-module(pig@session_store).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/pig/session_store.gleam").
-export([new_commit/2]).
-export_type([session_error/0, session/0, session_commit/0, session_store/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(" Durable session storage types for atomic agent-state transitions.\n").

-type session_error() :: {unavailable, binary()} |
    {corrupt, binary()} |
    {parent_conflict,
        gleam@option:option(binary()),
        gleam@option:option(binary())} |
    {invalid_commit, binary()}.

-type session() :: {session,
        gleam@option:option(binary()),
        list(pig_protocol@message:message())}.

-type session_commit() :: {session_commit,
        binary(),
        gleam@option:option(binary()),
        list(pig_protocol@message:message())}.

-type session_store() :: {session_store,
        fun(() -> {ok, session()} | {error, session_error()}),
        fun((session_commit()) -> {ok, session()} | {error, session_error()})}.

-file("src/pig/session_store.gleam", 34).
?DOC(
    " Create a commit with a fresh opaque ID, its expected parent, and its delta.\n"
    "\n"
    " The ID is generated independently of the messages, so commits with identical\n"
    " contents still have distinct identities.\n"
).
-spec new_commit(
    gleam@option:option(binary()),
    list(pig_protocol@message:message())
) -> session_commit().
new_commit(Parent, Messages) ->
    {session_commit,
        <<"commit-"/utf8,
            (gleam@bit_array:base64_url_encode(
                crypto:strong_rand_bytes(16),
                false
            ))/binary>>,
        Parent,
        Messages}.