-module(galchemy@orm@loading).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src\\galchemy\\orm\\loading.gleam").
-export([joinedload/2, selectinload/2, 'query'/1, apply/3, selectin_queries/2]).
-export_type([loader_option/0, select_in_plan/0, applied_options/0, loading_error/0]).

-type loader_option() :: {joined_load, binary(), galchemy@orm@query:model_ref()} |
    {select_in_load, binary(), galchemy@orm@query:model_ref()}.

-type select_in_plan() :: {select_in_plan,
        galchemy@orm@query:model_ref(),
        galchemy@schema@relation:relation(),
        galchemy@orm@query:model_ref()}.

-type applied_options() :: {applied_options,
        galchemy@ast@expression:select_query(),
        list(select_in_plan())}.

-type loading_error() :: {query_error, galchemy@orm@query:query_error()} |
    {missing_parent_field,
        galchemy@schema@relation:table_ref(),
        binary(),
        binary()}.

-file("src\\galchemy\\orm\\loading.gleam", 38).
-spec joinedload(binary(), galchemy@orm@query:model_ref()) -> loader_option().
joinedload(Relation_name, Related_model) ->
    {joined_load, Relation_name, Related_model}.

-file("src\\galchemy\\orm\\loading.gleam", 45).
-spec selectinload(binary(), galchemy@orm@query:model_ref()) -> loader_option().
selectinload(Relation_name, Related_model) ->
    {select_in_load, Relation_name, Related_model}.

-file("src\\galchemy\\orm\\loading.gleam", 60).
-spec 'query'(applied_options()) -> galchemy@ast@expression:select_query().
'query'(Applied) ->
    erlang:element(2, Applied).

-file("src\\galchemy\\orm\\loading.gleam", 306).
-spec relation_plan(
    galchemy@orm@query:model_ref(),
    binary(),
    galchemy@orm@query:model_ref()
) -> {ok, galchemy@schema@relation:relation()} |
    {error, galchemy@orm@query:query_error()}.
relation_plan(Parent_model, Relation_name, Related_model) ->
    case galchemy@orm@metadata:relation_named(
        erlang:element(2, Parent_model),
        Relation_name
    ) of
        none ->
            {error,
                {unknown_relation,
                    erlang:element(2, erlang:element(2, Parent_model)),
                    Relation_name}};

        {some, Next_relation} ->
            case erlang:element(5, Next_relation) =:= erlang:element(
                2,
                erlang:element(2, Related_model)
            ) of
                true ->
                    {ok, Next_relation};

                false ->
                    {error,
                        {related_table_mismatch,
                            erlang:element(2, Next_relation),
                            erlang:element(5, Next_relation),
                            erlang:element(2, erlang:element(2, Related_model))}}
            end
    end.

-file("src\\galchemy\\orm\\loading.gleam", 330).
-spec find_field(list(galchemy@session@unit_of_work:field_value()), binary()) -> gleam@option:option(galchemy@ast@expression:sql_value()).
find_field(Fields, Column_name) ->
    case Fields of
        [] ->
            none;

        [Field_value | Rest] ->
            case erlang:element(2, Field_value) =:= Column_name of
                true ->
                    {some, erlang:element(3, Field_value)};

                false ->
                    find_field(Rest, Column_name)
            end
    end.

-file("src\\galchemy\\orm\\loading.gleam", 289).
-spec parent_field_value(
    galchemy@orm@query:model_ref(),
    binary(),
    galchemy@orm@entity:entity(),
    binary()
) -> {ok, galchemy@ast@expression:sql_value()} | {error, loading_error()}.
parent_field_value(Parent_model, Relation_name, Parent, Column_name) ->
    case find_field(galchemy@orm@entity:fields(Parent), Column_name) of
        {some, Value} ->
            {ok, Value};

        none ->
            {error,
                {missing_parent_field,
                    erlang:element(2, erlang:element(2, Parent_model)),
                    Relation_name,
                    Column_name}}
    end.

