user.ex

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

defmodule Pleroma.User do
  use Ecto.Schema

  import Ecto.Changeset
  import Ecto.Query
  import Ecto, only: [assoc: 2]

  alias Ecto.Multi
  alias Pleroma.Activity
  alias Pleroma.Config
  alias Pleroma.Conversation.Participation
  alias Pleroma.Delivery
  alias Pleroma.EctoType.ActivityPub.ObjectValidators
  alias Pleroma.Emoji
  alias Pleroma.FollowingRelationship
  alias Pleroma.Formatter
  alias Pleroma.HTML
  alias Pleroma.Keys
  alias Pleroma.MFA
  alias Pleroma.Notification
  alias Pleroma.Object
  alias Pleroma.Registration
  alias Pleroma.Repo
  alias Pleroma.User
  alias Pleroma.UserRelationship
  alias Pleroma.Web
  alias Pleroma.Web.ActivityPub.ActivityPub
  alias Pleroma.Web.ActivityPub.Builder
  alias Pleroma.Web.ActivityPub.Pipeline
  alias Pleroma.Web.ActivityPub.Utils
  alias Pleroma.Web.CommonAPI
  alias Pleroma.Web.CommonAPI.Utils, as: CommonUtils
  alias Pleroma.Web.OAuth
  alias Pleroma.Web.RelMe
  alias Pleroma.Workers.BackgroundWorker

  require Logger

  @type t :: %__MODULE__{}
  @type account_status ::
          :active
          | :deactivated
          | :password_reset_pending
          | :confirmation_pending
          | :approval_pending
  @primary_key {:id, FlakeId.Ecto.CompatType, autogenerate: true}

  # credo:disable-for-next-line Credo.Check.Readability.MaxLineLength
  @email_regex ~r/^[a-zA-Z0-9.!#$%&'*+\/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$/

  @strict_local_nickname_regex ~r/^[a-zA-Z\d]+$/
  @extended_local_nickname_regex ~r/^[a-zA-Z\d_-]+$/

  # AP ID user relationships (blocks, mutes etc.)
  # Format: [rel_type: [outgoing_rel: :outgoing_rel_target, incoming_rel: :incoming_rel_source]]
  @user_relationships_config [
    block: [
      blocker_blocks: :blocked_users,
      blockee_blocks: :blocker_users
    ],
    mute: [
      muter_mutes: :muted_users,
      mutee_mutes: :muter_users
    ],
    reblog_mute: [
      reblog_muter_mutes: :reblog_muted_users,
      reblog_mutee_mutes: :reblog_muter_users
    ],
    notification_mute: [
      notification_muter_mutes: :notification_muted_users,
      notification_mutee_mutes: :notification_muter_users
    ],
    # Note: `inverse_subscription` relationship is inverse: subscriber acts as relationship target
    inverse_subscription: [
      subscribee_subscriptions: :subscriber_users,
      subscriber_subscriptions: :subscribee_users
    ]
  ]

  @cachex Pleroma.Config.get([:cachex, :provider], Cachex)

