-module(atproto_codegen@lower).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/atproto_codegen/lower.gleam").
-export([lower/1, properties_of/1, method_of/1, is_emittable/1, is_record/1, union_of/1, codec_units/1]).
-export_type([flat_type/0, flat_field/0, flat_def/0, method_kind/0, method_error/0, flat_body/0, flat_body_schema/0, method/0, flat_lexicon/0, codec_unit/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.

?MODULEDOC(
    " One-way lowering from `atproto_lexicon/ast.LexiconDoc` to the flat view\n"
    " plugins consume. `ast` stays the faithful, bidirectional representation;\n"
    " this module intentionally drops anything today's plugins do not need\n"
    " (method defs, record key strategy, constraint fields, descriptions) while\n"
    " keeping a handle on the source doc so a later constraint-aware plugin can\n"
    " still reach it. Growing the flat shape (e.g. surfacing a constraint) is\n"
    " fine; this module must never grow the ability to go the other way.\n"
    "\n"
    " A record/object def whose properties use a field type this pipeline\n"
    " cannot render becomes `FlatUnsupported` rather than emitted wrong. A\n"
    " query/procedure def becomes a `FlatMethod` (consumed by the xrpc-client\n"
    " plugin, not the per-unit codec path); any other non-record/object def\n"
    " (subscription, token, ...) becomes `FlatIgnored`, since no plugin\n"
    " generates code for those yet.\n"
).

-type flat_type() :: t_string |
    t_int |
    t_bool |
    t_cid_link |
    t_bytes |
    t_blob |
    t_unknown |
    {t_ref, binary()} |
    {t_array, flat_type()} |
    {t_union, list(binary()), boolean()} |
    {t_unsupported, binary()}.

-type flat_field() :: {flat_field, binary(), flat_type(), boolean(), boolean()}.

-type flat_def() :: {flat_record, binary(), list(flat_field())} |
    {flat_object, binary(), binary(), list(flat_field())} |
    {flat_unsupported, binary(), binary(), binary()} |
    {flat_method, method()} |
    flat_ignored.

-type method_kind() :: method_query | method_procedure.

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

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

-type flat_body_schema() :: {body_ref, binary()} |
    {body_inline, list(flat_field())} |
    {body_unsupported, binary()}.

-type method() :: {method,
        binary(),
        method_kind(),
        list(flat_field()),
        gleam@option:option(flat_body()),
        gleam@option:option(flat_body()),
        list(method_error())}.

-type flat_lexicon() :: {flat_lexicon,
        binary(),
        atproto_lexicon@ast:lexicon_doc(),
        list(flat_def())}.

-type codec_unit() :: {def_unit, flat_def()} |
    {union_unit, flat_def(), flat_field(), list(binary()), boolean()}.

-file("src/atproto_codegen/lower.gleam", 202).
-spec lower_errors(list(atproto_lexicon@ast:lexicon_error())) -> list(method_error()).
lower_errors(Errors) ->
    gleam@list:map(
        Errors,
        fun(E) -> {method_error, erlang:element(2, E), erlang:element(3, E)} end
    ).

-file("src/atproto_codegen/lower.gleam", 240).
-spec unsupported_kind(flat_type()) -> gleam@option:option(binary()).
unsupported_kind(Ft) ->
    case Ft of
        {t_unsupported, Kind} ->
            {some, Kind};

        {t_array, Inner} ->
            unsupported_kind(Inner);

        _ ->
            none
    end.

-file("src/atproto_codegen/lower.gleam", 227).
-spec first_unsupported(list(flat_field())) -> gleam@option:option(binary()).
first_unsupported(Fields) ->
    _pipe = Fields,
    _pipe@1 = gleam@list:filter_map(
        _pipe,
        fun(F) -> case unsupported_kind(erlang:element(3, F)) of
                {some, Kind} ->
                    {ok,
                        <<<<<<<<"field `"/utf8, (erlang:element(2, F))/binary>>/binary,
                                    "` has type `"/utf8>>/binary,
                                Kind/binary>>/binary,
                            "`"/utf8>>};

                none ->
                    {error, nil}
            end end
    ),
    _pipe@2 = gleam@list:first(_pipe@1),
    gleam@option:from_result(_pipe@2).

-file("src/atproto_codegen/lower.gleam", 277).
-spec lower_union(atproto_lexicon@ast:union_constraints()) -> flat_type().
lower_union(Constraints) ->
    {t_union,
        erlang:element(3, Constraints),
        erlang:element(4, Constraints) =:= {some, true}}.

-file("src/atproto_codegen/lower.gleam", 263).
-spec lower_array_item_type(atproto_lexicon@ast:array_item_type()) -> flat_type().
lower_array_item_type(Item) ->
    case Item of
        {item_boolean, _} ->
            t_bool;

        {item_integer, _} ->
            t_int;

        {item_string, _} ->
            t_string;

        {item_bytes, _} ->
            t_bytes;

        {item_cid_link, _} ->
            t_cid_link;

        {item_blob, _} ->
            t_blob;

        {item_ref, _, Ref} ->
            {t_ref, Ref};

        {item_union, Constraints} ->
            lower_union(Constraints);

        {item_unknown, _} ->
            t_unknown
    end.

