//! mailer-smtp: SMTP protocol engine (server + client).
//!
//! This crate provides the SMTP protocol implementation including:
//! - Command parsing (`command`)
//! - State machine (`state`)
//! - Response building (`response`)
//! - Email data accumulation (`data`)
//! - Per-connection session state (`session`)
//! - Address/input validation (`validation`)
//! - Server configuration (`config`)
//! - Rate limiting (`rate_limiter`)
//! - TCP/TLS server (`server`)
//! - Connection handling (`connection`)

pub mod client;
pub mod command;
pub mod config;
pub mod connection;
pub mod data;
pub mod rate_limiter;
pub mod response;
pub mod scram;
pub mod server;
pub mod session;
pub mod state;
pub mod validation;

pub use mailer_core;

// Re-export key types for convenience.
pub use command::{AuthMechanism, SmtpCommand};
pub use config::SmtpServerConfig;
pub use data::{DataAccumulator, DataAction};
pub use response::SmtpResponse;
pub use session::SmtpSession;
pub use state::SmtpState;

/// Crate version.
pub fn version() -> &'static str {
    env!("CARGO_PKG_VERSION")
}