# Pleroma: A lightweight social networking server
# Copyright © 2017-2021 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only

defmodule Pleroma.Web.CommonAPI.Utils do
  import Pleroma.Web.Gettext

  alias Calendar.Strftime
  alias Pleroma.Activity
  alias Pleroma.Config
  alias Pleroma.Conversation.Participation
  alias Pleroma.Formatter
  alias Pleroma.Object
  alias Pleroma.Repo
  alias Pleroma.User
  alias Pleroma.Web.ActivityPub.Utils
  alias Pleroma.Web.ActivityPub.Visibility
  alias Pleroma.Web.CommonAPI.ActivityDraft
  alias Pleroma.Web.MediaProxy
  alias Pleroma.Web.Utils.Params

  require Logger
  require Pleroma.Constants

  def attachments_from_ids(%{media_ids: ids, descriptions: desc}) do
    attachments_from_ids_descs(ids, desc)
  end

  def attachments_from_ids(%{media_ids: ids}) do
    attachments_from_ids_no_descs(ids)
  end

  def attachments_from_ids(_), do: []

  def attachments_from_ids_no_descs([]), do: []

  def attachments_from_ids_no_descs(ids) do
    Enum.map(ids, fn media_id ->
      case get_attachment(media_id) do
        %Object{data: data} -> data
        _ -> nil
      end
    end)
    |> Enum.reject(&is_nil/1)
  end

  def attachments_from_ids_descs([], _), do: []

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

    Enum.map(ids, fn media_id ->
      with %Object{data: data} <- get_attachment(media_id) do
        Map.put(data, "name", descs[media_id])
      end
    end)
    |> Enum.reject(&is_nil/1)
  end

  defp get_attachment(media_id) do
    Repo.get(Object, media_id)
  end

  @spec get_to_and_cc(ActivityDraft.t()) :: {list(String.t()), list(String.t())}

  def get_to_and_cc(%{in_reply_to_conversation: %Participation{} = participation}) do
    participation = Repo.preload(participation, :recipients)
    {Enum.map(participation.recipients, & &1.ap_id), []}
  end

  def get_to_and_cc(%{visibility: visibility} = draft) when visibility in ["public", "local"] do
    to =
      case visibility do
        "public" -> [Pleroma.Constants.as_public() | draft.mentions]
        "local" -> [Utils.as_local_public() | draft.mentions]
      end

    cc = [draft.user.follower_address]

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

  def get_to_and_cc(%{visibility: "unlisted"} = draft) do
    to = [draft.user.follower_address | draft.mentions]
    cc = [Pleroma.Constants.as_public()]

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

  def get_to_and_cc(%{visibility: "private"} = draft) do
    {to, cc} = get_to_and_cc(struct(draft, visibility: "direct"))
    {[draft.user.follower_address | to], cc}
  end

  def get_to_and_cc(%{visibility: "direct"} = draft) do
    # If the OP is a DM already, add the implicit actor.
    if draft.in_reply_to && Visibility.is_direct?(draft.in_reply_to) do
      {Enum.uniq([draft.in_reply_to.data["actor"] | draft.mentions]), []}
    else
      {draft.mentions, []}
    end
  end

  def get_to_and_cc(%{visibility: {:list, _}, mentions: mentions}), do: {mentions, []}

  def get_addressed_users(_, to) when is_list(to) do
    User.get_ap_ids_by_nicknames(to)
  end

  def get_addressed_users(mentioned_users, _), do: mentioned_users

  def maybe_add_list_data(activity_params, user, {:list, list_id}) do
    case Pleroma.List.get(list_id, user) do
      %Pleroma.List{} = list ->
        activity_params
        |> put_in([:additional, "bcc"], [list.ap_id])
        |> put_in([:additional, "listMessage"], list.ap_id)
        |> put_in([:object, "listMessage"], list.ap_id)

