-module(logic_admin).

-export([list_admins/2, get_admin/1, update_admin/2, delete_admin/1, create_admin/3]).

-include("records.hrl").

%% @doc Создаёт нового администратора (доступно только суперадмину).
%% Роль может быть superadmin, admin, moderator или support.
-spec create_admin(binary(), binary(), atom()) ->
  {ok, #admin{}} | {error, email_exists | invalid_role}.
create_admin(Email, Password, Role) when Role =:= superadmin; Role =:= admin; Role =:= moderator; Role =:= support ->
  case core_admin:get_by_email(Email) of
    {ok, _} -> {error, email_exists};
    {error, not_found} ->
      {ok, PasswordHash} = logic_auth:hash_password(Password),
      core_admin:create(Email, PasswordHash, Role)
  end;
create_admin(_, _, _) ->
  {error, invalid_role}.

%%%-------------------------------------------------------------------
%%% Административный список администраторов с пагинацией
%%%-------------------------------------------------------------------
-spec list_admins(map(), #{limit => integer(), offset => integer(), sort => binary(), order => binary()}) ->
  {ok, non_neg_integer(), [#admin{}]}.
list_admins(Filters, Pagination) ->
  #{limit := Limit, offset := Offset, sort := Sort, order := Order} = Pagination,
  AllAdmins = core_admin:list_all(),
  Filtered = apply_filters(AllAdmins, Filters),
  Sorted = sort_admins(Filtered, Sort, Order),
  Total = length(Sorted),
  Page = lists:sublist(Sorted, Offset + 1, Limit),
  {ok, Total, Page}.

%%%-------------------------------------------------------------------
%%% Получение администратора по ID
%%%-------------------------------------------------------------------
-spec get_admin(binary()) -> {ok, #admin{}} | {error, not_found}.
get_admin(AdminId) ->
  core_admin:get_by_id(AdminId).

%%%-------------------------------------------------------------------
%%% Обновление администратора
%%%-------------------------------------------------------------------
-spec update_admin(binary(), proplists:proplist()) ->
  {ok, #admin{}} | {error, not_found | invalid_field}.
update_admin(AdminId, Updates) ->
  case core_admin:get_by_id(AdminId) of
    {ok, _Admin} ->
      ValidUpdates = validate_admin_updates(Updates),
      core_admin:update(AdminId, ValidUpdates);
    Error ->
      Error
  end.

%%%-------------------------------------------------------------------
%%% Удалить администратора (физическое удаление из базы)
%%%-------------------------------------------------------------------
-spec delete_admin(binary()) -> {ok, deleted} | {error, not_found}.
delete_admin(AdminId) ->
  core_admin:delete(AdminId).

%%%===================================================================
%%% Внутренние функции
%%%===================================================================

apply_filters(Admins, Filters) ->
  Role = maps:get(role, Filters, undefined),
  Status = maps:get(status, Filters, undefined),
  F1 = case Role of
         undefined -> Admins;
         _ -> [A || A <- Admins, A#admin.role =:= Role]
       end,
  case Status of
    undefined -> F1;
    _ -> [A || A <- F1, A#admin.status =:= Status]
  end.

sort_admins(Admins, SortField, Order) ->
  Field = binary_to_existing_atom(SortField, utf8),
  Sorted = lists:sort(
    fun(A, B) ->
      ValA = admin_field(A, Field),
      ValB = admin_field(B, Field),
      if Order == <<"asc">> -> ValA =< ValB;
        true -> ValA >= ValB
      end
    end, Admins),
  Sorted.

admin_field(#admin{created_at = V}, created_at) -> V;
admin_field(#admin{email = V}, email) -> V;
admin_field(#admin{role = V}, role) -> V;
admin_field(_, _) -> undefined.

validate_admin_updates(Updates) ->
  lists:filter(fun validate_admin_update/1, Updates).

validate_admin_update({nickname, V}) when is_binary(V); V =:= undefined -> true;
validate_admin_update({avatar_url, V}) when is_binary(V); V =:= undefined -> true;
validate_admin_update({timezone, V}) when is_binary(V); V =:= undefined -> true;
validate_admin_update({language, V}) when is_binary(V); V =:= undefined -> true;
validate_admin_update({phone, V}) when is_binary(V); V =:= undefined -> true;
validate_admin_update({preferences, V}) when is_map(V); V =:= undefined -> true;
validate_admin_update(_) -> false.