-module(glance).
-compile([no_auto_import, nowarn_unused_vars]).

-export([module/1]).
-export_type([module_/0, import/0, unqualified_import/0, publicity/0, type_alias/0, custom_type/0, variant/0, field/0, type/0, error/0]).

-type module_() :: {module,
        list(import()),
        list(custom_type()),
        list(type_alias())}.

-type import() :: {import,
        binary(),
        gleam@option:option(binary()),
        list(unqualified_import())}.

-type unqualified_import() :: {unqualified_import,
        binary(),
        gleam@option:option(binary())}.

-type publicity() :: public | private.

-type type_alias() :: {type_alias,
        binary(),
        publicity(),
        list(binary()),
        type()}.

-type custom_type() :: {custom_type,
        binary(),
        publicity(),
        list(binary()),
        list(variant())}.

-type variant() :: {variant, binary(), list(field())}.

-type field() :: {field, gleam@option:option(binary()), type()}.

-type type() :: {named_type,
        binary(),
        gleam@option:option(binary()),
        list(type())} |
    {tuple_type, list(type())} |
    {function_type, list(type()), type()} |
    {variable_type, binary()}.

-type error() :: unexpected_end_of_input |
    {unexpected_token, glexer@token:token(), glexer:position()}.

-spec push_custom_type(module_(), custom_type()) -> module_().
push_custom_type(Module, Custom_type) ->
    Custom_type@1 = erlang:setelement(
        5,
        Custom_type,
        gleam@list:reverse(erlang:element(5, Custom_type))
    ),
    erlang:setelement(3, Module, [Custom_type@1 | erlang:element(3, Module)]).

-spec push_type_alias(module_(), type_alias()) -> module_().
push_type_alias(Module, Type_alias) ->
    erlang:setelement(4, Module, [Type_alias | erlang:element(4, Module)]).

-spec push_variant(custom_type(), variant()) -> custom_type().
push_variant(Custom_type, Variant) ->
    erlang:setelement(
        5,
        Custom_type,
        [Variant | erlang:element(5, Custom_type)]
    ).

-spec expect(
    glexer@token:token(),
    list({glexer@token:token(), glexer:position()}),
    fun((glexer:position(), list({glexer@token:token(), glexer:position()})) -> {ok,
            EZD} |
        {error, error()})
) -> {ok, EZD} | {error, error()}.
expect(Expected, Tokens, Next) ->
    case Tokens of
        [] ->
            {error, unexpected_end_of_input};

        [{Token, Position} | Tokens@1] when Token =:= Expected ->
            Next(Position, Tokens@1);

        [{Other, Position@1} | _] ->
            {error, {unexpected_token, Other, Position@1}}
    end.

-spec expect_upper_name(
    list({glexer@token:token(), glexer:position()}),
    fun((binary(), list({glexer@token:token(), glexer:position()})) -> {ok, EZI} |
        {error, error()})
) -> {ok, EZI} | {error, error()}.
expect_upper_name(Tokens, Next) ->
    case Tokens of
        [] ->
            {error, unexpected_end_of_input};

        [{{upper_name, Name}, _} | Tokens@1] ->
            Next(Name, Tokens@1);

        [{Other, Position} | _] ->
            {error, {unexpected_token, Other, Position}}
    end.

-spec optional_module_alias(list({glexer@token:token(), glexer:position()})) -> {gleam@option:option(binary()),
    list({glexer@token:token(), glexer:position()})}.
optional_module_alias(Tokens) ->
    case Tokens of
        [{as, _}, {{name, Alias}, _} | Tokens@1] ->
            {{some, Alias}, Tokens@1};

        _ ->
            {none, Tokens}
    end.

-spec slurp(module_(), list({glexer@token:token(), glexer:position()})) -> {ok,
        module_()} |
    {error, error()}.
slurp(Module, Tokens) ->
    case Tokens of
        [] ->
            {ok, Module};

        [{import, _} | Tokens@1] ->
            import_statement(Module, Tokens@1);

        [{pub, _}, {type, _} | Tokens@2] ->
            type_definition(Module, public, Tokens@2);

        [{type, _} | Tokens@3] ->
            type_definition(Module, private, Tokens@3);

        [_ | Tokens@4] ->
            slurp(Module, Tokens@4)
    end.

