trustee_api/

auth.rs

//! Authentication module for Trustee API.
//!
//! Uses PEP for OIDC/OAuth2:
//! - `ResourceServerClient` for JWT validation (offline, cached JWKS)
//! - `OidcClient` for authorization code + PKCE login flow
//! - `PkceCookieManager` for stateless PKCE state (HMAC-signed cookies)
//! - `DevConfig` for local development bypass
//!
//! Two deployment modes:
//! - **Standalone**: browser hits /auth/login → IdP redirect → /auth/callback → cookie
//! - **Centralized**: external auth app sends `Authorization: Bearer <token>` directly
//!
//! Token extraction order: `Authorization: Bearer` header → `trustee_token` cookie.

use std::sync::Arc;
use std::time::Duration as StdDuration;

use axum::{
    body::Body,
    extract::{Query, State},
    http::{header, StatusCode},
    response::{IntoResponse, Json, Redirect, Response},
};
use axum_extra::extract::cookie::{Cookie, SameSite};
use pep::oidc_client::OidcClient;
use pep::oidc_resource_server::ResourceServerClient;
use pep::oidc::pkce_cookie::PkceCookieManager;
use pep::session_manager::WebSessionManager;
use pep::{DevConfig, JwtClaims, JwtValidationOptions, OidcClientConfig};
use serde::Deserialize;
use time::Duration as TimeDuration;

use cedar_policy::{Context, Entities, EntityUid, Request};
use std::str::FromStr;

// ---------------------------------------------------------------------------
// Configuration
// ---------------------------------------------------------------------------

/// Authentication configuration parsed from `[oidc]` and `[dev]` TOML sections.
#[derive(Debug, Clone)]
pub struct AuthConfig {
    /// OIDC provider issuer URL
    pub issuer_url: String,
    /// OAuth2 client ID
    pub client_id: String,
    /// OAuth2 client secret (None → public client, PKCE only)
    pub client_secret: Option<String>,
    /// Redirect URI for OIDC callback
    pub redirect_uri: String,
    /// OAuth2 scopes
    pub scope: String,
    /// Token cookie name
    pub cookie_name: String,
    /// Development mode configuration
    pub dev_config: DevConfig,
    /// JWT validation options
    pub validation_options: JwtValidationOptions,
    /// Secret for signing PKCE state cookies
    pub pkce_cookie_secret: String,
}

impl AuthConfig {
    /// Parse auth config from the merged trustee TOML string.
    ///
    /// Reads `[oidc]` and `[dev]` sections. If neither is present, returns None
    /// (auth disabled — all endpoints open).
    pub fn from_toml(config_toml: &str) -> Option<Self> {
        let table: toml::Table = toml::from_str(config_toml).ok()?;

        // Check for dev mode
        let dev_config = table.get("dev").and_then(|d| d.as_table()).map(|d| {
            DevConfig {
                local_dev_mode: d.get("local_dev_mode").and_then(|v| v.as_bool()).unwrap_or(false),
                local_dev_email: d.get("local_dev_email").and_then(|v| v.as_str()).map(String::from),
                local_dev_name: d.get("local_dev_name").and_then(|v| v.as_str()).map(String::from),
                local_dev_username: d.get("local_dev_username").and_then(|v| v.as_str()).map(String::from),
            }
        });

        // Dev mode without OIDC — return early with dev-only config
        if let Some(ref dc) = dev_config {
            if dc.local_dev_mode {
                // Try to get OIDC config too (for login endpoint), but it's optional in dev mode
                let oidc = Self::parse_oidc_section(&table);
                return Some(Self {
                    issuer_url: oidc.as_ref().map(|o| o.0.clone()).unwrap_or_else(|| "https://auth.example.com".into()),
                    client_id: oidc.as_ref().map(|o| o.1.clone()).unwrap_or_else(|| "trustee".into()),
                    client_secret: oidc.as_ref().and_then(|o| o.2.clone()),
                    redirect_uri: oidc.as_ref().map(|o| o.3.clone()).unwrap_or_else(|| "http://localhost:3000/auth/callback".into()),
                    scope: oidc.as_ref().map(|o| o.4.clone()).unwrap_or_else(|| "openid profile email".into()),
                    cookie_name: "trustee_token".into(),
                    dev_config: dc.clone(),
                    validation_options: JwtValidationOptions::default(),
                    pkce_cookie_secret: oidc.as_ref().map(|o| o.6.clone()).unwrap_or_else(|| "trustee-default-pkce-secret-change-me".into()),
                });
            }
        }

        // Production mode — requires [oidc] section
        let (issuer_url, client_id, client_secret, redirect_uri, scope, validation_options, pkce_secret) =
            Self::parse_oidc_section(&table)?;

        Some(Self {
            issuer_url,
            client_id,
            client_secret,
            redirect_uri,
            scope,
            cookie_name: "trustee_token".into(),
            dev_config: dev_config.unwrap_or_default(),
            validation_options,
            pkce_cookie_secret: pkce_secret,
        })
    }

    /// Parse the `[oidc]` section from a TOML table.
    /// Returns (issuer_url, client_id, client_secret, redirect_uri, scope, validation_options, pkce_secret).
    fn parse_oidc_section(
        table: &toml::Table,
    ) -> Option<(String, String, Option<String>, String, String, JwtValidationOptions, String)> {
        let oidc = table.get("oidc")?.as_table()?;

        let issuer_url = oidc.get("issuer_url")?.as_str()?.to_string();
        let client_id = oidc.get("client_id")?.as_str()?.to_string();
        let client_secret = oidc.get("client_secret").and_then(|v| v.as_str()).map(String::from);
        let redirect_uri = oidc
            .get("redirect_uri")
            .or_else(|| oidc.get("redirect_url")) // backward compat
            .and_then(|v| v.as_str())
            .unwrap_or("http://localhost:3000/auth/callback")
            .to_string();
        let scope = oidc
            .get("scope")
            .and_then(|v| v.as_str())
            .unwrap_or("openid profile email")
            .to_string();

        let mut validation_options = JwtValidationOptions::default();
        if let Some(skip) = oidc.get("skip_issuer_validation").and_then(|v| v.as_bool()) {
            validation_options.skip_issuer_validation = skip;
        }
        if let Some(skip) = oidc.get("skip_audience_validation").and_then(|v| v.as_bool()) {
            validation_options.skip_audience_validation = skip;
        }
        validation_options.expected_audience = oidc
            .get("expected_audience")
            .and_then(|v| v.as_str())
            .map(String::from);

        let pkce_secret = oidc
            .get("pkce_cookie_secret")
            .and_then(|v| v.as_str())
            .unwrap_or("trustee-default-pkce-secret-change-me")
            .to_string();