  schema "users" do
    field(:bio, :string, default: "")
    field(:raw_bio, :string)
    field(:email, :string)
    field(:name, :string)
    field(:nickname, :string)
    field(:password_hash, :string)
    field(:password, :string, virtual: true)
    field(:password_confirmation, :string, virtual: true)
    field(:keys, :string)
    field(:public_key, :string)
    field(:ap_id, :string)
    field(:avatar, :map, default: %{})
    field(:local, :boolean, default: true)
    field(:follower_address, :string)
    field(:following_address, :string)
    field(:search_rank, :float, virtual: true)
    field(:search_type, :integer, virtual: true)
    field(:tags, {:array, :string}, default: [])
    field(:last_refreshed_at, :naive_datetime_usec)
    field(:last_digest_emailed_at, :naive_datetime)
    field(:banner, :map, default: %{})
    field(:background, :map, default: %{})
    field(:note_count, :integer, default: 0)
    field(:follower_count, :integer, default: 0)
    field(:following_count, :integer, default: 0)
    field(:is_locked, :boolean, default: false)
    field(:is_confirmed, :boolean, default: true)
    field(:password_reset_pending, :boolean, default: false)
    field(:is_approved, :boolean, default: true)
    field(:registration_reason, :string, default: nil)
    field(:confirmation_token, :string, default: nil)
    field(:default_scope, :string, default: "public")
    field(:domain_blocks, {:array, :string}, default: [])
    field(:is_active, :boolean, default: true)
    field(:no_rich_text, :boolean, default: false)
    field(:ap_enabled, :boolean, default: false)
    field(:is_moderator, :boolean, default: false)
    field(:is_admin, :boolean, default: false)
    field(:show_role, :boolean, default: true)
    field(:mastofe_settings, :map, default: nil)
    field(:uri, ObjectValidators.Uri, default: nil)
    field(:hide_followers_count, :boolean, default: false)
    field(:hide_follows_count, :boolean, default: false)
    field(:hide_followers, :boolean, default: false)
    field(:hide_follows, :boolean, default: false)
    field(:hide_favorites, :boolean, default: true)
    field(:pinned_activities, {:array, :string}, default: [])
    field(:email_notifications, :map, default: %{"digest" => false})
    field(:mascot, :map, default: nil)
    field(:emoji, :map, default: %{})
    field(:pleroma_settings_store, :map, default: %{})
    field(:fields, {:array, :map}, default: [])
    field(:raw_fields, {:array, :map}, default: [])
    field(:is_discoverable, :boolean, default: false)
    field(:invisible, :boolean, default: false)
    field(:allow_following_move, :boolean, default: true)
    field(:skip_thread_containment, :boolean, default: false)
    field(:actor_type, :string, default: "Person")
    field(:also_known_as, {:array, ObjectValidators.ObjectID}, default: [])
    field(:inbox, :string)
    field(:shared_inbox, :string)
    field(:accepts_chat_messages, :boolean, default: nil)
    field(:last_active_at, :naive_datetime)
    field(:disclose_client, :boolean, default: true)

    embeds_one(
      :notification_settings,
      Pleroma.User.NotificationSetting,
      on_replace: :update
    )

    has_many(:notifications, Notification)
    has_many(:registrations, Registration)
    has_many(:deliveries, Delivery)

    has_many(:outgoing_relationships, UserRelationship, foreign_key: :source_id)
    has_many(:incoming_relationships, UserRelationship, foreign_key: :target_id)

    for {relationship_type,
         [
           {outgoing_relation, outgoing_relation_target},
           {incoming_relation, incoming_relation_source}
         ]} <- @user_relationships_config do
      # Definitions of `has_many` relations: :blocker_blocks, :muter_mutes, :reblog_muter_mutes,
      #   :notification_muter_mutes, :subscribee_subscriptions
      has_many(outgoing_relation, UserRelationship,
        foreign_key: :source_id,
        where: [relationship_type: relationship_type]
      )

      # Definitions of `has_many` relations: :blockee_blocks, :mutee_mutes, :reblog_mutee_mutes,
      #   :notification_mutee_mutes, :subscriber_subscriptions
      has_many(incoming_relation, UserRelationship,
        foreign_key: :target_id,
        where: [relationship_type: relationship_type]
      )

      # Definitions of `has_many` relations: :blocked_users, :muted_users, :reblog_muted_users,
      #   :notification_muted_users, :subscriber_users
      has_many(outgoing_relation_target, through: [outgoing_relation, :target])

      # Definitions of `has_many` relations: :blocker_users, :muter_users, :reblog_muter_users,
      #   :notification_muter_users, :subscribee_users
      has_many(incoming_relation_source, through: [incoming_relation, :source])
    end