-file("src\\galchemy\\orm\\loading.gleam", 345).
-spec map_query_error({ok, PCB} | {error, galchemy@orm@query:query_error()}) -> {ok,
        PCB} |
    {error, loading_error()}.
map_query_error(Value) ->
    case Value of
        {ok, Inner} ->
            {ok, Inner};

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

-file("src\\galchemy\\orm\\loading.gleam", 354).
-spec result_try(
    {ok, PCG} | {error, PCH},
    fun((PCG) -> {ok, PCK} | {error, PCH})
) -> {ok, PCK} | {error, PCH}.
result_try(Value, Next) ->
    case Value of
        {ok, Inner} ->
            Next(Inner);

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

-file("src\\galchemy\\orm\\loading.gleam", 71).
-spec apply_loop(
    galchemy@ast@expression:select_query(),
    galchemy@orm@query:model_ref(),
    list(loader_option()),
    list(select_in_plan())
) -> {ok, applied_options()} | {error, loading_error()}.
apply_loop(Query, Parent_model, Options, Select_in) ->
    case Options of
        [] ->
            {ok, {applied_options, Query, lists:reverse(Select_in)}};

        [Next_option | Rest] ->
            case Next_option of
                {joined_load, Relation_name, Related_model} ->
                    result_try(
                        begin
                            _pipe = galchemy@orm@query:left_join_relation(
                                Query,
                                Parent_model,
                                Relation_name,
                                Related_model
                            ),
                            map_query_error(_pipe)
                        end,
                        fun(Next_query) ->
                            apply_loop(
                                Next_query,
                                Parent_model,
                                Rest,
                                Select_in
                            )
                        end
                    );

                {select_in_load, Relation_name@1, Related_model@1} ->
                    result_try(
                        begin
                            _pipe@1 = relation_plan(
                                Parent_model,
                                Relation_name@1,
                                Related_model@1
                            ),
                            map_query_error(_pipe@1)
                        end,
                        fun(Next_relation) ->
                            apply_loop(
                                Query,
                                Parent_model,
                                Rest,
                                [{select_in_plan,
                                        Parent_model,
                                        Next_relation,
                                        Related_model@1} |
                                    Select_in]
                            )
                        end
                    )
            end
    end.

-file("src\\galchemy\\orm\\loading.gleam", 52).
-spec apply(
    galchemy@ast@expression:select_query(),
    galchemy@orm@query:model_ref(),
    list(loader_option())
) -> {ok, applied_options()} | {error, loading_error()}.
apply(Query, Parent_model, Options) ->
    apply_loop(Query, Parent_model, Options, []).

-file("src\\galchemy\\orm\\loading.gleam", 265).
-spec pair_predicate(
    galchemy@orm@query:model_ref(),
    galchemy@schema@relation:relation(),
    galchemy@orm@query:model_ref(),
    galchemy@orm@entity:entity(),
    galchemy@schema@relation:column_pair()
) -> {ok, galchemy@ast@expression:predicate()} | {error, loading_error()}.
pair_predicate(Parent_model, Next_relation, Related_model, Parent, Next_pair) ->
    result_try(
        parent_field_value(
            Parent_model,
            erlang:element(2, Next_relation),
            Parent,
            erlang:element(2, Next_pair)
        ),
        fun(Value) ->
            {ok,
                {comparison,
                    {column_expr,
                        {column_meta,
                            erlang:element(3, Related_model),
                            erlang:element(3, Next_pair)}},
                    eq,
                    {value_expr, Value}}}
        end
    ).

-file("src\\galchemy\\orm\\loading.gleam", 234).
-spec parent_predicate_rest(
    galchemy@orm@query:model_ref(),
    galchemy@schema@relation:relation(),
    galchemy@orm@query:model_ref(),
    galchemy@orm@entity:entity(),
    list(galchemy@schema@relation:column_pair()),
    galchemy@ast@expression:predicate()
) -> {ok, galchemy@ast@expression:predicate()} | {error, loading_error()}.
parent_predicate_rest(
    Parent_model,
    Next_relation,
    Related_model,
    Parent,
    Pairs,
    Acc
) ->
    case Pairs of
        [] ->
            {ok, Acc};

        [Next_pair | Rest] ->
            result_try(
                pair_predicate(
                    Parent_model,
                    Next_relation,
                    Related_model,
                    Parent,
                    Next_pair
                ),
                fun(Next_predicate) ->
                    parent_predicate_rest(
                        Parent_model,
                        Next_relation,
                        Related_model,
                        Parent,
                        Rest,
                        {'and', Acc, Next_predicate}
                    )
                end
            )
    end.

-file("src\\galchemy\\orm\\loading.gleam", 205).
-spec parent_predicate(
    galchemy@orm@query:model_ref(),
    galchemy@schema@relation:relation(),
    galchemy@orm@query:model_ref(),
    galchemy@orm@entity:entity()
) -> {ok, galchemy@ast@expression:predicate()} | {error, loading_error()}.
parent_predicate(Parent_model, Next_relation, Related_model, Parent) ->
    case erlang:element(6, Next_relation) of
        [] ->
            erlang:error(#{gleam_error => panic,
                    message => <<"relation metadata requires at least one column pair"/utf8>>,
                    file => <<?FILEPATH/utf8>>,
                    module => <<"galchemy/orm/loading"/utf8>>,
                    function => <<"parent_predicate"/utf8>>,
                    line => 212});

        [First_pair | Rest] ->
            result_try(
                pair_predicate(
                    Parent_model,
                    Next_relation,
                    Related_model,
                    Parent,
                    First_pair
                ),
                fun(Initial) ->
                    parent_predicate_rest(
                        Parent_model,
                        Next_relation,
                        Related_model,
                        Parent,
                        Rest,
                        Initial
                    )
                end
            )
    end.

