-module(gose@cose@algorithm).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/gose/cose/algorithm.gleam").
-export([signature_alg_to_int/1, signature_alg_from_int/1, mac_alg_to_int/1, mac_alg_from_int/1, signing_alg_to_int/1, signing_alg_from_int/1, key_encryption_alg_to_int/1, key_encryption_alg_from_int/1, content_alg_to_int/1, content_alg_from_int/1]).

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

?MODULEDOC(
    " COSE algorithm integer ID mapping ([RFC 9053](https://www.rfc-editor.org/rfc/rfc9053.html)).\n"
    "\n"
    " Maps between `gose/algorithm` types and COSE integer identifiers.\n"
).

-file("src/gose/cose/algorithm.gleam", 11).
?DOC(" Convert a signature algorithm to its COSE integer identifier.\n").
-spec signature_alg_to_int(gose@algorithm:digital_signature_alg()) -> integer().
signature_alg_to_int(Alg) ->
    case Alg of
        {ecdsa, ecdsa_p256} ->
            -7;

        {ecdsa, ecdsa_p384} ->
            -35;

        {ecdsa, ecdsa_p521} ->
            -36;

        {ecdsa, ecdsa_secp256k1} ->
            -47;

        eddsa ->
            -8;

        {rsa_pkcs1, rsa_pkcs1_sha256} ->
            -257;

        {rsa_pkcs1, rsa_pkcs1_sha384} ->
            -258;

        {rsa_pkcs1, rsa_pkcs1_sha512} ->
            -259;

        {rsa_pss, rsa_pss_sha256} ->
            -37;

        {rsa_pss, rsa_pss_sha384} ->
            -38;

        {rsa_pss, rsa_pss_sha512} ->
            -39
    end.

-file("src/gose/cose/algorithm.gleam", 28).
?DOC(" Parse a signature algorithm from its COSE integer identifier.\n").
-spec signature_alg_from_int(integer()) -> {ok,
        gose@algorithm:digital_signature_alg()} |
    {error, gose:gose_error()}.
signature_alg_from_int(Id) ->
    case Id of
        -257 ->
            {ok, {rsa_pkcs1, rsa_pkcs1_sha256}};

        -258 ->
            {ok, {rsa_pkcs1, rsa_pkcs1_sha384}};

        -259 ->
            {ok, {rsa_pkcs1, rsa_pkcs1_sha512}};

        -35 ->
            {ok, {ecdsa, ecdsa_p384}};

        -36 ->
            {ok, {ecdsa, ecdsa_p521}};

        -37 ->
            {ok, {rsa_pss, rsa_pss_sha256}};

        -38 ->
            {ok, {rsa_pss, rsa_pss_sha384}};

        -39 ->
            {ok, {rsa_pss, rsa_pss_sha512}};

        -47 ->
            {ok, {ecdsa, ecdsa_secp256k1}};

        -7 ->
            {ok, {ecdsa, ecdsa_p256}};

        -8 ->
            {ok, eddsa};

        _ ->
            {error,
                {parse_error,
                    <<"unknown COSE signature algorithm: "/utf8,
                        (erlang:integer_to_binary(Id))/binary>>}}
    end.

-file("src/gose/cose/algorithm.gleam", 51).
?DOC(" Convert a MAC algorithm to its COSE integer identifier.\n").
-spec mac_alg_to_int(gose@algorithm:mac_alg()) -> integer().
mac_alg_to_int(Alg) ->
    case Alg of
        {hmac, hmac_sha256} ->
            5;

        {hmac, hmac_sha384} ->
            6;

        {hmac, hmac_sha512} ->
            7
    end.

-file("src/gose/cose/algorithm.gleam", 60).
?DOC(" Parse a MAC algorithm from its COSE integer identifier.\n").
-spec mac_alg_from_int(integer()) -> {ok, gose@algorithm:mac_alg()} |
    {error, gose:gose_error()}.
mac_alg_from_int(Id) ->
    case Id of
        5 ->
            {ok, {hmac, hmac_sha256}};

        6 ->
            {ok, {hmac, hmac_sha384}};

        7 ->
            {ok, {hmac, hmac_sha512}};

        _ ->
            {error,
                {parse_error,
                    <<"unknown COSE MAC algorithm: "/utf8,
                        (erlang:integer_to_binary(Id))/binary>>}}
    end.