    # `:blocks` is deprecated (replaced with `blocked_users` relation)
    field(:blocks, {:array, :string}, default: [])
    # `:mutes` is deprecated (replaced with `muted_users` relation)
    field(:mutes, {:array, :string}, default: [])
    # `:muted_reblogs` is deprecated (replaced with `reblog_muted_users` relation)
    field(:muted_reblogs, {:array, :string}, default: [])
    # `:muted_notifications` is deprecated (replaced with `notification_muted_users` relation)
    field(:muted_notifications, {:array, :string}, default: [])
    # `:subscribers` is deprecated (replaced with `subscriber_users` relation)
    field(:subscribers, {:array, :string}, default: [])

    embeds_one(
      :multi_factor_authentication_settings,
      MFA.Settings,
      on_replace: :delete
    )

    timestamps()
  end

  for {_relationship_type, [{_outgoing_relation, outgoing_relation_target}, _]} <-
        @user_relationships_config do
    # `def blocked_users_relation/2`, `def muted_users_relation/2`,
    #   `def reblog_muted_users_relation/2`, `def notification_muted_users/2`,
    #   `def subscriber_users/2`
    def unquote(:"#{outgoing_relation_target}_relation")(user, restrict_deactivated? \\ false) do
      target_users_query = assoc(user, unquote(outgoing_relation_target))

      if restrict_deactivated? do
        target_users_query
        |> User.Query.build(%{deactivated: false})
      else
        target_users_query
      end
    end

    # `def blocked_users/2`, `def muted_users/2`, `def reblog_muted_users/2`,
    #   `def notification_muted_users/2`, `def subscriber_users/2`
    def unquote(outgoing_relation_target)(user, restrict_deactivated? \\ false) do
      __MODULE__
      |> apply(unquote(:"#{outgoing_relation_target}_relation"), [
        user,
        restrict_deactivated?
      ])
      |> Repo.all()
    end

    # `def blocked_users_ap_ids/2`, `def muted_users_ap_ids/2`, `def reblog_muted_users_ap_ids/2`,
    #   `def notification_muted_users_ap_ids/2`, `def subscriber_users_ap_ids/2`
    def unquote(:"#{outgoing_relation_target}_ap_ids")(user, restrict_deactivated? \\ false) do
      __MODULE__
      |> apply(unquote(:"#{outgoing_relation_target}_relation"), [
        user,
        restrict_deactivated?
      ])
      |> select([u], u.ap_id)
      |> Repo.all()
    end
  end

  def cached_blocked_users_ap_ids(user) do
    @cachex.fetch!(:user_cache, "blocked_users_ap_ids:#{user.ap_id}", fn _ ->
      blocked_users_ap_ids(user)
    end)
  end

  def cached_muted_users_ap_ids(user) do
    @cachex.fetch!(:user_cache, "muted_users_ap_ids:#{user.ap_id}", fn _ ->
      muted_users_ap_ids(user)
    end)
  end

  defdelegate following_count(user), to: FollowingRelationship
  defdelegate following(user), to: FollowingRelationship
  defdelegate following?(follower, followed), to: FollowingRelationship
  defdelegate following_ap_ids(user), to: FollowingRelationship
  defdelegate get_follow_requests(user), to: FollowingRelationship
  defdelegate search(query, opts \\ []), to: User.Search

  @doc """
  Dumps Flake Id to SQL-compatible format (16-byte UUID).
  E.g. "9pQtDGXuq4p3VlcJEm" -> <<0, 0, 1, 110, 179, 218, 42, 92, 213, 41, 44, 227, 95, 213, 0, 0>>
  """
  def binary_id(source_id) when is_binary(source_id) do
    with {:ok, dumped_id} <- FlakeId.Ecto.CompatType.dump(source_id) do
      dumped_id
    else
      _ -> source_id
    end
  end

  def binary_id(source_ids) when is_list(source_ids) do
    Enum.map(source_ids, &binary_id/1)
  end

  def binary_id(%User{} = user), do: binary_id(user.id)

  @doc "Returns status account"
  @spec account_status(User.t()) :: account_status()
  def account_status(%User{is_active: false}), do: :deactivated
  def account_status(%User{password_reset_pending: true}), do: :password_reset_pending
  def account_status(%User{local: true, is_approved: false}), do: :approval_pending
  def account_status(%User{local: true, is_confirmed: false}), do: :confirmation_pending
  def account_status(%User{}), do: :active

