soma_auth/

state.rs

use std::collections::{BTreeMap, BTreeSet};
use std::net::IpAddr;
use std::sync::Arc;
use std::sync::RwLock;
use std::time::Instant;

use dashmap::DashMap;
use tokio::sync::Mutex;
use tracing::{debug, info, warn};
use url::Url;

use crate::authelia::AutheliaProvider;
use crate::config::{AuthConfig, AuthMode};
use crate::error::AuthError;
use crate::github::GitHubProvider;
use crate::google::GoogleProvider;
use crate::jwt::SigningKeys;
use crate::oauth_provider::OAuthProvider;
use crate::sqlite::SqliteStore;

const RATE_LIMIT_RETRY_AFTER_MS: u64 = 60_000;

/// Hard cap on distinct per-IP buckets held in memory. Without a cap an
/// attacker rotating IPv6 source addresses grows the map without bound
/// (pattern ported from labby-auth's bounded limiter).
const RATE_LIMIT_MAX_IP_BUCKETS: usize = 4096;

/// Buckets untouched for this long are eligible for eviction. Any bucket
/// idle this long has fully refilled, so dropping it loses no state.
const RATE_LIMIT_BUCKET_IDLE_SECS: u64 = 600;

/// Per-request parameters for rate-limiting. Each bucket is independent.
struct RateLimiterInner {
    /// Tokens available in the bucket.
    tokens: f64,
    /// Maximum tokens, equal to the full per-minute burst allowance.
    max_tokens: f64,
    /// Refill rate in tokens per second.
    refill_rate: f64,
    /// Last refill time.
    last_refill: Instant,
}

impl RateLimiterInner {
    fn new(requests_per_minute: u32) -> Self {
        let rate = requests_per_minute as f64 / 60.0;
        let max_tokens = requests_per_minute.max(1) as f64;
        Self {
            tokens: max_tokens,
            max_tokens,
            refill_rate: rate,
            last_refill: Instant::now(),
        }
    }

    fn try_acquire(&mut self) -> bool {
        let now = Instant::now();
        let elapsed = now.duration_since(self.last_refill).as_secs_f64();
        self.tokens = (self.tokens + elapsed * self.refill_rate).min(self.max_tokens);
        self.last_refill = now;
        if self.tokens >= 1.0 {
            self.tokens -= 1.0;
            true
        } else {
            false
        }
    }
}

/// Per-IP token-bucket rate limiter.
///
/// Uses a `DashMap` of `tokio::sync::Mutex<RateLimiterInner>` so:
/// - different IPs can be checked concurrently without serializing on a global lock
///   (lab-77y5.10 — one IP cannot exhaust the global bucket),
/// - the per-bucket lock is a `tokio::sync::Mutex` so contention does not park a
///   Tokio worker thread (lab-77y5.9).
///
/// Cheap to clone (all state is behind `Arc`).
#[derive(Clone)]
struct PerIpRateLimiter {
    requests_per_minute: u32,
    /// Per-IP buckets. Bounded: when the map reaches `max_buckets`, idle
    /// buckets are swept and, failing that, the least-recently-used bucket
    /// is evicted before a new one is inserted.
    buckets: Arc<DashMap<IpAddr, Mutex<RateLimiterInner>>>,
    /// Cap on `buckets` (constant in production; overridable in tests).
    max_buckets: usize,
    /// Serializes slow-path bucket creation so a burst of previously-unseen
    /// IPs cannot race past the `max_buckets` cap.
    maintenance: Arc<Mutex<()>>,
}

impl PerIpRateLimiter {
    fn new(requests_per_minute: u32) -> Self {
        Self::with_max_buckets(requests_per_minute, RATE_LIMIT_MAX_IP_BUCKETS)
    }

    fn with_max_buckets(requests_per_minute: u32, max_buckets: usize) -> Self {
        Self {
            requests_per_minute,
            buckets: Arc::new(DashMap::new()),
            max_buckets: max_buckets.max(1),
            maintenance: Arc::new(Mutex::new(())),
        }
    }

