argus

-module(argus).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([hasher/0, hasher_argon2i/0, algorithm/2, time_cost/2, memory_cost/2, parallelism/2, hash_length/2, gen_salt/0, hash/3, verify/2]).
-export_type([argon2_algorithm/0, hasher/0, hashes/0, hash_error/0]).

-type argon2_algorithm() :: argon2d | argon2i | argon2id.

-opaque hasher() :: {hasher,
        argon2_algorithm(),
        integer(),
        integer(),
        integer(),
        integer()}.

-type hashes() :: {hashes, bitstring(), binary()}.

-type hash_error() :: output_pointer_is_null |
    output_too_short |
    output_too_long |
    password_too_short |
    password_too_long |
    salt_too_short |
    salt_too_long |
    associated_data_too_short |
    associated_data_too_long |
    secret_too_short |
    secret_too_long |
    time_cost_too_small |
    time_cost_too_large |
    memory_cost_too_small |
    memory_cost_too_large |
    too_few_lanes |
    too_many_lanes |
    password_pointer_mismatch |
    salt_pointer_mismatch |
    secret_pointer_mismatch |
    associated_data_pointer_mismatch |
    memory_allocation_error |
    free_memory_callback_null |
    allocate_memory_callback_null |
    incorrect_parameter |
    incorrect_type |
    invalid_algorithm |
    output_pointer_mismatch |
    too_few_threads |
    too_many_threads |
    not_enough_memory |
    encoding_failed |
    decoding_failed |
    thread_failure |
    decoding_length_failure |
    verification_failure |
    unknown_error_code.

-spec hasher() -> hasher().
hasher() ->
    {hasher, argon2id, 2, 19456, 1, 32}.

-spec hasher_argon2i() -> hasher().
hasher_argon2i() ->
    {hasher, argon2i, 3, 12228, 1, 32}.

-spec algorithm(hasher(), argon2_algorithm()) -> hasher().
algorithm(Hasher, Algorithm) ->
    erlang:setelement(2, Hasher, Algorithm).

-spec time_cost(hasher(), integer()) -> hasher().
time_cost(Hasher, Time_cost) ->
    erlang:setelement(3, Hasher, Time_cost).

-spec memory_cost(hasher(), integer()) -> hasher().
memory_cost(Hasher, Memory_cost) ->
    erlang:setelement(4, Hasher, Memory_cost).

-spec parallelism(hasher(), integer()) -> hasher().
parallelism(Hasher, Parallelism) ->
    erlang:setelement(5, Hasher, Parallelism).

-spec hash_length(hasher(), integer()) -> hasher().
hash_length(Hasher, Hash_length) ->
    erlang:setelement(6, Hasher, Hash_length).

-spec gen_salt() -> binary().
gen_salt() ->
    argus_nif:gen_salt().

-spec hash(hasher(), binary(), binary()) -> {ok, hashes()} |
    {error, hash_error()}.
hash(Hasher, Password, Salt) ->
    Result = argus_nif:hash(
        Password,
        Salt,
        erlang:element(2, Hasher),
        erlang:element(3, Hasher),
        erlang:element(4, Hasher),
        erlang:element(5, Hasher),
        erlang:element(6, Hasher)
    ),
    case Result of
        {ok, {Raw_hash, Encoded_hash}} ->
            {ok, {hashes, Raw_hash, Encoded_hash}};

        {error, Error} ->
            {error, Error}
    end.

-spec verify(binary(), binary()) -> {ok, boolean()} | {error, hash_error()}.
verify(Encoded_hash, Password) ->
    jargon:verify(Encoded_hash, Password).