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

-export([parse/1]).
-export_type([modifier/0, dice/0, dice_error/0]).

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

-type modifier() :: {keep_highest, integer()} |
    {keep_lowest, integer()} |
    {drop_highest, integer()} |
    {drop_lowest, integer()} |
    {reroll, integer()} |
    {recursive_reroll, integer()} |
    {explode, integer()} |
    {minimum, integer()} |
    {maximum, integer()}.

-type dice() :: {basic, integer(), integer(), list(modifier())} |
    {fate, integer(), list(modifier())} |
    {number, integer(), list(modifier())}.

-type dice_error() :: invalid_amount |
    invalid_string |
    invalid_value |
    invalid_modifier.

-file("src/diced.gleam", 96).
-spec parse_amount(binary()) -> {ok, integer()} | {error, dice_error()}.
parse_amount(Amount) ->
    _pipe = gleam_stdlib:parse_int(Amount),
    gleam@result:replace_error(_pipe, invalid_amount).

-file("src/diced.gleam", 148).
-spec do_with_modifier_value(binary(), integer()) -> {binary(), integer()}.
do_with_modifier_value(String, Value) ->
    case String of
        <<"0"/utf8, Rest/binary>> ->
            do_with_modifier_value(Rest, Value * 10);

        <<"1"/utf8, Rest@1/binary>> ->
            do_with_modifier_value(Rest@1, (Value * 10) + 1);

        <<"2"/utf8, Rest@2/binary>> ->
            do_with_modifier_value(Rest@2, (Value * 10) + 2);

        <<"3"/utf8, Rest@3/binary>> ->
            do_with_modifier_value(Rest@3, (Value * 10) + 3);

        <<"4"/utf8, Rest@4/binary>> ->
            do_with_modifier_value(Rest@4, (Value * 10) + 4);

        <<"5"/utf8, Rest@5/binary>> ->
            do_with_modifier_value(Rest@5, (Value * 10) + 5);

        <<"6"/utf8, Rest@6/binary>> ->
            do_with_modifier_value(Rest@6, (Value * 10) + 6);

        <<"7"/utf8, Rest@7/binary>> ->
            do_with_modifier_value(Rest@7, (Value * 10) + 7);

        <<"8"/utf8, Rest@8/binary>> ->
            do_with_modifier_value(Rest@8, (Value * 10) + 8);

        <<"9"/utf8, Rest@9/binary>> ->
            do_with_modifier_value(Rest@9, (Value * 10) + 9);

        _ ->
            {String, Value}
    end.

-file("src/diced.gleam", 141).
-spec with_modifier_value(binary()) -> {binary(), integer()}.
with_modifier_value(String) ->
    case do_with_modifier_value(String, 0) of
        {A, V} when V =:= 0 ->
            {A, 1};

        {A@1, V@1} ->
            {A@1, V@1}
    end.

-file("src/diced.gleam", 101).
-spec parse_value(binary()) -> {ok, {integer(), binary()}} |
    {error, dice_error()}.
parse_value(Value) ->
    Modifier_splitter = splitter:new(
        [<<"kh"/utf8>>,
            <<"kl"/utf8>>,
            <<"dh"/utf8>>,
            <<"dl"/utf8>>,
            <<"r"/utf8>>,
            <<"R"/utf8>>,
            <<"!"/utf8>>,
            <<"m"/utf8>>,
            <<"M"/utf8>>]
    ),
    {Value@1, A, B} = splitter_ffi:split(Modifier_splitter, Value),
    gleam@result:'try'(
        gleam@result:replace_error(
            gleam_stdlib:parse_int(Value@1),
            invalid_value
        ),
        fun(Value@2) -> {ok, {Value@2, <<A/binary, B/binary>>}} end
    ).

-file("src/diced.gleam", 112).
-spec do_parse_modifiers(
    binary(),
    {ok, list(modifier())} | {error, dice_error()}
) -> {ok, list(modifier())} | {error, dice_error()}.
do_parse_modifiers(Modifiers, Found) ->
    gleam@result:'try'(
        Found,
        fun(Found@1) ->
            Splitter = splitter:new(
                [<<"kh"/utf8>>,
                    <<"kl"/utf8>>,
                    <<"dh"/utf8>>,
                    <<"dl"/utf8>>,
                    <<"r"/utf8>>,
                    <<"R"/utf8>>,
                    <<"!"/utf8>>,
                    <<"m"/utf8>>,
                    <<"M"/utf8>>]
            ),
            case splitter_ffi:split(Splitter, Modifiers) of
                {<<""/utf8>>, <<""/utf8>>, <<""/utf8>>} ->
                    {ok, lists:reverse(Found@1)};