        Some((issuer_url, client_id, client_secret, redirect_uri, scope, validation_options, pkce_secret))
    }

    /// Build OIDC client configuration for PEP's OidcClient.
    pub fn oidc_client_config(&self) -> OidcClientConfig {
        OidcClientConfig {
            issuer_url: self.issuer_url.clone(),
            client_id: self.client_id.clone(),
            client_secret: self.client_secret.clone(),
            redirect_uri: self.redirect_uri.clone(),
            scope: self.scope.clone(),
            code_challenge_method: "S256".to_string(),
        }
    }
}

/// Shared authentication state, stored in ServerState.
#[derive(Clone)]
pub struct AuthState {
    /// OIDC client for login flow (authorization code + PKCE)
    pub oidc_client: OidcClient,
    /// Resource server client for JWT validation (lazy-initialized)
    pub resource_server: ResourceServerClient,
    /// OIDC client configuration
    pub client_config: OidcClientConfig,
    /// Auth configuration
    pub config: AuthConfig,
    /// Stateless PKCE cookie manager
    pub pkce_manager: PkceCookieManager,
    /// Web session manager (cookie session_id → server-side token with auto-refresh)
    pub session_manager: Arc<WebSessionManager>,
    /// Cedar authorizer for ABAC authorization (None = Cedar disabled)
    pub cedar_authorizer: Option<Arc<pep::cedar::CedarAuthorizer>>,
}

impl AuthState {
    /// Create new auth state from configuration.
    pub fn new(config: AuthConfig) -> Self {
        Self::with_cedar(config, None)
    }

    /// Create new auth state with optional Cedar authorizer.
    pub fn with_cedar(config: AuthConfig, cedar_authorizer: Option<Arc<pep::cedar::CedarAuthorizer>>) -> Self {
        let pkce_manager = PkceCookieManager::new(
            config.pkce_cookie_secret.as_bytes(),
            "trustee_pkce_state",
            StdDuration::from_secs(600),
        );

        let session_manager = Arc::new(WebSessionManager::new(
            OidcClient::new(),
            config.issuer_url.clone(),
            config.client_id.clone(),
            config.client_secret.clone(),
            config.scope.clone(),
        ));

        Self {
            oidc_client: OidcClient::new(),
            resource_server: ResourceServerClient::new(),
            client_config: config.oidc_client_config(),
            pkce_manager,
            session_manager,
            config,
            cedar_authorizer,
        }
    }

    /// Check if development mode is enabled.
    pub fn is_dev_mode(&self) -> bool {
        self.config.dev_config.local_dev_mode
    }

    /// Validate a JWT token using PEP's ResourceServerClient.
    pub async fn validate_token(&self, token: &str) -> anyhow::Result<JwtClaims> {
        let mut claims = self
            .resource_server
            .validate_jwt_with_options(
                token,
                &self.config.issuer_url,
                &self.config.client_id,
                &self.config.validation_options,
            )
            .await
            .map_err(|e| anyhow::anyhow!("Token validation failed: {}", e))?;

        // Enrich with userinfo for role/groups (cached, no-op if already present)
        let _ = self
            .resource_server
            .enrich_claims_with_userinfo(&mut claims, token, &self.config.issuer_url, None)
            .await;

        // PEP only merges groups/role from userinfo. If name/email are missing
        // (Kanidm JWTs only contain sub), fetch them from userinfo directly.
        if claims.name.is_none() || claims.email.is_none() {
            self.fill_userinfo_fields(&mut claims, token).await;
        }

        Ok(claims)
    }

    /// Fetch name/email/preferred_username from the OIDC userinfo endpoint
    /// and fill in any that are missing from the JWT claims.
    async fn fill_userinfo_fields(&self, claims: &mut JwtClaims, token: &str) {
        // Derive userinfo URL from issuer
        // For Kanidm: issuer_url is the discovery endpoint,
        // userinfo is at {issuer_url}/userinfo
        let userinfo_url = format!("{}/userinfo", self.config.issuer_url.trim_end_matches('/'));

        let client = reqwest::Client::new();
        let resp = client
            .get(&userinfo_url)
            .header("Authorization", format!("Bearer {}", token))
            .header("Accept", "application/json")
            .send()
            .await;

        let Ok(resp) = resp else {
            tracing::debug!("Userinfo request failed for name/email enrichment");
            return;
        };

        if !resp.status().is_success() {
            tracing::debug!("Userinfo returned {} for name/email enrichment", resp.status());
            return;
        }

        let Ok(userinfo): Result<serde_json::Map<String, serde_json::Value>, _> = resp.json().await else {
            return;
        };

        tracing::debug!("Userinfo keys: {:?}", userinfo.keys().collect::<Vec<_>>());

        if claims.name.is_none() {
            if let Some(name) = userinfo.get("name").and_then(|v| v.as_str()) {
                claims.name = Some(name.to_string());
            }
        }
        if claims.email.is_none() {
            if let Some(email) = userinfo.get("email").and_then(|v| v.as_str()) {
                claims.email = Some(email.to_string());
            }
        }
        if claims.preferred_username.is_none() {
            if let Some(uname) = userinfo.get("preferred_username").and_then(|v| v.as_str()) {
                claims.preferred_username = Some(uname.to_string());
            }
        }
    }

    /// Check Cedar authorization for the authenticated user.
    ///
    /// Returns Ok(()) if allowed (or if Cedar is not configured).
    /// Returns Err(()) if denied — caller should return 403 Forbidden.
    fn check_cedar_authorized(&self, claims: &JwtClaims) -> Result<(), ()> {
        let Some(ref authorizer) = self.cedar_authorizer else {
            return Ok(()); // Cedar not configured — allow
        };

