//! # Subduction HTTP Long-Poll Transport
//!
//! An HTTP long-poll transport layer for the Subduction sync protocol,
//! providing an alternative to WebSocket for environments where WebSocket
//! connections are unreliable or unavailable (e.g., restrictive proxies,
//! corporate firewalls, some serverless platforms).
//!
//! # Protocol
//!
//! The transport maps Subduction's bidirectional message stream onto HTTP
//! request-response pairs:
//!
//! ```text
//! ┌────────┐                                ┌────────┐
//! │ Client │                                │ Server │
//! └───┬────┘                                └───┬────┘
//!     │                                         │
//!     │  POST /lp/handshake                     │
//!     │  Body: Signed<Challenge> (157 B)        │
//!     │ ──────────────────────────────────────► │
//!     │  200 + Signed<Response> (140 B)         │
//!     │  X-Session-Id: <session_id>             │
//!     │ ◄────────────────────────────────────── │
//!     │                                         │
//!     │  POST /lp/send                          │
//!     │  X-Session-Id: <id>                     │
//!     │  Body: SyncMessage (binary)             │
//!     │ ──────────────────────────────────────► │
//!     │  204 No Content                         │
//!     │ ◄────────────────────────────────────── │
//!     │                                         │
//!     │  POST /lp/recv                          │
//!     │  X-Session-Id: <id>                     │
//!     │ ──────────────────────────────────────► │
//!     │            ... (blocks) ...             │
//!     │  200 + SyncMessage (binary)             │
//!     │ ◄────────────────────────────────────── │
//!     │                                         │
//!     │  POST /lp/disconnect                    │
//!     │  X-Session-Id: <id>                     │
//!     │ ──────────────────────────────────────► │
//!     │  204 No Content                         │
//!     │ ◄────────────────────────────────────── │
//! ```
//!
//! # Architecture
//!
//! The server maintains per-session state with async channels that mirror
//! the WebSocket transport's internal architecture:
//!
//! ```text
//! ┌─────────────────────────────────────────────────┐
//! │            HttpLongPollTransport                │
//! │                                                 │
//! │  outbound_tx ──► [bounded channel] ──► /recv    │
//! │  /send ──► [bounded channel] ──► inbound_reader │
//! │  pending: Map<RequestId, oneshot::Tx>           │
//! └─────────────────────────────────────────────────┘
//! ```

extern crate alloc;

pub mod client;
pub mod error;
pub mod http_client;
pub mod session;
pub mod transport;

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

/// Default long-poll timeout in seconds.
///
/// If no message is available after this duration, the `/lp/recv`
/// endpoint returns 204 No Content and the client should re-poll.
pub const DEFAULT_POLL_TIMEOUT_SECS: u64 = 30;

/// Default maximum HTTP request body size (50 MB).
///
/// Matches the WebSocket transport's `DEFAULT_MAX_MESSAGE_SIZE`.
pub const DEFAULT_MAX_BODY_SIZE: usize = 50 * 1024 * 1024;

/// Session ID header name.
pub const SESSION_ID_HEADER: &str = "x-session-id";
