%%%-------------------------------------------------------------------
%%% @doc Web Push subscriptions (Back#75).
%%% @end
%%%-------------------------------------------------------------------
-module(core_push_subscription).
-export([upsert/4, list_by_user/1, delete_by_endpoint/2, delete_by_id/1,
         get_by_endpoint/1]).

-include("records.hrl").

-spec upsert(binary(), binary(), binary(), binary()) ->
  {ok, #push_subscription{}} | {error, term()}.
upsert(UserId, Endpoint, P256dh, Auth) ->
  Now = calendar:universal_time(),
  case get_by_endpoint(Endpoint) of
    {ok, #push_subscription{} = Existing} ->
      Rec = Existing#push_subscription{
        user_id = UserId,
        p256dh = P256dh,
        auth = Auth,
        created_at = Now
      },
      case mnesia:transaction(fun() -> mnesia:write(Rec) end) of
        {atomic, ok} -> {ok, Rec};
        {aborted, Reason} -> {error, Reason}
      end;
    {error, not_found} ->
      Rec = #push_subscription{
        id = infra_utils:generate_id(16),
        user_id = UserId,
        endpoint = Endpoint,
        p256dh = P256dh,
        auth = Auth,
        created_at = Now
      },
      case mnesia:transaction(fun() -> mnesia:write(Rec) end) of
        {atomic, ok} -> {ok, Rec};
        {aborted, Reason} -> {error, Reason}
      end
  end.

-spec list_by_user(binary()) -> [#push_subscription{}].
list_by_user(UserId) ->
  mnesia:dirty_match_object(#push_subscription{user_id = UserId, _ = '_'}).

-spec get_by_endpoint(binary()) -> {ok, #push_subscription{}} | {error, not_found}.
get_by_endpoint(Endpoint) ->
  case mnesia:dirty_index_read(push_subscription, Endpoint, #push_subscription.endpoint) of
    [Rec | _] -> {ok, Rec};
    [] ->
      case mnesia:dirty_match_object(#push_subscription{endpoint = Endpoint, _ = '_'}) of
        [Rec | _] -> {ok, Rec};
        [] -> {error, not_found}
      end
  end.

-spec delete_by_endpoint(binary(), binary()) -> ok | {error, not_found | forbidden}.
delete_by_endpoint(UserId, Endpoint) ->
  case get_by_endpoint(Endpoint) of
    {ok, #push_subscription{id = Id, user_id = UserId}} ->
      delete_by_id(Id);
    {ok, #push_subscription{}} ->
      {error, forbidden};
    {error, not_found} ->
      {error, not_found}
  end.

-spec delete_by_id(binary()) -> ok | {error, term()}.
delete_by_id(Id) ->
  case mnesia:transaction(fun() -> mnesia:delete({push_subscription, Id}) end) of
    {atomic, ok} -> ok;
    {aborted, Reason} -> {error, Reason}
  end.