      _ ->
        activity_params
    end
  end

  def maybe_add_list_data(activity_params, _, _), do: activity_params

  def make_poll_data(%{"poll" => %{"expires_in" => expires_in}} = data)
      when is_binary(expires_in) do
    # In some cases mastofe sends out strings instead of integers
    data
    |> put_in(["poll", "expires_in"], String.to_integer(expires_in))
    |> make_poll_data()
  end

  def make_poll_data(%{poll: %{options: options, expires_in: expires_in}} = data)
      when is_list(options) do
    limits = Config.get([:instance, :poll_limits])

    options = options |> Enum.uniq()

    with :ok <- validate_poll_expiration(expires_in, limits),
         :ok <- validate_poll_options_amount(options, limits),
         :ok <- validate_poll_options_length(options, limits) do
      {option_notes, emoji} =
        Enum.map_reduce(options, %{}, fn option, emoji ->
          note = %{
            "name" => option,
            "type" => "Note",
            "replies" => %{"type" => "Collection", "totalItems" => 0}
          }

          {note, Map.merge(emoji, Pleroma.Emoji.Formatter.get_emoji_map(option))}
        end)

      end_time =
        DateTime.utc_now()
        |> DateTime.add(expires_in)
        |> DateTime.to_iso8601()

      key = if Params.truthy_param?(data.poll[:multiple]), do: "anyOf", else: "oneOf"
      poll = %{"type" => "Question", key => option_notes, "closed" => end_time}

      {:ok, {poll, emoji}}
    end
  end

  def make_poll_data(%{"poll" => poll}) when is_map(poll) do
    {:error, "Invalid poll"}
  end

  def make_poll_data(_data) do
    {:ok, {%{}, %{}}}
  end

  defp validate_poll_options_amount(options, %{max_options: max_options}) do
    cond do
      Enum.count(options) < 2 ->
        {:error, "Poll must contain at least 2 options"}

      Enum.count(options) > max_options ->
        {:error, "Poll can't contain more than #{max_options} options"}

      true ->
        :ok
    end
  end

  defp validate_poll_options_length(options, %{max_option_chars: max_option_chars}) do
    if Enum.any?(options, &(String.length(&1) > max_option_chars)) do
      {:error, "Poll options cannot be longer than #{max_option_chars} characters each"}
    else
      :ok
    end
  end

  defp validate_poll_expiration(expires_in, %{min_expiration: min, max_expiration: max}) do
    cond do
      expires_in > max -> {:error, "Expiration date is too far in the future"}
      expires_in < min -> {:error, "Expiration date is too soon"}
      true -> :ok
    end
  end

  def make_content_html(%ActivityDraft{} = draft) do
    attachment_links =
      draft.params
      |> Map.get("attachment_links", Config.get([:instance, :attachment_links]))
      |> Params.truthy_param?()

    content_type = get_content_type(draft.params[:content_type])

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

    draft.status
    |> format_input(content_type, options)
    |> maybe_add_attachments(draft.attachments, attachment_links)
  end

  def 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

  def make_context(%{in_reply_to_conversation: %Participation{} = participation}) do
    Repo.preload(participation, :conversation).conversation.ap_id
  end

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

  def maybe_add_attachments(parsed, _attachments, false = _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, &build_attachment_link/1)
    Enum.join([text | attachment_text], "<br>")
  end

  defp build_attachment_link(%{"url" => [%{"href" => href} | _]} = attachment) do
    name = attachment["name"] || URI.decode(Path.basename(href))
    href = MediaProxy.url(href)
    "<a href=\"#{href}\" class='attachment'>#{shortname(name)}</a>"
  end

  defp build_attachment_link(_), do: ""

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

  @doc """
  Formatting text to plain text, BBCode, HTML, or Markdown
  """
  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

  def format_input(text, "text/bbcode", options) do
    text
    |> String.replace(~r/\r/, "")
    |> Formatter.html_escape("text/plain")
    |> BBCode.to_html()
    |> (fn {:ok, html} -> html end).()
    |> Formatter.linkify(options)
  end