  @spec visible_for(User.t(), User.t() | nil) ::
          :visible
          | :invisible
          | :restricted_unauthenticated
          | :deactivated
          | :confirmation_pending
  def visible_for(user, for_user \\ nil)

  def visible_for(%User{invisible: true}, _), do: :invisible

  def visible_for(%User{id: user_id}, %User{id: user_id}), do: :visible

  def visible_for(%User{} = user, nil) do
    if restrict_unauthenticated?(user) do
      :restrict_unauthenticated
    else
      visible_account_status(user)
    end
  end

  def visible_for(%User{} = user, for_user) do
    if superuser?(for_user) do
      :visible
    else
      visible_account_status(user)
    end
  end

  def visible_for(_, _), do: :invisible

  defp restrict_unauthenticated?(%User{local: true}) do
    Config.restrict_unauthenticated_access?(:profiles, :local)
  end

  defp restrict_unauthenticated?(%User{local: _}) do
    Config.restrict_unauthenticated_access?(:profiles, :remote)
  end

  defp visible_account_status(user) do
    status = account_status(user)

    if status in [:active, :password_reset_pending] do
      :visible
    else
      status
    end
  end

  @spec superuser?(User.t()) :: boolean()
  def superuser?(%User{local: true, is_admin: true}), do: true
  def superuser?(%User{local: true, is_moderator: true}), do: true
  def superuser?(_), do: false

  @spec invisible?(User.t()) :: boolean()
  def invisible?(%User{invisible: true}), do: true
  def invisible?(_), do: false

  def avatar_url(user, options \\ []) do
    case user.avatar do
      %{"url" => [%{"href" => href} | _]} ->
        href

      _ ->
        unless options[:no_default] do
          Config.get([:assets, :default_user_avatar], "#{Web.base_url()}/images/avi.png")
        end
    end
  end

  def banner_url(user, options \\ []) do
    case user.banner do
      %{"url" => [%{"href" => href} | _]} -> href
      _ -> !options[:no_default] && "#{Web.base_url()}/images/banner.png"
    end
  end

  # Should probably be renamed or removed
  def ap_id(%User{nickname: nickname}), do: "#{Web.base_url()}/users/#{nickname}"

  def ap_followers(%User{follower_address: fa}) when is_binary(fa), do: fa
  def ap_followers(%User{} = user), do: "#{ap_id(user)}/followers"

  @spec ap_following(User.t()) :: String.t()
  def ap_following(%User{following_address: fa}) when is_binary(fa), do: fa
  def ap_following(%User{} = user), do: "#{ap_id(user)}/following"

  defp truncate_fields_param(params) do
    if Map.has_key?(params, :fields) do
      Map.put(params, :fields, Enum.map(params[:fields], &truncate_field/1))
    else
      params
    end
  end

  defp truncate_if_exists(params, key, max_length) do
    if Map.has_key?(params, key) and is_binary(params[key]) do
      {value, _chopped} = String.split_at(params[key], max_length)
      Map.put(params, key, value)
    else
      params
    end
  end

  defp fix_follower_address(%{follower_address: _, following_address: _} = params), do: params

  defp fix_follower_address(%{nickname: nickname} = params),
    do: Map.put(params, :follower_address, ap_followers(%User{nickname: nickname}))

  defp fix_follower_address(params), do: params

  def remote_user_changeset(struct \\ %User{local: false}, params) do
    bio_limit = Config.get([:instance, :user_bio_length], 5000)
    name_limit = Config.get([:instance, :user_name_length], 100)

    name =
      case params[:name] do
        name when is_binary(name) and byte_size(name) > 0 -> name
        _ -> params[:nickname]
      end

    params =
      params
      |> Map.put(:name, name)
      |> Map.put_new(:last_refreshed_at, NaiveDateTime.utc_now())
      |> truncate_if_exists(:name, name_limit)
      |> truncate_if_exists(:bio, bio_limit)
      |> truncate_fields_param()
      |> fix_follower_address()

    struct
    |> cast(
      params,
      [
        :bio,
        :emoji,
        :ap_id,
        :inbox,
        :shared_inbox,
        :nickname,
        :public_key,
        :avatar,
        :ap_enabled,
        :banner,
        :is_locked,
        :last_refreshed_at,
        :uri,
        :follower_address,
        :following_address,
        :hide_followers,
        :hide_follows,
        :hide_followers_count,
        :hide_follows_count,
        :follower_count,
        :fields,
        :following_count,
        :is_discoverable,
        :invisible,
        :actor_type,
        :also_known_as,
        :accepts_chat_messages
      ]
    )
    |> cast(params, [:name], empty_values: [])
    |> validate_required([:ap_id])
    |> validate_required([:name], trim: false)
    |> unique_constraint(:nickname)
    |> validate_format(:nickname, @email_regex)
    |> validate_length(:bio, max: bio_limit)
    |> validate_length(:name, max: name_limit)
    |> validate_fields(true)
    |> validate_non_local()
  end

