use chrono::{DateTime, Utc};
use serde::{Deserialize, Serialize};
use std::{collections::HashMap, sync::Arc, time::Duration};
use tokio::sync::RwLock;
use async_trait::async_trait;
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct TrustScore {
pub value: f64,
pub confidence: f64,
pub evidence_count: u64,
pub last_updated: DateTime<Utc>,
pub degradation_rate: f64,
}
impl Default for TrustScore {
fn default() -> Self {
Self {
value: 0.5,
confidence: 0.1,
evidence_count: 0,
last_updated: Utc::now(),
degradation_rate: 0.01,
}
}
}
impl TrustScore {
#[must_use]
pub fn new(initial_value: f64) -> Self {
Self {
value: initial_value.clamp(0.0, 1.0),
confidence: 0.1,
evidence_count: 0,
last_updated: Utc::now(),
degradation_rate: 0.01,
}
}
#[must_use]
pub fn weighted(&self) -> f64 {
self.value * self.confidence
}
#[allow(clippy::cast_precision_loss)]
pub fn on_compliant_behavior(&mut self, severity: f64) {
let delta = 0.01 * severity;
self.value = (self.value + delta).min(1.0);
self.evidence_count += 1;
self.confidence = (1.0 - (1.0 / (1.0 + self.evidence_count as f64 / 100.0))).min(0.99);
self.last_updated = Utc::now();
}
#[allow(clippy::cast_precision_loss)]
pub fn on_policy_violation(&mut self, severity: f64) {
let penalty = if severity > 0.8 {
0.3 * severity
} else {
0.1 * severity
};
self.value = (self.value - penalty).max(0.0);
self.evidence_count += 1;
self.confidence = (1.0 - (1.0 / (1.0 + self.evidence_count as f64 / 100.0))).min(0.99);
self.last_updated = Utc::now();
}
pub fn degrade(&mut self, elapsed: Duration) {
let hours = elapsed.as_secs_f64() / 3600.0;
let decay = self.degradation_rate * hours;
self.value = (self.value - decay).max(0.0);
self.confidence = (self.confidence - decay * 0.5).max(0.1);
self.last_updated = Utc::now();
}
}
#[async_trait]
pub trait TrustScoreStore: Send + Sync {
async fn get(&self, delegator_id: &str) -> anyhow::Result<Option<TrustScore>>;
async fn set(&self, delegator_id: &str, score: TrustScore) -> anyhow::Result<()>;
async fn delete(&self, delegator_id: &str) -> anyhow::Result<()>;
async fn sweep_stale(&self, max_age: Duration) -> anyhow::Result<Vec<String>>;
async fn list_ids(&self) -> anyhow::Result<Vec<String>>;
}
pub struct InMemoryTrustScoreStore {
scores: RwLock<HashMap<String, TrustScore>>,
}
impl InMemoryTrustScoreStore {
#[must_use]
pub fn new() -> Self {
Self {
scores: RwLock::new(HashMap::new()),
}
}
}
impl Default for InMemoryTrustScoreStore {
fn default() -> Self {
Self::new()
}
}
#[async_trait]
impl TrustScoreStore for InMemoryTrustScoreStore {
async fn get(&self, delegator_id: &str) -> anyhow::Result<Option<TrustScore>> {
let scores = self.scores.read().await;
Ok(scores.get(delegator_id).cloned())
}
async fn set(&self, delegator_id: &str, score: TrustScore) -> anyhow::Result<()> {
let mut scores = self.scores.write().await;
scores.insert(delegator_id.to_string(), score);
Ok(())
}
async fn delete(&self, delegator_id: &str) -> anyhow::Result<()> {
let mut scores = self.scores.write().await;
scores.remove(delegator_id);
Ok(())
}
async fn sweep_stale(&self, max_age: Duration) -> anyhow::Result<Vec<String>> {
let cutoff = Utc::now() - chrono::Duration::from_std(max_age).unwrap_or_default();
let mut scores = self.scores.write().await;
let stale: Vec<String> = scores
.iter()
.filter(|(_, s)| s.last_updated < cutoff)
.map(|(k, _)| k.clone())
.collect();
for id in &stale {
scores.remove(id);
}
Ok(stale)
}
async fn list_ids(&self) -> anyhow::Result<Vec<String>> {
let scores = self.scores.read().await;
Ok(scores.keys().cloned().collect())
}
}
pub struct TrustDecayWorker {
store: Arc<dyn TrustScoreStore>,
interval: Duration,
decay_elapsed: Duration,
}
impl TrustDecayWorker {
pub fn new(
store: Arc<dyn TrustScoreStore>,
interval: Duration,
decay_elapsed: Duration,
) -> Self {
Self {
store,
interval,
decay_elapsed,
}
}
pub fn hourly(store: Arc<dyn TrustScoreStore>) -> Self {
Self::new(store, Duration::from_hours(1), Duration::from_hours(1))
}
#[allow(clippy::missing_errors_doc)]
pub async fn run_once(&self) -> anyhow::Result<usize> {
let ids = self.store.list_ids().await?;
let mut decayed = 0;
for id in &ids {
if let Some(mut score) = self.store.get(id).await? {
score.degrade(self.decay_elapsed);
self.store.set(id, score).await?;
decayed += 1;
}
}
Ok(decayed)
}
pub async fn run(self) -> ! {
