defmodule Tempel do
  @moduledoc """
  This module is used to manage file attachments. It accept a single or list of file
  formatted to match file format of [Plug.Upload](https://hexdocs.pm/plug/Plug.Upload.html)

  ```
  %{
    filename :: binary(),
    path :: Path.t,
    content_type: binary()
  }
  ```
  # Get Started

  define your own file uploader

  ```
  defmodule MyUploader do
    use Temple.Gate

    def init(opts) do
      # add important configuration here such as storage key and cridentials
      %{}
    end

    # Define file pipeline

    # This pipeline will only save the main image, no other variants will be saved
    @impl true
    def pipeline(:product, files, _opts) do
      no_variants(files, [])
    end

    # Define file pipeline with other variants

    def pipeline(:avatar, files, opts) do
      create_variants(files,
        variants: [
          avatar: [
            operation: :avatar,
            resize_options: [size: 100],
            filename: fn name ->
              user_id = Access.get(opts, :user_id, "")
              "radom" <> "-" <> user_id <> "-" <> name
            end
          ],
          thumbnail: [
            operation: :thumbnail,
            resize_options: [size: "300x400", options: [fit: :cover]],
            write_options: [path: :memory, options: [suffix: ".jpeg"]],
            filename: fn name -> name end
          ]
        ],
        save_original: true,
        filename: fn name ->
          user_id = Access.get(opts, :user_id, "")
          "main" <> "-" <> user_id <> "-" <> name
        end
      )
    end
  end
  ```

  To call this uploader in you uploading process
  ```
    # file from `Plug.Upload`

    MyUploader.save(:avatar, file)
    # => {:ok, %{"main" => object_key, "thumbnail" => object_key}}

    Myuploader.save(:product, file)
    # => {:ok, %{"main" => object_key}}
  ```
  """
end