-spec module(binary()) -> {ok, module_()} | {error, error()}.
module(Src) ->
    _pipe = glexer:new(Src),
    _pipe@1 = glexer:lex(_pipe),
    _pipe@2 = gleam@list:filter(
        _pipe@1,
        fun(Pair) -> erlang:element(1, Pair) /= comment_normal end
    ),
    slurp({module, [], [], []}, _pipe@2).

-spec until(
    glexer@token:token(),
    EZN,
    list({glexer@token:token(), glexer:position()}),
    fun((EZN, list({glexer@token:token(), glexer:position()})) -> {ok,
            {EZN, list({glexer@token:token(), glexer:position()})}} |
        {error, error()})
) -> {ok, {EZN, list({glexer@token:token(), glexer:position()})}} |
    {error, error()}.
until(Limit, Acc, Tokens, Callback) ->
    case Tokens of
        [] ->
            {error, unexpected_end_of_input};

        [{Token, _} | Tokens@1] when Token =:= Limit ->
            {ok, {Acc, Tokens@1}};

        [_ | _] ->
            case Callback(Acc, Tokens) of
                {ok, {Acc@1, Tokens@2}} ->
                    until(Limit, Acc@1, Tokens@2, Callback);

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

-spec module_name(binary(), list({glexer@token:token(), glexer:position()})) -> {ok,
        {binary(), list({glexer@token:token(), glexer:position()})}} |
    {error, error()}.
module_name(Name, Tokens) ->
    case Tokens of
        [{slash, _}, {{name, S}, _} | Tokens@1] when Name =/= <<""/utf8>> ->
            module_name(
                <<<<Name/binary, "/"/utf8>>/binary, S/binary>>,
                Tokens@1
            );

        [{{name, S@1}, _} | Tokens@2] when Name =:= <<""/utf8>> ->
            module_name(S@1, Tokens@2);

        [] when Name =:= <<""/utf8>> ->
            {error, unexpected_end_of_input};

        [{Other, Position} | _] when Name =:= <<""/utf8>> ->
            {error, {unexpected_token, Other, Position}};

        _ ->
            {ok, {Name, Tokens}}
    end.

-spec unqualified_imports(
    list(unqualified_import()),
    list({glexer@token:token(), glexer:position()})
) -> {ok,
        {list(unqualified_import()),
            list({glexer@token:token(), glexer:position()})}} |
    {error, error()}.
unqualified_imports(Items, Tokens) ->
    case Tokens of
        [] ->
            {error, unexpected_end_of_input};

        [{right_brace, _} | Tokens@1] ->
            {ok, {gleam@list:reverse(Items), Tokens@1}};

        [{{upper_name, Name}, _},
            {as, _},
            {{upper_name, Alias}, _},
            {comma, _} |
            Tokens@2] ->
            Import_ = {unqualified_import, Name, {some, Alias}},
            unqualified_imports([Import_ | Items], Tokens@2);

        [{{name, Name}, _}, {as, _}, {{name, Alias}, _}, {comma, _} | Tokens@2] ->
            Import_ = {unqualified_import, Name, {some, Alias}},
            unqualified_imports([Import_ | Items], Tokens@2);

        [{{upper_name, Name@1}, _},
            {as, _},
            {{upper_name, Alias@1}, _},
            {right_brace, _} |
            Tokens@3] ->
            Import_@1 = {unqualified_import, Name@1, {some, Alias@1}},
            {ok, {gleam@list:reverse([Import_@1 | Items]), Tokens@3}};

        [{{name, Name@1}, _},
            {as, _},
            {{name, Alias@1}, _},
            {right_brace, _} |
            Tokens@3] ->
            Import_@1 = {unqualified_import, Name@1, {some, Alias@1}},
            {ok, {gleam@list:reverse([Import_@1 | Items]), Tokens@3}};

        [{{upper_name, Name@2}, _}, {comma, _} | Tokens@4] ->
            Import_@2 = {unqualified_import, Name@2, none},
            unqualified_imports([Import_@2 | Items], Tokens@4);

