//! Live chat shared by Multithreaded forums and MNW stream pages.
//!
//! Design + decisions: maintainer wiki.
//! <!-- wiki: livechat-design -->
//!
//! A thin crate. It owns the message and event vocabulary, bounded retention,
//! and (as they land) the hub and SSE transport. It owns no schema, no authz, and
//! no moderation policy: those arrive through four traits the host implements, so
//! Multithreaded can gate on `CommunityScope` and the MNW server on
//! `SubscriptionGate` without either concept appearing here.
//!
//! # Shape
//!
//! SSE downstream, plain `POST` upstream. Not a WebSocket. The upstream volume is
//! one request per message typed, so bidirectionality buys nothing, and a `POST`
//! passes through the CSRF, rate-limit, and session middleware both apps already
//! run. It also avoids adding a `connect-src` CSP directive on the Multithreaded
//! side, which currently has none.
//!
//! # Ephemeral, but written down
//!
//! Chat in both consumers expires. Messages are stored anyway, for two reasons:
//! a deploy is a symlink swap plus a restart with no connection draining, so
//! every client reconnects and needs its backlog replayed from a cursor; and
//! moderation has to be able to reach a message that already scrolled past.
//!
//! [`Retention`] makes the bound un-opt-out-able. There is no `Option`, no
//! "forever" sentinel, and no public field: the only constructor rejects anything
//! over the crate ceilings.
//!
//! # Not here, on purpose
//!
//! No presence, no typing indicators, no edit path, and no link previews. The
//! first two are the largest drivers of event volume against a hard 512M cgroup
//! cap where an OOM restarts the whole site. Edit is surface with no benefit in a
//! stream nobody re-reads. Link previews would point a server-side fetcher at
//! unreviewed user input at chat volume, which is a much hotter SSRF surface than
//! the forum-post path it would borrow.

mod chat;
mod error;
mod event;
mod hub;
mod ids;
mod message;
mod rate_limit;
mod retention;
mod room;
mod send;
#[cfg(feature = "axum")]
mod sse;
mod stream;
mod traits;

pub use chat::{Chat, SendRequest};
pub use error::{ChatError, LimitScope};
pub use event::ChatEvent;
pub use hub::{Hub, HubLimits, Subscription};
pub use ids::{MessageId, Nonce, RoomId, UserId};
pub use message::{MAX_MESSAGE_LEN, Message, MessageBody};
pub use rate_limit::{RateDecision, RateLimiter, RateLimits};
pub use retention::{MAX_AGE_CEILING, MAX_MESSAGES_CEILING, Retention};
pub use room::{Room, RoomState};
pub use send::SendRejection;
#[cfg(feature = "axum")]
pub use sse::{KEEPALIVE_INTERVAL, sse_response};
pub use stream::ChatStream;
pub use traits::{
    ChatAuthz, ChatIdentity, ChatModeration, ChatRooms, DenyReason, Identity, WriteAccess,
};