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

-export([to_sql/3, to_postgresql/1]).
-export_type([query_error/0, 'query'/0, value/0, query_value/0, condition/0, case_sensitivity/0, direction/0]).

-type query_error() :: {constraint_violation, binary(), binary()} |
    {database_error, binary()}.

-type 'query'() :: {select,
        binary(),
        list({gleam@option:option(binary()), binary()}),
        {binary(), direction()},
        integer(),
        integer(),
        list(condition())} |
    {update, binary(), list({binary(), query_value()}), list(condition())} |
    {delete, binary(), list(condition())}.

-type value() :: {text_value, binary()} |
    {int_value, integer()} |
    {float_value, float()} |
    null_value.

-type query_value() :: {relation_value, gleam@option:option(binary()), binary()} |
    {parameter, integer()}.

-type condition() :: {equal, query_value(), query_value()} |
    {string_contains, query_value(), query_value(), case_sensitivity()} |
    {'or', list(condition())}.

-type case_sensitivity() :: case_sensitive | case_insensitive.

-type direction() :: ascending | descending.

-spec escape_name(binary(), binary()) -> binary().
escape_name(Name, Quote) ->
    <<<<"\""/utf8, (gleam@string:replace(Name, <<"\""/utf8>>, Quote))/binary>>/binary,
        "\""/utf8>>.

-spec value_to_sql(binary(), query_value(), binary(), binary()) -> binary().
value_to_sql(Query, Value, Param, Quote) ->
    case Value of
        {relation_value, none, Column} ->
            <<Query/binary, (escape_name(Column, Quote))/binary>>;

        {relation_value, {some, Table}, Column@1} ->
            <<<<<<Query/binary, (escape_name(Table, Quote))/binary>>/binary,
                    "."/utf8>>/binary,
                (escape_name(Column@1, Quote))/binary>>;

        {parameter, Index} ->
            <<<<Query/binary, Param/binary>>/binary,
                (gleam@int:to_string(Index))/binary>>
    end.

-spec updates_to_sql(
    binary(),
    list({binary(), query_value()}),
    boolean(),
    binary(),
    binary()
) -> binary().
updates_to_sql(Query, Updates, First, Param, Quote) ->
    case Updates of
        [] ->
            Query;

        [{Name, Value} | Updates@1] ->
            Query@1 = case First of
                true ->
                    <<Query/binary, " set "/utf8>>;

                false ->
                    <<Query/binary, ", "/utf8>>
            end,
            Query@2 = <<<<Query@1/binary, (escape_name(Name, Quote))/binary>>/binary,
                " = "/utf8>>,
            Query@3 = value_to_sql(Query@2, Value, Param, Quote),
            updates_to_sql(Query@3, Updates@1, false, Param, Quote)
    end.

-spec condition_to_sql(binary(), condition(), binary(), binary()) -> binary().
condition_to_sql(Query, Condition, Param, Quote) ->
    case Condition of
        {'or', Conditions} ->
            gleam@list:index_fold(
                Conditions,
                Query,
                fun(Query@1, Condition@1, I) ->
                    Query@2 = case I of
                        0 ->
                            Query@1;

                        _ ->
                            <<Query@1/binary, " or "/utf8>>
                    end,
                    <<(condition_to_sql(
                            <<Query@2/binary, "("/utf8>>,
                            Condition@1,
                            Param,
                            Quote
                        ))/binary,
                        ")"/utf8>>
                end
            );

        {equal, Left, Right} ->
            Query@3 = <<(value_to_sql(Query, Left, Param, Quote))/binary,
                " = "/utf8>>,
            value_to_sql(Query@3, Right, Param, Quote);

        {string_contains, Left@1, Right@1, Sensitivity} ->
            Query@4 = value_to_sql(Query, Left@1, Param, Quote),
            Query@5 = case Sensitivity of
                case_sensitive ->
                    <<Query@4/binary, " like '%'||"/utf8>>;

                case_insensitive ->
                    <<Query@4/binary, " ilike '%'||"/utf8>>
            end,
            <<(value_to_sql(Query@5, Right@1, Param, Quote))/binary,
                "||'%'"/utf8>>
    end.