  defp validate_non_local(cng) do
    local? = get_field(cng, :local)

    if local? do
      cng
      |> add_error(:local, "User is local, can't update with this changeset.")
    else
      cng
    end
  end

  def update_changeset(struct, params \\ %{}) do
    bio_limit = Config.get([:instance, :user_bio_length], 5000)
    name_limit = Config.get([:instance, :user_name_length], 100)

    struct
    |> cast(
      params,
      [
        :bio,
        :raw_bio,
        :name,
        :emoji,
        :avatar,
        :public_key,
        :inbox,
        :shared_inbox,
        :is_locked,
        :no_rich_text,
        :default_scope,
        :banner,
        :hide_follows,
        :hide_followers,
        :hide_followers_count,
        :hide_follows_count,
        :hide_favorites,
        :allow_following_move,
        :also_known_as,
        :background,
        :show_role,
        :skip_thread_containment,
        :fields,
        :raw_fields,
        :pleroma_settings_store,
        :is_discoverable,
        :actor_type,
        :accepts_chat_messages,
        :disclose_client
      ]
    )
    |> unique_constraint(:nickname)
    |> validate_format(:nickname, local_nickname_regex())
    |> validate_length(:bio, max: bio_limit)
    |> validate_length(:name, min: 1, max: name_limit)
    |> validate_inclusion(:actor_type, ["Person", "Service"])
    |> put_fields()
    |> put_emoji()
    |> put_change_if_present(:bio, &{:ok, parse_bio(&1, struct)})
    |> put_change_if_present(:avatar, &put_upload(&1, :avatar))
    |> put_change_if_present(:banner, &put_upload(&1, :banner))
    |> put_change_if_present(:background, &put_upload(&1, :background))
    |> put_change_if_present(
      :pleroma_settings_store,
      &{:ok, Map.merge(struct.pleroma_settings_store, &1)}
    )
    |> validate_fields(false)
  end

  defp put_fields(changeset) do
    if raw_fields = get_change(changeset, :raw_fields) do
      raw_fields =
        raw_fields
        |> Enum.filter(fn %{"name" => n} -> n != "" end)

      fields =
        raw_fields
        |> Enum.map(fn f -> Map.update!(f, "value", &parse_fields(&1)) end)

      changeset
      |> put_change(:raw_fields, raw_fields)
      |> put_change(:fields, fields)
    else
      changeset
    end
  end

  defp parse_fields(value) do
    value
    |> Formatter.linkify(mentions_format: :full)
    |> elem(0)
  end

  defp put_emoji(changeset) do
    emojified_fields = [:bio, :name, :raw_fields]

    if Enum.any?(changeset.changes, fn {k, _} -> k in emojified_fields end) do
      bio = Emoji.Formatter.get_emoji_map(get_field(changeset, :bio))
      name = Emoji.Formatter.get_emoji_map(get_field(changeset, :name))

      emoji = Map.merge(bio, name)

      emoji =
        changeset
        |> get_field(:raw_fields)
        |> Enum.reduce(emoji, fn x, acc ->
          Map.merge(acc, Emoji.Formatter.get_emoji_map(x["name"] <> x["value"]))
        end)

      put_change(changeset, :emoji, emoji)
    else
      changeset
    end
  end

  defp put_change_if_present(changeset, map_field, value_function) do
    with {:ok, value} <- fetch_change(changeset, map_field),
         {:ok, new_value} <- value_function.(value) do
      put_change(changeset, map_field, new_value)
    else
      _ -> changeset
    end
  end

  defp put_upload(value, type) do
    with %Plug.Upload{} <- value,
         {:ok, object} <- ActivityPub.upload(value, type: type) do
      {:ok, object.data}
    end
  end

  def update_as_admin_changeset(struct, params) do
    struct
    |> update_changeset(params)
    |> cast(params, [:email])
    |> delete_change(:also_known_as)
    |> unique_constraint(:email)
    |> validate_format(:email, @email_regex)
    |> validate_inclusion(:actor_type, ["Person", "Service"])
  end

