten(value, final_key))
        else
          Map.put(acc, final_key, value)
        end
      end)
    rescue
      _e ->
        raise ArgumentError, "Invalid data type: `data` must be a map or a list."
    end
  end

  @doc """

  Validates that the given data is not `nil`.



  ## Parameters



    - `data` (`any`): The data to check.



  ## Returns



    - The data itself if it is valid.



  ## Raises



    - `ArgumentError` if the data is `nil`.



  ## Examples



      iex> Appwrite.Service.ensure_not_nil(%{})

      %{}



      iex> Appwrite.Service.ensure_not_nil(nil)

      ** (ArgumentError) Input cannot be nil

  """
  @spec ensure_not_nil(any()) :: any()
  def ensure_not_nil(data) do
    if data == nil do
      raise ArgumentError, "Input cannot be nil"
    else
      data
    end
  end
end