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

-export([run/2]).
-export_type([ast/0]).

-type ast() :: {constant, integer(), binary()} |
    {property, integer(), list(binary())} |
    {if_block, integer(), list(binary()), list(ast())} |
    {unless_block, integer(), list(binary()), list(ast())} |
    {each_block, integer(), list(binary()), list(ast())}.

-spec run(list(handles@internal@tokenizer:token()), list(ast())) -> list(ast()).
run(Tokens, Ast) ->
    case Tokens of
        [] ->
            lists:reverse(Ast);

        [Head | Tail] ->
            case Head of
                {constant, Index, Value} ->
                    run(Tail, [{constant, Index, Value} | Ast]);

                {property, Index@1, Path} ->
                    run(Tail, [{property, Index@1, Path} | Ast]);

                {if_block_start, Index@2, Path@1} ->
                    Children = run(Tail, []),
                    run(
                        gleam@list:drop(Tail, erlang:length(Children) + 1),
                        [{if_block, Index@2, Path@1, Children} | Ast]
                    );

                {unless_block_start, Index@3, Path@2} ->
                    Children@1 = run(Tail, []),
                    run(
                        gleam@list:drop(Tail, erlang:length(Children@1) + 1),
                        [{unless_block, Index@3, Path@2, Children@1} | Ast]
                    );

                {each_block_start, Index@4, Path@3} ->
                    Children@2 = run(Tail, []),
                    run(
                        gleam@list:drop(Tail, erlang:length(Children@2) + 1),
                        [{each_block, Index@4, Path@3, Children@2} | Ast]
                    );

                {if_block_end, _} ->
                    lists:reverse(Ast);

                {unless_block_end, _} ->
                    lists:reverse(Ast);

                {each_block_end, _} ->
                    lists:reverse(Ast)
            end
    end.