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

-export([map/2, to/2, alt/2, any/0, eof/0, satisfying/1, then/2, item/1, pair/2, left/2, right/2, many0/1, many1/1, lazy/1, char/1, string/1, parse/2, one_of/1, digit/0, number/0, between/3, whitespace/0, whitespace0/0, whitespace1/0]).
-export_type([parsed/2, parse_error/1]).

-type parsed(FKC, FKD) :: {parsed, list(FKC), FKD}.

-type parse_error(FKE) :: {parse_error, list(FKE), list(binary())}.

-spec ok(list(FKX), FKZ) -> {ok, parsed(FKX, FKZ)} | {error, parse_error(FKX)}.
ok(Input, Value) ->
    {ok, {parsed, Input, Value}}.

-spec map(
    fun((list(FLC)) -> {ok, parsed(FLC, FLD)} | {error, parse_error(FLC)}),
    fun((FLD) -> FLG)
) -> fun((list(FLC)) -> {ok, parsed(FLC, FLG)} | {error, parse_error(FLC)}).
map(P, Fun) ->
    fun(Input) -> _pipe = P(Input),
        gleam@result:map(
            _pipe,
            fun(Parsed) ->
                {parsed,
                    erlang:element(2, Parsed),
                    Fun(erlang:element(3, Parsed))}
            end
        ) end.

-spec to(
    fun((list(FLJ)) -> {ok, parsed(FLJ, any())} | {error, parse_error(FLJ)}),
    FLN
) -> fun((list(FLJ)) -> {ok, parsed(FLJ, FLN)} | {error, parse_error(FLJ)}).
to(Parser, Value) ->
    map(Parser, fun(_) -> Value end).

-spec alt(
    fun((list(FLQ)) -> {ok, parsed(FLQ, FLR)} | {error, parse_error(FLQ)}),
    fun((list(FLQ)) -> {ok, parsed(FLQ, FLR)} | {error, parse_error(FLQ)})
) -> fun((list(FLQ)) -> {ok, parsed(FLQ, FLR)} | {error, parse_error(FLQ)}).
alt(Parser_1, Parser_2) ->
    fun(Input) -> case Parser_1(Input) of
            {ok, Result} ->
                {ok, Result};

            {error, _} ->
                Parser_2(Input)
        end end.

-spec any() -> fun((list(FLY)) -> {ok, parsed(FLY, FLY)} |
    {error, parse_error(FLY)}).
any() ->
    fun(In) -> case pears@input:get(In) of
            none ->
                {error, {parse_error, In, [<<"any"/utf8>>]}};

            {some, {Value, Next}} ->
                ok(Next, Value)
        end end.

-spec eof() -> fun((list(FMB)) -> {ok, parsed(FMB, nil)} |
    {error, parse_error(FMB)}).
eof() ->
    fun(Input) -> case Input of
            [] ->
                ok(Input, nil);

            _ ->
                {error, {parse_error, Input, [<<"EOF"/utf8>>]}}
        end end.

-spec satisfying(fun((FME) -> boolean())) -> fun((list(FME)) -> {ok,
        parsed(FME, FME)} |
    {error, parse_error(FME)}).
satisfying(F) ->
    fun(In) -> case pears@input:get(In) of
            none ->
                {error, {parse_error, In, [<<"satisfying"/utf8>>]}};

            {some, {Value, Next}} ->
                case F(Value) of
                    true ->
                        ok(Next, Value);

                    false ->
                        {error, {parse_error, In, [<<"satisfying"/utf8>>]}}
                end
        end end.

-spec then(
    fun((list(FMI)) -> {ok, parsed(FMI, any())} | {error, parse_error(FMI)}),
    fun((list(FMI)) -> {ok, parsed(FMI, FMM)} | {error, parse_error(FMI)})
) -> fun((list(FMI)) -> {ok, parsed(FMI, FMM)} | {error, parse_error(FMI)}).
then(Parser_a, Parser_b) ->
    fun(Input) -> case Parser_a(Input) of
            {ok, Parsed} ->
                Parser_b(erlang:element(2, Parsed));

            {error, Err} ->
                {error, Err}
        end end.

