-module(yodel@resolver).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/yodel/resolver.gleam").
-export([resolve_placeholders/2]).
-export_type([placeholder/0]).

-type placeholder() :: {placeholder,
        binary(),
        binary(),
        gleam@option:option(binary())}.

-file("src/yodel/resolver.gleam", 65).
-spec find_next_placeholder(binary(), gleam@regexp:regexp()) -> gleam@option:option(placeholder()).
find_next_placeholder(Value, Pattern) ->
    case gleam@regexp:scan(Pattern, Value) of
        [] ->
            none;

        [Match | _] ->
            case erlang:element(3, Match) of
                [{some, Env_var}, Default] ->
                    {some,
                        {placeholder,
                            erlang:element(2, Match),
                            Env_var,
                            Default}};

                [{some, Env_var@1}] ->
                    {some,
                        {placeholder, erlang:element(2, Match), Env_var@1, none}};

                _ ->
                    none
            end
    end.

-file("src/yodel/resolver.gleam", 79).
-spec resolve_placeholder(placeholder(), yodel@options:resolve_mode()) -> {ok,
        binary()} |
    {error, yodel@errors:config_error()}.
resolve_placeholder(Placeholder, Mode) ->
    case envoy_ffi:get(erlang:element(3, Placeholder)) of
        {ok, Value} ->
            {ok, Value};

        {error, _} ->
            case {erlang:element(4, Placeholder), Mode} of
                {{some, Default_value}, _} ->
                    {ok, Default_value};

                {none, lenient} ->
                    {ok, erlang:element(2, Placeholder)};

                {none, strict} ->
                    {error,
                        {resolver_error,
                            {unresolved_placeholder,
                                erlang:element(3, Placeholder),
                                erlang:element(2, Placeholder)}}}
            end
    end.

-file("src/yodel/resolver.gleam", 31).
-spec resolve_value(
    binary(),
    gleam@regexp:regexp(),
    yodel@options:resolve_mode(),
    list(binary())
) -> {ok, binary()} | {error, yodel@errors:config_error()}.
resolve_value(Value, Pattern, Mode, Attempted) ->
    case find_next_placeholder(Value, Pattern) of
        none ->
            {ok, Value};

        {some, Placeholder} ->
            case gleam@list:contains(Attempted, erlang:element(3, Placeholder)) of
                true ->
                    case Mode of
                        lenient ->
                            {ok, Value};

                        strict ->
                            {error,
                                {resolver_error,
                                    {unresolved_placeholder,
                                        erlang:element(3, Placeholder),
                                        erlang:element(2, Placeholder)}}}
                    end;

                false ->
                    gleam@result:'try'(
                        resolve_placeholder(Placeholder, Mode),
                        fun(Resolved) ->
                            Updated = gleam@string:replace(
                                Value,
                                erlang:element(2, Placeholder),
                                Resolved
                            ),
                            resolve_value(
                                Updated,
                                Pattern,
                                Mode,
                                [erlang:element(3, Placeholder) | Attempted]
                            )
                        end
                    )
            end
    end.

-file("src/yodel/resolver.gleam", 104).
-spec map_compile_error(gleam@regexp:compile_error()) -> yodel@errors:config_error().
map_compile_error(Error) ->
    {resolver_error,
        {regex_error,
            <<<<(erlang:element(2, Error))/binary, " at "/utf8>>/binary,
                (erlang:integer_to_binary(erlang:element(3, Error)))/binary>>}}.

-file("src/yodel/resolver.gleam", 100).
-spec compile_placeholder_regex() -> {ok, gleam@regexp:regexp()} |
    {error, yodel@errors:config_error()}.
compile_placeholder_regex() ->
    _pipe = gleam@regexp:from_string(
        <<"\\$\\{([^:}]+)(?::((?:[^${}]+|\\$\\{(?:[^{}]*\\{[^{}]*\\})*[^{}]*\\})*))?\\}"/utf8>>
    ),
    gleam@result:map_error(_pipe, fun map_compile_error/1).

-file("src/yodel/resolver.gleam", 19).
-spec resolve_placeholders(binary(), yodel@options:options()) -> {ok, binary()} |
    {error, yodel@errors:config_error()}.
resolve_placeholders(Input, Options) ->
    gleam@result:'try'(
        compile_placeholder_regex(),
        fun(Pattern) ->
            case resolve_value(
                Input,
                Pattern,
                yodel@options:get_resolve_mode(Options),
                []
            ) of
                {ok, Resolved_value} ->
                    {ok, Resolved_value};

                {error, E} ->
                    {error, E}
            end
        end
    ).