        // Build principal entity from JWT claims
        let principal_entity = match pep::cedar::build_principal_entity(claims) {
            Ok(e) => e,
            Err(e) => {
                tracing::error!("Cedar: failed to build principal entity: {}", e);
                return Err(());
            }
        };

        // Build entities set with principal + TrusteeApp resource
        let mut entities_vec = vec![principal_entity];

        // Add a TrusteeApp entity as the resource
        let app_uid = match EntityUid::from_str(r#"TrusteeApp::"default""#) {
            Ok(uid) => uid,
            Err(e) => {
                tracing::error!("Cedar: failed to build TrusteeApp uid: {}", e);
                return Err(());
            }
        };
        let app_entity = match cedar_policy::Entity::new(
            app_uid,
            std::collections::HashMap::new(),
            std::collections::HashSet::new(),
        ) {
            Ok(e) => e,
            Err(e) => {
                tracing::error!("Cedar: failed to build TrusteeApp entity: {}", e);
                return Err(());
            }
        };
        entities_vec.push(app_entity);

        let entities = match Entities::from_entities(entities_vec, None) {
            Ok(e) => e,
            Err(e) => {
                tracing::error!("Cedar: failed to build entities set: {}", e);
                return Err(());
            }
        };

        // Build the Cedar authorization request
        let principal_uid = match pep::cedar::build_principal_uid(claims) {
            Ok(uid) => uid,
            Err(e) => {
                tracing::error!("Cedar: failed to build principal uid: {}", e);
                return Err(());
            }
        };

        let action_uid = match EntityUid::from_str(r#"Action::"Access""#) {
            Ok(uid) => uid,
            Err(e) => {
                tracing::error!("Cedar: failed to build action uid: {}", e);
                return Err(());
            }
        };

        let resource_uid = match EntityUid::from_str(r#"TrusteeApp::"default""#) {
            Ok(uid) => uid,
            Err(e) => {
                tracing::error!("Cedar: failed to build resource uid: {}", e);
                return Err(());
            }
        };

        let request = match Request::new(principal_uid, action_uid, resource_uid, Context::empty(), None) {
            Ok(r) => r,
            Err(e) => {
                tracing::error!("Cedar: failed to build request: {}", e);
                return Err(());
            }
        };

        let response = authorizer.is_allowed_with_entities(&request, &entities);

        if response.allowed() {
            tracing::debug!(
                "Cedar: authorized user {} (sub={})",
                claims.email.as_deref().unwrap_or("unknown"),
                claims.sub
            );
            Ok(())
        } else {
            tracing::warn!(
                "Cedar: DENIED user {} (sub={}) — matched policies: {:?}, errors: {:?}",
                claims.email.as_deref().unwrap_or("unknown"),
                claims.sub,
                response.matched_policies(),
                response.errors()
            );
            Err(())
        }
    }
}

// ---------------------------------------------------------------------------
// Auth checking — called by protected route handlers
// ---------------------------------------------------------------------------

/// Authenticated user info extracted from the token.
#[derive(Debug, Clone)]
pub struct AuthUser {
    pub sub: String,
    pub email: Option<String>,
    pub name: Option<String>,
    pub username: Option<String>,
    pub is_dev: bool,
}

impl From<JwtClaims> for AuthUser {
    fn from(claims: JwtClaims) -> Self {
        Self {
            sub: claims.sub,
            email: claims.email,
            name: claims.name,
            username: claims.preferred_username,
            is_dev: false,
        }
    }
}

/// Cookie max-age for session cookies (1 hour, matching the server-side idle timeout).
const SESSION_COOKIE_MAX_AGE: StdDuration = StdDuration::from_secs(3600);

/// Check authentication for a protected endpoint.
///
/// Returns `Ok(None)` if auth is not configured (open mode), or if a valid
/// token is present without needing cookie renewal. Returns `Ok(Some(cookie))`
/// if auth succeeded and the caller should include the given `Set-Cookie`
/// header value in the response (rolling session). Returns `Err(StatusCode)`
/// if auth is configured but no valid token is found.
///
/// Token sources (in order):
/// 1. `Authorization: Bearer <token>` header (raw JWT — validated directly)
/// 2. `trustee_token=<session_id>` cookie (looked up in WebSessionManager,
///    auto-refreshed if near expiry)
///
/// Dev mode tokens use the format `dev:email:name:username`.
pub async fn check_auth(
    auth: &Option<Arc<AuthState>>,
    headers: &axum::http::HeaderMap,
) -> Result<Option<String>, StatusCode> {
    let Some(auth) = auth.as_ref() else {
        return Ok(None); // Auth not configured — allow
    };

    // 1. Try Bearer header first (raw JWT — e.g. from API clients, Torpi proxy)
    if let Some(token) = headers
        .get(header::AUTHORIZATION)
        .and_then(|v| v.to_str().ok())
        .and_then(|v| v.strip_prefix("Bearer "))
        .map(|s| s.to_string())
    {
        // Dev mode token — only accepted when dev mode is currently enabled
        if token.starts_with("dev:") {
            if !auth.config.dev_config.local_dev_mode {
                tracing::warn!("Dev token presented but dev mode is disabled — rejecting");
                return Err(StatusCode::UNAUTHORIZED);
            }
            let parts: Vec<&str> = token.splitn(4, ':').collect();
            return if parts.len() >= 4 {
                Ok(None)
            } else {
                Err(StatusCode::UNAUTHORIZED)
            };
        }

        return match auth.validate_token(&token).await {
            Ok(claims) => {
                if auth.check_cedar_authorized(&claims).is_err() {
                    return Err(StatusCode::FORBIDDEN);
                }
                Ok(None)
            }
            Err(e) => {
                tracing::warn!("Bearer token validation failed: {}", e);
                Err(StatusCode::UNAUTHORIZED)
            }
        };
    }

