-module(gleeth@wei).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/gleeth/wei.gleam").
-export([from_int/1, from_ether/1, from_gwei/1, to_int/1, to_ether/1, to_gwei/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(
    " Convert between human-readable values (ETH, gwei, integers) and the\n"
    " `0x`-prefixed hex strings used by the Ethereum JSON-RPC wire format.\n"
    "\n"
    " All RPC methods in gleeth accept and return hex strings. This module\n"
    " bridges the gap so users don't have to construct hex manually.\n"
    "\n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " let assert Ok(hex) = wei.from_ether(\"1.0\")\n"
    " // hex = \"0xde0b6b3a7640000\"\n"
    "\n"
    " let assert Ok(eth) = wei.to_ether(\"0xde0b6b3a7640000\")\n"
    " // eth = \"1.0\"\n"
    " ```\n"
).

-file("src/gleeth/wei.gleam", 80).
?DOC(
    " Convert a decimal integer to a hex string.\n"
    "\n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " wei.from_int(21000)  // -> \"0x5208\"\n"
    " wei.from_int(0)      // -> \"0x0\"\n"
    " ```\n"
).
-spec from_int(integer()) -> binary().
from_int(Value) ->
    case Value of
        0 ->
            <<"0x0"/utf8>>;

        _ ->
            <<"0x"/utf8, (string:lowercase(gleam@int:to_base16(Value)))/binary>>
    end.

-file("src/gleeth/wei.gleam", 208).
-spec nibble_to_char(integer()) -> binary().
nibble_to_char(N) ->
    case N of
        0 ->
            <<"0"/utf8>>;

        1 ->
            <<"1"/utf8>>;

        2 ->
            <<"2"/utf8>>;

        3 ->
            <<"3"/utf8>>;

        4 ->
            <<"4"/utf8>>;

        5 ->
            <<"5"/utf8>>;

        6 ->
            <<"6"/utf8>>;

        7 ->
            <<"7"/utf8>>;

        8 ->
            <<"8"/utf8>>;

        9 ->
            <<"9"/utf8>>;

        10 ->
            <<"a"/utf8>>;

        11 ->
            <<"b"/utf8>>;

        12 ->
            <<"c"/utf8>>;

        13 ->
            <<"d"/utf8>>;

        14 ->
            <<"e"/utf8>>;

        15 ->
            <<"f"/utf8>>;

        _ ->
            <<"0"/utf8>>
    end.

-file("src/gleeth/wei.gleam", 193).
-spec bigint_to_hex_loop(bigi:big_int(), binary()) -> binary().
bigint_to_hex_loop(Value, Acc) ->
    Zero = bigi_ffi:from(0),
    Sixteen = bigi_ffi:from(16),
    case bigi_ffi:compare(Value, Zero) of
        eq ->
            Acc;

        _ ->
            Remainder = bigi_ffi:remainder(Value, Sixteen),
            Quotient = bigi_ffi:divide(Value, Sixteen),
            Nibble@1 = case bigi_ffi:to(Remainder) of
                {ok, Nibble} -> Nibble;
                _assert_fail ->
                    erlang:error(#{gleam_error => let_assert,
                                message => <<"Pattern match failed, no pattern matched the value."/utf8>>,
                                file => <<?FILEPATH/utf8>>,
                                module => <<"gleeth/wei"/utf8>>,
                                function => <<"bigint_to_hex_loop"/utf8>>,
                                line => 201,
                                value => _assert_fail,
                                start => 5930,
                                'end' => 5976,
                                pattern_start => 5941,
                                pattern_end => 5951})
            end,
            Hex_char = nibble_to_char(Nibble@1),
            bigint_to_hex_loop(Quotient, <<Hex_char/binary, Acc/binary>>)
    end.

-file("src/gleeth/wei.gleam", 182).
-spec bigint_to_hex(bigi:big_int()) -> binary().
bigint_to_hex(Value) ->
    Zero = bigi_ffi:from(0),
    case bigi_ffi:compare(Value, Zero) of
        eq ->
            <<"0x0"/utf8>>;

        _ ->
            Hex_str = bigint_to_hex_loop(Value, <<""/utf8>>),
            <<"0x"/utf8, (string:lowercase(Hex_str))/binary>>
    end.

-file("src/gleeth/wei.gleam", 230).
-spec power_of_10_string(integer()) -> binary().
power_of_10_string(N) ->
    <<"1"/utf8, (gleam@string:repeat(<<"0"/utf8>>, N))/binary>>.