    /// Try to consume one token for `ip`. Returns `true` if allowed.
    async fn try_acquire(&self, ip: IpAddr) -> bool {
        // Fast path: bucket already exists.
        if let Some(bucket) = self.buckets.get(&ip) {
            return bucket.value().lock().await.try_acquire();
        }
        // Slow path: create the bucket under the maintenance lock so
        // concurrent new IPs cannot collectively exceed the cap.
        let _guard = self.maintenance.lock().await;
        if !self.buckets.contains_key(&ip) {
            if self.buckets.len() >= self.max_buckets {
                self.evict_one();
            }
            self.buckets.insert(
                ip,
                Mutex::new(RateLimiterInner::new(self.requests_per_minute)),
            );
        }
        // Safe expect: inserted above (or by a racing task) and only
        // `evict_one` removes entries, which runs under the same lock.
        self.buckets
            .get(&ip)
            .expect("bucket just inserted")
            .value()
            .lock()
            .await
            .try_acquire()
    }

    /// Make room for one new bucket: drop every idle bucket, and if none
    /// were idle, drop the least-recently-used one. Buckets whose mutex is
    /// currently held are in active use and are never candidates. Must be
    /// called while holding `maintenance`.
    fn evict_one(&self) {
        let now = Instant::now();
        let mut stale: Vec<IpAddr> = Vec::new();
        let mut oldest: Option<(IpAddr, Instant)> = None;
        for entry in self.buckets.iter() {
            let Ok(inner) = entry.value().try_lock() else {
                continue;
            };
            let last_used = inner.last_refill;
            if now.duration_since(last_used).as_secs() >= RATE_LIMIT_BUCKET_IDLE_SECS {
                stale.push(*entry.key());
            } else if oldest.is_none_or(|(_, t)| last_used < t) {
                oldest = Some((*entry.key(), last_used));
            }
        }
        if stale.is_empty() {
            if let Some((ip, _)) = oldest {
                self.buckets.remove(&ip);
            }
            return;
        }
        for ip in stale {
            self.buckets.remove(&ip);
        }
    }
}

#[derive(Clone)]
pub struct AuthState {
    pub config: Arc<AuthConfig>,
    pub store: SqliteStore,
    pub signing_keys: Arc<SigningKeys>,
    pub providers: Arc<BTreeMap<String, Arc<dyn OAuthProvider>>>,
    pub default_provider: String,
    allowed_resource_scopes: Arc<RwLock<BTreeMap<String, BTreeSet<String>>>>,
    authorize_limiter: PerIpRateLimiter,
    register_limiter: PerIpRateLimiter,
    /// Single-flight, TTL-cached OAuth Client ID Metadata Document store for
    /// `/authorize`'s CIMD path (`crate::cimd`). Gated behind `http-axum`
    /// alongside `crate::cimd` itself, even though `AuthState` (this struct)
    /// is otherwise usable without that feature.
    #[cfg(feature = "http-axum")]
    pub(crate) cimd_cache: Arc<crate::cimd::document::DocumentCache>,
}

impl AuthState {
    pub async fn new(config: AuthConfig) -> Result<Self, AuthError> {
        // Run the full validator first — struct-literal callers (test
        // fixtures, or a downstream consumer bypassing AuthConfigBuilder)
        // otherwise skip every safety check `validate()` enforces (HTTPS-only
        // Authelia issuer, callback-path collisions, GitHub scope
        // requirements, etc.). `validate()` only asserts OAuth-mode-specific
        // invariants when `mode == AuthMode::OAuth`, so the manual mode check
        // immediately below is NOT redundant with it — it's the only thing
        // that rejects a non-OAuth config reaching `AuthState::new` at all.
        config.validate()?;

        if !matches!(config.mode, AuthMode::OAuth) {
            return Err(AuthError::Config(format!(
                "AuthState requires {prefix}_AUTH_MODE=oauth",
                prefix = config.env_prefix
            )));
        }