    // 2. Try cookie (session_id → WebSessionManager → access token with auto-refresh)
    let session_id = headers
        .get(header::COOKIE)
        .and_then(|v| v.to_str().ok())
        .and_then(|cookies| extract_token_from_cookies(cookies, &auth.config.cookie_name));

    let Some(session_id) = session_id else {
        tracing::warn!("No auth token found in request");
        return Err(StatusCode::UNAUTHORIZED);
    };

    // Dev mode token in cookie — only accepted when dev mode is currently enabled
    if session_id.starts_with("dev:") {
        if !auth.config.dev_config.local_dev_mode {
            tracing::warn!("Dev cookie presented but dev mode is disabled — rejecting");
            return Err(StatusCode::UNAUTHORIZED);
        }
        let parts: Vec<&str> = session_id.splitn(4, ':').collect();
        return if parts.len() >= 4 {
            Ok(None)
        } else {
            Err(StatusCode::UNAUTHORIZED)
        };
    }

    // Session-based: look up via WebSessionManager (auto-refreshes)
    match auth.session_manager.get_token(&session_id).await {
        Ok(access_token) => match auth.validate_token(&access_token).await {
            Ok(claims) => {
                // Cedar authorization check
                if auth.check_cedar_authorized(&claims).is_err() {
                    return Err(StatusCode::FORBIDDEN);
                }
                // Roll the cookie — reset max-age so active users stay logged in
                let secure = auth.client_config.redirect_uri.starts_with("https");
                let cookie = create_auth_cookie(
                    &auth.config.cookie_name,
                    &session_id,
                    SESSION_COOKIE_MAX_AGE,
                    secure,
                );
                Ok(Some(cookie.to_string()))
            }
            Err(e) => {
                // Token was returned but JWT validation failed (e.g. ExpiredSignature
                // due to clock skew). Force-refresh and retry once.
                tracing::warn!("Session token validation failed: {} — attempting force-refresh", e);
                match auth.session_manager.force_refresh(&session_id).await {
                    Ok(new_token) => match auth.validate_token(&new_token).await {
                        Ok(claims) => {
                            // Cedar authorization check
                            if auth.check_cedar_authorized(&claims).is_err() {
                                return Err(StatusCode::FORBIDDEN);
                            }
                            let secure = auth.client_config.redirect_uri.starts_with("https");
                            let cookie = create_auth_cookie(
                                &auth.config.cookie_name,
                                &session_id,
                                SESSION_COOKIE_MAX_AGE,
                                secure,
                            );
                            Ok(Some(cookie.to_string()))
                        }
                        Err(e2) => {
                            tracing::warn!("Session token still invalid after force-refresh: {}", e2);
                            Err(StatusCode::UNAUTHORIZED)
                        }
                    },
                    Err(e2) => {
                        tracing::warn!("Force-refresh failed: {}", e2);
                        Err(StatusCode::UNAUTHORIZED)
                    }
                }
            }
        },
        Err(e) => {
            tracing::warn!("Session lookup/refresh failed: {}", e);
            Err(StatusCode::UNAUTHORIZED)
        }
    }
}

/// Extract a valid access token from the request (for use by handlers that
/// need the token itself, not just auth checking).
///
/// Resolves session_id cookies to actual access tokens via WebSessionManager.
/// Bearer headers are returned as-is.
async fn resolve_access_token(
    auth: &AuthState,
    headers: &axum::http::HeaderMap,
) -> Result<String, StatusCode> {
    // Bearer header — return as-is
    if let Some(token) = headers
        .get(header::AUTHORIZATION)
        .and_then(|v| v.to_str().ok())
        .and_then(|v| v.strip_prefix("Bearer "))
        .map(|s| s.to_string())
    {
        return Ok(token);
    }

    // Cookie — resolve session_id → access_token
    let session_id = headers
        .get(header::COOKIE)
        .and_then(|v| v.to_str().ok())
        .and_then(|cookies| extract_token_from_cookies(cookies, &auth.config.cookie_name));

    match session_id {
        Some(sid) if sid.starts_with("dev:") => {
            if !auth.config.dev_config.local_dev_mode {
                tracing::warn!("Dev cookie in resolve_access_token but dev mode is disabled — rejecting");
                Err(StatusCode::UNAUTHORIZED)
            } else {
                Ok(sid)
            }
        }
        Some(sid) => auth.session_manager.get_token(&sid).await.map_err(|e| {
            tracing::warn!("Failed to resolve session token: {}", e);
            StatusCode::UNAUTHORIZED
        }),
        None => Err(StatusCode::UNAUTHORIZED),
    }
}

/// Extract token value from a cookie header string.
fn extract_token_from_cookies(cookie_header: &str, cookie_name: &str) -> Option<String> {
    for cookie in cookie_header.split(';') {
        let cookie = cookie.trim();
        if let Some(value) = cookie.strip_prefix(&format!("{}=", cookie_name)) {
            return Some(value.to_string());
        }
    }
    None
}

// ---------------------------------------------------------------------------
// Auth routes: /auth/login, /auth/callback, /auth/me, /auth/logout
// ---------------------------------------------------------------------------

/// Build the auth routes as a nested Router.
pub fn auth_routes() -> axum::Router<crate::ServerState> {
    axum::Router::new()
        .route("/login", axum::routing::get(login_handler))
        .route("/callback", axum::routing::get(callback_handler))
        .route("/me", axum::routing::get(me_handler))
        .route("/logout", axum::routing::post(logout_handler))
        .route("/mcp/login", axum::routing::get(mcp_login_handler))
        .route("/mcp/callback", axum::routing::get(mcp_callback_handler))
        .route("/mcp/status", axum::routing::get(mcp_status_handler))
        .route("/mcp/logout", axum::routing::post(mcp_logout_handler))
}

/// Query parameters for OIDC callback.
#[derive(Debug, Deserialize)]
pub struct CallbackQuery {
    pub code: Option<String>,
    pub state: Option<String>,
    pub error: Option<String>,
    pub error_description: Option<String>,
}

/// GET /auth/login — initiate OIDC login with PKCE, or create dev session.
async fn login_handler(
    State(state): State<crate::ServerState>,
) -> Result<Response, AuthError> {
    let auth = state.auth.as_ref().ok_or(AuthError::AuthNotConfigured)?;

