# Pleroma: A lightweight social networking server
# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only

defmodule Pleroma.Web.CommonAPI.Utils do
  alias Calendar.Strftime
  alias Comeonin.Pbkdf2
  alias Pleroma.Activity
  alias Pleroma.Config
  alias Pleroma.Formatter
  alias Pleroma.List
  alias Pleroma.Object
  alias Pleroma.Repo
  alias Pleroma.User
  alias Pleroma.Web.ActivityPub.Utils
  alias Pleroma.Web.ActivityPub.Visibility
  alias Pleroma.Web.Endpoint
  alias Pleroma.Web.MediaProxy

  require Logger

  # This is a hack for twidere.
  def get_by_id_or_ap_id(id) do
    activity =
      Activity.get_by_id_with_object(id) || Activity.get_create_by_object_ap_id_with_object(id)

    activity &&
      if activity.data["type"] == "Create" do
        activity
      else
        Activity.get_create_by_object_ap_id_with_object(activity.data["object"])
      end
  end

  def get_replied_to_activity(""), do: nil

  def get_replied_to_activity(id) when not is_nil(id) do
    Activity.get_by_id(id)
  end

  def get_replied_to_activity(_), do: nil

  def attachments_from_ids(data) do
    if Map.has_key?(data, "descriptions") do
      attachments_from_ids_descs(data["media_ids"], data["descriptions"])
    else
      attachments_from_ids_no_descs(data["media_ids"])
    end
  end

  def attachments_from_ids_no_descs(ids) do
    Enum.map(ids || [], fn media_id ->
      Repo.get(Object, media_id).data
    end)
  end

  def attachments_from_ids_descs(ids, descs_str) do
    {_, descs} = Jason.decode(descs_str)

    Enum.map(ids || [], fn media_id ->
      Map.put(Repo.get(Object, media_id).data, "name", descs[media_id])
    end)
  end

  def to_for_user_and_mentions(user, mentions, inReplyTo, "public") do
    mentioned_users = Enum.map(mentions, fn {_, %{ap_id: ap_id}} -> ap_id end)

    to = ["https://www.w3.org/ns/activitystreams#Public" | mentioned_users]
    cc = [user.follower_address]

    if inReplyTo do
      {Enum.uniq([inReplyTo.data["actor"] | to]), cc}
    else
      {to, cc}
    end
  end

  def to_for_user_and_mentions(user, mentions, inReplyTo, "unlisted") do
    mentioned_users = Enum.map(mentions, fn {_, %{ap_id: ap_id}} -> ap_id end)

    to = [user.follower_address | mentioned_users]
    cc = ["https://www.w3.org/ns/activitystreams#Public"]

    if inReplyTo do
      {Enum.uniq([inReplyTo.data["actor"] | to]), cc}
    else
      {to, cc}
    end
  end

  def to_for_user_and_mentions(user, mentions, inReplyTo, "private") do
    {to, cc} = to_for_user_and_mentions(user, mentions, inReplyTo, "direct")
    {[user.follower_address | to], cc}
  end

  def to_for_user_and_mentions(_user, mentions, inReplyTo, "direct") do
    mentioned_users = Enum.map(mentions, fn {_, %{ap_id: ap_id}} -> ap_id end)

    if inReplyTo do
      {Enum.uniq([inReplyTo.data["actor"] | mentioned_users]), []}
    else
      {mentioned_users, []}
    end
  end

  def to_for_user_and_mentions(_user, _mentions, _inReplyTo, _), do: {[], []}

  def bcc_for_list(user, {:list, list_id}) do
    with {_, %List{} = list} <- {:list, List.get(list_id, user)},
         {:ok, following} <- List.get_following(list) do
      {:ok, Enum.map(following, & &1.ap_id)}
    else
      {:list, _} -> {:error, "List not found"}
      err -> err
    end
  end

  def bcc_for_list(_, _), do: {:ok, []}

  def make_content_html(
        status,
        attachments,
        data,
        visibility
      ) do
    no_attachment_links =
      data
      |> Map.get("no_attachment_links", Config.get([:instance, :no_attachment_links]))
      |> Kernel.in([true, "true"])