-file("src/gose/cose/algorithm.gleam", 71).
?DOC(" Convert a signing algorithm to its COSE integer identifier.\n").
-spec signing_alg_to_int(gose@algorithm:signing_alg()) -> integer().
signing_alg_to_int(Alg) ->
    case Alg of
        {digital_signature, Sig_alg} ->
            signature_alg_to_int(Sig_alg);

        {mac, Mac_alg} ->
            mac_alg_to_int(Mac_alg)
    end.

-file("src/gose/cose/algorithm.gleam", 79).
?DOC(" Parse a signing algorithm from its COSE integer identifier.\n").
-spec signing_alg_from_int(integer()) -> {ok, gose@algorithm:signing_alg()} |
    {error, gose:gose_error()}.
signing_alg_from_int(Id) ->
    case signature_alg_from_int(Id) of
        {ok, Alg} ->
            {ok, {digital_signature, Alg}};

        {error, _} ->
            case mac_alg_from_int(Id) of
                {ok, Alg@1} ->
                    {ok, {mac, Alg@1}};

                {error, _} ->
                    {error,
                        {parse_error,
                            <<"unknown COSE signing algorithm: "/utf8,
                                (erlang:integer_to_binary(Id))/binary>>}}
            end
    end.

-file("src/gose/cose/algorithm.gleam", 99).
?DOC(
    " Convert a key encryption algorithm to its COSE integer identifier.\n"
    "\n"
    " Some key encryption algorithms are JOSE-only and have no COSE\n"
    " identifier, in which case this returns an error.\n"
).
-spec key_encryption_alg_to_int(gose@algorithm:key_encryption_alg()) -> {ok,
        integer()} |
    {error, gose:gose_error()}.
key_encryption_alg_to_int(Alg) ->
    case Alg of
        direct ->
            {ok, -6};

        {aes_key_wrap, aes_kw, aes128} ->
            {ok, -3};

        {aes_key_wrap, aes_kw, aes192} ->
            {ok, -4};

        {aes_key_wrap, aes_kw, aes256} ->
            {ok, -5};

        {ecdh_es, ecdh_es_direct} ->
            {ok, -25};

        {ecdh_es, {ecdh_es_aes_kw, aes128}} ->
            {ok, -29};

        {ecdh_es, {ecdh_es_aes_kw, aes192}} ->
            {ok, -30};

        {ecdh_es, {ecdh_es_aes_kw, aes256}} ->
            {ok, -31};

        {rsa_encryption, rsa_oaep_sha1} ->
            {ok, -40};

        {rsa_encryption, rsa_oaep_sha256} ->
            {ok, -41};

        {aes_key_wrap, aes_gcm_kw, _} ->
            {error,
                {invalid_state,
                    <<"no COSE identifier for algorithm: "/utf8,
                        (gleam@string:inspect(Alg))/binary>>}};

        {cha_cha20_key_wrap, _} ->
            {error,
                {invalid_state,
                    <<"no COSE identifier for algorithm: "/utf8,
                        (gleam@string:inspect(Alg))/binary>>}};

        {rsa_encryption, rsa_pkcs1v15} ->
            {error,
                {invalid_state,
                    <<"no COSE identifier for algorithm: "/utf8,
                        (gleam@string:inspect(Alg))/binary>>}};

        {ecdh_es, {ecdh_es_cha_cha20_kw, _}} ->
            {error,
                {invalid_state,
                    <<"no COSE identifier for algorithm: "/utf8,
                        (gleam@string:inspect(Alg))/binary>>}};

        {pbes2, _} ->
            {error,
                {invalid_state,
                    <<"no COSE identifier for algorithm: "/utf8,
                        (gleam@string:inspect(Alg))/binary>>}}
    end.

