defmodule Box do
  @moduledoc """
  Unofficial Box SDK for Elixir. See the BoxOAuth2 module to get started.
  """
  alias Tesla.Multipart

  @box_api_url "https://api.box.com/2.0"
  @box_upload_url "https://upload.box.com/api/2.0"

  @doc """
  Folder items returns the entries in a folder.

      {:ok, folder} = Box.folder_from_path(auth.client, "/")
      {:ok, entries} = Box.folder_items(auth.client, folder.id, [:id, :name])
      IO.inspect(entries)
  """
  def folder_items(client, folder, fields \\ []) do
    with {:ok, response} <-
           Tesla.get(client, @box_api_url <> "/folders/#{folder}/items",
             query: [fields: Enum.join(fields, ",")]
           ) do
      case response do
        %{status: 200, body: %{entries: entries}} ->
          {:ok, entries}

        %{status: status, body: %{message: message}} ->
          {:error, status, message}

        %{status: status} ->
          {:error, status, to_string(status)}
      end
    end
  end

  @doc """
  Folder from path returns the folder id for a path in Box.

      {:ok, folder} = Box.folder_from_path(auth.client, "/")
  """
  def folder_from_path(_client, path) do
    if path == "/" or path == "." do
      {:ok, %{id: "0"}}
    else
      # TODO: fetch id for other paths
      raise "not implemented: folder_from_path #{path}"
    end
  end

  @doc """
  File from path returns the file name and id for a path in Box.

      {:ok, file} = Box.file_from_path(auth.client, "file.ext")
  """
  def file_from_path(client, path) do
    with {:ok, folder} <- folder_from_path(client, Path.dirname(path)),
         {:ok, files} <- folder_items(client, folder.id, [:id, :name]) do
      filename = Path.basename(path)

      case Enum.find(files, fn f -> f.type == "file" and f.name == filename end) do
        nil -> {:error, "file not found"}
        f -> {:ok, f}
      end
    end
  end

  @doc """
  Create shared link for a file.

      {:ok, file} = Box.file_from_path(auth.client, "file.ext")
      {:ok, response.shared_link} = Box.create_shared_link(auth.client, file.id)
      IO.puts(response.shared_link.download_url)

  """
  def create_shared_link(client, file_id) do
    # https://developer.box.com/reference#shared-link-object
    body = %{
      shared_link: %{
        access: "open",
        # TODO: password, unshared_at?
        permissions: %{
          can_download: true
        }
      }
    }

    with {:ok, response} <- Tesla.put(client, @box_api_url <> "/files/#{file_id}", body) do
      case response do
        %{status: 200, body: body} ->
          {:ok, body}

        %{status: status, body: %{message: message}} ->
          {:error, status, message}

        %{status: status} ->
          {:error, status, to_string(status)}
      end
    end
  end

  @doc """
  File info for a file id.

      {:ok, file} = Box.file_from_path(auth.client, "file.ext")
      {:ok, response} = Box.file_info(auth.client, file.id)
      IO.puts(response.shared_link.download_url)
  """
  def file_info(client, file_id) do
    fields = [
      :type,
      :id,
      :sequence_id,
      :etag,
      :name,
      :created_at,
      :modified_at,
      :description,
      :size,
      :path_collection,
      :created_by,
      :modified_by,
      :trashed_at,
      :purged_at,
      :content_created_at,
      :content_modified_at,
      :owned_by,
      :shared_link,
      :folder_upload_email,
      :parent,
      :item_status,
      :item_collection,
      :sync_state,
      :has_collaborations,
      :permissions,
      :tags,
      :sha1,
      :shared_link,
      :version_number,
      :comment_count,
      :lock,
      :extension,
      :is_package,
      :can_non_owners_invite
    ]

    with {:ok, response} <-
           Tesla.get(client, @box_api_url <> "/files/#{file_id}",
             query: [fields: Enum.join(fields, ",")]
           ) do
      {:ok, response.body}
    end
  end

  @doc """
  Upload a local file to a folder on Box.

      {:ok, folder} = Box.folder_from_path(auth.client, "/")
      {:ok, _response} = Box.upload(auth.client, "path/to/file.ext", folder.id, "file.ext")
  """
  def upload(client, path, folder_id, name) do
    attributes =
      Jason.encode!(%{
        name: name,
        parent: %{id: folder_id}
      })

    mp =
      Multipart.new()
      |> Multipart.add_field("attributes", attributes)
      |> Multipart.add_file(path)

    with {:ok, response} <- Tesla.post(client, @box_upload_url <> "/files/content", mp) do
      case response do
        %{status: 201, body: body} ->
          {:ok, body}

        %{status: status, body: %{message: message}} ->
          {:error, status, message}

        %{status: status} ->
          {:error, status, to_string(status)}
      end
    end
  end

  @doc """
  Create folder in a parent folder.

      {:ok, folder} = Box.folder_from_path(auth.client, "/")
      {:ok, response} = Box.create_folder(auth.client, "folder", folder.id)
  """
  def create_folder(client, name, folder_id) do
    body = %{
      name: name,
      parent: %{id: folder_id}
    }

    with {:ok, response} <- Tesla.post(client, @box_api_url <> "/folders", body) do
      case response do
        %{status: 201, body: body} ->
          {:ok, body}

        %{status: status, body: %{message: message}} ->
          {:error, status, message}

        %{status: status} ->
          {:error, status, to_string(status)}
      end
    end
  end
end