  @spec update_as_admin(User.t(), map()) :: {:ok, User.t()} | {:error, Changeset.t()}
  def update_as_admin(user, params) do
    params = Map.put(params, "password_confirmation", params["password"])
    changeset = update_as_admin_changeset(user, params)

    if params["password"] do
      reset_password(user, changeset, params)
    else
      User.update_and_set_cache(changeset)
    end
  end

  def password_update_changeset(struct, params) do
    struct
    |> cast(params, [:password, :password_confirmation])
    |> validate_required([:password, :password_confirmation])
    |> validate_confirmation(:password)
    |> put_password_hash()
    |> put_change(:password_reset_pending, false)
  end

  @spec reset_password(User.t(), map()) :: {:ok, User.t()} | {:error, Changeset.t()}
  def reset_password(%User{} = user, params) do
    reset_password(user, user, params)
  end

  def reset_password(%User{id: user_id} = user, struct, params) do
    multi =
      Multi.new()
      |> Multi.update(:user, password_update_changeset(struct, params))
      |> Multi.delete_all(:tokens, OAuth.Token.Query.get_by_user(user_id))
      |> Multi.delete_all(:auth, OAuth.Authorization.delete_by_user_query(user))

    case Repo.transaction(multi) do
      {:ok, %{user: user} = _} -> set_cache(user)
      {:error, _, changeset, _} -> {:error, changeset}
    end
  end

  def update_password_reset_pending(user, value) do
    user
    |> change()
    |> put_change(:password_reset_pending, value)
    |> update_and_set_cache()
  end

  def force_password_reset_async(user) do
    BackgroundWorker.enqueue("force_password_reset", %{"user_id" => user.id})
  end

  @spec force_password_reset(User.t()) :: {:ok, User.t()} | {:error, Ecto.Changeset.t()}
  def force_password_reset(user), do: update_password_reset_pending(user, true)

  # Used to auto-register LDAP accounts which won't have a password hash stored locally
  def register_changeset_ldap(struct, params = %{password: password})
      when is_nil(password) do
    params = Map.put_new(params, :accepts_chat_messages, true)

    params =
      if Map.has_key?(params, :email) do
        Map.put_new(params, :email, params[:email])
      else
        params
      end

    struct
    |> cast(params, [
      :name,
      :nickname,
      :email,
      :accepts_chat_messages
    ])
    |> validate_required([:name, :nickname])
    |> unique_constraint(:nickname)
    |> validate_exclusion(:nickname, Config.get([User, :restricted_nicknames]))
    |> validate_format(:nickname, local_nickname_regex())
    |> put_ap_id()
    |> unique_constraint(:ap_id)
    |> put_following_and_follower_address()
  end

  def register_changeset(struct, params \\ %{}, opts \\ []) do
    bio_limit = Config.get([:instance, :user_bio_length], 5000)
    name_limit = Config.get([:instance, :user_name_length], 100)
    reason_limit = Config.get([:instance, :registration_reason_length], 500)
    params = Map.put_new(params, :accepts_chat_messages, true)

    confirmed? =
      if is_nil(opts[:confirmed]) do
        !Config.get([:instance, :account_activation_required])
      else
        opts[:confirmed]
      end

    approved? =
      if is_nil(opts[:approved]) do
        !Config.get([:instance, :account_approval_required])
      else
        opts[:approved]
      end

    struct
    |> confirmation_changeset(set_confirmation: confirmed?)
    |> approval_changeset(set_approval: approved?)
    |> cast(params, [
      :bio,
      :raw_bio,
      :email,
      :name,
      :nickname,
      :password,
      :password_confirmation,
      :emoji,
      :accepts_chat_messages,
      :registration_reason
    ])
    |> validate_required([:name, :nickname, :password, :password_confirmation])
    |> validate_confirmation(:password)
    |> unique_constraint(:email)
    |> validate_format(:email, @email_regex)
    |> validate_change(:email, fn :email, email ->
      valid? =
        Config.get([User, :email_blacklist])
        |> Enum.all?(fn blacklisted_domain ->
          !String.ends_with?(email, ["@" <> blacklisted_domain, "." <> blacklisted_domain])
        end)

