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

-export([prepare/1, run/2]).
-export_type([handles_error/0, template/0]).

-type handles_error() :: {lex_error, handles@lexer:lex_error()} |
    {parse_error, list(handles@parser:parse_error())} |
    {runtime_error, handles@engine:runtime_error()}.

-type template() :: {template, list(handles@parser:ast())}.

-spec prepare(binary()) -> {ok, template()} | {error, handles_error()}.
prepare(Template) ->
    gleam@result:'try'(
        gleam@result:map_error(
            handles@lexer:run(Template),
            fun(Field@0) -> {lex_error, Field@0} end
        ),
        fun(Tokens) ->
            gleam@result:'try'(
                gleam@result:map_error(
                    handles@parser:run(
                        Tokens,
                        [<<"if"/utf8>>, <<"unless"/utf8>>, <<"each"/utf8>>]
                    ),
                    fun(Err) -> {parse_error, Err} end
                ),
                fun(Ast) -> {ok, {template, Ast}} end
            )
        end
    ).

-spec run(template(), gleam@dynamic:dynamic_()) -> {ok, binary()} |
    {error, handles_error()}.
run(Template, Ctx) ->
    {template, Ast} = Template,
    _pipe = handles@engine:run(Ast, Ctx),
    gleam@result:map_error(_pipe, fun(Field@0) -> {runtime_error, Field@0} end).