-spec item(FMR) -> fun((list(FMR)) -> {ok, parsed(FMR, FMR)} |
    {error, parse_error(FMR)}).
item(Item) ->
    fun(Input) -> case Input of
            [Head | Next] when Head =:= Item ->
                ok(Next, Head);

            _ ->
                {error, {parse_error, Input, [<<"item"/utf8>>]}}
        end end.

-spec pair(
    fun((list(FMU)) -> {ok, parsed(FMU, FMV)} | {error, parse_error(FMU)}),
    fun((list(FMU)) -> {ok, parsed(FMU, FMY)} | {error, parse_error(FMU)})
) -> fun((list(FMU)) -> {ok, parsed(FMU, {FMV, FMY})} |
    {error, parse_error(FMU)}).
pair(P1, P2) ->
    fun(In) ->
        gleam@result:'try'(
            P1(In),
            fun(Parsed_1) ->
                gleam@result:'try'(
                    P2(erlang:element(2, Parsed_1)),
                    fun(Parsed_2) ->
                        ok(
                            erlang:element(2, Parsed_2),
                            {erlang:element(3, Parsed_1),
                                erlang:element(3, Parsed_2)}
                        )
                    end
                )
            end
        )
    end.

-spec left(
    fun((list(FND)) -> {ok, parsed(FND, FNE)} | {error, parse_error(FND)}),
    fun((list(FND)) -> {ok, parsed(FND, any())} | {error, parse_error(FND)})
) -> fun((list(FND)) -> {ok, parsed(FND, FNE)} | {error, parse_error(FND)}).
left(P1, P2) ->
    fun(In) ->
        gleam@result:'try'(
            P1(In),
            fun(Parsed_1) ->
                gleam@result:'try'(
                    P2(erlang:element(2, Parsed_1)),
                    fun(Parsed_2) ->
                        ok(
                            erlang:element(2, Parsed_2),
                            erlang:element(3, Parsed_1)
                        )
                    end
                )
            end
        )
    end.

-spec right(
    fun((list(FNM)) -> {ok, parsed(FNM, any())} | {error, parse_error(FNM)}),
    fun((list(FNM)) -> {ok, parsed(FNM, FNQ)} | {error, parse_error(FNM)})
) -> fun((list(FNM)) -> {ok, parsed(FNM, FNQ)} | {error, parse_error(FNM)}).
right(P1, P2) ->
    fun(In) ->
        gleam@result:'try'(
            P1(In),
            fun(Parsed_1) ->
                gleam@result:'try'(
                    P2(erlang:element(2, Parsed_1)),
                    fun(Parsed_2) ->
                        ok(
                            erlang:element(2, Parsed_2),
                            erlang:element(3, Parsed_2)
                        )
                    end
                )
            end
        )
    end.

-spec many0(
    fun((list(FNV)) -> {ok, parsed(FNV, FNW)} | {error, parse_error(FNV)})
) -> fun((list(FNV)) -> {ok, parsed(FNV, list(FNW))} | {error, parse_error(FNV)}).
many0(Parser) ->
    fun(In) -> case Parser(In) of
            {ok, Parsed} ->
                gleam@result:'try'(
                    (many0(Parser))(erlang:element(2, Parsed)),
                    fun(Next) ->
                        ok(
                            erlang:element(2, Next),
                            [erlang:element(3, Parsed) |
                                erlang:element(3, Next)]
                        )
                    end
                );

            {error, _} ->
                ok(In, [])
        end end.

-spec many1(
    fun((list(FOC)) -> {ok, parsed(FOC, FOD)} | {error, parse_error(FOC)})
) -> fun((list(FOC)) -> {ok, parsed(FOC, list(FOD))} | {error, parse_error(FOC)}).
many1(Parser) ->
    fun(In) ->
        gleam@result:'try'(
            Parser(In),
            fun(Parsed) ->
                gleam@result:'try'(
                    (many0(Parser))(erlang:element(2, Parsed)),
                    fun(Rest) ->
                        ok(
                            erlang:element(2, Rest),
                            [erlang:element(3, Parsed) |
                                erlang:element(3, Rest)]
                        )
                    end
                )
            end
        )
    end.

-spec lazy(
    fun(() -> fun((list(FOJ)) -> {ok, parsed(FOJ, FOK)} |
        {error, parse_error(FOJ)}))
) -> fun((list(FOJ)) -> {ok, parsed(FOJ, FOK)} | {error, parse_error(FOJ)}).
lazy(F) ->
    fun(Input) -> (F())(Input) end.