-file("src/gleeth/wei.gleam", 148).
?DOC(
    " Parse a decimal string like \"1.5\" or \"100\" into a BigInt representing\n"
    " wei (multiplied by 10^decimals).\n"
).
-spec parse_decimal_to_bigint(binary(), integer()) -> {ok, bigi:big_int()} |
    {error, binary()}.
parse_decimal_to_bigint(Amount, Decimals) ->
    case gleam@string:split(Amount, <<"."/utf8>>) of
        [Whole] ->
            gleam@result:'try'(
                begin
                    _pipe = bigi_ffi:from_string(Whole),
                    gleam@result:map_error(
                        _pipe,
                        fun(_) -> <<"Invalid number: "/utf8, Amount/binary>> end
                    )
                end,
                fun(Whole_big) ->
                    Multiplier@1 = case bigi_ffi:from_string(
                        power_of_10_string(Decimals)
                    ) of
                        {ok, Multiplier} -> Multiplier;
                        _assert_fail ->
                            erlang:error(#{gleam_error => let_assert,
                                        message => <<"Pattern match failed, no pattern matched the value."/utf8>>,
                                        file => <<?FILEPATH/utf8>>,
                                        module => <<"gleeth/wei"/utf8>>,
                                        function => <<"parse_decimal_to_bigint"/utf8>>,
                                        line => 159,
                                        value => _assert_fail,
                                        start => 4642,
                                        'end' => 4716,
                                        pattern_start => 4653,
                                        pattern_end => 4667})
                    end,
                    {ok, bigi_ffi:multiply(Whole_big, Multiplier@1)}
                end
            );

        [Whole@1, Frac] ->
            Frac_len = string:length(Frac),
            case Frac_len > Decimals of
                true ->
                    {error,
                        <<<<"Too many decimal places (max "/utf8,
                                (erlang:integer_to_binary(Decimals))/binary>>/binary,
                            ")"/utf8>>};

                false ->
                    Padded_frac = <<Frac/binary,
                        (gleam@string:repeat(<<"0"/utf8>>, Decimals - Frac_len))/binary>>,
                    Combined = <<Whole@1/binary, Padded_frac/binary>>,
                    _pipe@1 = bigi_ffi:from_string(Combined),
                    gleam@result:map_error(
                        _pipe@1,
                        fun(_) -> <<"Invalid number: "/utf8, Amount/binary>> end
                    )
            end;

        _ ->
            {error, <<"Invalid decimal format: "/utf8, Amount/binary>>}
    end.

-file("src/gleeth/wei.gleam", 110).
?DOC(
    " Parse a decimal string (possibly with fractional part) and multiply by\n"
    " 10^decimals to get the wei value as a BigInt, then convert to hex.\n"
).
-spec decimal_to_wei(binary(), integer()) -> {ok, binary()} | {error, binary()}.
decimal_to_wei(Amount, Decimals) ->
    Trimmed = gleam@string:trim(Amount),
    case Trimmed of
        <<""/utf8>> ->
            {error, <<"Empty amount"/utf8>>};

        _ ->
            gleam@result:'try'(
                parse_decimal_to_bigint(Trimmed, Decimals),
                fun(Wei) ->
                    Zero = bigi_ffi:from(0),
                    case bigi_ffi:compare(Wei, Zero) of
                        lt ->
                            {error, <<"Negative amounts not supported"/utf8>>};

                        _ ->
                            {ok, bigint_to_hex(Wei)}
                    end
                end
            )
    end.

-file("src/gleeth/wei.gleam", 33).
?DOC(
    " Convert an ether amount string to a wei hex string.\n"
    " Handles integers (\"1\", \"100\") and decimals (\"1.5\", \"0.001\").\n"
    "\n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " wei.from_ether(\"1.0\")   // -> Ok(\"0xde0b6b3a7640000\")\n"
    " wei.from_ether(\"0.5\")   // -> Ok(\"0x6f05b59d3b20000\")\n"
    " wei.from_ether(\"0\")     // -> Ok(\"0x0\")\n"
    " ```\n"
).
-spec from_ether(binary()) -> {ok, binary()} | {error, binary()}.
from_ether(Ether) ->
    decimal_to_wei(Ether, 18).

-file("src/gleeth/wei.gleam", 45).
?DOC(
    " Convert a gwei amount string to a wei hex string.\n"
    "\n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " wei.from_gwei(\"1.0\")    // -> Ok(\"0x3b9aca00\")\n"
    " wei.from_gwei(\"20\")     // -> Ok(\"0x4a817c800\")\n"
    " ```\n"
).
-spec from_gwei(binary()) -> {ok, binary()} | {error, binary()}.
from_gwei(Gwei) ->
    decimal_to_wei(Gwei, 9).

