defmodule ClacksWeb.FrontendView do
  use ClacksWeb, :view
  alias Clacks.{Actor, Activity, Repo}
  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(datetime :: String.t() | DateTime.t() | NaiveDateTime.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"

      diff < 60 * 60 * 24 * 30 ->
        # less than a month(ish), weeks
        "#{Integer.floor_div(diff, 60 * 60 * 24 * 7)}wk"

      diff < 60 * 60 * 24 * 365 ->
        # less than a year, months(ish)
        # todo: figure out actually how many months
        "#{Integer.floor_div(diff, 60 * 60 * 24 * 30)}mo"

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

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

  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() | nil

  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

  @spec mentions_for_replying_to(Activity.t()) :: String.t()
  defp mentions_for_replying_to(conn, %Activity{
         data: %{"object" => %{"actor" => actor, "tag" => tags}}
       }) do
    current_user = conn.assigns[:user] |> Repo.preload(:actor)

    tag_actors =
      tags
      |> Enum.filter(fn
        %{"type" => "Mention"} -> true
        _ -> false
      end)
      |> Enum.map(fn %{"href" => ap_id} -> ap_id end)

    actors =
      [actor | tag_actors]
      |> List.delete(current_user.actor.ap_id)
      |> Enum.uniq()

    mentions =
      actors
      |> Enum.map(fn ap_id ->
        actor = Actor.get_cached_by_ap_id(ap_id)
        "@#{actor.nickname}"
      end)
      |> Enum.join(" ")

    "#{mentions} "
  end

  defp mentions_for_replying_to(_), do: ""
end