let mut interval = tokio::time::interval(self.interval);
loop {
interval.tick().await;
match self.run_once().await {
Ok(count) => {
tracing::debug!(target: "kirino::dynamic::trust::decay",
decayed_count = count,
"trust decay cycle completed"
);
}
Err(e) => {
tracing::error!(target: "kirino::dynamic::trust::decay",
error = %e,
"trust decay cycle failed"
);
}
}
}
}
#[must_use]
pub fn spawn(self) -> tokio::task::JoinHandle<()> {
tokio::spawn(async move { self.run().await })
}
pub fn spawn_resilient(
store: Arc<dyn TrustScoreStore>,
interval: Duration,
) -> tokio::task::JoinHandle<()> {
tokio::spawn(async move {
let worker = Self::new(store.clone(), interval, interval);
let mut interval_tick = tokio::time::interval(interval);
loop {
interval_tick.tick().await;
match worker.run_once().await {
Ok(count) => {
tracing::debug!(target: "kirino::dynamic::trust::decay",
decayed_count = count,
"trust decay cycle completed"
);
}
Err(e) => {
tracing::error!(target: "kirino::dynamic::trust::decay",
error = %e,
"trust decay cycle failed, will retry next interval"
);
}
}
}
})
}
}
#[cfg(test)]
mod tests {
use super::*;
use std::sync::Arc;
#[test]
fn test_trust_score_default() {
let ts = TrustScore::default();
assert!((ts.value - 0.5).abs() < f64::EPSILON);
assert!((ts.confidence - 0.1).abs() < f64::EPSILON);
assert_eq!(ts.evidence_count, 0);
}
#[test]
fn test_trust_score_compliant_increases() {
let mut ts = TrustScore::new(0.5);
ts.on_compliant_behavior(1.0);
assert!(ts.value > 0.5);
assert_eq!(ts.evidence_count, 1);
}
#[test]
fn test_trust_score_violation_decreases() {
let mut ts = TrustScore::new(0.5);
ts.on_policy_violation(0.5);
assert!(ts.value < 0.5);
}
#[test]
fn test_trust_score_severe_violation_cliff() {
let mut ts = TrustScore::new(0.9);
ts.on_policy_violation(0.9);
assert!(ts.value < 0.7);
}
#[test]
fn test_trust_score_degrade() {
let mut ts = TrustScore::new(0.8);
ts.degrade(Duration::from_secs(3600));
assert!(ts.value < 0.8);
}
#[test]
fn test_trust_score_clamped() {
let mut ts = TrustScore::new(1.0);
ts.on_compliant_behavior(1.0);
assert!(ts.value <= 1.0);
let mut ts = TrustScore::new(0.01);
ts.on_policy_violation(1.0);
assert!(ts.value >= 0.0);
}
#[test]
fn test_confidence_grows_with_evidence() {
let mut ts = TrustScore::new(0.5);
let initial = ts.confidence;
for _ in 0..200 {
ts.on_compliant_behavior(1.0);
}
assert!(ts.confidence > initial);
assert!(ts.confidence <= 0.99);
}
#[tokio::test]
async fn test_in_memory_store_crud() {
let store = InMemoryTrustScoreStore::new();
let id = "agent-001";
assert!(store.get(id).await.unwrap().is_none());
let score = TrustScore::new(0.8);
store.set(id, score.clone()).await.unwrap();
let got = store.get(id).await.unwrap().unwrap();
assert!((got.value - 0.8).abs() < f64::EPSILON);
store.delete(id).await.unwrap();
assert!(store.get(id).await.unwrap().is_none());
}
#[tokio::test]
async fn test_sweep_stale() {
let store = InMemoryTrustScoreStore::new();
let mut old = TrustScore::new(0.5);
old.last_updated = Utc::now() - chrono::Duration::hours(48);
store.set("old-agent", old).await.unwrap();
let mut recent = TrustScore::new(0.9);
recent.last_updated = Utc::now();
store.set("recent-agent", recent).await.unwrap();
let swept = store
.sweep_stale(Duration::from_secs(24 * 3600))
.await
.unwrap();
assert_eq!(swept, vec!["old-agent"]);
assert!(store.get("old-agent").await.unwrap().is_none());
assert!(store.get("recent-agent").await.unwrap().is_some());
}
#[tokio::test]
async fn test_list_ids() {
let store = InMemoryTrustScoreStore::new();
store.set("a1", TrustScore::new(0.5)).await.unwrap();
store.set("a2", TrustScore::new(0.8)).await.unwrap();
store.set("a3", TrustScore::new(0.3)).await.unwrap();
let mut ids = store.list_ids().await.unwrap();
ids.sort();
assert_eq!(ids, vec!["a1", "a2", "a3"]);
}
#[tokio::test]
async fn test_decay_worker_run_once() {
let store = Arc::new(InMemoryTrustScoreStore::new());
store.set("a1", TrustScore::new(0.8)).await.unwrap();
store.set("a2", TrustScore::new(0.5)).await.unwrap();
let worker = TrustDecayWorker::new(
store.clone(),
Duration::from_secs(3600),
Duration::from_secs(3600),
);
let before_a1 = store.get("a1").await.unwrap().unwrap().value;
let count = worker.run_once().await.unwrap();
assert_eq!(count, 2);
let after_a1 = store.get("a1").await.unwrap().unwrap().value;
assert!(after_a1 < before_a1);
}
}