    content_type = get_content_type(data["content_type"])

    options =
      if visibility == "direct" && Config.get([:instance, :safe_dm_mentions]) do
        [safe_mention: true]
      else
        []
      end

    status
    |> format_input(content_type, options)
    |> maybe_add_attachments(attachments, no_attachment_links)
    |> maybe_add_nsfw_tag(data)
  end

  defp get_content_type(content_type) do
    if Enum.member?(Config.get([:instance, :allowed_post_formats]), content_type) do
      content_type
    else
      "text/plain"
    end
  end

  defp maybe_add_nsfw_tag({text, mentions, tags}, %{"sensitive" => sensitive})
       when sensitive in [true, "True", "true", "1"] do
    {text, mentions, [{"#nsfw", "nsfw"} | tags]}
  end

  defp maybe_add_nsfw_tag(data, _), do: data

  def make_context(%Activity{data: %{"context" => context}}), do: context
  def make_context(_), do: Utils.generate_context_id()

  def maybe_add_attachments(parsed, _attachments, true = _no_links), do: parsed

  def maybe_add_attachments({text, mentions, tags}, attachments, _no_links) do
    text = add_attachments(text, attachments)
    {text, mentions, tags}
  end

  def add_attachments(text, attachments) do
    attachment_text =
      Enum.map(attachments, fn
        %{"url" => [%{"href" => href} | _]} = attachment ->
          name = attachment["name"] || URI.decode(Path.basename(href))
          href = MediaProxy.url(href)
          "<a href=\"#{href}\" class='attachment'>#{shortname(name)}</a>"

        _ ->
          ""
      end)

    Enum.join([text | attachment_text], "<br>")
  end

  def format_input(text, format, options \\ [])

  @doc """
  Formatting text to plain text.
  """
  def format_input(text, "text/plain", options) do
    text
    |> Formatter.html_escape("text/plain")
    |> Formatter.linkify(options)
    |> (fn {text, mentions, tags} ->
          {String.replace(text, ~r/\r?\n/, "<br>"), mentions, tags}
        end).()
  end

  @doc """
  Formatting text to html.
  """
  def format_input(text, "text/html", options) do
    text
    |> Formatter.html_escape("text/html")
    |> Formatter.linkify(options)
  end

  @doc """
  Formatting text to markdown.
  """
  def format_input(text, "text/markdown", options) do
    text
    |> Formatter.mentions_escape(options)
    |> Earmark.as_html!()
    |> Formatter.linkify(options)
    |> Formatter.html_escape("text/html")
  end

  def make_note_data(
        actor,
        to,
        context,
        content_html,
        attachments,
        in_reply_to,
        tags,
        cw \\ nil,
        cc \\ []
      ) do
    object = %{
      "type" => "Note",
      "to" => to,
      "cc" => cc,
      "content" => content_html,
      "summary" => cw,
      "context" => context,
      "attachment" => attachments,
      "actor" => actor,
      "tag" => tags |> Enum.map(fn {_, tag} -> tag end) |> Enum.uniq()
    }

    if in_reply_to do
      in_reply_to_object = Object.normalize(in_reply_to)

      object
      |> Map.put("inReplyTo", in_reply_to_object.data["id"])
    else
      object
    end
  end

  def format_naive_asctime(date) do
    date |> DateTime.from_naive!("Etc/UTC") |> format_asctime
  end

  def format_asctime(date) do
    Strftime.strftime!(date, "%a %b %d %H:%M:%S %z %Y")
  end

  def date_to_asctime(date) when is_binary(date) do
    with {:ok, date, _offset} <- DateTime.from_iso8601(date) do
      format_asctime(date)
    else
      _e ->
        Logger.warn("Date #{date} in wrong format, must be ISO 8601")
        ""
    end
  end

  def date_to_asctime(date) do
    Logger.warn("Date #{date} in wrong format, must be ISO 8601")
    ""
  end

  def to_masto_date(%NaiveDateTime{} = date) do
    date
    |> NaiveDateTime.to_iso8601()
    |> String.replace(~r/(\.\d+)?$/, ".000Z", global: false)
  end

