gleeth

-module(gleeth@ens).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/gleeth/ens.gleam").
-export([namehash/1, resolve/2]).

-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(
    " ENS (Ethereum Name Service) resolution.\n"
    "\n"
    " Resolves human-readable `.eth` names to Ethereum addresses by querying\n"
    " the ENS registry and resolver contracts on-chain.\n"
    "\n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " let assert Ok(address) = ens.resolve(provider, \"vitalik.eth\")\n"
    " // address = \"0xd8da6bf26964af9d7eed9e03e53415d37aa96045\"\n"
    " ```\n"
).

-file("src/gleeth/ens.gleam", 86).
?DOC(
    " Compute the ENS namehash for a domain name.\n"
    "\n"
    " The namehash algorithm recursively hashes labels:\n"
    " `namehash(\"\") = 0x00...00`\n"
    " `namehash(\"eth\") = keccak256(namehash(\"\") + keccak256(\"eth\"))`\n"
    " `namehash(\"vitalik.eth\") = keccak256(namehash(\"eth\") + keccak256(\"vitalik\"))`\n"
    "\n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " let hash = ens.namehash(\"vitalik.eth\")\n"
    " ```\n"
).
-spec namehash(binary()) -> bitstring().
namehash(Name) ->
    case Name of
        <<""/utf8>> ->
            <<0:256>>;

        _ ->
            Labels = gleam@string:split(Name, <<"."/utf8>>),
            Reversed = lists:reverse(Labels),
            gleam@list:fold(
                Reversed,
                <<0:256>>,
                fun(Node, Label) ->
                    Label_hash = gleeth@crypto@keccak:keccak256_binary(
                        gleam_stdlib:identity(Label)
                    ),
                    gleeth@crypto@keccak:keccak256_binary(
                        gleam_stdlib:bit_array_concat([Node, Label_hash])
                    )
                end
            )
    end.

-file("src/gleeth/ens.gleam", 105).
?DOC(" Call a function that takes a bytes32 arg and returns an address.\n").
-spec call_address(gleeth@provider:provider(), binary(), binary(), binary()) -> {ok,
        binary()} |
    {error, gleeth@rpc@types:gleeth_error()}.
call_address(Provider, Contract, Selector, Arg_hex) ->
    Arg_clean = gleeth@utils@hex:strip_prefix(Arg_hex),
    Padded = gleam@string:pad_start(Arg_clean, 64, <<"0"/utf8>>),
    Calldata = <<Selector/binary, Padded/binary>>,
    gleam@result:'try'(
        gleeth@rpc@methods:call_contract(Provider, Contract, Calldata),
        fun(Result_hex) -> case gleeth@utils@hex:decode(Result_hex) of
                {ok, Bytes} ->
                    Size = erlang:byte_size(Bytes),
                    case Size >= 32 of
                        true ->
                            Addr_bytes@1 = case gleam_stdlib:bit_array_slice(
                                Bytes,
                                12,
                                20
                            ) of
                                {ok, Addr_bytes} -> Addr_bytes;
                                _assert_fail ->
                                    erlang:error(#{gleam_error => let_assert,
                                                message => <<"Pattern match failed, no pattern matched the value."/utf8>>,
                                                file => <<?FILEPATH/utf8>>,
                                                module => <<"gleeth/ens"/utf8>>,
                                                function => <<"call_address"/utf8>>,
                                                line => 128,
                                                value => _assert_fail,
                                                start => 3716,
                                                'end' => 3774,
                                                pattern_start => 3727,
                                                pattern_end => 3741})
                            end,
                            Addr = <<"0x"/utf8,
                                (string:lowercase(
                                    gleam_stdlib:base16_encode(Addr_bytes@1)
                                ))/binary>>,
                            {ok, Addr};

                        false ->
                            {ok, <<""/utf8>>}
                    end;

                {error, _} ->
                    {ok, <<""/utf8>>}
            end end
    ).

-file("src/gleeth/ens.gleam", 37).
?DOC(
    " Resolve an ENS name to an Ethereum address.\n"
    "\n"
    " Queries the ENS registry for the resolver, then queries the resolver\n"
    " for the address. Returns an error if the name has no resolver or no\n"
    " address set.\n"
    "\n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " let assert Ok(addr) = ens.resolve(provider, \"vitalik.eth\")\n"
    " ```\n"
).
-spec resolve(gleeth@provider:provider(), binary()) -> {ok, binary()} |
    {error, gleeth@rpc@types:gleeth_error()}.
resolve(Provider, Name) ->
    Node = namehash(Name),
    Node_hex = gleeth@utils@hex:encode(Node),
    gleam@result:'try'(
        call_address(
            Provider,
            <<"0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e"/utf8>>,
            <<"0x0178b8bf"/utf8>>,
            Node_hex
        ),
        fun(Resolver_address) -> case Resolver_address of
                <<""/utf8>> ->
                    {error,
                        {parse_error,
                            <<"No resolver found for: "/utf8, Name/binary>>}};

                <<"0x0000000000000000000000000000000000000000"/utf8>> ->
                    {error,
                        {parse_error,
                            <<"No resolver found for: "/utf8, Name/binary>>}};

                Resolver ->
                    gleam@result:'try'(
                        call_address(
                            Provider,
                            Resolver,
                            <<"0x3b3b57de"/utf8>>,
                            Node_hex
                        ),
                        fun(Address) -> case Address of
                                <<""/utf8>> ->
                                    {error,
                                        {parse_error,
                                            <<"No address set for: "/utf8,
                                                Name/binary>>}};

                                <<"0x0000000000000000000000000000000000000000"/utf8>> ->
                                    {error,
                                        {parse_error,
                                            <<"No address set for: "/utf8,
                                                Name/binary>>}};

                                Addr ->
                                    {ok, Addr}
                            end end
                    )
            end end
    ).