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-module(jchat_utils).
-export([now_iso8601/0,
generate_id/0,
validate_id/1,
json_encode/1,
json_decode/1,
format_error/1,
validate_account_id/1,
extract_auth_token/1,
validate_method_call/1,
format_method_response/3,
format_error_response/3]).
%% Generate ISO8601 timestamp
now_iso8601() ->
{{Year, Month, Day}, {Hour, Minute, Second}} = calendar:universal_time(),
iolist_to_binary(io_lib:format("~4..0w-~2..0w-~2..0wT~2..0w:~2..0w:~2..0wZ",
[Year, Month, Day, Hour, Minute, Second])).
%% Generate a new ID (UUID v4)
generate_id() ->
<<U0:32, U1:16, _:4, U2:12, _:2, U3:62>> = crypto:strong_rand_bytes(16),
iolist_to_binary(io_lib:format("~8.16.0b-~4.16.0b-4~3.16.0b-~4.16.0b-~12.16.0b",
[U0, U1, U2, ((U3 bsr 60) band 16#03) bor 16#08, U3 band 16#0fffffffffff])).
%% Validate ID format (URL-safe base64 characters)
validate_id(Id) when is_binary(Id) ->
Size = byte_size(Id),
case Size >= 1 andalso Size =< 255 of
true ->
validate_id_chars(Id);
false ->
false
end;
validate_id(_) ->
false.
validate_id_chars(<<>>) ->
true;
validate_id_chars(<<C, Rest/binary>>) ->
case is_valid_id_char(C) of
true -> validate_id_chars(Rest);
false -> false
end.
is_valid_id_char(C) ->
(C >= $A andalso C =< $Z) orelse
(C >= $a andalso C =< $z) orelse
(C >= $0 andalso C =< $9) orelse
C =:= $- orelse C =:= $_.
%% JSON encoding/decoding
json_encode(Term) ->
jsx:encode(Term).
json_decode(JSON) ->
try
{ok, jsx:decode(JSON, [return_maps])}
catch
_:_ -> {error, invalid_json}
end.
%% Format errors for JMAP responses (RFC 8620 compliant)
format_error(not_found) ->
#{type => <<"notFound">>};
format_error(invalid_arguments) ->
#{type => <<"invalidArguments">>};
format_error(account_not_found) ->
#{type => <<"accountNotFound">>};
format_error(forbidden) ->
#{type => <<"forbidden">>};
format_error(invalid_result_reference) ->
#{type => <<"invalidResultReference">>};
format_error(anchor_not_found) ->
#{type => <<"anchorNotFound">>};
format_error(unsupported_sort) ->
#{type => <<"unsupportedSort">>};
format_error(unsupported_filter) ->
#{type => <<"unsupportedFilter">>};
format_error(cannot_calculate_changes) ->
#{type => <<"cannotCalculateChanges">>};
format_error(too_large) ->
#{type => <<"tooLarge">>};
format_error(too_many_changes) ->
#{type => <<"tooManyChanges">>};
format_error(rate_limited) ->
#{type => <<"rateLimited">>};
format_error(request_too_large) ->
#{type => <<"requestTooLarge">>};
format_error(limit_exceeded) ->
#{type => <<"limitExceeded">>};
format_error(state_mismatch) ->
#{type => <<"stateMismatch">>};
format_error(will_destroy) ->
#{type => <<"willDestroy">>};
format_error({invalid_arguments, Description}) ->
#{type => <<"invalidArguments">>, description => Description};
format_error({not_found, Description}) ->
#{type => <<"notFound">>, description => Description};
format_error({forbidden, Description}) ->
#{type => <<"forbidden">>, description => Description};
format_error({server_fail, Description}) ->
#{type => <<"serverFail">>, description => Description};
format_error(Error) ->
#{type => <<"serverFail">>, description => iolist_to_binary(io_lib:format("~p", [Error]))}.
%% JMAP-specific utility functions
%% Validate account ID format (as per JMAP spec)
validate_account_id(AccountId) when is_binary(AccountId) ->
validate_id(AccountId);
validate_account_id(_) ->
false.
%% Extract Bearer token from Authorization header
extract_auth_token(undefined) ->
{error, no_auth_header};
extract_auth_token(<<"Bearer ", Token/binary>>) ->
{ok, Token};
extract_auth_token(_) ->
{error, invalid_auth_format}.
%% Validate JMAP method call structure
validate_method_call([Method, Args, CallId])
when is_binary(Method), is_map(Args), is_binary(CallId) ->
case validate_method_name(Method) of
true -> ok;
false -> {error, invalid_method_name}
end;
validate_method_call(_) ->
{error, invalid_method_call_structure}.
validate_method_name(Method) ->
case binary:split(Method, <<"/">>) of
[Type, Operation] when byte_size(Type) > 0, byte_size(Operation) > 0 ->
validate_method_chars(Method);
_ ->
false
end.
validate_method_chars(<<>>) ->
true;
validate_method_chars(<<C, Rest/binary>>) ->
case is_valid_method_char(C) of
true -> validate_method_chars(Rest);
false -> false
end.
is_valid_method_char(C) ->
(C >= $A andalso C =< $Z) orelse
(C >= $a andalso C =< $z) orelse
(C >= $0 andalso C =< $9) orelse
C =:= $/ orelse C =:= $_.
%% Format successful method response
format_method_response(Method, Result, CallId) ->
[Method, Result, CallId].
%% Format error method response
format_error_response(Error, CallId, Method) ->
ErrorMap = format_error(Error),
[<<"error">>, ErrorMap#{<<"description">> => <<"Error in method: ", Method/binary>>}, CallId].
|
