# Pleroma: A lightweight social networking server
# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only

defmodule Pleroma.Web.CommonAPI.Utils do
  import Pleroma.Web.Gettext
  import Pleroma.Web.ControllerHelper, only: [truthy_param?: 1]

  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.MediaProxy
  alias Pleroma.Web.Plugs.AuthenticationPlug

  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 Repo.get(Object, 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 ->
      case Repo.get(Object, media_id) do
        %Object{data: data} ->
          Map.put(data, "name", descs[media_id])

        _ ->
          nil
      end
    end)
    |> Enum.reject(&is_nil/1)
  end

  @spec get_to_and_cc(
          User.t(),
          list(String.t()),
          Activity.t() | nil,
          String.t(),
          Participation.t() | nil
        ) :: {list(String.t()), list(String.t())}

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

  def get_to_and_cc(user, mentioned_users, inReplyTo, "public", _) do
    to = [Pleroma.Constants.as_public() | mentioned_users]
    cc = [user.follower_address]

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

  def get_to_and_cc(user, mentioned_users, inReplyTo, "unlisted", _) do
    to = [user.follower_address | mentioned_users]
    cc = [Pleroma.Constants.as_public()]

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

  def get_to_and_cc(user, mentioned_users, inReplyTo, "private", _) do
    {to, cc} = get_to_and_cc(user, mentioned_users, inReplyTo, "direct", nil)
    {[user.follower_address | to], cc}
  end

  def get_to_and_cc(_user, mentioned_users, inReplyTo, "direct", _) do
    # If the OP is a DM already, add the implicit actor.
    if inReplyTo && Visibility.is_direct?(inReplyTo) do
      {Enum.uniq([inReplyTo.data["actor"] | mentioned_users]), []}
    else
      {mentioned_users, []}
    end
  end

  def get_to_and_cc(_user, mentions, _inReplyTo, {:list, _}, _), 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])

    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 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
    if Enum.count(options) > max_options do
      {:error, "Poll can't contain more than #{max_options} options"}
    else
      :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(
        status,
        attachments,
        data,
        visibility
      ) do
    attachment_links =
      data
      |> Map.get("attachment_links", Config.get([:instance, :attachment_links]))
      |> truthy_param?()

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

  def make_context(%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.
  """
  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 as BBCode.
  """
  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

  @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!(%Earmark.Options{renderer: Pleroma.EarmarkRenderer})
    |> Formatter.linkify(options)
    |> Formatter.html_escape("text/html")
  end

  def make_note_data(
        actor,
        to,
        context,
        content_html,
        attachments,
        in_reply_to,
        tags,
        summary \\ nil,
        cc \\ [],
        sensitive \\ false,
        extra_params \\ %{}
      ) do
    %{
      "type" => "Note",
      "to" => to,
      "cc" => cc,
      "content" => content_html,
      "summary" => summary,
      "sensitive" => truthy_param?(sensitive),
      "context" => context,
      "attachment" => attachments,
      "actor" => actor,
      "tag" => Keyword.values(tags) |> Enum.uniq()
    }
    |> add_in_reply_to(in_reply_to)
    |> Map.merge(extra_params)
  end

  defp add_in_reply_to(object, nil), do: object

  defp add_in_reply_to(object, in_reply_to) do
    with %Object{} = in_reply_to_object <- Object.normalize(in_reply_to) do
      Map.put(object, "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) when is_binary(date) do
    with {:ok, date} <- NaiveDateTime.from_iso8601(date) do
      to_masto_date(date)
    else
      _ -> ""
    end
  end

  def to_masto_date(_), do: ""

  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 <- AuthenticationPlug.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, 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

  # Do not notify subscribers if author is making a reply
  def maybe_notify_subscribers(recipients, %Activity{
        object: %Object{data: %{"inReplyTo" => _ap_id}}
      }) do
    recipients
  end

  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.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}

  # 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, dgettext("errors", "No such conversation")}
    end
  end

  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