defmodule Pleroma.Web.TwitterAPI.Representers.ActivityRepresenter do
  use Pleroma.Web.TwitterAPI.Representers.BaseRepresenter
  alias Pleroma.Web.TwitterAPI.Representers.{UserRepresenter, ObjectRepresenter}
  alias Pleroma.{Activity, User, Formatter}
  alias Pleroma.Web.TwitterAPI.TwitterAPI

  defp user_by_ap_id(user_list, ap_id) do
    Enum.find(user_list, fn (%{ap_id: user_id}) -> ap_id == user_id end)
  end

  def to_map(%Activity{data: %{"type" => "Announce", "actor" => actor, "published" => created_at}} = activity,
             %{users: users, announced_activity: announced_activity} = opts) do
    user = user_by_ap_id(users, actor)
    created_at = created_at |> date_to_asctime

    text = "#{user.nickname} retweeted a status."

    announced_user = user_by_ap_id(users, announced_activity.data["actor"])
    retweeted_status = to_map(announced_activity, Map.merge(%{user: announced_user}, opts))
    %{
      "id" => activity.id,
      "user" => UserRepresenter.to_map(user, opts),
      "statusnet_html" => text,
      "text" => text,
      "is_local" => true,
      "is_post_verb" => false,
      "uri" => "tag:#{activity.data["id"]}:objectType=note",
      "created_at" => created_at,
      "retweeted_status" => retweeted_status,
      "statusnet_conversation_id" => conversation_id(announced_activity),
      "external_url" => activity.data["id"]
    }
  end

  def to_map(%Activity{data: %{"type" => "Like", "published" => created_at}} = activity,
             %{user: user, liked_activity: liked_activity} = opts) do
    created_at = created_at |> date_to_asctime

    text = "#{user.nickname} favorited a status."

    %{
      "id" => activity.id,
      "user" => UserRepresenter.to_map(user, opts),
      "statusnet_html" => text,
      "text" => text,
      "is_local" => true,
      "is_post_verb" => false,
      "uri" => "tag:#{activity.data["id"]}:objectType=Favourite",
      "created_at" => created_at,
      "in_reply_to_status_id" => liked_activity.id,
      "external_url" => activity.data["id"]
    }
  end

  def to_map(%Activity{data: %{"type" => "Follow", "published" => created_at, "object" => followed_id}} = activity, %{user: user} = opts) do
    created_at = created_at |> date_to_asctime

    followed = User.get_cached_by_ap_id(followed_id)
    text = "#{user.nickname} started following #{followed.nickname}"
    %{
      "id" => activity.id,
      "user" => UserRepresenter.to_map(user, opts),
      "attentions" => [],
      "statusnet_html" => text,
      "text" => text,
      "is_local" => true,
      "is_post_verb" => false,
      "created_at" => created_at,
      "in_reply_to_status_id" => nil,
      "external_url" => activity.data["id"]
    }
  end

  def content_with_tags(content, tags) do
    tags = tags || []
    text_content = HtmlSanitizeEx.strip_tags(content)
    found_tags = Formatter.parse_tags(text_content)
    |> Enum.map(fn ({_, tag}) -> tag end)

    missing_tags = tags -- found_tags
    |> Enum.map(&"##{&1}")

    Enum.join([content | missing_tags], "<br>\n")
  end

  def to_map(%Activity{data: %{"object" => %{"content" => content} = object}} = activity, %{user: user} = opts) do
    created_at = object["published"] |> date_to_asctime
    like_count = object["like_count"] || 0
    announcement_count = object["announcement_count"] || 0
    favorited = opts[:for] && opts[:for].ap_id in (object["likes"] || [])
    repeated = opts[:for] && opts[:for].ap_id in (object["announcements"] || [])

    mentions = opts[:mentioned] || []

    attentions = activity.data["to"]
    |> Enum.map(fn (ap_id) -> Enum.find(mentions, fn(user) -> ap_id == user.ap_id end) end)
    |> Enum.filter(&(&1))
    |> Enum.map(fn (user) -> UserRepresenter.to_map(user, opts) end)

    conversation_id = conversation_id(activity)

    content = content_with_tags(content, object["tag"])

    %{
      "id" => activity.id,
      "user" => UserRepresenter.to_map(user, opts),
      "attentions" => [],
      "statusnet_html" => HtmlSanitizeEx.basic_html(content),
      "text" => HtmlSanitizeEx.strip_tags(content),
      "is_local" => true,
      "is_post_verb" => true,
      "created_at" => created_at,
      "in_reply_to_status_id" => object["inReplyToStatusId"],
      "statusnet_conversation_id" => conversation_id,
      "attachments" => (object["attachment"] || []) |> ObjectRepresenter.enum_to_list(opts),
      "attentions" => attentions,
      "fave_num" => like_count,
      "repeat_num" => announcement_count,
      "favorited" => to_boolean(favorited),
      "repeated" => to_boolean(repeated),
      "external_url" => activity.data["id"]
    }
  end

  def conversation_id(activity) do
    with context when not is_nil(context) <- activity.data["context"] do
      TwitterAPI.context_to_conversation_id(context)
    else _e -> nil
    end
  end

  defp to_boolean(false) do
    false
  end

  defp to_boolean(nil) do
    false
  end

  defp to_boolean(_) do
    true
  end
end