                {<<""/utf8>>, Mod, Rest} ->
                    {Rest@1, Value} = with_modifier_value(Rest),
                    Modifier = case Mod of
                        <<"kh"/utf8>> ->
                            {keep_highest, Value};

                        <<"kl"/utf8>> ->
                            {keep_lowest, Value};

                        <<"dh"/utf8>> ->
                            {drop_highest, Value};

                        <<"dl"/utf8>> ->
                            {drop_lowest, Value};

                        <<"r"/utf8>> ->
                            {reroll, Value};

                        <<"R"/utf8>> ->
                            {recursive_reroll, Value};

                        <<"!"/utf8>> ->
                            {explode, Value};

                        <<"m"/utf8>> ->
                            {minimum, Value};

                        <<"M"/utf8>> ->
                            {maximum, Value};

                        _ ->
                            erlang:error(#{gleam_error => panic,
                                    message => <<"unreachable"/utf8>>,
                                    module => <<"diced"/utf8>>,
                                    function => <<"do_parse_modifiers"/utf8>>,
                                    line => 133})
                    end,
                    do_parse_modifiers(Rest@1, {ok, [Modifier | Found@1]});

                _ ->
                    {error, invalid_modifier}
            end
        end
    ).

-file("src/diced.gleam", 108).
-spec parse_modifiers(binary()) -> {ok, list(modifier())} |
    {error, dice_error()}.
parse_modifiers(Modifiers) ->
    do_parse_modifiers(Modifiers, {ok, []}).

-file("src/diced.gleam", 62).
?DOC(
    " Convert a string containing algebraic dice notation into a type describing how the dice should behave when rolled.\n"
    "\n"
    " ```gleam\n"
    " diced.parse(\"2d20kh\")\n"
    " // Ok(diced.Basic(2, 20, [KeepHighest(1)]))\n"
    " ```\n"
).
-spec parse(binary()) -> {ok, dice()} | {error, dice_error()}.
parse(String) ->
    Dice_splitter = splitter:new([<<"d"/utf8>>, <<"dF"/utf8>>]),
    case splitter_ffi:split(Dice_splitter, String) of
        {Value, <<""/utf8>>, Mods} ->
            gleam@result:'try'(
                begin
                    _pipe = gleam_stdlib:parse_int(Value),
                    gleam@result:replace_error(_pipe, invalid_value)
                end,
                fun(Value@1) ->
                    gleam@result:'try'(
                        parse_modifiers(Mods),
                        fun(Modifiers) -> {ok, {number, Value@1, Modifiers}} end
                    )
                end
            );

        {Amount, <<"d"/utf8>>, <<""/utf8>>} ->
            gleam@result:'try'(
                parse_amount(Amount),
                fun(Amount@1) -> {ok, {basic, Amount@1, 6, []}} end
            );

        {<<""/utf8>>, <<"d"/utf8>>, Mods@1} ->
            gleam@result:'try'(
                parse_value(Mods@1),
                fun(_use0) ->
                    {Value@2, Rest} = _use0,
                    gleam@result:'try'(
                        parse_modifiers(Rest),
                        fun(Modifiers@1) ->
                            {ok, {basic, 1, Value@2, Modifiers@1}}
                        end
                    )
                end
            );

        {Amount@2, <<"d"/utf8>>, Mods@2} ->
            gleam@result:'try'(
                parse_amount(Amount@2),
                fun(Amount@3) ->
                    gleam@result:'try'(
                        parse_value(Mods@2),
                        fun(_use0@1) ->
                            {Value@3, Rest@1} = _use0@1,
                            gleam@result:'try'(
                                parse_modifiers(Rest@1),
                                fun(Modifiers@2) ->
                                    {ok,
                                        {basic, Amount@3, Value@3, Modifiers@2}}
                                end
                            )
                        end
                    )
                end
            );

        {Amount@4, <<"dF"/utf8>>, Mods@3} ->
            gleam@result:'try'(
                parse_amount(Amount@4),
                fun(Amount@5) ->
                    gleam@result:'try'(
                        parse_modifiers(Mods@3),
                        fun(Modifiers@3) ->
                            {ok, {fate, Amount@5, Modifiers@3}}
                        end
                    )
                end
            );

        {_, _, _} ->
            {error, invalid_string}
    end.