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

  def format_input(text, "text/x.misskeymarkdown", options) do
    text
    |> Formatter.markdown_to_html(%{breaks: true})
    |> MfmParser.Parser.parse()
    |> MfmParser.Encoder.to_html()
    |> Formatter.linkify(options)
    |> Formatter.html_escape("text/html")
  end

  def format_input(text, "text/markdown", options) do
    text
    |> Formatter.mentions_escape(options)
    |> Formatter.markdown_to_html()
    |> Formatter.linkify(options)
    |> Formatter.html_escape("text/html")
  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
    # NOTE: Elixir’s ISO 8601 format is a superset of the real standard
    # It supports negative years for example.
    # ISO8601 only supports years before 1583 with mutual agreement
    if date.year < 1583 do
      "1970-01-01T00:00:00Z"
    else
      date
      |> NaiveDateTime.to_iso8601()
      |> String.replace(~r/(\.\d+)?$/, ".000Z", global: false)
    end
  end

  def to_masto_date(date) when is_binary(date) do
    with {:ok, date} <- NaiveDateTime.from_iso8601(date) do
      to_masto_date(date)
    else
      _ -> "1970-01-01T00:00:00Z"
    end
  end

  def to_masto_date(_), do: "1970-01-01T00:00:00Z"

  defp shortname(name) do
    with max_length when max_length > 0 <-
           Config.get([Pleroma.Upload, :filename_display_max_length], 30),
         true <- String.length(name) > max_length do
      String.slice(name, 0..max_length) <> "…"
    else
      _ -> name
    end
  end

  @spec confirm_current_password(User.t(), String.t()) :: {:ok, User.t()} | {:error, String.t()}
  def confirm_current_password(user, password) do
    with %User{local: true} = db_user <- User.get_cached_by_id(user.id),
         true <- Pleroma.Password.checkpw(password, db_user.password_hash) do
      {:ok, db_user}
    else
      _ -> {:error, dgettext("errors", "Invalid password.")}
    end
  end

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

  def maybe_notify_to_recipients(recipients, _), do: recipients

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

    object_data =
      cond do
        not 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" => "Create"}} = activity
      ) do
    # Do not notify subscribers if author is making a reply
    with %Object{data: object} <- Object.normalize(activity, fetch: false),
         nil <- object["inReplyTo"],
         %User{} = user <- User.get_cached_by_ap_id(actor) do
      subscriber_ids =
        user
        |> User.subscriber_users()
        |> Enum.filter(&Visibility.visible_for_user?(activity, &1))
        |> Enum.map(& &1.ap_id)

      recipients ++ subscriber_ids
    else
      _e -> recipients
    end
  end

  def maybe_notify_subscribers(recipients, _), do: recipients

  def maybe_notify_followers(recipients, %Activity{data: %{"type" => "Move"}} = activity) do
    with %User{} = user <- User.get_cached_by_ap_id(activity.actor) do
      user
      |> User.get_followers()
      |> Enum.map(& &1.ap_id)
      |> Enum.concat(recipients)
    else
      _e -> recipients
    end
  end

  def maybe_notify_followers(recipients, _), do: recipients

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

  def maybe_extract_mentions(_), do: []

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

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

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

  def get_report_statuses(%User{ap_id: actor}, %{status_ids: status_ids})
      when is_list(status_ids) do
    {:ok, Activity.all_by_actor_and_id(actor, status_ids)}
  end

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

  def validate_character_limit("" = _full_payload, [] = _attachments) do
    {:error, dgettext("errors", "Cannot post an empty status without attachments")}
  end

  def validate_character_limit(full_payload, _attachments) do
    limit = Config.get([:instance, :limit])
    length = String.length(full_payload)

    if length <= limit do
      :ok
    else
      {:error, dgettext("errors", "The status is over the character limit")}
    end
  end
end