      if valid?, do: [], else: [email: "Invalid email"]
    end)
    |> unique_constraint(:nickname)
    |> validate_exclusion(:nickname, Config.get([User, :restricted_nicknames]))
    |> validate_format(:nickname, local_nickname_regex())
    |> validate_length(:bio, max: bio_limit)
    |> validate_length(:name, min: 1, max: name_limit)
    |> validate_length(:registration_reason, max: reason_limit)
    |> maybe_validate_required_email(opts[:external])
    |> put_password_hash
    |> put_ap_id()
    |> unique_constraint(:ap_id)
    |> put_following_and_follower_address()
  end

  def maybe_validate_required_email(changeset, true), do: changeset

  def maybe_validate_required_email(changeset, _) do
    if Config.get([:instance, :account_activation_required]) do
      validate_required(changeset, [:email])
    else
      changeset
    end
  end

  defp put_ap_id(changeset) do
    ap_id = ap_id(%User{nickname: get_field(changeset, :nickname)})
    put_change(changeset, :ap_id, ap_id)
  end

  defp put_following_and_follower_address(changeset) do
    followers = ap_followers(%User{nickname: get_field(changeset, :nickname)})

    changeset
    |> put_change(:follower_address, followers)
  end

  defp autofollow_users(user) do
    candidates = Config.get([:instance, :autofollowed_nicknames])

    autofollowed_users =
      User.Query.build(%{nickname: candidates, local: true, is_active: true})
      |> Repo.all()

    follow_all(user, autofollowed_users)
  end

  defp autofollowing_users(user) do
    candidates = Config.get([:instance, :autofollowing_nicknames])

    User.Query.build(%{nickname: candidates, local: true, deactivated: false})
    |> Repo.all()
    |> Enum.each(&follow(&1, user, :follow_accept))

    {:ok, :success}
  end

  @doc "Inserts provided changeset, performs post-registration actions (confirmation email sending etc.)"
  def register(%Ecto.Changeset{} = changeset) do
    with {:ok, user} <- Repo.insert(changeset) do
      post_register_action(user)
    end
  end

  def post_register_action(%User{is_confirmed: false} = user) do
    with {:ok, _} <- maybe_send_confirmation_email(user) do
      {:ok, user}
    end
  end

  def post_register_action(%User{is_approved: false} = user) do
    with {:ok, _} <- send_user_approval_email(user),
         {:ok, _} <- send_admin_approval_emails(user) do
      {:ok, user}
    end
  end

  def post_register_action(%User{is_approved: true, is_confirmed: true} = user) do
    with {:ok, user} <- autofollow_users(user),
         {:ok, _} <- autofollowing_users(user),
         {:ok, user} <- set_cache(user),
         {:ok, _} <- maybe_send_registration_email(user),
         {:ok, _} <- maybe_send_welcome_email(user),
         {:ok, _} <- maybe_send_welcome_message(user),
         {:ok, _} <- maybe_send_welcome_chat_message(user) do
      {:ok, user}
    end
  end

  defp send_user_approval_email(user) do
    user
    |> Pleroma.Emails.UserEmail.approval_pending_email()
    |> Pleroma.Emails.Mailer.deliver_async()

    {:ok, :enqueued}
  end

  defp send_admin_approval_emails(user) do
    all_superusers()
    |> Enum.filter(fn user -> not is_nil(user.email) end)
    |> Enum.each(fn superuser ->
      superuser
      |> Pleroma.Emails.AdminEmail.new_unapproved_registration(user)
      |> Pleroma.Emails.Mailer.deliver_async()
    end)

