thrifty

-module(thrifty@fuzz_persistence).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/thrifty/fuzz_persistence.gleam").
-export([persist_failure/5]).

-if(?OTP_RELEASE >= 27).
-define(MODULEDOC(Str), -moduledoc(Str)).
-define(DOC(Str), -doc(Str)).
-else.
-define(MODULEDOC(Str), -compile([])).
-define(DOC(Str), -compile([])).
-endif.

-file("src/thrifty/fuzz_persistence.gleam", 36).
?DOC(
    " Persist a failing fuzz payload and associated metadata.\n"
    "\n"
    " Inputs\n"
    " - `dir`: output directory. Created if it does not already exist.\n"
    " - `seed`: deterministic seed used when generating the payload.\n"
    " - `iter`: iteration index within the seed loop.\n"
    " - `data`: the mutated payload bytes to persist.\n"
    " - `reason`: the decode error that triggered persistence.\n"
    "\n"
    " Outputs\n"
    " - `Ok(Nil)` when both payload and metadata are written successfully.\n"
    " - `Error(String)` when directory creation or file writes fail.\n"
    "\n"
    " The metadata is stored as a text file containing simple `key=value` lines\n"
    " for quick inspection.\n"
).
-spec persist_failure(
    binary(),
    integer(),
    integer(),
    bitstring(),
    thrifty@types:decode_error()
) -> {ok, nil} | {error, binary()}.
persist_failure(Dir, Seed, Iter, Data, Reason) ->
    case thrifty@file_io:ensure_dir(Dir) of
        {error, E} ->
            {error, E};

        {ok, _} ->
            Basename = <<<<<<"fuzz-failure-"/utf8,
                        (erlang:integer_to_binary(Seed))/binary>>/binary,
                    "-"/utf8>>/binary,
                (erlang:integer_to_binary(Iter))/binary>>,
            Bin_path = <<<<<<Dir/binary, "/"/utf8>>/binary, Basename/binary>>/binary,
                ".bin"/utf8>>,
            Meta_path = <<<<<<Dir/binary, "/"/utf8>>/binary, Basename/binary>>/binary,
                ".meta"/utf8>>,
            case thrifty@file_io:write_binary_to_path(Bin_path, Data) of
                {error, E@1} ->
                    {error, E@1};

                {ok, _} ->
                    Meta = <<<<<<<<<<<<"seed="/utf8,
                                            (erlang:integer_to_binary(Seed))/binary>>/binary,
                                        "\niter="/utf8>>/binary,
                                    (erlang:integer_to_binary(Iter))/binary>>/binary,
                                "\nreason="/utf8>>/binary,
                            (thrifty@types:decode_error_to_string(Reason))/binary>>/binary,
                        "\n"/utf8>>,
                    Meta_bits = gleam_stdlib:identity(Meta),
                    case thrifty@file_io:write_binary_to_path(
                        Meta_path,
                        Meta_bits
                    ) of
                        {error, E@2} ->
                            {error, E@2};

                        {ok, _} ->
                            {ok, nil}
                    end
            end
    end.