feat(calendar): single Default personal with guards and backfill

Ensure title Default; reject second personal and delete/type-change of
the sole personal; migrate extras to commercial or soft-delete.

Refs EventHub/EventHubBack#64

src/handlers/handler_calendar_by_id.erl

@@ -152,6 +152,8 @@ update_calendar(Req) ->
               handler_utils:send_error(Req2, 403, <<"Access denied">>);
             {error, subscription_required} ->
               handler_utils:send_error(Req2, 402, <<"Subscription required for commercial calendar">>);
+            {error, default_calendar} ->
+              handler_utils:send_error(Req2, 403, <<"default_calendar">>);
             {error, not_found} ->
               handler_utils:send_error(Req2, 404, <<"Calendar not found">>);
             {error, {invalid_settings, Key}} when is_binary(Key) ->
@@ -176,6 +178,8 @@ delete_calendar(Req) ->
       case logic_calendar:delete_calendar(UserId, CalendarId) of
         {ok, _} ->
           handler_utils:send_json(Req1, 200, #{status => <<"deleted">>});
+        {error, default_calendar} ->
+          handler_utils:send_error(Req1, 403, <<"default_calendar">>);
         {error, access_denied} ->
           handler_utils:send_error(Req1, 403, <<"Access denied">>);
         {error, not_found} ->

src/handlers/handler_calendars.erl

@@ -140,6 +140,8 @@ create_calendar(Req) ->
                   handler_utils:send_json(Req2, 201, Response);
                 {error, subscription_required} ->
                   handler_utils:send_error(Req2, 402, <<"Subscription required for commercial calendar">>);
+                {error, personal_exists} ->
+                  handler_utils:send_error(Req2, 409, <<"personal_exists">>);
                 {error, user_inactive} ->
                   handler_utils:send_error(Req2, 403, <<"User account is not active">>);
                 {error, {content_banned, _Words}} ->

src/logic/logic_calendar.erl

@@ -2,11 +2,13 @@
 -include("records.hrl").
 
 -export([create_calendar/3, create_calendar/4, create_calendar/5, get_calendar/2, list_calendars/1,
-  update_calendar/3, delete_calendar/2, ensure_default_calendar/1]).
+  update_calendar/3, delete_calendar/2, ensure_default_calendar/1, backfill_single_personal/0]).
 -export([can_access/2, can_edit/2, booking_open/1]).
 -export([normalize_settings/1]).
 -export([admin_list_all/0, admin_get_by_id/1, admin_update/2, admin_delete/1]).
 
+-define(DEFAULT_PERSONAL_TITLE, <<"Default">>).
+
 %% Создание календаря с политикой по умолчанию (manual)
 create_calendar(UserId, Title, Description) ->
   create_calendar(UserId, Title, Description, manual).
@@ -34,7 +36,12 @@ create_calendar(UserId, Title, Description, Confirmation, Type) ->
                       {error, subscription_required}
                   end;
                 personal ->
-                  core_calendar:create(UserId, Title2, Desc2, Confirmation, Type)
+                  case has_active_personal_calendar(UserId) of
+                    true ->
+                      {error, personal_exists};
+                    false ->
+                      core_calendar:create(UserId, Title2, Desc2, Confirmation, Type)
+                  end
               end,
               case Result of
                 {ok, Cal} ->
@@ -51,42 +58,91 @@ create_calendar(UserId, Title, Description, Confirmation, Type) ->
       {error, user_not_found}
   end.
 
