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use crate::ffi;
use std::ffi::{CStr, CString};
use std::fmt;
/// `ServerRole` describes the functional role of an NWEP server node.
///
/// The role affects how the C library routes incoming requests internally:
/// certain path prefixes are intercepted and handled by built-in subsystems
/// rather than dispatched to application-level handlers. A server built with
/// the Rust bindings must choose a role at construction time via
/// `ServerBuilder::role`.
///
/// The `Default` implementation returns [`ServerRole::Regular`], which is the
/// appropriate choice for application-level servers.
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Default)]
pub enum ServerRole {
/// `Regular` identifies a standard application server.
///
/// All incoming requests are dispatched to the application's registered
/// handlers. No paths are intercepted by the library. This is the default
/// role and should be used for all nodes that do not serve trust-log or
/// anchor functions.
#[default]
Regular,
/// `LogServer` identifies a node that hosts the distributed Merkle
/// identity log.
///
/// In addition to application handlers, a `LogServer` intercepts all
/// requests whose path begins with `/log/` and routes them to the C
/// library's built-in log management subsystem. These paths handle log
/// entry submission, Merkle proof retrieval, and checkpoint synchronization.
///
/// Only designate a node as `LogServer` if it has been provisioned with
/// persistent log storage and configured as a trust authority in the
/// network's root anchoring document.
LogServer,
/// `Anchor` identifies a BLS threshold signing authority node.
///
/// An `Anchor` intercepts all requests whose path begins with
/// `/checkpoint/` and routes them to the C library's built-in BLS
/// checkpoint subsystem. Anchor nodes hold a BLS private key share and
/// participate in threshold signing rounds to produce periodic checkpoints
/// over the Merkle log root.
///
/// The network requires at least [`crate::types::DEFAULT_ANCHOR_THRESHOLD`]
/// functioning anchor nodes to ratify a checkpoint. Anchor nodes are
/// registered in the trust root and their BLS public keys are well-known.
Anchor,
}
impl ServerRole {
/// `from_str` parses a role string (as advertised in the `roles` header)
/// and returns the corresponding [`ServerRole`] variant.
///
/// The parsing is delegated to the C library. Unrecognized strings map to
/// [`ServerRole::Regular`], which is the safe default.
///
/// # Example
///
/// ```rust
/// use nwep::role::ServerRole;
///
/// assert_eq!(ServerRole::from_str("regular"), ServerRole::Regular);
/// assert_eq!(ServerRole::from_str("log_server"), ServerRole::LogServer);
/// assert_eq!(ServerRole::from_str("anchor"), ServerRole::Anchor);
/// assert_eq!(ServerRole::from_str("unknown"), ServerRole::Regular);
/// ```
pub fn from_str(s: &str) -> Self {
let c = CString::new(s).unwrap_or_default();
let r = unsafe { ffi::nwep_role_from_str(c.as_ptr()) };
match r {
ffi::nwep_server_role_NWEP_ROLE_LOG_SERVER => ServerRole::LogServer,
ffi::nwep_server_role_NWEP_ROLE_ANCHOR => ServerRole::Anchor,
_ => ServerRole::Regular,
}
}
/// `as_str` returns the canonical lowercase wire-format string for this
/// role.
///
/// The string is retrieved from the C library's string table and is valid
/// for the lifetime of the process. It is the same value that appears in
/// the `roles` header of a `connect` response.
///
/// # Example
///
/// ```rust
/// use nwep::role::ServerRole;
///
/// assert_eq!(ServerRole::Regular.as_str(), "regular");
/// assert_eq!(ServerRole::LogServer.as_str(), "log_server");
/// assert_eq!(ServerRole::Anchor.as_str(), "anchor");
/// ```
pub fn as_str(&self) -> &'static str {
let r = match self {
ServerRole::Regular => ffi::nwep_server_role_NWEP_ROLE_REGULAR,
ServerRole::LogServer => ffi::nwep_server_role_NWEP_ROLE_LOG_SERVER,
ServerRole::Anchor => ffi::nwep_server_role_NWEP_ROLE_ANCHOR,
};
unsafe {
let ptr = ffi::nwep_role_to_str(r);
if ptr.is_null() {
"regular"
} else {
CStr::from_ptr(ptr).to_str().unwrap_or("regular")
}
}
}
/// `to_ffi` converts this [`ServerRole`] to the raw `nwep_server_role`
/// integer discriminant expected by C library functions.
#[allow(dead_code)]
pub(crate) fn to_ffi(&self) -> ffi::nwep_server_role {
match self {
ServerRole::Regular => ffi::nwep_server_role_NWEP_ROLE_REGULAR,
ServerRole::LogServer => ffi::nwep_server_role_NWEP_ROLE_LOG_SERVER,
ServerRole::Anchor => ffi::nwep_server_role_NWEP_ROLE_ANCHOR,
}
}
}
impl fmt::Display for ServerRole {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str(self.as_str())
}
}
impl From<ffi::nwep_server_role> for ServerRole {
fn from(r: ffi::nwep_server_role) -> Self {
match r {
ffi::nwep_server_role_NWEP_ROLE_LOG_SERVER => ServerRole::LogServer,
ffi::nwep_server_role_NWEP_ROLE_ANCHOR => ServerRole::Anchor,
_ => ServerRole::Regular,
}
}
}