    // Dev mode — create synthetic session
    if auth.is_dev_mode() {
        tracing::info!("Dev mode: creating dev session");
        let dev = &auth.config.dev_config;
        let dev_token = format!(
            "dev:{}:{}:{}",
            dev.local_dev_email.as_deref().unwrap_or("dev@localhost"),
            dev.local_dev_name.as_deref().unwrap_or("Dev User"),
            dev.local_dev_username.as_deref().unwrap_or("dev")
        );
        let cookie = create_auth_cookie(&auth.config.cookie_name, &dev_token, StdDuration::from_secs(86400), false);
        return Ok(Response::builder()
            .status(StatusCode::FOUND)
            .header(header::LOCATION, "/")
            .header(header::SET_COOKIE, cookie.to_string())
            .body(Body::empty())
            .unwrap());
    }

    // Production — redirect to IdP with PKCE
    let pkce_session = auth.pkce_manager.create();
    let challenge = OidcClient::generate_code_challenge(&pkce_session.verifier);

    let auth_url = auth
        .oidc_client
        .build_authorization_url(&auth.client_config, &pkce_session.state, Some(&challenge))
        .await
        .map_err(|e| AuthError::OidcError(e.to_string()))?;

    // Set PKCE state cookie (HttpOnly, SameSite=Lax)
    // Secure flag follows the redirect_uri scheme — HTTP localhost/LAN must not
    // set Secure or the browser drops the cookie and PKCE state is lost.
    let secure = auth.client_config.redirect_uri.starts_with("https");
    let pkce_cookie = Cookie::build((
        auth.pkce_manager.cookie_name().to_string(),
        pkce_session.cookie_value,
    ))
        .path("/")
        .http_only(true)
        .same_site(SameSite::Lax)
        .secure(secure)
        .max_age(TimeDuration::seconds(auth.pkce_manager.ttl().as_secs() as i64))
        .build();

    Ok(Response::builder()
        .status(StatusCode::TEMPORARY_REDIRECT)
        .header(header::LOCATION, &auth_url)
        .header(header::SET_COOKIE, pkce_cookie.to_string())
        .body(Body::empty())
        .unwrap())
}

/// GET /auth/callback — exchange authorization code for tokens, set cookie.
async fn callback_handler(
    State(state): State<crate::ServerState>,
    Query(query): Query<CallbackQuery>,
    headers: axum::http::HeaderMap,
) -> Result<Response, AuthError> {
    let auth = state.auth.as_ref().ok_or(AuthError::AuthNotConfigured)?;

    // Check for errors from IdP
    if let Some(error) = query.error {
        let desc = query.error_description.unwrap_or_default();
        tracing::error!("OIDC error: {} - {}", error, desc);
        return Ok(Redirect::temporary(&format!(
            "/?error={}&error_description={}",
            urlencoding::encode(&error),
            urlencoding::encode(&desc)
        ))
        .into_response());
    }

    let code = query.code.ok_or(AuthError::MissingCode)?;
    let oauth_state = query.state.ok_or(AuthError::MissingState)?;

    // Retrieve PKCE cookie
    let cookie_header = headers
        .get(header::COOKIE)
        .and_then(|v| v.to_str().ok())
        .unwrap_or("");
    let pkce_value = extract_token_from_cookies(cookie_header, auth.pkce_manager.cookie_name())
        .ok_or(AuthError::InvalidState)?;

    // Verify PKCE cookie (HMAC + expiry + state match)
    let verifier = auth
        .pkce_manager
        .verify(&pkce_value, &oauth_state)
        .ok_or(AuthError::InvalidState)?;

    // Exchange code for tokens
    tracing::info!("Exchanging authorization code for tokens");
    let token_response = auth
        .oidc_client
        .exchange_code_for_tokens(&auth.client_config, &code, Some(&verifier))
        .await
        .map_err(|e| AuthError::TokenExchangeFailed(e.to_string()))?;

    let session_id = auth
        .session_manager
        .create_session(&token_response)
        .await
        .map_err(|e| AuthError::TokenExchangeFailed(format!("Session creation failed: {}", e)))?;

    // Cookie lifetime matches server-side idle timeout (1 hour).
    // The cookie is rolled on every successful request via check_auth().
    let max_age = SESSION_COOKIE_MAX_AGE;

    // Set auth cookie — Secure only when redirect_uri is HTTPS
    let secure = auth.client_config.redirect_uri.starts_with("https");
    let cookie = create_auth_cookie(&auth.config.cookie_name, &session_id, max_age, secure);

    // Clear PKCE cookie (single-use)
    let clear_pkce = Cookie::build((auth.pkce_manager.cookie_name().to_string(), ""))
        .path("/")
        .http_only(true)
        .same_site(SameSite::Lax)
        .max_age(TimeDuration::seconds(-1))
        .build();

    tracing::info!("Authentication successful, redirecting to /");

    Ok(Response::builder()
        .status(StatusCode::FOUND)
        .header(header::LOCATION, "/")
        .header(header::SET_COOKIE, cookie.to_string())
        .header(header::SET_COOKIE, clear_pkce.to_string())
        .body(Body::empty())
        .unwrap())
}

/// GET /auth/me — return current user info.
async fn me_handler(
    State(state): State<crate::ServerState>,
    headers: axum::http::HeaderMap,
) -> Response {
    let Some(ref auth) = state.auth else {
        // Auth not configured — always authenticated (no auth required)
        return axum::Json(serde_json::json!({
            "authenticated": true,
            "auth_enabled": false
        }))
        .into_response();
    };

    let cookie_header = headers
        .get(header::COOKIE)
        .and_then(|v| v.to_str().ok())
        .unwrap_or("");

    // Also try Authorization: Bearer header
    let bearer = headers
        .get(header::AUTHORIZATION)
        .and_then(|v| v.to_str().ok())
        .and_then(|v| v.strip_prefix("Bearer "))
        .map(String::from);

    let token = bearer.clone().or_else(|| extract_token_from_cookies(cookie_header, &auth.config.cookie_name));

    let Some(cookie_value) = token else {
        return axum::Json(serde_json::json!({
            "authenticated": false,
            "auth_enabled": true
        }))
        .into_response();
    };

