ex_line

defmodule ExLine.Message.Template do
  @moduledoc """
  Builders for LINE template messages.

  Ref: https://developers.line.biz/en/reference/messaging-api/#template-messages
  """

  @doc """
  Buttons template.

  Options: `:alt_text` (defaults to `text`), `:thumbnail_image_url`,
  `:image_aspect_ratio`, `:image_size`, `:image_background_color`, `:title`,
  `:default_action`.

  Ref: https://developers.line.biz/en/reference/messaging-api/#buttons

      iex> ExLine.Message.Template.buttons("Pick one", [ExLine.Message.Action.message("A", "a")])
      %{
        type: "template",
        altText: "Pick one",
        template: %{type: "buttons", text: "Pick one", actions: [%{type: "message", label: "A", text: "a"}]}
      }
  """
  @spec buttons(String.t(), [map()], keyword()) :: map()
  def buttons(text, actions, opts \\ []) do
    template =
      %{type: "buttons", text: text}
      |> maybe_put(:thumbnailImageUrl, opts[:thumbnail_image_url])
      |> maybe_put(:imageAspectRatio, opts[:image_aspect_ratio])
      |> maybe_put(:imageSize, opts[:image_size])
      |> maybe_put(:imageBackgroundColor, opts[:image_background_color])
      |> maybe_put(:title, opts[:title])
      |> maybe_put(:defaultAction, opts[:default_action])
      |> Map.put(:actions, actions)

    %{type: "template", altText: opts[:alt_text] || text, template: template}
  end

  @doc """
  Confirm template — two actions (yes/no).

  Ref: https://developers.line.biz/en/reference/messaging-api/#confirm

      iex> ExLine.Message.Template.confirm("OK?", [ExLine.Message.Action.message("Yes", "y"), ExLine.Message.Action.message("No", "n")])
      %{
        type: "template",
        altText: "OK?",
        template: %{type: "confirm", text: "OK?", actions: [
          %{type: "message", label: "Yes", text: "y"},
          %{type: "message", label: "No", text: "n"}
        ]}
      }
  """
  @spec confirm(String.t(), [map()], keyword()) :: map()
  def confirm(text, actions, opts \\ []) do
    %{
      type: "template",
      altText: opts[:alt_text] || text,
      template: %{type: "confirm", text: text, actions: actions}
    }
  end

  @doc """
  Carousel template — up to 10 columns built with `carousel_column/3`.

  Options: `:alt_text`, `:image_aspect_ratio`, `:image_size`.

  Ref: https://developers.line.biz/en/reference/messaging-api/#carousel
  """
  @spec carousel([map()], keyword()) :: map()
  def carousel(columns, opts \\ []) do
    template =
      %{type: "carousel", columns: columns}
      |> maybe_put(:imageAspectRatio, opts[:image_aspect_ratio])
      |> maybe_put(:imageSize, opts[:image_size])

    %{type: "template", altText: opts[:alt_text] || "carousel", template: template}
  end

  @doc """
  A carousel column. `text` and `actions` are required.

  Options: `:title`, `:thumbnail_image_url`, `:image_background_color`, `:default_action`.

      iex> ExLine.Message.Template.carousel_column("desc", [ExLine.Message.Action.message("A", "a")])
      %{text: "desc", actions: [%{type: "message", label: "A", text: "a"}]}
  """
  @spec carousel_column(String.t(), [map()], keyword()) :: map()
  def carousel_column(text, actions, opts \\ []) do
    %{text: text, actions: actions}
    |> maybe_put(:title, opts[:title])
    |> maybe_put(:thumbnailImageUrl, opts[:thumbnail_image_url])
    |> maybe_put(:imageBackgroundColor, opts[:image_background_color])
    |> maybe_put(:defaultAction, opts[:default_action])
  end

  @doc """
  Image carousel template — columns built with `image_carousel_column/2`.

  Ref: https://developers.line.biz/en/reference/messaging-api/#image-carousel
  """
  @spec image_carousel([map()], keyword()) :: map()
  def image_carousel(columns, opts \\ []) do
    %{
      type: "template",
      altText: opts[:alt_text] || "image carousel",
      template: %{type: "image_carousel", columns: columns}
    }
  end

  @doc """
  An image carousel column: an image with a single action.

      iex> ExLine.Message.Template.image_carousel_column("https://x/i.jpg", ExLine.Message.Action.uri("Open", "https://x"))
      %{imageUrl: "https://x/i.jpg", action: %{type: "uri", label: "Open", uri: "https://x"}}
  """
  @spec image_carousel_column(String.t(), map()) :: map()
  def image_carousel_column(image_url, action), do: %{imageUrl: image_url, action: action}

  defp maybe_put(map, _key, nil), do: map
  defp maybe_put(map, key, value), do: Map.put(map, key, value)
end