    {:ok, :enqueued}
  end

  defp maybe_send_welcome_message(user) do
    if User.WelcomeMessage.enabled?() do
      User.WelcomeMessage.post_message(user)
      {:ok, :enqueued}
    else
      {:ok, :noop}
    end
  end

  defp maybe_send_welcome_chat_message(user) do
    if User.WelcomeChatMessage.enabled?() do
      User.WelcomeChatMessage.post_message(user)
      {:ok, :enqueued}
    else
      {:ok, :noop}
    end
  end

  defp maybe_send_welcome_email(%User{email: email} = user) when is_binary(email) do
    if User.WelcomeEmail.enabled?() do
      User.WelcomeEmail.send_email(user)
      {:ok, :enqueued}
    else
      {:ok, :noop}
    end
  end

  defp maybe_send_welcome_email(_), do: {:ok, :noop}

  @spec maybe_send_confirmation_email(User.t()) :: {:ok, :enqueued | :noop}
  def maybe_send_confirmation_email(%User{is_confirmed: false, email: email} = user)
      when is_binary(email) do
    if Config.get([:instance, :account_activation_required]) do
      send_confirmation_email(user)
      {:ok, :enqueued}
    else
      {:ok, :noop}
    end
  end

  def maybe_send_confirmation_email(_), do: {:ok, :noop}

  @spec send_confirmation_email(Uset.t()) :: User.t()
  def send_confirmation_email(%User{} = user) do
    user
    |> Pleroma.Emails.UserEmail.account_confirmation_email()
    |> Pleroma.Emails.Mailer.deliver_async()

    user
  end

  @spec maybe_send_registration_email(User.t()) :: {:ok, :enqueued | :noop}
  defp maybe_send_registration_email(%User{email: email} = user) when is_binary(email) do
    with false <- User.WelcomeEmail.enabled?(),
         false <- Config.get([:instance, :account_activation_required], false),
         false <- Config.get([:instance, :account_approval_required], false) do
      user
      |> Pleroma.Emails.UserEmail.successful_registration_email()
      |> Pleroma.Emails.Mailer.deliver_async()

      {:ok, :enqueued}
    else
      _ ->
        {:ok, :noop}
    end
  end

  defp maybe_send_registration_email(_), do: {:ok, :noop}

  def needs_update?(%User{local: true}), do: false

  def needs_update?(%User{local: false, last_refreshed_at: nil}), do: true

  def needs_update?(%User{local: false} = user) do
    NaiveDateTime.diff(NaiveDateTime.utc_now(), user.last_refreshed_at) >= 86_400
  end

  def needs_update?(_), do: true

  @spec maybe_direct_follow(User.t(), User.t()) :: {:ok, User.t()} | {:error, String.t()}

  # "Locked" (self-locked) users demand explicit authorization of follow requests
  def maybe_direct_follow(%User{} = follower, %User{local: true, is_locked: true} = followed) do
    follow(follower, followed, :follow_pending)
  end

  def maybe_direct_follow(%User{} = follower, %User{local: true} = followed) do
    follow(follower, followed)
  end

  def maybe_direct_follow(%User{} = follower, %User{} = followed) do
    if not ap_enabled?(followed) do
      follow(follower, followed)
    else
      {:ok, follower, followed}
    end
  end

  @doc "A mass follow for local users. Respects blocks in both directions but does not create activities."
  @spec follow_all(User.t(), list(User.t())) :: {atom(), User.t()}
  def follow_all(follower, followeds) do
    followeds
    |> Enum.reject(fn followed -> blocks?(follower, followed) || blocks?(followed, follower) end)
    |> Enum.each(&follow(follower, &1, :follow_accept))

    set_cache(follower)
  end

  def follow(%User{} = follower, %User{} = followed, state \\ :follow_accept) do
    deny_follow_blocked = Config.get([:user, :deny_follow_blocked])

    cond do
      not followed.is_active ->
        {:error, "Could not follow user: #{followed.nickname} is deactivated."}

      deny_follow_blocked and blocks?(followed, follower) ->
        {:error, "Could not follow user: #{followed.nickname} blocked you."}

      true ->
        FollowingRelationship.follow(follower, followed, state)
    end
  end

  def unfollow(%User{ap_id: ap_id}, %User{ap_id: ap_id}) do
    {:error, "Not subscribed!"}
  end

  @spec unfollow(User.t(), User.t()) :: {:ok, User.t(), Activity.t()} | {:error, String.t()}
  def unfollow(%User{} = follower, %User{} = followed) do