-%% @doc Создаёт дефолтный personal-календарь после активации пользователя.
-%% Идемпотентно: если у владельца уже есть active personal — ok.
+%% @doc Единственный personal владельца: title Default; лишние → commercial|delete.
+%% Вызывается после verify; идемпотентно.
 -spec ensure_default_calendar(UserId :: binary()) -> ok | {error, term()}.
 ensure_default_calendar(UserId) ->
-  case has_active_personal_calendar(UserId) of
-    true ->
-      ok;
-    false ->
+  normalize_owner_personals(UserId).
+
+%% @doc Backfill всех владельцев: ≤1 personal с title Default.
+-spec backfill_single_personal() -> ok.
+backfill_single_personal() ->
+  Owners = lists:usort([
+    C#calendar.owner_id
+    || C <- core_calendar:list_all(),
+       C#calendar.status =:= active,
+       C#calendar.type =:= personal
+  ]),
+  lists:foreach(fun(OwnerId) -> _ = normalize_owner_personals(OwnerId) end, Owners),
+  ok.
+
+-spec normalize_owner_personals(UserId :: binary()) -> ok | {error, term()}.
+normalize_owner_personals(UserId) ->
+  Personals = active_personals(UserId),
+  case Personals of
+    [] ->
       case core_user:get_by_id(UserId) of
-        {ok, User} ->
-          Title = default_calendar_title(User),
-          case create_calendar(UserId, Title, <<>>, manual, personal) of
+        {ok, #user{status = active}} ->
+          case create_calendar(UserId, ?DEFAULT_PERSONAL_TITLE, <<>>, manual, personal) of
             {ok, _} -> ok;
             Error -> Error
           end;
+        {ok, _} ->
+          {error, user_inactive};
         Error ->
           Error
-      end
+      end;
+    [Keep | Rest] ->
+      _ = core_calendar:update(Keep#calendar.id, [{title, ?DEFAULT_PERSONAL_TITLE}]),
+      lists:foreach(fun convert_or_delete_extra_personal/1, Rest),
+      ok
+  end.
+
+active_personals(UserId) ->
+  case core_calendar:list_by_owner(UserId) of
+    {ok, Calendars} ->
+      lists:sort(
+        fun(#calendar{created_at = A, id = IdA}, #calendar{created_at = B, id = IdB}) ->
+          {A, IdA} =< {B, IdB}
+        end,
+        [C || C <- Calendars, C#calendar.type =:= personal]
+      );
+    _ ->
+      []
   end.
 
 has_active_personal_calendar(UserId) ->
-  case core_calendar:list_by_owner(UserId) of
-    {ok, Calendars} ->
-      lists:any(
-        fun(#calendar{type = personal}) -> true;
-           (_) -> false
-        end,
-        Calendars);
-    _ ->
-      false
-  end.
+  active_personals(UserId) =/= [].
 
-default_calendar_title(#user{nickname = Nick}) when is_binary(Nick), byte_size(Nick) > 0 ->
-  Nick;
-default_calendar_title(_) ->
-  <<"Мой календарь">>.
+convert_or_delete_extra_personal(#calendar{id = Id} = Cal) ->
+  case calendar_has_content(Id) of
+    true ->
+      %% System backfill: bypass subscription gate.
+      _ = core_calendar:update(Id, [{type, commercial}]),
+      ok;
+    false ->
+      _ = core_calendar:delete(Id),
+      ok
+  end,
+  Cal.
+
+calendar_has_content(CalendarId) ->
+  Events =
+    try
+      case core_event:list_by_calendar(CalendarId) of
+        {ok, Es} -> Es;
+        _ -> []
+      end
+    catch
+      _:_ -> []
+    end,
+  Specs =
+    try
+      core_calendar_specialist:list_by_calendar(CalendarId)
+    catch
+      _:_ -> []
+    end,
+  Events =/= [] orelse Specs =/= [].
 
 %% Получение календаря с проверкой доступа
 get_calendar(UserId, CalendarId) ->
@@ -155,13 +211,11 @@ apply_calendar_update(CalendarId, Calendar, ValidUpdates) ->
       end
   end.
 
-gate_type_change(UserId, #calendar{type = personal}, Updates) ->
+%% Единственный personal нельзя превратить в commercial (дневник пользователя).
+gate_type_change(_UserId, #calendar{type = personal}, Updates) ->
   case lists:keyfind(type, 1, Updates) of
     {type, commercial} ->
-      case logic_subscription:can_create_commercial_calendar(UserId) of
-        true -> {ok, Updates};
-        false -> {error, subscription_required}
-      end;
+      {error, default_calendar};
     _ ->
       {ok, Updates}
   end;
@@ -200,9 +254,11 @@ apply_text_results(Updates, [], []) -> Updates;
 apply_text_results(Updates, [F | Fs], [T | Ts]) ->
   apply_text_results(lists:keystore(F, 1, Updates, {F, T}), Fs, Ts).
 
-%% Удаление календаря
+%% Удаление календаря (единственный personal удалять нельзя)
 delete_calendar(UserId, CalendarId) ->
   case core_calendar:get_by_id(CalendarId) of
+    {ok, #calendar{type = personal}} ->
+      {error, default_calendar};
     {ok, Calendar} ->
       case can_edit(UserId, Calendar) of
         true ->

src/migrations/20260730200000_single_default_personal.erl

@@ -0,0 +1,11 @@
+%% @doc Backfill: ≤1 personal per owner, title Default; extras → commercial | delete.
+-module('20260730200000_single_default_personal').
+
+-export([up/0, down/0]).
+
+up() ->
+  logic_calendar:backfill_single_personal(),
+  ok.
+
+down() ->
+  ok.