toon_codec

-module(toon_codec@encode@internal).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/toon_codec/encode/internal.gleam").
-export([is_primitive/1, is_object/1, is_array/1, is_array_of_primitives/1, is_array_of_arrays/1, is_array_of_objects/1, all_arrays_of_primitives/1, all_values_primitive/1, detect_tabular/1, extract_field_values/2]).

-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(
    " Internal utilities for array structure detection.\n"
    "\n"
    " This module provides functions to analyze arrays and determine\n"
    " whether they should be encoded as inline, tabular, or expanded form.\n"
    " Check if a JSON value is a primitive (not array or object).\n"
    " Check if a JSON value is an object.\n"
    " Check if a JSON value is an array.\n"
    " Check if all values in a list are primitives.\n"
    "\n"
    " Returns True if the list is empty or all elements are primitives.\n"
    " Check if all values in a list are arrays.\n"
    " Check if all values in a list are objects.\n"
    " Check if all arrays in a list contain only primitives.\n"
    "\n"
    " Used to detect arrays of primitive arrays.\n"
    " Detect if an array of objects can be encoded in tabular form.\n"
    "\n"
    " Returns Some(fields) if tabular encoding is possible, where fields\n"
    " is the ordered list of field names. Returns None otherwise.\n"
    "\n"
    " Tabular encoding requires:\n"
    " 1. All elements are objects\n"
    " 2. All objects have the same set of keys\n"
    " 3. All values in all objects are primitives (no nested structures)\n"
    "\n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " let objects = [\n"
    "   Object([#(\"id\", Number(1.0)), #(\"name\", JsonString(\"Alice\"))]),\n"
    "   Object([#(\"id\", Number(2.0)), #(\"name\", JsonString(\"Bob\"))]),\n"
    " ]\n"
    " detect_tabular(objects)\n"
    " // -> Some([\"id\", \"name\"])\n"
    " ```\n"
    " Check if all values in an object are primitives.\n"
    " Check if all objects in a list have the same keys and all primitive values.\n"
    " Extract field values from an object in a specified order.\n"
    "\n"
    " Returns the values corresponding to the given field names,\n"
    " in the same order as the field names list.\n"
    "\n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " let obj = Object([#(\"name\", JsonString(\"Alice\")), #(\"id\", Number(1.0))])\n"
    " extract_field_values(obj, [\"id\", \"name\"])\n"
    " // -> [Number(1.0), JsonString(\"Alice\")]\n"
    " ```\n"
).

-file("src/toon_codec/encode/internal.gleam", 60).
-spec is_primitive(toon_codec@types:json_value()) -> boolean().
is_primitive(Value) ->
    case Value of
        null ->
            true;

        {bool, _} ->
            true;

        {number, _} ->
            true;

        {string, _} ->
            true;

        {array, _} ->
            false;

        {object, _} ->
            false
    end.

-file("src/toon_codec/encode/internal.gleam", 67).
-spec is_object(toon_codec@types:json_value()) -> boolean().
is_object(Value) ->
    case Value of
        {object, _} ->
            true;

        _ ->
            false
    end.

-file("src/toon_codec/encode/internal.gleam", 74).
-spec is_array(toon_codec@types:json_value()) -> boolean().
is_array(Value) ->
    case Value of
        {array, _} ->
            true;

        _ ->
            false
    end.

-file("src/toon_codec/encode/internal.gleam", 83).
-spec is_array_of_primitives(list(toon_codec@types:json_value())) -> boolean().
is_array_of_primitives(Values) ->
    gleam@list:all(Values, fun is_primitive/1).

-file("src/toon_codec/encode/internal.gleam", 87).
-spec is_array_of_arrays(list(toon_codec@types:json_value())) -> boolean().
is_array_of_arrays(Values) ->
    case Values of
        [] ->
            false;

        _ ->
            gleam@list:all(Values, fun is_array/1)
    end.

-file("src/toon_codec/encode/internal.gleam", 94).
-spec is_array_of_objects(list(toon_codec@types:json_value())) -> boolean().
is_array_of_objects(Values) ->
    case Values of
        [] ->
            false;

        _ ->
            gleam@list:all(Values, fun is_object/1)
    end.

-file("src/toon_codec/encode/internal.gleam", 101).
-spec all_arrays_of_primitives(list(toon_codec@types:json_value())) -> boolean().
all_arrays_of_primitives(Values) ->
    gleam@list:all(Values, fun(Value) -> case Value of
                {array, Items} ->
                    is_array_of_primitives(Items);

                _ ->
                    false
            end end).

-file("src/toon_codec/encode/internal.gleam", 135).
-spec all_values_primitive(list({binary(), toon_codec@types:json_value()})) -> boolean().
all_values_primitive(Fields) ->
    gleam@list:all(
        Fields,
        fun(Pair) -> is_primitive(erlang:element(2, Pair)) end
    ).

-file("src/toon_codec/encode/internal.gleam", 139).
-spec check_uniform_objects(list(toon_codec@types:json_value()), list(binary())) -> boolean().
check_uniform_objects(Objects, Expected_keys) ->
    gleam@list:all(Objects, fun(Obj) -> case Obj of
                {object, Fields} ->
                    Keys = gleam@list:map(
                        Fields,
                        fun(Pair) -> erlang:element(1, Pair) end
                    ),
                    Keys_set = gleam@set:from_list(Keys),
                    Expected_set = gleam@set:from_list(Expected_keys),
                    (Keys_set =:= Expected_set) andalso all_values_primitive(
                        Fields
                    );

                _ ->
                    false
            end end).

-file("src/toon_codec/encode/internal.gleam", 112).
-spec detect_tabular(list(toon_codec@types:json_value())) -> gleam@option:option(list(binary())).
detect_tabular(Values) ->
    case Values of
        [] ->
            none;

        [{object, First_fields} | Rest] ->
            First_keys = gleam@list:map(
                First_fields,
                fun(Pair) -> erlang:element(1, Pair) end
            ),
            case all_values_primitive(First_fields) of
                false ->
                    none;

                true ->
                    case check_uniform_objects(Rest, First_keys) of
                        true ->
                            {some, First_keys};

                        false ->
                            none
                    end
            end;

        _ ->
            none
    end.

-file("src/toon_codec/encode/internal.gleam", 160).
-spec extract_field_values(toon_codec@types:json_value(), list(binary())) -> list(toon_codec@types:json_value()).
extract_field_values(Obj, Field_names) ->
    case Obj of
        {object, Fields} ->
            gleam@list:map(
                Field_names,
                fun(Name) -> case gleam@list:key_find(Fields, Name) of
                        {ok, Value} ->
                            Value;

                        {error, _} ->
                            null
                    end end
            );

        _ ->
            []
    end.