  def to_masto_date(date) do
    try do
      date
      |> NaiveDateTime.from_iso8601!()
      |> NaiveDateTime.to_iso8601()
      |> String.replace(~r/(\.\d+)?$/, ".000Z", global: false)
    rescue
      _e -> ""
    end
  end

  defp shortname(name) do
    if String.length(name) < 30 do
      name
    else
      String.slice(name, 0..30) <> "…"
    end
  end

  def confirm_current_password(user, password) do
    with %User{local: true} = db_user <- User.get_cached_by_id(user.id),
         true <- Pbkdf2.checkpw(password, db_user.password_hash) do
      {:ok, db_user}
    else
      _ -> {:error, "Invalid password."}
    end
  end

  def emoji_from_profile(%{info: _info} = user) do
    (Formatter.get_emoji(user.bio) ++ Formatter.get_emoji(user.name))
    |> Enum.map(fn {shortcode, url, _} ->
      %{
        "type" => "Emoji",
        "icon" => %{"type" => "Image", "url" => "#{Endpoint.url()}#{url}"},
        "name" => ":#{shortcode}:"
      }
    end)
  end

  def maybe_notify_to_recipients(
        recipients,
        %Activity{data: %{"to" => to, "type" => _type}} = _activity
      ) do
    recipients ++ to
  end

  def maybe_notify_mentioned_recipients(
        recipients,
        %Activity{data: %{"to" => _to, "type" => type} = data} = activity
      )
      when type == "Create" do
    object = Object.normalize(activity)

    object_data =
      cond do
        !is_nil(object) ->
          object.data

        is_map(data["object"]) ->
          data["object"]

        true ->
          %{}
      end

    tagged_mentions = maybe_extract_mentions(object_data)

    recipients ++ tagged_mentions
  end

  def maybe_notify_mentioned_recipients(recipients, _), do: recipients

  def maybe_notify_subscribers(
        recipients,
        %Activity{data: %{"actor" => actor, "type" => type}} = activity
      )
      when type == "Create" do
    with %User{} = user <- User.get_cached_by_ap_id(actor) do
      subscriber_ids =
        user
        |> User.subscribers()
        |> Enum.filter(&Visibility.visible_for_user?(activity, &1))
        |> Enum.map(& &1.ap_id)

      recipients ++ subscriber_ids
    end
  end

  def maybe_notify_subscribers(recipients, _), do: recipients

  def maybe_extract_mentions(%{"tag" => tag}) do
    tag
    |> Enum.filter(fn x -> is_map(x) end)
    |> Enum.filter(fn x -> x["type"] == "Mention" end)
    |> Enum.map(fn x -> x["href"] end)
  end

  def maybe_extract_mentions(_), do: []

  def make_report_content_html(nil), do: {:ok, {nil, [], []}}

  def make_report_content_html(comment) do
    max_size = Pleroma.Config.get([:instance, :max_report_comment_size], 1000)

    if String.length(comment) <= max_size do
      {:ok, format_input(comment, "text/plain")}
    else
      {:error, "Comment must be up to #{max_size} characters"}
    end
  end

  def get_report_statuses(%User{ap_id: actor}, %{"status_ids" => status_ids}) do
    {:ok, Activity.all_by_actor_and_id(actor, status_ids)}
  end

  def get_report_statuses(_, _), do: {:ok, nil}

  # DEPRECATED mostly, context objects are now created at insertion time.
  def context_to_conversation_id(context) do
    with %Object{id: id} <- Object.get_cached_by_ap_id(context) do
      id
    else
      _e ->
        changeset = Object.context_mapping(context)

        case Repo.insert(changeset) do
          {:ok, %{id: id}} ->
            id

          # This should be solved by an upsert, but it seems ecto
          # has problems accessing the constraint inside the jsonb.
          {:error, _} ->
            Object.get_cached_by_ap_id(context).id
        end
    end
  end

  def conversation_id_to_context(id) do
    with %Object{data: %{"id" => context}} <- Repo.get(Object, id) do
      context
    else
      _e ->
        {:error, "No such conversation"}
    end
  end
end