-module(gwr@parser@instruction_parser).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([parse_instruction/1, parse_expression/1]).

-spec parse_instruction(gwr@parser@binary_reader:binary_reader()) -> {ok,
        {gwr@parser@binary_reader:binary_reader(),
            gwr@syntax@instruction:instruction()}} |
    {error, binary()}.
parse_instruction(Reader) ->
    gleam@result:'try'(case gwr@parser@binary_reader:read(Reader, 1) of
            {ok, {Reader@1, <<Opcode>>}} ->
                {ok, {Reader@1, Opcode}};

            {error, Reason} ->
                {error,
                    <<"gwr/parser/instruction_parser.parse_instruction: couldn't read opcode: "/utf8,
                        Reason/binary>>};

            _ ->
                {error,
                    <<"gwr/parser/instruction_parser.parse_instruction: unknown error reading opcode"/utf8>>}
        end, fun(_use0) ->
            {Reader@2, Opcode@1} = _use0,
            gleam@result:'try'(case Opcode@1 of
                    16#00 ->
                        {ok, {Reader@2, unreachable}};

                    16#01 ->
                        {ok, {Reader@2, no_op}};

                    16#20 ->
                        gleam@result:'try'(
                            gwr@parser@value_parser:parse_unsigned_leb128_integer(
                                Reader@2
                            ),
                            fun(_use0@1) ->
                                {Reader@3, Local_index} = _use0@1,
                                {ok, {Reader@3, {local_get, Local_index}}}
                            end
                        );

                    16#6a ->
                        {ok, {Reader@2, i32_add}};

                    16#41 ->
                        gleam@result:'try'(
                            gwr@parser@value_parser:parse_uninterpreted_leb128_integer(
                                Reader@2
                            ),
                            fun(_use0@2) ->
                                {Reader@4, Value} = _use0@2,
                                {ok, {Reader@4, {i32_const, Value}}}
                            end
                        );

                    16#0b ->
                        {ok, {Reader@2, 'end'}};

                    Unknown ->
                        {error,
                            <<<<"gwr/parser/instruction_parser.parse_instruction: unknown opcode \"0x"/utf8,
                                    (gleam@int:to_base16(Unknown))/binary>>/binary,
                                "\""/utf8>>}
                end, fun(_use0@3) ->
                    {Reader@5, Instruction} = _use0@3,
                    {ok, {Reader@5, Instruction}}
                end)
        end).

-spec parse_expression(gwr@parser@binary_reader:binary_reader()) -> {ok,
        {gwr@parser@binary_reader:binary_reader(),
            list(gwr@syntax@instruction:instruction())}} |
    {error, binary()}.
parse_expression(Reader) ->
    gleam@result:'try'(
        gwr@parser@binary_reader:get_remaining(Reader),
        fun(Data) ->
            Data_length = erlang:byte_size(Data),
            gleam@result:'try'(
                gleam@iterator:fold(
                    gleam@iterator:range(1, Data_length),
                    {ok, {Reader, []}},
                    fun(State, _) ->
                        gleam@result:'try'(
                            State,
                            fun(_use0) ->
                                {Reader@1, Current_expression} = _use0,
                                gleam@bool:guard(
                                    gleam@list:last(Current_expression) =:= {ok,
                                        'end'},
                                    State,
                                    fun() ->
                                        gleam@bool:guard(
                                            not gwr@parser@binary_reader:can_read(
                                                Reader@1
                                            )
                                            andalso (gleam@list:last(
                                                Current_expression
                                            )
                                            /= {ok, 'end'}),
                                            {error,
                                                <<"gwr/parser/instruction_parser.parse_expression: an expression must terminate with a End instruction"/utf8>>},
                                            fun() ->
                                                gleam@result:'try'(
                                                    parse_instruction(Reader@1),
                                                    fun(_use0@1) ->
                                                        {Reader@2, Instruction} = _use0@1,
                                                        {ok,
                                                            {Reader@2,
                                                                lists:append(
                                                                    Current_expression,
                                                                    [Instruction]
                                                                )}}
                                                    end
                                                )
                                            end
                                        )
                                    end
                                )
                            end
                        )
                    end
                ),
                fun(_use0@2) ->
                    {Reader@3, Expression} = _use0@2,
                    {ok, {Reader@3, Expression}}
                end
            )
        end
    ).