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

    # define service that will be used to handle file persistence and file variants
    service(persistence: Tempel.Local, variant: Tempel.Variant)

    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
    pipeline(:product)

    # Define file pipeline with other variants

    pipeline(:avatar, %{
      filename: fn name, setting ->
        user_id = Map.get(setting, :user_id)
        "main" <> "-" <> user_id <> "-" <> name
      end,
      variants: %{
        thumbnail: [
          operation: :thumbnail,
          resize_options: [size: "300x400", options: [fit: :cover]],
          write_options: [path: :memory, options: [suffix: ".jpeg"]]
        ]
      }
    })
  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