-file("src/gleeth/wei.gleam", 234).
-spec strip_0x(binary()) -> binary().
strip_0x(S) ->
    case gleam_stdlib:string_starts_with(S, <<"0x"/utf8>>) of
        true ->
            gleam@string:drop_start(S, 2);

        false ->
            S
    end.

-file("src/gleeth/wei.gleam", 94).
?DOC(
    " Convert a hex string to a decimal integer.\n"
    "\n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " wei.to_int(\"0x5208\")  // -> Ok(21000)\n"
    " ```\n"
).
-spec to_int(binary()) -> {ok, integer()} | {error, binary()}.
to_int(Hex_string) ->
    Clean = strip_0x(Hex_string),
    case Clean of
        <<""/utf8>> ->
            {ok, 0};

        _ ->
            _pipe = gleam@int:base_parse(Clean, 16),
            gleam@result:map_error(
                _pipe,
                fun(_) -> <<"Invalid hex: "/utf8, Hex_string/binary>> end
            )
    end.

-file("src/gleeth/wei.gleam", 241).
-spec trim_trailing_zeros(binary()) -> binary().
trim_trailing_zeros(S) ->
    case gleam_stdlib:string_ends_with(S, <<"0"/utf8>>) of
        true ->
            Trimmed = gleam@string:drop_end(S, 1),
            case Trimmed of
                <<""/utf8>> ->
                    <<"0"/utf8>>;

                _ ->
                    trim_trailing_zeros(Trimmed)
            end;

        false ->
            case S of
                <<""/utf8>> ->
                    <<"0"/utf8>>;

                _ ->
                    S
            end
    end.

-file("src/gleeth/wei.gleam", 127).
?DOC(
    " Convert wei BigInt back to a decimal string with the given number of\n"
    " decimal places.\n"
).
-spec wei_to_decimal(binary(), integer()) -> {ok, binary()} | {error, binary()}.
wei_to_decimal(Hex_string, Decimals) ->
    gleam@result:'try'(
        begin
            _pipe = gleeth@utils@hex:hex_to_bigint(Hex_string),
            gleam@result:map_error(
                _pipe,
                fun(_) -> <<"Invalid hex: "/utf8, Hex_string/binary>> end
            )
        end,
        fun(Wei) ->
            Divisor_str = power_of_10_string(Decimals),
            Divisor@1 = case bigi_ffi:from_string(Divisor_str) of
                {ok, Divisor} -> Divisor;
                _assert_fail ->
                    erlang:error(#{gleam_error => let_assert,
                                message => <<"Pattern match failed, no pattern matched the value."/utf8>>,
                                file => <<?FILEPATH/utf8>>,
                                module => <<"gleeth/wei"/utf8>>,
                                function => <<"wei_to_decimal"/utf8>>,
                                line => 133,
                                value => _assert_fail,
                                start => 3658,
                                'end' => 3712,
                                pattern_start => 3669,
                                pattern_end => 3680})
            end,
            Whole = bigi_ffi:divide(Wei, Divisor@1),
            Remainder = bigi_ffi:remainder(Wei, Divisor@1),
            Whole_str = erlang:integer_to_binary(Whole),
            Remainder_str = erlang:integer_to_binary(Remainder),
            Padded = <<(gleam@string:repeat(
                    <<"0"/utf8>>,
                    Decimals - string:length(Remainder_str)
                ))/binary,
                Remainder_str/binary>>,
            Trimmed = trim_trailing_zeros(Padded),
            {ok, <<<<Whole_str/binary, "."/utf8>>/binary, Trimmed/binary>>}
        end
    ).

-file("src/gleeth/wei.gleam", 57).
?DOC(
    " Convert a wei hex string to an ether decimal string.\n"
    "\n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " wei.to_ether(\"0xde0b6b3a7640000\")  // -> Ok(\"1.0\")\n"
    " wei.to_ether(\"0x0\")                 // -> Ok(\"0.0\")\n"
    " ```\n"
).
-spec to_ether(binary()) -> {ok, binary()} | {error, binary()}.
to_ether(Wei_hex) ->
    wei_to_decimal(Wei_hex, 18).

-file("src/gleeth/wei.gleam", 68).
?DOC(
    " Convert a wei hex string to a gwei decimal string.\n"
    "\n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " wei.to_gwei(\"0x3b9aca00\")  // -> Ok(\"1.0\")\n"
    " ```\n"
).
-spec to_gwei(binary()) -> {ok, binary()} | {error, binary()}.
to_gwei(Wei_hex) ->
    wei_to_decimal(Wei_hex, 9).