        let public_url = config.public_url.clone().ok_or_else(|| {
            AuthError::Config(format!(
                "{prefix}_PUBLIC_URL is required when {prefix}_AUTH_MODE=oauth",
                prefix = config.env_prefix
            ))
        })?;
        let store = SqliteStore::open(config.sqlite_path.clone()).await?;
        let signing_keys = SigningKeys::load_or_create(&config.key_path)?;
        let providers = build_providers(&public_url, &config)?;
        if !providers.contains_key(&config.default_provider) {
            return Err(AuthError::Config(format!(
                "{prefix}_AUTH_DEFAULT_PROVIDER `{provider}` is not a configured provider",
                prefix = config.env_prefix,
                provider = config.default_provider,
            )));
        }
        info!(
            crate_name = "soma-auth",
            env_prefix = %config.env_prefix,
            auth_mode = "oauth",
            public_url = %public_url,
            configured_providers = ?providers.keys().collect::<Vec<_>>(),
            default_provider = %config.default_provider,
            sqlite_path = %config.sqlite_path.display(),
            key_path = %config.key_path.display(),
            "auth state initialized"
        );
        // Security posture note (see this plan's Global Constraints): the
        // email allowlist is a single flat list shared across every
        // configured provider, and being on it grants full admin scope
        // regardless of which provider authenticated the user. With 2+
        // providers configured, the deployment's effective admin-gate
        // strength is that of its weakest provider's identity-verification
        // signal (GitHub's non-re-verified "primary && verified" email flag
        // is weaker than Google/Authelia's live per-login ID-token claim).
        // `admin_email` is always non-empty in OAuth mode (enforced by
        // `AuthConfig::validate`), so this warning fires on every startup
        // where it's relevant — never silently.
        if providers.len() > 1 {
            warn!(
                crate_name = "soma-auth",
                env_prefix = %config.env_prefix,
                configured_providers = ?providers.keys().collect::<Vec<_>>(),
                "multiple OAuth providers configured — the email allowlist is shared across all \
                 of them, so admin access is only as strong as the weakest configured provider's \
                 identity verification; see docs/AUTH.md"
            );
        }

        let authorize_limiter = PerIpRateLimiter::new(config.authorize_requests_per_minute);
        let register_limiter = PerIpRateLimiter::new(config.register_requests_per_minute);
        let default_provider = config.default_provider.clone();
        Ok(Self {
            config: Arc::new(config),
            store,
            signing_keys: Arc::new(signing_keys),
            providers: Arc::new(providers),
            default_provider,
            allowed_resource_scopes: Arc::new(RwLock::new(BTreeMap::new())),
            authorize_limiter,
            register_limiter,
            #[cfg(feature = "http-axum")]
            cimd_cache: Arc::new(crate::cimd::document::DocumentCache::new()),
        })
    }

    /// Replace the extra OAuth resource audiences accepted by `/authorize` and `/token`.
    ///
    /// The canonical `{LAB_PUBLIC_URL}/mcp` resource is always accepted; callers use this
    /// to publish Gateway-managed protected MCP resources such as
    /// `https://mcp.example.com/syslog` or `https://syslog.example.com/mcp`.
    pub fn set_allowed_resource_urls(&self, resources: impl IntoIterator<Item = String>) {
        self.set_allowed_resource_scopes(
            resources
                .into_iter()
                .map(|resource| (resource, self.config.scopes_supported.to_vec())),
        );
    }

    /// Replace the extra OAuth resource audiences and the scopes each resource accepts.
    pub fn set_allowed_resource_scopes(
        &self,
        resources: impl IntoIterator<Item = (String, Vec<String>)>,
    ) {
        let mut allowed = self
            .allowed_resource_scopes
            .write()
            .expect("allowed resource scope lock");
        allowed.clear();
        for (resource, scopes) in resources {
            let resource = resource.trim().trim_end_matches('/').to_string();
            if resource.is_empty() {
                continue;
            }
            let scopes = scopes
                .into_iter()
                .map(|scope| scope.trim().to_string())
                .filter(|scope| !scope.is_empty())
                .collect::<BTreeSet<_>>();
            allowed.insert(resource, scopes);
        }
        debug!(
            resource_count = allowed.len(),
            "oauth allowed protected resource scopes refreshed"
        );
    }