        [{{name, Name@2}, _}, {comma, _} | Tokens@4] ->
            Import_@2 = {unqualified_import, Name@2, none},
            unqualified_imports([Import_@2 | Items], Tokens@4);

        [{{upper_name, Name@3}, _}, {right_brace, _} | Tokens@5] ->
            Import_@3 = {unqualified_import, Name@3, none},
            {ok, {gleam@list:reverse([Import_@3 | Items]), Tokens@5}};

        [{{name, Name@3}, _}, {right_brace, _} | Tokens@5] ->
            Import_@3 = {unqualified_import, Name@3, none},
            {ok, {gleam@list:reverse([Import_@3 | Items]), Tokens@5}};

        [{Other, Position} | _] ->
            {error, {unexpected_token, Other, Position}}
    end.

-spec optional_unqualified_imports(
    list({glexer@token:token(), glexer:position()})
) -> {ok,
        {list(unqualified_import()),
            list({glexer@token:token(), glexer:position()})}} |
    {error, error()}.
optional_unqualified_imports(Tokens) ->
    case Tokens of
        [{dot, _}, {left_brace, _} | Tokens@1] ->
            unqualified_imports([], Tokens@1);

        _ ->
            {ok, {[], Tokens}}
    end.

-spec import_statement(
    module_(),
    list({glexer@token:token(), glexer:position()})
) -> {ok, module_()} | {error, error()}.
import_statement(Module, Tokens) ->
    gleam@result:'try'(
        module_name(<<""/utf8>>, Tokens),
        fun(_use0) ->
            {Module_name, Tokens@1} = _use0,
            gleam@result:'try'(
                optional_unqualified_imports(Tokens@1),
                fun(_use0@1) ->
                    {Unqualified, Tokens@2} = _use0@1,
                    {Alias, Tokens@3} = optional_module_alias(Tokens@2),
                    Import_ = {import, Module_name, Alias, Unqualified},
                    slurp(
                        erlang:setelement(
                            2,
                            Module,
                            [Import_ | erlang:element(2, Module)]
                        ),
                        Tokens@3
                    )
                end
            )
        end
    ).

-spec type_parameters(
    list(binary()),
    list({glexer@token:token(), glexer:position()})
) -> {ok, {list(binary()), list({glexer@token:token(), glexer:position()})}} |
    {error, error()}.
type_parameters(Parameters, Tokens) ->
    case Tokens of
        [] ->
            {error, unexpected_end_of_input};

        [{{name, Name}, _}, {right_paren, _} | Tokens@1] ->
            {ok, {gleam@list:reverse([Name | Parameters]), Tokens@1}};

        [{{name, Name}, _}, {comma, _}, {right_paren, _} | Tokens@1] ->
            {ok, {gleam@list:reverse([Name | Parameters]), Tokens@1}};

        [{{name, Name@1}, _}, {comma, _} | Tokens@2] ->
            type_parameters([Name@1 | Parameters], Tokens@2);

        [{right_paren, _} | Tokens@3] ->
            {ok, {gleam@list:reverse(Parameters), Tokens@3}}
    end.

-spec optional_type_parameters(list({glexer@token:token(), glexer:position()})) -> {ok,
        {list(binary()), list({glexer@token:token(), glexer:position()})}} |
    {error, error()}.
optional_type_parameters(Tokens) ->
    case Tokens of
        [{left_paren, _} | Tokens@1] ->
            type_parameters([], Tokens@1);

        _ ->
            {ok, {[], Tokens}}
    end.

