defmodule ClacksWeb.FrontendView do
  use ClacksWeb, :view
  alias Clacks.{Actor, Activity}
  alias ClacksWeb.Router.Helpers, as: Routes
  alias ClacksWeb.Endpoint

  @spec display_username(actor :: Actor.t()) :: String.t()

  def display_username(%Actor{local: true, data: %{"name" => name}}) do
    "@" <> name
  end

  def display_username(%Actor{local: false, ap_id: ap_id, data: %{"name" => name}}) do
    %URI{host: host} = URI.parse(ap_id)
    "@" <> name <> "@" <> host
  end

  def local_actor_link(%Actor{local: true, ap_id: ap_id}), do: ap_id

  def local_actor_link(%Actor{local: false, id: id}),
    do: Routes.frontend_path(Endpoint, :actor, id)

  @spec display_timestamp(str :: String.t()) :: String.t()

  def display_timestamp(str) when is_binary(str) do
    display_timestamp(Timex.parse!(str, "{ISO:Extended}"))
  end

  def display_timestamp(datetime) do
    diff = Timex.diff(Timex.now(), datetime, :seconds)

    cond do
      diff < 60 ->
        # less than a minute, seconds
        "#{diff}sec"

      diff < 60 * 60 ->
        # less than an hour, minutes
        "#{Integer.floor_div(diff, 60)}min"

      diff < 60 * 60 * 24 ->
        # less than a day, hours
        "#{Integer.floor_div(diff, 60 * 60)}hr"

      diff < 60 * 60 * 24 * 7 ->
        # less than a week, days
        "#{Integer.floor_div(diff, 60 * 60 * 24)}d"

      true ->
        Timex.format!(datetime, "%FT%T%:z", :strftime)
    end
  end

  @spec prev_page_path(conn :: Plug.Conn.t(), [Activity.t() | {Activity.t(), Actor.t()}]) ::
          String.t()

  def prev_page_path(conn, activities) do
    if Map.has_key?(conn.query_params, "max_id") do
      Phoenix.Controller.current_path(conn, %{
        since_id: activities |> List.first() |> activity_id()
      })
    else
      nil
    end
  end

  @spec next_page_path(conn :: Plug.Conn.t(), [Activity.t() | {Activity.t(), Actor.t()}]) ::
          String.t()

  def next_page_path(conn, activities) do
    if length(activities) < 20 do
      nil
    else
      Phoenix.Controller.current_path(conn, %{
        max_id: activities |> List.last() |> activity_id()
      })
    end
  end

  defp activity_id(%Activity{id: id}), do: id
  defp activity_id({%Activity{id: id}, _}), do: id
end