    // Dev mode token (stored directly in cookie, no session manager)
    // Only report as authenticated when dev mode is currently enabled
    if cookie_value.starts_with("dev:") && auth.config.dev_config.local_dev_mode {
        let parts: Vec<&str> = cookie_value.splitn(4, ':').collect();
        if parts.len() >= 4 {
            return axum::Json(serde_json::json!({
                "authenticated": true,
                "auth_enabled": true,
                "email": parts[1],
                "name": parts[2],
                "username": parts[3],
                "dev_mode": true
            }))
            .into_response();
        }
    }

    // Bearer header = raw JWT; Cookie value = session_id → resolve to access token
    let access_token = if bearer.is_some() {
        // Already have the raw token from Bearer header
        cookie_value
    } else {
        // Cookie value is a session_id — resolve via WebSessionManager
        match auth.session_manager.get_token(&cookie_value).await {
            Ok(token) => token,
            Err(e) => {
                tracing::debug!("Session token resolution failed for /auth/me: {}", e);
                return axum::Json(serde_json::json!({
                    "authenticated": false,
                    "auth_enabled": true
                }))
                .into_response();
            }
        }
    };

    // Real JWT — validate and return claims
    match auth.validate_token(&access_token).await {
        Ok(claims) => axum::Json(serde_json::json!({
            "authenticated": true,
            "auth_enabled": true,
            "sub": claims.sub,
            "email": claims.email,
            "name": claims.name,
            "username": claims.preferred_username,
            "dev_mode": false
        }))
        .into_response(),
        Err(e) => {
            tracing::debug!("Token validation failed for /auth/me: {}", e);
            axum::Json(serde_json::json!({
                "authenticated": false,
                "auth_enabled": true
            }))
            .into_response()
        }
    }
}

/// POST /auth/logout — destroy session and clear auth cookie.
async fn logout_handler(
    State(state): State<crate::ServerState>,
    headers: axum::http::HeaderMap,
) -> Response {
    let cookie_name = state
        .auth
        .as_ref()
        .map(|a| a.config.cookie_name.as_str())
        .unwrap_or("trustee_token");

    // Destroy the session on the server side
    if let Some(ref auth) = state.auth {
        if let Some(cookie_header) = headers.get(header::COOKIE).and_then(|v| v.to_str().ok()) {
            if let Some(session_id) = extract_token_from_cookies(cookie_header, cookie_name) {
                if !session_id.starts_with("dev:") {
                    let _ = auth.session_manager.destroy_session(&session_id);
                }
            }
        }
    }

    let cookie = Cookie::build((cookie_name.to_string(), ""))
        .path("/")
        .http_only(true)
        .same_site(SameSite::Lax)
        .max_age(TimeDuration::seconds(-1))
        .build();

    Response::builder()
        .status(StatusCode::FOUND)
        .header(header::LOCATION, "/")
        .header(header::SET_COOKIE, cookie.to_string())
        .body(Body::empty())
        .unwrap()
}

// ---------------------------------------------------------------------------
// MCP auth routes: /auth/mcp/login, /callback, /status, /logout (C2)
// ---------------------------------------------------------------------------

/// Query parameters for MCP login initiation.
#[derive(Debug, Deserialize)]
pub struct McpLoginQuery {
    pub cred: String,
}

/// Query parameters for MCP OIDC callback.
#[derive(Debug, Deserialize)]
pub struct McpCallbackQuery {
    pub code: Option<String>,
    pub state: Option<String>,
    pub error: Option<String>,
    pub error_description: Option<String>,
}

/// GET /auth/mcp/login?cred=<name> — initiate per-server OIDC PKCE login.
///
/// Reads the credential config from the session's config_toml, verifies it's
/// `type = "web-interactive"`, then redirects to the OIDC provider.
async fn mcp_login_handler(
    State(state): State<crate::ServerState>,
    Query(query): Query<McpLoginQuery>,
    headers: axum::http::HeaderMap,
) -> Result<Response, AuthError> {
    // Require authentication — user must be logged into trustee-web
    crate::auth::check_auth(&state.auth, &headers)
        .await
        .map_err(|_| AuthError::AuthNotConfigured)?;

    let auth = state.auth.as_ref().ok_or(AuthError::AuthNotConfigured)?;

    // Parse MCP credential config from session's config_toml
    let cred_config = load_mcp_credential(&state, &query.cred).await?;

    let (issuer_url, client_id, client_secret, scope) = match &cred_config {
        McpCredentialInfo::WebInteractive {
            issuer_url,
            client_id,
            client_secret,
            scope,
        } => (issuer_url.clone(), client_id.clone(), client_secret.clone(), scope.clone()),
        _ => {
            return Ok(Redirect::temporary(&format!(
                "/?mcp_error={}",
                urlencoding::encode(&format!("Credential '{}' is not web-interactive type", query.cred))
            ))
            .into_response());
        }
    };

    // Build PKCE pair using a separate PkceCookieManager for MCP
    let oidc_client = OidcClient::new();
    let verifier = OidcClient::generate_code_verifier();
    let challenge = OidcClient::generate_code_challenge(&verifier);
    let oauth_state = OidcClient::generate_state();

    // Build OidcClientConfig for the MCP credential's OIDC client
    let mcp_redirect_uri = format!(
        "{}/auth/mcp/callback",
        auth.client_config.redirect_uri.trim_end_matches('/').trim_end_matches("/auth/callback")
    );

    let mcp_client_config = OidcClientConfig {
        issuer_url: issuer_url.clone(),
        client_id: client_id.clone(),
        client_secret: client_secret.clone(),
        redirect_uri: mcp_redirect_uri.clone(),
        scope: scope.clone(),
        code_challenge_method: "S256".to_string(),
    };

    // Build authorization URL
    let auth_url = oidc_client
        .build_authorization_url(&mcp_client_config, &oauth_state, Some(&challenge))
        .await
        .map_err(|e| AuthError::OidcError(e.to_string()))?;