-spec types_then_paren(
    list(type()),
    list({glexer@token:token(), glexer:position()})
) -> {ok, {list(type()), list({glexer@token:token(), glexer:position()})}} |
    {error, error()}.
types_then_paren(Types, Tokens) ->
    case Tokens of
        [] ->
            {error, unexpected_end_of_input};

        [{right_paren, _} | Tokens@1] ->
            {ok, {gleam@list:reverse(Types), Tokens@1}};

        _ ->
            gleam@result:'try'(
                type_(Tokens),
                fun(_use0) ->
                    {Type_, Tokens@2} = _use0,
                    case Tokens@2 of
                        [] ->
                            {error, unexpected_end_of_input};

                        [{right_paren, _} | Tokens@3] ->
                            {ok,
                                {gleam@list:reverse([Type_ | Types]), Tokens@3}};

                        [{comma, _} | Tokens@4] ->
                            types_then_paren([Type_ | Types], Tokens@4);

                        [{Token, Position} | _] ->
                            {error, {unexpected_token, Token, Position}}
                    end
                end
            )
    end.

-spec named_type(
    binary(),
    gleam@option:option(binary()),
    list({glexer@token:token(), glexer:position()})
) -> {ok, {type(), list({glexer@token:token(), glexer:position()})}} |
    {error, error()}.
named_type(Name, Module, Tokens) ->
    gleam@result:'try'(case Tokens of
            [{left_paren, _} | Tokens@1] ->
                types_then_paren([], Tokens@1);

            _ ->
                {ok, {[], Tokens}}
        end, fun(_use0) ->
            {Parameters, Tokens@2} = _use0,
            T = {named_type, Name, Module, Parameters},
            {ok, {T, Tokens@2}}
        end).

-spec tuple_type(list({glexer@token:token(), glexer:position()})) -> {ok,
        {type(), list({glexer@token:token(), glexer:position()})}} |
    {error, error()}.
tuple_type(Tokens) ->
    gleam@result:'try'(
        types_then_paren([], Tokens),
        fun(_use0) ->
            {Types, Tokens@1} = _use0,
            {ok, {{tuple_type, Types}, Tokens@1}}
        end
    ).

-spec variant_fields(
    list(field()),
    list({glexer@token:token(), glexer:position()})
) -> {ok, {list(field()), list({glexer@token:token(), glexer:position()})}} |
    {error, error()}.
variant_fields(Fields, Tokens) ->
    {Label, Tokens@2} = case Tokens of
        [{{name, Name}, _}, {colon, _} | Tokens@1] ->
            {{some, Name}, Tokens@1};

        _ ->
            {none, Tokens}
    end,
    gleam@result:'try'(
        type_(Tokens@2),
        fun(_use0) ->
            {Type_, Tokens@3} = _use0,
            case Tokens@3 of
                [] ->
                    {error, unexpected_end_of_input};

                [{right_paren, _} | Tokens@4] ->
                    {ok,
                        {gleam@list:reverse([{field, Label, Type_} | Fields]),
                            Tokens@4}};

                [{comma, _}, {right_paren, _} | Tokens@4] ->
                    {ok,
                        {gleam@list:reverse([{field, Label, Type_} | Fields]),
                            Tokens@4}};

                [{comma, _} | Tokens@5] ->
                    variant_fields([{field, Label, Type_} | Fields], Tokens@5);

                [{Token, Position} | _] ->
                    {error, {unexpected_token, Token, Position}}
            end
        end
    ).

-spec optional_variant_fields(list({glexer@token:token(), glexer:position()})) -> {ok,
        {list(field()), list({glexer@token:token(), glexer:position()})}} |
    {error, error()}.
optional_variant_fields(Tokens) ->
    case Tokens of
        [{left_paren, _}, {right_paren, _} | Tokens@1] ->
            {ok, {[], Tokens@1}};

        [{left_paren, _} | Tokens@2] ->
            variant_fields([], Tokens@2);

        _ ->
            {ok, {[], Tokens}}
    end.

-spec variants(custom_type(), list({glexer@token:token(), glexer:position()})) -> {ok,
        {custom_type(), list({glexer@token:token(), glexer:position()})}} |
    {error, error()}.
variants(Ct, Tokens) ->
    until(
        right_brace,
        Ct,
        Tokens,
        fun(Ct@1, Tokens@1) ->
            expect_upper_name(
                Tokens@1,
                fun(Name, Tokens@2) ->
                    gleam@result:'try'(
                        optional_variant_fields(Tokens@2),
                        fun(_use0) ->
                            {Parameters, Tokens@3} = _use0,
                            Ct@2 = push_variant(
                                Ct@1,
                                {variant, Name, Parameters}
                            ),
                            {ok, {Ct@2, Tokens@3}}
                        end
                    )
                end
            )
        end
    ).