    pub fn is_allowed_resource_url(&self, resource: &str) -> bool {
        self.allowed_resource_scopes
            .read()
            .expect("allowed resource scope lock")
            .contains_key(resource.trim().trim_end_matches('/'))
    }

    pub fn allowed_resource_scopes(&self, resource: &str) -> Option<Vec<String>> {
        self.allowed_resource_scopes
            .read()
            .expect("allowed resource scope lock")
            .get(resource.trim().trim_end_matches('/'))
            .map(|scopes| scopes.iter().cloned().collect())
    }

    /// Rate-limit guard for `/authorize` and `/browser_login` endpoints.
    ///
    /// Keyed per remote IP so one client cannot exhaust the global bucket
    /// (lab-77y5.10). Uses `tokio::sync::Mutex` internally so contention does
    /// not park a Tokio worker thread (lab-77y5.9).
    pub async fn check_authorize_rate_limit(&self, ip: IpAddr) -> Result<(), AuthError> {
        if self.authorize_limiter.try_acquire(ip).await {
            Ok(())
        } else {
            Err(AuthError::RateLimited {
                message: "authorize rate limit exceeded".to_string(),
                retry_after_ms: RATE_LIMIT_RETRY_AFTER_MS,
            })
        }
    }

    /// Rate-limit guard for `/register` endpoint.
    ///
    /// Keyed per remote IP — see `check_authorize_rate_limit` for the rationale.
    pub async fn check_register_rate_limit(&self, ip: IpAddr) -> Result<(), AuthError> {
        if self.register_limiter.try_acquire(ip).await {
            Ok(())
        } else {
            Err(AuthError::RateLimited {
                message: "register rate limit exceeded".to_string(),
                retry_after_ms: RATE_LIMIT_RETRY_AFTER_MS,
            })
        }
    }

    /// Returns the merged email allowlist: admin first, then all `allowed_users` rows,
    /// deduplicating case-insensitively so admin is never counted twice.
    ///
    /// This is the single source of truth used in both OAuth callback branches. A DB
    /// error is surfaced as [`AuthError::Storage`] (fail-closed — server fault, not
    /// user fault).
    ///
    /// Never log the returned emails directly — pass them only to
    /// `check_email_allowlist`, which uses `fingerprint()` for safe diagnostics.
    pub async fn resolve_allowed_emails(&self) -> Result<Vec<String>, AuthError> {
        let mut emails = vec![self.config.admin_email.clone()];
        for row in self.store.list_allowed_users().await? {
            if !row.email.eq_ignore_ascii_case(&self.config.admin_email) {
                emails.push(row.email);
            }
        }
        Ok(emails)
    }

    /// Rejects new OAuth state rows when the pending count exceeds `max_pending_oauth_states`.
    pub async fn ensure_pending_oauth_state_capacity(&self) -> Result<(), AuthError> {
        let count = self.store.count_pending_oauth_states().await?;
        if count >= self.config.max_pending_oauth_states {
            return Err(AuthError::RateLimited {
                message: "too many pending authorization requests".to_string(),
                retry_after_ms: 5_000,
            });
        }
        Ok(())
    }

    /// Look up a specific configured provider by id. Returns
    /// [`AuthError::Validation`] if `id` does not name a configured
    /// provider — this is a request-shaped error (bad `?provider=` query
    /// param, or a stale DB row naming a provider that has since been
    /// unconfigured), not a server fault.
    pub fn provider(&self, id: &str) -> Result<Arc<dyn OAuthProvider>, AuthError> {
        self.providers
            .get(id)
            .cloned()
            .ok_or_else(|| AuthError::Validation(format!("unknown oauth provider `{id}`")))
    }

    /// [`Self::provider`], falling back to [`Self::default_provider`] when
    /// `id` is `None`.
    pub fn provider_or_default(
        &self,
        id: Option<&str>,
    ) -> Result<Arc<dyn OAuthProvider>, AuthError> {
        self.provider(id.unwrap_or(self.default_provider.as_str()))
    }