-file("src/atproto_codegen/lower.gleam", 248).
-spec lower_property_type(atproto_lexicon@ast:property_type()) -> flat_type().
lower_property_type(Prop) ->
    case Prop of
        {prop_boolean, _} ->
            t_bool;

        {prop_integer, _} ->
            t_int;

        {prop_string, _} ->
            t_string;

        {prop_bytes, _} ->
            t_bytes;

        {prop_cid_link, _} ->
            t_cid_link;

        {prop_blob, _} ->
            t_blob;

        {prop_ref, _, Ref} ->
            {t_ref, Ref};

        {prop_union, Constraints} ->
            lower_union(Constraints);

        {prop_unknown, _} ->
            t_unknown;

        {prop_array, Shape} ->
            {t_array, lower_array_item_type(erlang:element(3, Shape))}
    end.

-file("src/atproto_codegen/lower.gleam", 208).
-spec lower_properties(atproto_lexicon@ast:object_schema()) -> {ok,
        list(flat_field())} |
    {error, binary()}.
lower_properties(Schema) ->
    Fields = gleam@list:map(
        erlang:element(5, Schema),
        fun(Pair) ->
            {Json_name, Prop} = Pair,
            {flat_field,
                Json_name,
                lower_property_type(Prop),
                gleam@list:contains(erlang:element(3, Schema), Json_name),
                gleam@list:contains(erlang:element(4, Schema), Json_name)}
        end
    ),
    case first_unsupported(Fields) of
        {some, Reason} ->
            {error, Reason};

        none ->
            {ok, Fields}
    end.

-file("src/atproto_codegen/lower.gleam", 189).
-spec lower_body_schema(gleam@option:option(atproto_lexicon@ast:body_schema())) -> gleam@option:option(flat_body_schema()).
lower_body_schema(Schema) ->
    case Schema of
        none ->
            none;

        {some, {body_schema_ref, Ref}} ->
            {some, {body_ref, Ref}};

        {some, {body_schema_object, Obj}} ->
            case lower_properties(Obj) of
                {ok, Props} ->
                    {some, {body_inline, Props}};

                {error, Reason} ->
                    {some, {body_unsupported, Reason}}
            end;

        {some, {body_schema_union, _}} ->
            {some, {body_unsupported, <<"union body"/utf8>>}}
    end.

-file("src/atproto_codegen/lower.gleam", 181).
-spec lower_body(gleam@option:option(atproto_lexicon@ast:body())) -> gleam@option:option(flat_body()).
lower_body(Body) ->
    case Body of
        none ->
            none;

        {some, B} ->
            {some,
                {flat_body,
                    erlang:element(3, B),
                    lower_body_schema(erlang:element(4, B))}}
    end.

-file("src/atproto_codegen/lower.gleam", 173).
-spec lower_params_item_type(atproto_lexicon@ast:params_item_type()) -> flat_type().
lower_params_item_type(Item) ->
    case Item of
        {params_item_boolean, _} ->
            t_bool;

        {params_item_integer, _} ->
            t_int;

        {params_item_string, _} ->
            t_string
    end.

-file("src/atproto_codegen/lower.gleam", 163).
-spec lower_params_property_type(atproto_lexicon@ast:params_property_type()) -> flat_type().
lower_params_property_type(Prop) ->
    case Prop of
        {params_boolean, _} ->
            t_bool;

        {params_integer, _} ->
            t_int;

        {params_string, _} ->
            t_string;

        {params_unknown, _} ->
            {t_unsupported, <<"unknown"/utf8>>};

        {params_array, _, Items, _, _} ->
            {t_array, lower_params_item_type(Items)}
    end.

-file("src/atproto_codegen/lower.gleam", 147).
-spec lower_params(gleam@option:option(atproto_lexicon@ast:params_schema())) -> list(flat_field()).
lower_params(Params) ->
    case Params of
        none ->
            [];

        {some, Schema} ->
            gleam@list:map(
                erlang:element(4, Schema),
                fun(Pair) ->
                    {Json_name, Prop} = Pair,
                    {flat_field,
                        Json_name,
                        lower_params_property_type(Prop),
                        gleam@list:contains(
                            erlang:element(3, Schema),
                            Json_name
                        ),
                        false}
                end
            )
    end.