-file("src/gose/cose/algorithm.gleam", 132).
?DOC(
    " Parse a key encryption algorithm from its COSE integer identifier.\n"
    "\n"
    " Both ECDH-ES+HKDF-256 (-25) and ECDH-ES+HKDF-512 (-26) map to\n"
    " `EcdhEs(EcdhEsDirect)` because the shared algorithm type does not\n"
    " distinguish the HKDF variant. The HKDF variant is preserved at the\n"
    " `cose/encrypt` layer via `EcdhEsDirectVariant`. Use\n"
    " `new_ecdh_es_direct_recipient` and `ecdh_es_direct_decryptor` for\n"
    " HKDF-512 support.\n"
).
-spec key_encryption_alg_from_int(integer()) -> {ok,
        gose@algorithm:key_encryption_alg()} |
    {error, gose:gose_error()}.
key_encryption_alg_from_int(Id) ->
    case Id of
        -25 ->
            {ok, {ecdh_es, ecdh_es_direct}};

        -26 ->
            {ok, {ecdh_es, ecdh_es_direct}};

        -29 ->
            {ok, {ecdh_es, {ecdh_es_aes_kw, aes128}}};

        -3 ->
            {ok, {aes_key_wrap, aes_kw, aes128}};

        -30 ->
            {ok, {ecdh_es, {ecdh_es_aes_kw, aes192}}};

        -31 ->
            {ok, {ecdh_es, {ecdh_es_aes_kw, aes256}}};

        -4 ->
            {ok, {aes_key_wrap, aes_kw, aes192}};

        -5 ->
            {ok, {aes_key_wrap, aes_kw, aes256}};

        -6 ->
            {ok, direct};

        -40 ->
            {ok, {rsa_encryption, rsa_oaep_sha1}};

        -41 ->
            {ok, {rsa_encryption, rsa_oaep_sha256}};

        _ ->
            {error,
                {parse_error,
                    <<"unknown COSE key encryption algorithm: "/utf8,
                        (erlang:integer_to_binary(Id))/binary>>}}
    end.

-file("src/gose/cose/algorithm.gleam", 157).
?DOC(
    " Convert a content encryption algorithm to its COSE integer identifier.\n"
    "\n"
    " Some content encryption algorithms are JOSE-only and have no COSE\n"
    " identifier, in which case this returns an error.\n"
).
-spec content_alg_to_int(gose@algorithm:content_alg()) -> {ok, integer()} |
    {error, gose:gose_error()}.
content_alg_to_int(Alg) ->
    case Alg of
        {aes_gcm, aes128} ->
            {ok, 1};

        {aes_gcm, aes192} ->
            {ok, 2};

        {aes_gcm, aes256} ->
            {ok, 3};

        cha_cha20_poly1305 ->
            {ok, 24};

        {aes_cbc_hmac, _} ->
            {error,
                {invalid_state,
                    <<"no COSE identifier for algorithm: "/utf8,
                        (gleam@string:inspect(Alg))/binary>>}};

        x_cha_cha20_poly1305 ->
            {error,
                {invalid_state,
                    <<"no COSE identifier for algorithm: "/utf8,
                        (gleam@string:inspect(Alg))/binary>>}}
    end.

-file("src/gose/cose/algorithm.gleam", 173).
?DOC(" Parse a content encryption algorithm from its COSE integer identifier.\n").
-spec content_alg_from_int(integer()) -> {ok, gose@algorithm:content_alg()} |
    {error, gose:gose_error()}.
content_alg_from_int(Id) ->
    case Id of
        1 ->
            {ok, {aes_gcm, aes128}};

        2 ->
            {ok, {aes_gcm, aes192}};

        3 ->
            {ok, {aes_gcm, aes256}};

        24 ->
            {ok, cha_cha20_poly1305};

        _ ->
            {error,
                {parse_error,
                    <<"unknown COSE content encryption algorithm: "/utf8,
                        (erlang:integer_to_binary(Id))/binary>>}}
    end.