-spec char(binary()) -> fun((list(binary())) -> {ok, parsed(binary(), binary())} |
    {error, parse_error(binary())}).
char(C) ->
    item(C).

-spec string(binary()) -> fun((list(binary())) -> {ok,
        parsed(binary(), binary())} |
    {error, parse_error(binary())}).
string(Str) ->
    fun(Input) ->
        S = gleam@string:to_graphemes(Str),
        Length = gleam@list:length(S),
        case gleam@list:length(Input) >= Length of
            true ->
                Candidate = gleam@list:take(Input, Length),
                case Candidate =:= S of
                    true ->
                        ok(gleam@list:drop(Input, Length), Str);

                    false ->
                        {error, {parse_error, Input, [Str]}}
                end;

            false ->
                {error, {parse_error, Input, [Str]}}
        end
    end.

-spec parse(
    fun((list(binary())) -> {ok, parsed(binary(), FKS)} |
        {error, parse_error(binary())}),
    binary()
) -> {ok, parsed(binary(), FKS)} | {error, parse_error(binary())}.
parse(Parser, Input) ->
    Parser(gleam@string:to_graphemes(Input)).

-spec one_of(list(FOT)) -> fun((list(FOT)) -> {ok, parsed(FOT, FOT)} |
    {error, parse_error(FOT)}).
one_of(Items) ->
    satisfying(fun(C) -> gleam@list:contains(Items, C) end).

-spec digit() -> fun((list(binary())) -> {ok, parsed(binary(), binary())} |
    {error, parse_error(binary())}).
digit() ->
    one_of(
        [<<"0"/utf8>>,
            <<"1"/utf8>>,
            <<"2"/utf8>>,
            <<"3"/utf8>>,
            <<"4"/utf8>>,
            <<"5"/utf8>>,
            <<"6"/utf8>>,
            <<"7"/utf8>>,
            <<"8"/utf8>>,
            <<"9"/utf8>>]
    ).

-spec number() -> fun((list(binary())) -> {ok, parsed(binary(), integer())} |
    {error, parse_error(binary())}).
number() ->
    _pipe = many1(digit()),
    map(
        _pipe,
        fun(Digits) ->
            gleam@list:fold(
                Digits,
                0,
                fun(Acc, Digit) ->
                    _assert_subject = gleam@int:parse(Digit),
                    {ok, Digit@1} = case _assert_subject of
                        {ok, _} -> _assert_subject;
                        _assert_fail ->
                            erlang:error(#{gleam_error => let_assert,
                                        message => <<"Assertion pattern match failed"/utf8>>,
                                        value => _assert_fail,
                                        module => <<"pears"/utf8>>,
                                        function => <<"number"/utf8>>,
                                        line => 199})
                    end,
                    (Acc * 10) + Digit@1
                end
            )
        end
    ).

-spec between(
    fun((list(FPB)) -> {ok, parsed(FPB, any())} | {error, parse_error(FPB)}),
    fun((list(FPB)) -> {ok, parsed(FPB, any())} | {error, parse_error(FPB)}),
    fun((list(FPB)) -> {ok, parsed(FPB, FPI)} | {error, parse_error(FPB)})
) -> fun((list(FPB)) -> {ok, parsed(FPB, FPI)} | {error, parse_error(FPB)}).
between(Open, Close, Parser) ->
    _pipe = Open,
    _pipe@1 = right(_pipe, Parser),
    left(_pipe@1, Close).

-spec whitespace() -> fun((list(binary())) -> {ok, parsed(binary(), binary())} |
    {error, parse_error(binary())}).
whitespace() ->
    satisfying(fun(C) -> gleam@string:trim(C) =:= <<""/utf8>> end).

-spec whitespace0() -> fun((list(binary())) -> {ok,
        parsed(binary(), list(binary()))} |
    {error, parse_error(binary())}).
whitespace0() ->
    many0(whitespace()).

-spec whitespace1() -> fun((list(binary())) -> {ok,
        parsed(binary(), list(binary()))} |
    {error, parse_error(binary())}).
whitespace1() ->
    many1(whitespace()).