-spec conditions_to_sql(
    binary(),
    list(condition()),
    boolean(),
    binary(),
    binary()
) -> binary().
conditions_to_sql(Query, Conditions, First, Param, Quote) ->
    case Conditions of
        [] ->
            Query;

        [Condition | Conditions@1] ->
            Query@1 = case First of
                true ->
                    <<Query/binary, " where "/utf8>>;

                false ->
                    <<Query/binary, " and "/utf8>>
            end,
            Query@2 = condition_to_sql(Query@1, Condition, Param, Quote),
            conditions_to_sql(Query@2, Conditions@1, false, Param, Quote)
    end.

-spec select_column(binary(), gleam@option:option(binary()), binary(), binary()) -> binary().
select_column(Query, Table, Column, Quote) ->
    case Table of
        none ->
            <<Query/binary, (escape_name(Column, Quote))/binary>>;

        {some, Table@1} ->
            <<<<<<Query/binary, (escape_name(Table@1, Quote))/binary>>/binary,
                    "."/utf8>>/binary,
                (escape_name(Column, Quote))/binary>>
    end.

-spec select_columns(
    binary(),
    list({gleam@option:option(binary()), binary()}),
    boolean(),
    binary()
) -> binary().
select_columns(Query, Names, First, Quote) ->
    case Names of
        [] ->
            Query;

        [{Table, Column} | Names@1] when First ->
            Query@1 = select_column(Query, Table, Column, Quote),
            select_columns(Query@1, Names@1, false, Quote);

        [{Table@1, Column@1} | Names@2] ->
            Query@2 = select_column(
                <<Query/binary, ", "/utf8>>,
                Table@1,
                Column@1,
                Quote
            ),
            select_columns(Query@2, Names@2, false, Quote)
    end.

-spec to_sql('query'(), binary(), binary()) -> binary().
to_sql(Query, Param, Quote) ->
    case Query of
        {delete, Table, Conditions} ->
            Query@1 = <<"delete from "/utf8,
                (escape_name(Table, Quote))/binary>>,
            conditions_to_sql(Query@1, Conditions, true, Param, Quote);

        {update, Table@1, Updates, Conditions@1} ->
            Query@2 = <<"update "/utf8, (escape_name(Table@1, Quote))/binary>>,
            Query@3 = updates_to_sql(Query@2, Updates, true, Param, Quote),
            conditions_to_sql(Query@3, Conditions@1, true, Param, Quote);

        {select,
            Table@2,
            Columns,
            {Order_by_column, Direction},
            Limit,
            Offset,
            Conditions@2} ->
            Query@4 = select_columns(<<"select "/utf8>>, Columns, true, Quote),
            Query@5 = <<<<Query@4/binary, " from "/utf8>>/binary,
                (escape_name(Table@2, Quote))/binary>>,
            Query@6 = conditions_to_sql(
                Query@5,
                Conditions@2,
                true,
                Param,
                Quote
            ),
            Query@7 = <<<<Query@6/binary, " order by "/utf8>>/binary,
                (escape_name(Order_by_column, Quote))/binary>>,
            Query@8 = case Direction of
                ascending ->
                    <<Query@7/binary, " asc"/utf8>>;

                descending ->
                    <<Query@7/binary, " desc"/utf8>>
            end,
            Query@9 = <<<<Query@8/binary, " limit "/utf8>>/binary,
                (gleam@int:to_string(Limit))/binary>>,
            case Offset of
                0 ->
                    Query@9;

                _ ->
                    <<<<Query@9/binary, " offset "/utf8>>/binary,
                        (gleam@int:to_string(Offset))/binary>>
            end
    end.

-spec to_postgresql('query'()) -> binary().
to_postgresql(Query) ->
    to_sql(Query, <<"$"/utf8>>, <<"\""/utf8>>).