    // Store PKCE state + credential name in the in-memory map
    mcp_pkce().insert(oauth_state.clone(), verifier.clone(), query.cred.clone()).await;

    tracing::info!(
        "Initiating MCP browser login for credential '{}' (issuer={})",
        query.cred, issuer_url
    );

    Ok(Response::builder()
        .status(StatusCode::TEMPORARY_REDIRECT)
        .header(header::LOCATION, &auth_url)
        .body(Body::empty())
        .unwrap())
}

/// GET /auth/mcp/callback — handle MCP OIDC callback, store tokens.
async fn mcp_callback_handler(
    State(state): State<crate::ServerState>,
    Query(query): Query<McpCallbackQuery>,
    headers: axum::http::HeaderMap,
) -> Result<Response, AuthError> {
    let auth = state.auth.as_ref().ok_or(AuthError::AuthNotConfigured)?;

    // Check for errors from IdP
    if let Some(error) = query.error {
        let desc = query.error_description.unwrap_or_default();
        tracing::error!("MCP OIDC error: {} - {}", error, desc);
        return Ok(Redirect::temporary(&format!(
            "/?mcp_error={}&error_description={}",
            urlencoding::encode(&error),
            urlencoding::encode(&desc)
        ))
        .into_response());
    }

    let code = query.code.ok_or(AuthError::MissingCode)?;
    let oauth_state = query.state.ok_or(AuthError::MissingState)?;

    // Look up PKCE verifier + credential name from in-memory store
    let pkce_data = mcp_pkce().take(&oauth_state).await
        .ok_or(AuthError::InvalidState)?;

    let verifier = pkce_data.verifier;
    let cred_name = &pkce_data.cred_name;

    // Parse the MCP credential config to get OIDC settings for token exchange
    let cred_config = load_mcp_credential(&state, cred_name).await?;

    let (issuer_url, client_id, client_secret, scope) = match &cred_config {
        McpCredentialInfo::WebInteractive {
            issuer_url,
            client_id,
            client_secret,
            scope,
        } => (issuer_url.clone(), client_id.clone(), client_secret.clone(), scope.clone()),
        _ => {
            return Ok(Redirect::temporary(&format!(
                "/?mcp_error={}",
                urlencoding::encode("Credential is not web-interactive type")
            ))
            .into_response());
        }
    };

    // Build redirect URI (must match what was used in login)
    let mcp_redirect_uri = format!(
        "{}/auth/mcp/callback",
        auth.client_config.redirect_uri.trim_end_matches('/').trim_end_matches("/auth/callback")
    );

    let mcp_client_config = OidcClientConfig {
        issuer_url: issuer_url.clone(),
        client_id: client_id.clone(),
        client_secret: client_secret.clone(),
        redirect_uri: mcp_redirect_uri,
        scope: scope.clone(),
        code_challenge_method: "S256".to_string(),
    };

    // Exchange code for tokens
    tracing::info!("Exchanging MCP authorization code for tokens (credential={})", cred_name);
    let oidc_client = OidcClient::new();
    let token_response = oidc_client
        .exchange_code_for_tokens(&mcp_client_config, &code, Some(&verifier))
        .await
        .map_err(|e| AuthError::TokenExchangeFailed(e.to_string()))?;

    // Compute expires_at
    let expires_at = {
        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap_or_default()
            .as_secs();
        let expires_epoch = now + token_response.expires_in.unwrap_or(900);
        let days = expires_epoch / 86400;
        let rem = expires_epoch % 86400;
        let h = rem / 3600;
        let m = (rem % 3600) / 60;
        let s = rem % 60;
        let z = days as i64 + 719468;
        let era = if z >= 0 { z } else { z - 146096 } / 146097;
        let doe = (z - era * 146097) as u64;
        let yoe = (doe - doe / 1460 + doe / 36524 - doe / 146096) / 365;
        let y = yoe as i64 + era * 400;
        let doy = doe - (365 * yoe + yoe / 4 - yoe / 100);
        let mp = (5 * doy + 2) / 153;
        let d = doy - (153 * mp + 2) / 5 + 1;
        let mon = if mp < 10 { mp + 3 } else { mp - 9 };
        let yr = if mon <= 2 { y + 1 } else { y };
        format!("{:04}-{:02}-{:02}T{:02}:{:02}:{:02}Z", yr, mon, d, h, m, s)
    };

    // Store via FileTokenStore (same as `trustee mcp auth`)
    use pep::{FileTokenStore, StoredToken, TokenStore};

    let stored = StoredToken::new(
        &token_response.access_token,
        token_response.refresh_token.clone(),
        "Bearer",
        &expires_at,
        token_response.scope.clone(),
    );

    let agent_name = {
        let user_key = state.resolve_user_key(&headers).await;
        let (_sid, session_arc, _, _) = state.ensure_active_session(&user_key).await;
        let session = session_arc.lock().await;
        session.agent_name.clone()
    };
    let token_store = FileTokenStore::new(&agent_name);

    if let Err(e) = token_store.save(cred_name, &stored) {
        tracing::error!("Failed to store MCP token: {}", e);
        return Ok(Redirect::temporary(&format!(
            "/?mcp_error={}",
            urlencoding::encode(&format!("Failed to store token: {}", e))
        ))
        .into_response());
    }

    tracing::info!(
        "MCP authentication successful for credential '{}' (expires {})",
        cred_name, expires_at
    );

    Ok(Response::builder()
        .status(StatusCode::FOUND)
        .header(header::LOCATION, format!("/?mcp_connected={}", urlencoding::encode(cred_name)))
        .body(Body::empty())
        .unwrap())
}

/// GET /auth/mcp/status — return connection status for all MCP credentials.
async fn mcp_status_handler(
    State(state): State<crate::ServerState>,
    headers: axum::http::HeaderMap,
) -> Response {
    use pep::{FileTokenStore, TokenStore};

    // Require auth
    if let Err(code) = crate::auth::check_auth(&state.auth, &headers).await {
        return (code, Json(serde_json::json!({"error": "Unauthorized"}))).into_response();
    }