    #[cfg(test)]
    pub fn for_tests(
        config: AuthConfig,
        store: SqliteStore,
        signing_keys: SigningKeys,
        providers: BTreeMap<String, Arc<dyn OAuthProvider>>,
    ) -> Self {
        let authorize_limiter = PerIpRateLimiter::new(config.authorize_requests_per_minute);
        let register_limiter = PerIpRateLimiter::new(config.register_requests_per_minute);
        let default_provider = config.default_provider.clone();
        Self {
            config: Arc::new(config),
            store,
            signing_keys: Arc::new(signing_keys),
            providers: Arc::new(providers),
            default_provider,
            allowed_resource_scopes: Arc::new(RwLock::new(BTreeMap::new())),
            authorize_limiter,
            register_limiter,
            #[cfg(feature = "http-axum")]
            cimd_cache: Arc::new(crate::cimd::document::DocumentCache::new()),
        }
    }

    #[cfg(test)]
    pub fn google_only_providers(
        google: GoogleProvider,
    ) -> BTreeMap<String, Arc<dyn OAuthProvider>> {
        let mut providers: BTreeMap<String, Arc<dyn OAuthProvider>> = BTreeMap::new();
        providers.insert("google".to_string(), Arc::new(google));
        providers
    }
}

fn build_providers(
    public_url: &Url,
    config: &AuthConfig,
) -> Result<BTreeMap<String, Arc<dyn OAuthProvider>>, AuthError> {
    let mut providers: BTreeMap<String, Arc<dyn OAuthProvider>> = BTreeMap::new();

    if !config.google.client_id.is_empty() {
        let redirect_uri = build_provider_redirect_uri(public_url, &config.google.callback_path);
        let mut google = GoogleProvider::new(
            config.google.client_id.clone(),
            config.google.client_secret.clone(),
            redirect_uri,
        )?;
        google.scopes.clone_from(&config.google.scopes);
        providers.insert("google".to_string(), Arc::new(google));
    }

    if !config.authelia.client_id.is_empty() {
        let issuer = config.authelia.issuer_url.clone().ok_or_else(|| {
            AuthError::Config(format!(
                "{}_AUTHELIA_ISSUER_URL is required when {}_AUTHELIA_CLIENT_ID is set",
                config.env_prefix, config.env_prefix
            ))
        })?;
        let redirect_uri = build_provider_redirect_uri(public_url, &config.authelia.callback_path);
        let mut authelia = AutheliaProvider::new(
            issuer,
            config.authelia.client_id.clone(),
            config.authelia.client_secret.clone(),
            redirect_uri,
        )?;
        authelia.scopes.clone_from(&config.authelia.scopes);
        providers.insert("authelia".to_string(), Arc::new(authelia));
    }

    if !config.github.client_id.is_empty() {
        let redirect_uri = build_provider_redirect_uri(public_url, &config.github.callback_path);
        let mut github = GitHubProvider::new(
            config.github.client_id.clone(),
            config.github.client_secret.clone(),
            redirect_uri,
        )?;
        github.scopes.clone_from(&config.github.scopes);
        providers.insert("github".to_string(), Arc::new(github));
    }

    if providers.is_empty() {
        return Err(AuthError::Config(format!(
            "at least one OAuth provider must be configured when {}_AUTH_MODE=oauth",
            config.env_prefix
        )));
    }

    Ok(providers)
}

fn build_provider_redirect_uri(public_url: &Url, callback_path: &str) -> Url {
    let mut redirect_uri = public_url.clone();
    let base_path = redirect_uri.path().trim_end_matches('/');
    let callback_path = callback_path.trim_start_matches('/');
    let next_path = if base_path.is_empty() {
        format!("/{callback_path}")
    } else {
        format!("{base_path}/{callback_path}")
    };

    redirect_uri.set_path(&next_path);
    redirect_uri.set_query(None);
    redirect_uri.set_fragment(None);
    redirect_uri
}