-file("src\\galchemy\\orm\\loading.gleam", 177).
-spec selectin_predicate_rest(
    galchemy@orm@query:model_ref(),
    galchemy@schema@relation:relation(),
    galchemy@orm@query:model_ref(),
    list(galchemy@orm@entity:entity()),
    galchemy@ast@expression:predicate()
) -> {ok, galchemy@ast@expression:predicate()} | {error, loading_error()}.
selectin_predicate_rest(
    Parent_model,
    Next_relation,
    Related_model,
    Parents,
    Acc
) ->
    case Parents of
        [] ->
            {ok, Acc};

        [Next_parent | Rest] ->
            result_try(
                parent_predicate(
                    Parent_model,
                    Next_relation,
                    Related_model,
                    Next_parent
                ),
                fun(Next_predicate) ->
                    selectin_predicate_rest(
                        Parent_model,
                        Next_relation,
                        Related_model,
                        Rest,
                        {'or', Acc, Next_predicate}
                    )
                end
            )
    end.

-file("src\\galchemy\\orm\\loading.gleam", 150).
-spec selectin_predicate(
    galchemy@orm@query:model_ref(),
    galchemy@schema@relation:relation(),
    galchemy@orm@query:model_ref(),
    list(galchemy@orm@entity:entity())
) -> {ok, galchemy@ast@expression:predicate()} | {error, loading_error()}.
selectin_predicate(Parent_model, Next_relation, Related_model, Parents) ->
    case Parents of
        [] ->
            erlang:error(#{gleam_error => panic,
                    message => <<"selectin predicate requires at least one parent"/utf8>>,
                    file => <<?FILEPATH/utf8>>,
                    module => <<"galchemy/orm/loading"/utf8>>,
                    function => <<"selectin_predicate"/utf8>>,
                    line => 157});

        [First_parent | Rest] ->
            result_try(
                parent_predicate(
                    Parent_model,
                    Next_relation,
                    Related_model,
                    First_parent
                ),
                fun(Initial) ->
                    selectin_predicate_rest(
                        Parent_model,
                        Next_relation,
                        Related_model,
                        Rest,
                        Initial
                    )
                end
            )
    end.

-file("src\\galchemy\\orm\\loading.gleam", 128).
-spec selectin_query(select_in_plan(), list(galchemy@orm@entity:entity())) -> {ok,
        galchemy@ast@query:'query'()} |
    {error, loading_error()}.
selectin_query(Plan, Parents) ->
    case Parents of
        [] ->
            {ok,
                {select, galchemy@orm@query:select_all(erlang:element(4, Plan))}};

        _ ->
            result_try(
                selectin_predicate(
                    erlang:element(2, Plan),
                    erlang:element(3, Plan),
                    erlang:element(4, Plan),
                    Parents
                ),
                fun(Where_) ->
                    {ok,
                        {select,
                            begin
                                _pipe = galchemy@orm@query:select_all(
                                    erlang:element(4, Plan)
                                ),
                                galchemy@orm@query:where_(_pipe, Where_)
                            end}}
                end
            )
    end.

-file("src\\galchemy\\orm\\loading.gleam", 114).
-spec build_selectin_queries(
    list(select_in_plan()),
    list(galchemy@orm@entity:entity()),
    list(galchemy@ast@query:'query'())
) -> {ok, list(galchemy@ast@query:'query'())} | {error, loading_error()}.
build_selectin_queries(Plans, Parents, Acc) ->
    case Plans of
        [] ->
            {ok, lists:reverse(Acc)};

        [Next_plan | Rest] ->
            result_try(
                selectin_query(Next_plan, Parents),
                fun(Next_query) ->
                    build_selectin_queries(Rest, Parents, [Next_query | Acc])
                end
            )
    end.

-file("src\\galchemy\\orm\\loading.gleam", 64).
-spec selectin_queries(applied_options(), list(galchemy@orm@entity:entity())) -> {ok,
        list(galchemy@ast@query:'query'())} |
    {error, loading_error()}.
selectin_queries(Applied, Parents) ->
    build_selectin_queries(erlang:element(3, Applied), Parents, []).