//! alktty: Terminal session protocol for the `alk/tty` ALPN.
//!
//! Producer/consumer protocol crate on top of alkcall channels. Two
//! halves (per alkcall's protocol-crate pattern):
//!
//! - **Producer half** — [`adapter::TtyAdapter`] (direct `alk/tty`
//!   ALPN via `ProtocolHandler`) + [`channels`] (registers the
//!   `channels/tty/sub` open op via `ChannelCore::register_openable`
//!   for the `alk/channels` multiplexed path).
//! - **Consumer half** — [`session::TtySession`] (typed client wrapper
//!   around the wire protocol, with `connect_direct` and
//!   `open_via_channels` constructors).
//!
//! Two-carriage wire format (ADR-052): a JSON negotiation frame, then
//! raw chunks (`[stream_type: u8][length: u32 be][payload]`).
//! Backend-agnostic via the [`backend::TtyBackend`] trait (ADR-053).
//! Depends on alkcall (ADR-057 — the negotiation framing is
//! self-contained; alkcall's `EventEnvelope` framing is not reused).
//!
//! # WASM target
//!
//! The default crate (no features) compiles to
//! `wasm32-unknown-unknown`. The [`local`] module is feature-gated
//! and non-wasm by design (`portable-pty` + `tokio::process` need a
//! real OS). Downstream TS/Python adapters compile the protocol
//! layer in a sandbox; the local-process backend runs on a real OS.
//!
//! # Local backend
//!
//! The local backend ([`local::LocalTtyBackend`]) is gated behind the
//! `local` feature. It implements [`backend::TtyBackend`] via
//! `portable_pty` (PTY mode, terminal semantics) and
//! `tokio::process::Command` (pipe mode, the runner case). The
//! blocking→async bridge for PTY mode uses three dedicated std
//! threads feeding tokio mpsc/oneshot channels (REQ-TTY-01).
//!
//! # Assembly pattern
//!
//! ```ignore
//! let mut backends = std::collections::HashMap::new();
//! backends.insert(
//!     "local".into(),
//!     std::sync::Arc::new(alktty::local::LocalTtyBackend::new())
//!         as std::sync::Arc<dyn alktty::backend::TtyBackend>,
//! );
//! let tty_adapter = alktty::adapter::TtyAdapter::new(backends);
//! ```

pub mod adapter;
pub mod backend;
pub mod channels;
pub mod control;
pub mod negotiation;
pub mod session;
pub mod wire;

#[cfg(feature = "local")]
pub mod local;