#[cfg(test)]
mod tests {
    use std::time::Duration;

    use tempfile::tempdir;

    use super::*;
    use crate::config::{GitHubConfig, GoogleConfig};
    use crate::util::now_unix;

    /// Builds a minimal `AuthState` for unit-testing `resolve_allowed_emails`.
    async fn resolve_state(admin_email: &str) -> AuthState {
        let dir = tempdir().expect("tempdir");
        AuthState::new(AuthConfig {
            mode: AuthMode::OAuth,
            public_url: Some(Url::parse("https://lab.example.com").expect("url")),
            sqlite_path: dir.path().join("auth.db"),
            key_path: dir.path().join("auth.pem"),
            bootstrap_secret: None,
            allowed_client_redirect_uris: Vec::new(),
            admin_email: admin_email.to_string(),
            google: GoogleConfig {
                client_id: "client-id".to_string(),
                client_secret: "client-secret".to_string(),
                callback_path: "/auth/google/callback".to_string(),
                scopes: vec![
                    "openid".to_string(),
                    "email".to_string(),
                    "profile".to_string(),
                ],
            },
            access_token_ttl: Duration::from_secs(3600),
            refresh_token_ttl: Duration::from_secs(3600),
            auth_code_ttl: Duration::from_secs(300),
            register_requests_per_minute: 10,
            authorize_requests_per_minute: 20,
            max_pending_oauth_states: 1024,
            default_provider: "google".to_string(),
            ..AuthConfig::default()
        })
        .await
        .expect("auth state")
    }

    /// `build_providers` hand-writes each provider's map key (e.g.
    /// `"google".to_string()`) as a string literal, independently of
    /// `OAuthProvider::provider_id()` on the value stored under that key —
    /// two never-cross-checked sources of truth for the same fact. Assert
    /// they actually agree for a multi-provider deployment.
    #[tokio::test]
    async fn provider_map_keys_match_each_providers_provider_id() {
        let dir = tempdir().expect("tempdir");
        let state = AuthState::new(AuthConfig {
            mode: AuthMode::OAuth,
            public_url: Some(Url::parse("https://lab.example.com").expect("url")),
            sqlite_path: dir.path().join("auth.db"),
            key_path: dir.path().join("auth.pem"),
            bootstrap_secret: None,
            allowed_client_redirect_uris: Vec::new(),
            admin_email: "admin@example.com".to_string(),
            google: GoogleConfig {
                client_id: "client-id".to_string(),
                client_secret: "client-secret".to_string(),
                callback_path: "/auth/google/callback".to_string(),
                scopes: vec![
                    "openid".to_string(),
                    "email".to_string(),
                    "profile".to_string(),
                ],
            },
            github: GitHubConfig {
                client_id: "gh-client".to_string(),
                client_secret: "gh-secret".to_string(),
                callback_path: "/auth/github/callback".to_string(),
                scopes: vec!["read:user".to_string(), "user:email".to_string()],
            },
            access_token_ttl: Duration::from_secs(3600),
            refresh_token_ttl: Duration::from_secs(3600),
            auth_code_ttl: Duration::from_secs(300),
            register_requests_per_minute: 10,
            authorize_requests_per_minute: 20,
            max_pending_oauth_states: 1024,
            default_provider: "google".to_string(),
            ..AuthConfig::default()
        })
        .await
        .expect("auth state");

        assert_eq!(
            state.providers.len(),
            2,
            "expected both configured providers: {:?}",
            state.providers.keys().collect::<Vec<_>>()
        );
        assert!(
            state
                .providers
                .iter()
                .all(|(key, provider)| key.as_str() == provider.provider_id()),
            "provider map key must match provider_id() for every entry: {:?}",
            state
                .providers
                .iter()
                .map(|(key, provider)| (key.clone(), provider.provider_id()))
                .collect::<Vec<_>>()
        );
    }

    #[tokio::test]
    async fn resolve_allowed_emails_returns_admin_when_table_is_empty() {
        let state = resolve_state("admin@example.com").await;
        let emails = state.resolve_allowed_emails().await.unwrap();
        assert_eq!(emails, vec!["admin@example.com"]);
    }