-spec custom_type(
    module_(),
    binary(),
    list(binary()),
    publicity(),
    list({glexer@token:token(), glexer:position()})
) -> {ok, module_()} | {error, error()}.
custom_type(Module, Name, Parameters, Publicity, Tokens) ->
    Ct = {custom_type, Name, Publicity, Parameters, []},
    gleam@result:'try'(
        variants(Ct, Tokens),
        fun(_use0) ->
            {Ct@1, Tokens@1} = _use0,
            Module@1 = push_custom_type(Module, Ct@1),
            slurp(Module@1, Tokens@1)
        end
    ).

-spec fn_type(list({glexer@token:token(), glexer:position()})) -> {ok,
        {type(), list({glexer@token:token(), glexer:position()})}} |
    {error, error()}.
fn_type(Tokens) ->
    gleam@result:'try'(
        types_then_paren([], Tokens),
        fun(_use0) ->
            {Parameters, Tokens@1} = _use0,
            expect(
                right_arrow,
                Tokens@1,
                fun(_, Tokens@2) ->
                    gleam@result:'try'(
                        type_(Tokens@2),
                        fun(_use0@1) ->
                            {Return, Tokens@3} = _use0@1,
                            {ok,
                                {{function_type, Parameters, Return}, Tokens@3}}
                        end
                    )
                end
            )
        end
    ).

-spec type_(list({glexer@token:token(), glexer:position()})) -> {ok,
        {type(), list({glexer@token:token(), glexer:position()})}} |
    {error, error()}.
type_(Tokens) ->
    case Tokens of
        [] ->
            {error, unexpected_end_of_input};

        [{fn, _}, {left_paren, _} | Tokens@1] ->
            fn_type(Tokens@1);

        [{hash, _}, {left_paren, _} | Tokens@2] ->
            tuple_type(Tokens@2);

        [{{name, Module}, _}, {dot, _}, {{upper_name, Name}, _} | Tokens@3] ->
            named_type(Name, {some, Module}, Tokens@3);

        [{{upper_name, Name@1}, _} | Tokens@4] ->
            named_type(Name@1, none, Tokens@4);

        [{{name, Name@2}, _} | Tokens@5] ->
            {ok, {{variable_type, Name@2}, Tokens@5}};

        [{Token, Position} | _] ->
            {error, {unexpected_token, Token, Position}}
    end.

-spec type_alias(
    module_(),
    binary(),
    list(binary()),
    publicity(),
    list({glexer@token:token(), glexer:position()})
) -> {ok, module_()} | {error, error()}.
type_alias(Module, Name, Parameters, Publicity, Tokens) ->
    gleam@result:'try'(
        type_(Tokens),
        fun(_use0) ->
            {Type_, Tokens@1} = _use0,
            _pipe = Module,
            _pipe@1 = push_type_alias(
                _pipe,
                {type_alias, Name, Publicity, Parameters, Type_}
            ),
            slurp(_pipe@1, Tokens@1)
        end
    ).

-spec type_definition(
    module_(),
    publicity(),
    list({glexer@token:token(), glexer:position()})
) -> {ok, module_()} | {error, error()}.
type_definition(Module, Publicity, Tokens) ->
    expect_upper_name(
        Tokens,
        fun(Name, Tokens@1) ->
            gleam@result:'try'(
                optional_type_parameters(Tokens@1),
                fun(_use0) ->
                    {Parameters, Tokens@2} = _use0,
                    case Tokens@2 of
                        [] ->
                            {error, unexpected_end_of_input};

                        [{equal, _} | Tokens@3] ->
                            type_alias(
                                Module,
                                Name,
                                Parameters,
                                Publicity,
                                Tokens@3
                            );

                        [{left_brace, _} | Tokens@4] ->
                            custom_type(
                                Module,
                                Name,
                                Parameters,
                                Publicity,
                                Tokens@4
                            )
                    end
                end
            )
        end
    ).