-module(libero@remote_data).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/libero/remote_data.gleam").
-export([map/2, map_error/2, unwrap/2, to_option/1, is_success/1, is_loading/1, to_remote/2, to_result/2]).
-export_type([remote_data/2, rpc_failure/0]).

-if(?OTP_RELEASE >= 27).
-define(MODULEDOC(Str), -moduledoc(Str)).
-define(DOC(Str), -doc(Str)).
-else.
-define(MODULEDOC(Str), -compile([])).
-define(DOC(Str), -compile([])).
-endif.

?MODULEDOC(
    " Typed states for async data loading.\n"
    " Inspired by Elm's RemoteData package.\n"
    "\n"
    " Use instead of Bool flags + Option fields for data that loads asynchronously.\n"
    " The view pattern matches directly on the state - impossible to show stale\n"
    " data while loading or forget to handle errors.\n"
    "\n"
    " `to_remote` is the bridge from a libero RPC response (a Dynamic value\n"
    " shipped from the server) to a `RemoteData` value the page stores in\n"
    " its model. It collapses three wire outcomes - domain success, domain\n"
    " failure, framework failure - into the two post-response states\n"
    " (`Success` or `Failure`). The `NotAsked` and `Loading` states are\n"
    " page-lifecycle concerns the page sets itself in `init` and `update`.\n"
).

-type remote_data(WQW, WQX) :: not_asked |
    loading |
    {failure, WQX} |
    {success, WQW}.

-type rpc_failure() :: {domain_failure, binary()} |
    {framework_failure, binary()}.

-file("src/libero/remote_data.gleam", 35).
?DOC(" Apply a function to the success value.\n").
-spec map(remote_data(WQY, WQZ), fun((WQY) -> WRC)) -> remote_data(WRC, WQZ).
map(Data, Transform) ->
    case Data of
        not_asked ->
            not_asked;

        loading ->
            loading;

        {failure, Error} ->
            {failure, Error};

        {success, Value} ->
            {success, Transform(Value)}
    end.

-file("src/libero/remote_data.gleam", 48).
?DOC(" Apply a function to the error value.\n").
-spec map_error(remote_data(WRF, WRG), fun((WRG) -> WRJ)) -> remote_data(WRF, WRJ).
map_error(Data, Transform) ->
    case Data of
        not_asked ->
            not_asked;

        loading ->
            loading;

        {failure, Error} ->
            {failure, Transform(Error)};

        {success, Value} ->
            {success, Value}
    end.

-file("src/libero/remote_data.gleam", 61).
?DOC(" Extract the success value, or return a default.\n").
-spec unwrap(remote_data(WRM, any()), WRM) -> WRM.
unwrap(Data, Default) ->
    case Data of
        {success, Value} ->
            Value;

        _ ->
            Default
    end.

-file("src/libero/remote_data.gleam", 69).
?DOC(" Convert to Option - Some for Success, None for everything else.\n").
-spec to_option(remote_data(WRQ, any())) -> gleam@option:option(WRQ).
to_option(Data) ->
    case Data of
        {success, Value} ->
            {some, Value};

        _ ->
            none
    end.

-file("src/libero/remote_data.gleam", 77).
?DOC(" Check if the data is loaded successfully.\n").
-spec is_success(remote_data(any(), any())) -> boolean().
is_success(Data) ->
    case Data of
        {success, _} ->
            true;

        _ ->
            false
    end.

-file("src/libero/remote_data.gleam", 85).
?DOC(" Check if the data is currently loading.\n").
-spec is_loading(remote_data(any(), any())) -> boolean().
is_loading(Data) ->
    case Data of
        loading ->
            true;

        _ ->
            false
    end.

-file("src/libero/remote_data.gleam", 159).
?DOC(
    " Default formatter for framework-level RPC errors.\n"
    " Domain errors travel inside `Ok(Error(domain))` and are formatted\n"
    " by the caller's `format_domain` function.\n"
).
-spec format_rpc_error(libero@error:rpc_error(any())) -> rpc_failure().
format_rpc_error(Err) ->
    case Err of
        {app_error, _} ->
            {framework_failure, <<"Server application error"/utf8>>};

        {internal_error, _, Message} ->
            {framework_failure, Message};

        {unknown_function, Name} ->
            {framework_failure, <<"Unknown RPC: "/utf8, Name/binary>>};

        malformed_request ->
            {framework_failure, <<"Malformed request"/utf8>>}
    end.

-file("src/libero/remote_data.gleam", 103).
?DOC(
    " Convert a libero RPC response (Dynamic) into a `RemoteData` value.\n"
    "\n"
    " The server-side dispatch ships the full MsgFromServer envelope so the\n"
    " wire response is `Result(MsgFromServer.Variant(Result(payload, domain_err)), RpcError(app_err))`.\n"
    " This helper peels the MsgFromServer wrapper and collapses the result\n"
    " into the two post-response states.\n"
    "\n"
    " The `format_domain` callback formats domain errors (which the page\n"
    " owns and pattern-matches on its specific error type). Framework\n"
    " errors (internal, unknown function, malformed request, server\n"
    " AppError) are formatted by libero's default formatter.\n"
).
-spec to_remote(gleam@dynamic:dynamic_(), fun((any()) -> binary())) -> remote_data(any(), rpc_failure()).
to_remote(Raw, Format_domain) ->
    Outer = libero_ffi:identity(Raw),
    case Outer of
        {error, Rpc_err} ->
            {failure, format_rpc_error(Rpc_err)};

        {ok, Wrapped} ->
            Inner = libero_ffi:peel_msg_wrapper(Wrapped),
            Result = libero_ffi:identity(Inner),
            case Result of
                {ok, Payload} ->
                    {success, Payload};

                {error, Domain_err} ->
                    {failure, {domain_failure, Format_domain(Domain_err)}}
            end
    end.

-file("src/libero/remote_data.gleam", 142).
?DOC(
    " Adapter for action responses that the page wants as a flat `Result`\n"
    " rather than `RemoteData`. Useful when the response only feeds a flash\n"
    " message or triggers a redirect - the page never needs to render\n"
    " `NotAsked`/`Loading` states for the action result itself.\n"
).
-spec to_result(gleam@dynamic:dynamic_(), fun((any()) -> binary())) -> {ok,
        any()} |
    {error, rpc_failure()}.
to_result(Raw, Format_domain) ->
    case to_remote(Raw, Format_domain) of
        {success, Payload} ->
            {ok, Payload};

        {failure, Err} ->
            {error, Err};

        not_asked ->
            {error,
                {framework_failure,
                    <<"Unexpected response state: to_result called on a non-response"/utf8>>}};

        loading ->
            {error,
                {framework_failure,
                    <<"Unexpected response state: to_result called on a non-response"/utf8>>}}
    end.