-file("src/atproto_codegen/lower.gleam", 113).
-spec lower_def(binary(), binary(), atproto_lexicon@ast:primary_def()) -> flat_def().
lower_def(Nsid, Name, Def) ->
    case Def of
        {def_record, Record_def} ->
            case lower_properties(erlang:element(4, Record_def)) of
                {ok, Props} ->
                    {flat_record, Nsid, Props};

                {error, Reason} ->
                    {flat_unsupported, Nsid, Name, Reason}
            end;

        {def_object, Schema} ->
            case lower_properties(Schema) of
                {ok, Props@1} ->
                    {flat_object, Nsid, Name, Props@1};

                {error, Reason@1} ->
                    {flat_unsupported, Nsid, Name, Reason@1}
            end;

        {def_query, Q} ->
            {flat_method,
                {method,
                    Nsid,
                    method_query,
                    lower_params(erlang:element(3, Q)),
                    none,
                    lower_body(erlang:element(4, Q)),
                    lower_errors(erlang:element(5, Q))}};

        {def_procedure, P} ->
            {flat_method,
                {method,
                    Nsid,
                    method_procedure,
                    lower_params(erlang:element(3, P)),
                    lower_body(erlang:element(4, P)),
                    lower_body(erlang:element(5, P)),
                    lower_errors(erlang:element(6, P))}};

        _ ->
            flat_ignored
    end.

-file("src/atproto_codegen/lower.gleam", 108).
-spec lower_doc(atproto_lexicon@ast:lexicon_doc()) -> flat_lexicon().
lower_doc(Doc) ->
    Defs = gleam@list:map(
        erlang:element(6, Doc),
        fun(Pair) ->
            lower_def(
                erlang:element(3, Doc),
                erlang:element(1, Pair),
                erlang:element(2, Pair)
            )
        end
    ),
    {flat_lexicon, erlang:element(3, Doc), Doc, Defs}.

-file("src/atproto_codegen/lower.gleam", 104).
-spec lower(list(atproto_lexicon@ast:lexicon_doc())) -> list(flat_lexicon()).
lower(Docs) ->
    gleam@list:map(Docs, fun lower_doc/1).

-file("src/atproto_codegen/lower.gleam", 281).
-spec properties_of(flat_def()) -> list(flat_field()).
properties_of(Def) ->
    case Def of
        {flat_record, _, Props} ->
            Props;

        {flat_object, _, _, Props@1} ->
            Props@1;

        {flat_unsupported, _, _, _} ->
            [];

        {flat_method, _} ->
            [];

        flat_ignored ->
            []
    end.

-file("src/atproto_codegen/lower.gleam", 292).
?DOC(
    " The lowered method for a def, when it is one. Methods are not emittable\n"
    " through the per-unit codec path (`is_emittable` is `False` for them); the\n"
    " xrpc-client plugin reads them off `lex.defs` via this accessor instead.\n"
).
-spec method_of(flat_def()) -> gleam@option:option(method()).
method_of(Def) ->
    case Def of
        {flat_method, Method} ->
            {some, Method};

        _ ->
            none
    end.

-file("src/atproto_codegen/lower.gleam", 299).
-spec is_emittable(flat_def()) -> boolean().
is_emittable(Def) ->
    case Def of
        {flat_record, _, _} ->
            true;

        {flat_object, _, _, _} ->
            true;

        {flat_unsupported, _, _, _} ->
            false;

        {flat_method, _} ->
            false;

        flat_ignored ->
            false
    end.

-file("src/atproto_codegen/lower.gleam", 306).
-spec is_record(flat_def()) -> boolean().
is_record(Def) ->
    case Def of
        {flat_record, _, _} ->
            true;

        _ ->
            false
    end.

-file("src/atproto_codegen/lower.gleam", 313).
-spec union_of(flat_type()) -> gleam@option:option({list(binary()), boolean()}).
union_of(Ft) ->
    case Ft of
        {t_union, Refs, Closed} ->
            {some, {Refs, Closed}};

        {t_array, Inner} ->
            union_of(Inner);

        _ ->
            none
    end.

-file("src/atproto_codegen/lower.gleam", 325).
?DOC(
    " The ordered codec units for one module's emittable defs: each def's own\n"
    " unit, immediately followed by one unit per union-typed field on it, in\n"
    " field order. Both the `types` and `decode-json` plugins fold over this\n"
    " same list so their outputs line up position for position.\n"
).
-spec codec_units(list(flat_def())) -> list(codec_unit()).
codec_units(Defs) ->
    _pipe = Defs,
    _pipe@1 = gleam@list:filter(_pipe, fun is_emittable/1),
    gleam@list:flat_map(
        _pipe@1,
        fun(Def) ->
            Unions = begin
                _pipe@2 = properties_of(Def),
                gleam@list:filter_map(
                    _pipe@2,
                    fun(Field) -> case union_of(erlang:element(3, Field)) of
                            {some, {Refs, Closed}} ->
                                {ok, {union_unit, Def, Field, Refs, Closed}};

                            none ->
                                {error, nil}
                        end end
                )
            end,
            [{def_unit, Def} | Unions]
        end
    ).