liminal-server 0.2.3

use std::net::SocketAddr;
use std::path::PathBuf;
use std::time::Duration;

/// Declarative configuration for the standalone liminal server wrapper.
#[derive(Debug, Clone, serde::Deserialize)]
#[serde(deny_unknown_fields)]
pub struct ServerConfig {
    /// Socket address where the standalone server will listen for client traffic.
    pub listen_address: SocketAddr,
    /// Socket address where the health endpoint server will listen for probes.
    pub health_listen_address: SocketAddr,
    /// Maximum time to allow existing connections to drain during graceful shutdown.
    pub drain_timeout_ms: u64,
    /// Channel topology definitions declared by the operator.
    pub channels: Vec<ChannelDef>,
    /// Declarative routing rules that connect configured channels.
    pub routing_rules: Vec<RoutingRuleDef>,
    /// Optional filesystem location for durable server state.
    pub persistence_path: Option<PathBuf>,
    /// Optional beamr distribution cluster membership configuration.
    pub cluster: Option<ClusterConfig>,
    /// Optional connection authentication configuration.
    ///
    /// When present, every client `Connect` handshake must carry a matching
    /// `auth_token`; when absent the server is open (byte-identical to the
    /// pre-auth behaviour). Not an ACL system — a single shared bearer token.
    #[serde(default)]
    pub auth: Option<AuthConfig>,
}

impl ServerConfig {
    /// Returns the configured graceful-shutdown drain timeout.
    #[must_use]
    pub const fn drain_timeout(&self) -> Duration {
        Duration::from_millis(self.drain_timeout_ms)
    }
}

/// Declarative channel definition loaded from server configuration.
#[derive(Debug, Clone, serde::Deserialize)]
#[serde(deny_unknown_fields)]
pub struct ChannelDef {
    /// Unique channel name used by routing rules and operators.
    pub name: String,
    /// Filesystem path to a JSON Schema document that validates every message
    /// published to this channel.
    ///
    /// The path is resolved relative to the directory containing the config file
    /// (absolute paths are used verbatim). Config validation reads and parses the
    /// referenced document and stores the result in [`Self::loaded_schema`]; a
    /// missing file, an unreadable file, or a file that is not valid JSON is an
    /// accumulated validation error that stops startup.
    ///
    /// `None` means the channel has no schema: it keeps the permissive empty
    /// schema (`{}`) that accepts any JSON payload.
    #[serde(default)]
    pub schema_ref: Option<PathBuf>,
    /// Whether this channel requires durable persistence.
    pub durable: bool,
    /// Schema document loaded and parsed from [`Self::schema_ref`] during config
    /// validation. Populated only by [`crate::config::validate`]; a directly
    /// constructed [`ChannelDef`] that skips validation carries `None` here and is
    /// therefore built with the permissive empty schema regardless of
    /// [`Self::schema_ref`]. Never deserialized from the config file.
    #[serde(skip)]
    pub loaded_schema: Option<LoadedSchema>,
}

/// A channel's JSON Schema document as loaded from disk during config validation.
///
/// Carries both the parsed document (fed to the validation engine when the channel
/// is built) and the raw file bytes (hashed into the protocol schema id advertised
/// at subscribe time, so an SDK deriving ids from the same schema bytes converges).
#[derive(Debug, Clone)]
pub struct LoadedSchema {
    /// Raw bytes of the schema file, hashed to derive the protocol schema id.
    pub bytes: Vec<u8>,
    /// Parsed JSON Schema document, fed to the channel's validation engine.
    pub document: serde_json::Value,
}

/// Declarative routing rule definition loaded from server configuration.
#[derive(Debug, Clone, serde::Deserialize)]
#[serde(deny_unknown_fields)]
pub struct RoutingRuleDef {
    /// Source channel name from which messages are routed.
    pub source_channel: String,
    /// Target channel name to which matching messages are routed.
    pub target_channel: String,
    /// Optional predicate expression that filters routed messages.
    pub predicate: Option<String>,
}

/// Default beamr distribution handshake cookie, used when the operator does not
/// configure one. Mirrors beamr's own [`beamr::distribution::DEFAULT_COOKIE`].
pub const DEFAULT_COOKIE: &str = "beamr-cookie";

/// Beamr distribution cluster configuration for standalone deployment.
#[derive(Debug, Clone, serde::Deserialize)]
#[serde(deny_unknown_fields)]
pub struct ClusterConfig {
    /// Unique node name advertised to the beamr distribution cluster.
    pub node_name: String,
    /// Socket address this node binds for inbound distribution links from peers.
    ///
    /// This is distinct from [`ServerConfig::listen_address`] (the client wire
    /// port): a clustered node listens on two ports — one for clients, one for
    /// peer distribution traffic.
    pub listen_address: SocketAddr,
    /// Seed node socket addresses used to join an existing cluster.
    pub seed_nodes: Vec<SocketAddr>,
    /// Shared distribution handshake cookie. Every node in a cluster MUST use the
    /// same cookie or the OTP handshake is rejected. Defaults to
    /// [`DEFAULT_COOKIE`] when omitted.
    #[serde(default = "default_cookie")]
    pub cookie: String,
}

fn default_cookie() -> String {
    DEFAULT_COOKIE.to_owned()
}

/// Connection authentication configuration.
///
/// A single shared bearer token compared (constant-time) against the `auth_token`
/// carried on every client `Connect` handshake. This is the table-stakes access
/// gate, not an ACL system: one token grants full access, its absence (no `[auth]`
/// section) leaves the server open.
#[derive(Debug, Clone, serde::Deserialize)]
#[serde(deny_unknown_fields)]
pub struct AuthConfig {
    /// Shared secret token a client must present in its `Connect` handshake. Must
    /// be non-empty when the `[auth]` section is present (an empty token is a
    /// config validation error, since it would gate nothing).
    pub token: String,
}