    #[tokio::test]
    async fn resolve_allowed_emails_includes_db_rows_after_admin() {
        let state = resolve_state("admin@example.com").await;
        state
            .store
            .add_allowed_user("alice@example.com", "admin", now_unix())
            .await
            .unwrap();
        state
            .store
            .add_allowed_user("bob@example.com", "admin", now_unix() + 1)
            .await
            .unwrap();
        let emails = state.resolve_allowed_emails().await.unwrap();
        // Admin is always first; DB rows follow in created_at ASC order.
        assert_eq!(
            emails,
            vec!["admin@example.com", "alice@example.com", "bob@example.com"]
        );
    }

    #[tokio::test]
    async fn resolve_allowed_emails_deduplicates_admin_present_in_db() {
        let state = resolve_state("admin@example.com").await;
        // add_allowed_user lowercases; admin_email may differ in case → still deduped.
        state
            .store
            .add_allowed_user("Admin@Example.COM", "self", now_unix())
            .await
            .unwrap();
        state
            .store
            .add_allowed_user("other@example.com", "admin", now_unix() + 1)
            .await
            .unwrap();
        let emails = state.resolve_allowed_emails().await.unwrap();
        // "admin@example.com" from DB is deduped; "other@example.com" remains.
        assert_eq!(emails, vec!["admin@example.com", "other@example.com"]);
    }

    #[tokio::test]
    async fn auth_state_preserves_public_url_path_prefix_in_google_redirect_uri() {
        let temp = tempdir().expect("tempdir");
        let state = AuthState::new(AuthConfig {
            mode: AuthMode::OAuth,
            public_url: Some(Url::parse("https://lab.example.com/gateway").expect("public url")),
            sqlite_path: temp.path().join("auth.db"),
            key_path: temp.path().join("auth.pem"),
            bootstrap_secret: None,
            allowed_client_redirect_uris: Vec::new(),
            admin_email: "admin@example.com".to_string(),
            google: GoogleConfig {
                client_id: "client-id".to_string(),
                client_secret: "client-secret".to_string(),
                callback_path: "/auth/google/callback".to_string(),
                scopes: vec![
                    "openid".to_string(),
                    "email".to_string(),
                    "profile".to_string(),
                ],
            },
            access_token_ttl: Duration::from_secs(3600),
            refresh_token_ttl: Duration::from_secs(3600),
            auth_code_ttl: Duration::from_secs(300),
            register_requests_per_minute: 10,
            authorize_requests_per_minute: 20,
            max_pending_oauth_states: 1024,
            default_provider: "google".to_string(),
            ..AuthConfig::default()
        })
        .await
        .expect("auth state");

        assert_eq!(
            state.provider("google").unwrap().callback_path(),
            "/gateway/auth/google/callback"
        );
    }

    #[tokio::test(flavor = "current_thread")]
    async fn per_ip_rate_limiter_evicts_at_cap_instead_of_growing() {
        let limiter = PerIpRateLimiter::with_max_buckets(60, 4);
        for i in 0..4u8 {
            assert!(limiter.try_acquire(IpAddr::from([10, 0, 0, i])).await);
        }
        assert_eq!(limiter.buckets.len(), 4);

        // A fifth previously-unseen IP evicts an existing bucket (none are
        // idle yet, so the least-recently-used one goes) rather than
        // growing the map past the cap.
        let newcomer = IpAddr::from([10, 0, 0, 200]);
        assert!(limiter.try_acquire(newcomer).await);
        assert_eq!(limiter.buckets.len(), 4);
        assert!(limiter.buckets.contains_key(&newcomer));
    }

    #[tokio::test(flavor = "current_thread")]
    async fn per_ip_rate_limiter_stays_bounded_under_address_churn() {
        let limiter = PerIpRateLimiter::with_max_buckets(60, 8);
        for i in 0..100u32 {
            let ip = IpAddr::from([10, 1, (i / 256) as u8, (i % 256) as u8]);
            assert!(limiter.try_acquire(ip).await);
        }
        assert!(limiter.buckets.len() <= 8);
    }
}