//! The protocol's own data in the document: everything under `_continuum`. The names
//! of its parts, and the paths to them, are defined here only.
//!
//! * `members/<pk>`: the member registry (`swarm::members`).
//! * `forgotten/<pk>`: forget records (`swarm::peer`).
//! * `remakes/<id>`: remake records (`remake::records`).
//! * `votes/<pk>`: the votes register (`remake::records`).
//! * `epochs/<generation>`: epoch metadata, written by snapshots (`remake::snapshot`).
//! * `swarm`: the swarm ID, written once by the genesis node (`swarm::bootstrap`).
//! * `neighbours`: the neighbours each member keeps, written by the genesis node, and
//!   changed by a protocol writer if need be (`swarm::topology::swarm_neighbours`).
//! * `relays`: relays for the swarm's nodes, listed by an operator
//!   (`swarm::members::relays`).
//! * `topology`, `dissemination`: how members' neighbours are chosen, and how a change
//!   reaches every member, written by the genesis node, and changed by a protocol
//!   writer if need be (`swarm::topology::swarm_ways`).
//! * `users/<name>`: the user registry: who the users are, and what each may do
//!   (`access::registry`).
//! * `access/signed`: the paths whose writes are signed (`document::signatures`).
//! * `access/policy`: whether every node judges received changes (`access::policy`).
//! * `access/userSigned`: the paths whose values their users sign (`access::envelope`).
//! * `banned/<pk>`: banned nodes (`access::bans`).
//! * `logouts/<name>`: when a user's tokens were last revoked (`access::registry`).
//! * `sessions/<name>/<session>`: a session of the user ended (logged out of), until
//!   when it would have lasted: its tokens aren't taken (`access::registry`).
//! * `local/<pk>/<name>`: never stored, and never writable: what a node holds alone
//!   (its log filter, its configuration, its debug endpoints), named for capabilities
//!   (`api::access::needed`).

/// The key every protocol path starts with.
pub(crate) const ROOT: &str = "_continuum";
pub(crate) const MEMBERS: &str = "members";
pub(crate) const FORGOTTEN: &str = "forgotten";
pub(crate) const REMAKES: &str = "remakes";
pub(crate) const VOTES: &str = "votes";
pub(crate) const EPOCHS: &str = "epochs";
pub(crate) const SWARM: &str = "swarm";
pub(crate) const NEIGHBOURS: &str = "neighbours";
pub(crate) const RELAYS: &str = "relays";
pub(crate) const TOPOLOGY: &str = "topology";
pub(crate) const DISSEMINATION: &str = "dissemination";
pub(crate) const USERS: &str = "users";
pub(crate) const ACCESS: &str = "access";
pub(crate) const BANNED: &str = "banned";
pub(crate) const LOGOUTS: &str = "logouts";
pub(crate) const SESSIONS: &str = "sessions";
pub(crate) const LOCAL: &str = "local";

/// The store path `_continuum/<parts…>`.
pub(crate) fn path(parts: &[&str]) -> Vec<String> {
    std::iter::once(ROOT)
        .chain(parts.iter().copied())
        .map(str::to_owned)
        .collect()
}

/// Whether a store path is protocol data (under `_continuum`).
pub(crate) fn is_protocol(path: &[String]) -> bool {
    path.first().is_some_and(|root| root == ROOT)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn paths_start_at_the_root() {
        assert_eq!(path(&[]), vec!["_continuum"]);
        assert_eq!(path(&[MEMBERS, "pk"]), vec!["_continuum", "members", "pk"]);
        assert!(is_protocol(&path(&[VOTES])));
        assert!(!is_protocol(&["users".to_owned()]));
        assert!(!is_protocol(&[]));
    }
}