-module(kv_sessions@session).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([generate_id/0, id_to_string/1, id_from_string/1, expiry_to_date/1, builder_from/1, builder/0, with_id/2, with_id_string/2, with_expiry/2, with_expires_at/2, with_data/2, with_entry/3, build/1]).
-export_type([session_error/0, session_id/0, session/0, expiry/0, session_builder/0]).

-type session_error() :: unknown_error |
    decode_error |
    db_setup_error |
    {db_error_insert_error, binary()} |
    {db_error_get_error, binary()} |
    {db_error_delete_error, binary()} |
    {deserialize_error, binary()} |
    session_expired_error |
    no_session_error.

-opaque session_id() :: {session_id, binary()}.

-type session() :: {session,
        session_id(),
        {{integer(), integer(), integer()}, {integer(), integer(), integer()}},
        gleam@dict:dict(binary(), binary())}.

-type expiry() :: {expire_at, birl:time()} | {expire_in, integer()}.

-type session_builder() :: {session_builder,
        session_id(),
        gleam@option:option(expiry()),
        gleam@dict:dict(binary(), binary())}.

-spec generate_id() -> session_id().
generate_id() ->
    {session_id, wisp:random_string(200)}.

-spec id_to_string(session_id()) -> binary().
id_to_string(Id) ->
    case Id of
        {session_id, Id_string} ->
            Id_string
    end.

-spec id_from_string(binary()) -> session_id().
id_from_string(Id) ->
    {session_id, Id}.

-spec expiry_to_date(expiry()) -> {{integer(), integer(), integer()},
    {integer(), integer(), integer()}}.
expiry_to_date(Expiry) ->
    _pipe@1 = case Expiry of
        {expire_at, Time} ->
            Time;

        {expire_in, Seconds} ->
            _pipe = birl:now(),
            birl:add(_pipe, birl@duration:seconds(Seconds))
    end,
    birl:to_erlang_universal_datetime(_pipe@1).

-spec builder_from(session()) -> session_builder().
builder_from(Session) ->
    {session_builder,
        erlang:element(2, Session),
        {some,
            {expire_at,
                birl:from_erlang_universal_datetime(erlang:element(3, Session))}},
        erlang:element(4, Session)}.

-spec builder() -> session_builder().
builder() ->
    {session_builder, generate_id(), none, gleam@dict:new()}.

-spec with_id(session_builder(), session_id()) -> session_builder().
with_id(Session, Id) ->
    erlang:setelement(2, Session, Id).

-spec with_id_string(session_builder(), binary()) -> session_builder().
with_id_string(Session, Id) ->
    erlang:setelement(2, Session, {session_id, Id}).

-spec with_expiry(session_builder(), expiry()) -> session_builder().
with_expiry(Session, Expiry) ->
    erlang:setelement(3, Session, {some, Expiry}).

-spec with_expires_at(session_builder(), birl:time()) -> session_builder().
with_expires_at(Session, Expires_at) ->
    erlang:setelement(3, Session, {some, {expire_at, Expires_at}}).

-spec with_data(session_builder(), gleam@dict:dict(binary(), binary())) -> session_builder().
with_data(Session, Data) ->
    erlang:setelement(4, Session, Data).

-spec with_entry(session_builder(), binary(), binary()) -> session_builder().
with_entry(Session, Key, Data) ->
    erlang:setelement(
        4,
        Session,
        gleam@dict:insert(erlang:element(4, Session), Key, Data)
    ).

-spec build(session_builder()) -> session().
build(Session) ->
    Expiry = gleam@option:unwrap(
        erlang:element(3, Session),
        {expire_in, 60 * 60}
    ),
    {session,
        erlang:element(2, Session),
        expiry_to_date(Expiry),
        erlang:element(4, Session)}.