    // Parse MCP config from session
    let config_toml = {
        let user_key = state.resolve_user_key(&headers).await;
        let (_sid, session_arc, _, _) = state.ensure_active_session(&user_key).await;
        let session = session_arc.lock().await;
        match &session.config_toml {
            Some(t) => t.clone(),
            None => return (StatusCode::INTERNAL_SERVER_ERROR, "Config not loaded").into_response(),
        }
    };

    let mcp_config: toml::Value = match toml::from_str(&config_toml) {
        Ok(v) => v,
        Err(_) => return Json(serde_json::json!([])).into_response(),
    };

    let agent_name = {
        let user_key = state.resolve_user_key(&headers).await;
        let (_sid, session_arc, _, _) = state.ensure_active_session(&user_key).await;
        let session = session_arc.lock().await;
        session.agent_name.clone()
    };
    let token_store = FileTokenStore::new(&agent_name);

    // Build server → credential mapping
    let servers = mcp_config
        .get("mcp")
        .and_then(|m| m.get("servers"))
        .and_then(|s| s.as_array());
    let credentials = mcp_config
        .get("mcp")
        .and_then(|m| m.get("credentials"))
        .and_then(|c| c.as_table());

    let mut cred_servers: std::collections::HashMap<String, Vec<String>> = std::collections::HashMap::new();
    if let Some(servers) = servers {
        for server in servers {
            let name = server.get("name").and_then(|n| n.as_str()).unwrap_or("");
            let cred_ref = server.get("credentials").and_then(|c| c.as_str()).unwrap_or("");
            if !cred_ref.is_empty() {
                cred_servers
                    .entry(cred_ref.to_string())
                    .or_default()
                    .push(name.to_string());
            }
        }
    }

    let mut result = Vec::new();

    if let Some(creds) = credentials {
        for (cred_name, cred_config) in creds {
            let cred_type = cred_config.get("type").and_then(|t| t.as_str()).unwrap_or("unknown");
            let servers_using = cred_servers.get(cred_name).cloned().unwrap_or_default();

            if cred_type == "web-session" {
                // Session credentials are always "connected" if auth is enabled
                let connected = state.auth.is_some();
                result.push(serde_json::json!({
                    "credential": cred_name,
                    "type": cred_type,
                    "connected": connected,
                    "servers": servers_using,
                }));
            } else if cred_type == "web-interactive" || cred_type == "interactive" {
                // Check token store
                let status = match token_store.load(cred_name) {
                    Ok(Some(token)) => {
                        let expired = token.is_expired();
                        serde_json::json!({
                            "credential": cred_name,
                            "type": cred_type,
                            "connected": !expired,
                            "expires_at": token.expires_at,
                            "servers": servers_using,
                        })
                    }
                    _ => serde_json::json!({
                        "credential": cred_name,
                        "type": cred_type,
                        "connected": false,
                        "servers": servers_using,
                    }),
                };
                result.push(status);
            }
        }
    }

    Json(serde_json::Value::Array(result)).into_response()
}

/// POST /auth/mcp/logout?cred=<name> — remove stored MCP tokens.
async fn mcp_logout_handler(
    State(state): State<crate::ServerState>,
    Query(query): Query<McpLoginQuery>,
    headers: axum::http::HeaderMap,
) -> Response {
    use pep::{FileTokenStore, TokenStore};

    // Require auth
    if let Err(code) = crate::auth::check_auth(&state.auth, &headers).await {
        return (code, Json(serde_json::json!({"error": "Unauthorized"}))).into_response();
    }

    let agent_name = {
        let user_key = state.resolve_user_key(&headers).await;
        let (_sid, session_arc, _, _) = state.ensure_active_session(&user_key).await;
        let session = session_arc.lock().await;
        session.agent_name.clone()
    };
    let token_store = FileTokenStore::new(&agent_name);

    match token_store.delete(&query.cred) {
        Ok(()) => {
            tracing::info!("Removed MCP credentials for '{}'", query.cred);
            Json(serde_json::json!({"success": true})).into_response()
        }
        Err(e) => {
            tracing::error!("Failed to remove MCP credentials: {}", e);
            (
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(serde_json::json!({"error": e.to_string()})),
            )
                .into_response()
        }
    }
}

// ---------------------------------------------------------------------------
// MCP auth helpers
// ---------------------------------------------------------------------------

/// In-memory store for MCP PKCE state (state token → verifier + credential name).
/// Entries expire after 10 minutes. Not persisted across restarts.
struct McpPkceStore {
    entries: tokio::sync::Mutex<std::collections::HashMap<String, McpPkceEntry>>,
}

struct McpPkceEntry {
    verifier: String,
    cred_name: String,
    created_at: std::time::Instant,
}

impl McpPkceStore {
    fn new() -> Self {
        Self {
            entries: tokio::sync::Mutex::new(std::collections::HashMap::new()),
        }
    }

    /// Insert a PKCE entry. Cleans up entries older than 10 minutes.
    async fn insert(&self, state: String, verifier: String, cred_name: String) {
        let mut map = self.entries.lock().await;
        // Cleanup expired entries (older than 10 min)
        let cutoff = std::time::Instant::now() - std::time::Duration::from_secs(600);
        map.retain(|_, v| v.created_at > cutoff);
        map.insert(state, McpPkceEntry {
            verifier,
            cred_name,
            created_at: std::time::Instant::now(),
        });
    }

    /// Take and remove a PKCE entry (single-use).
    async fn take(&self, state: &str) -> Option<McpPkceEntry> {
        let mut map = self.entries.lock().await;
        map.remove(state)
    }
}

/// Global singleton PKCE store for MCP browser logins.
static MCP_PKCE: std::sync::OnceLock<McpPkceStore> = std::sync::OnceLock::new();

/// Get or initialize the global MCP PKCE store.
fn mcp_pkce() -> &'static McpPkceStore {
    MCP_PKCE.get_or_init(McpPkceStore::new)
}

/// Simplified MCP credential info (parsed from TOML).
enum McpCredentialInfo {
    WebInteractive {
        issuer_url: String,
        client_id: String,
        client_secret: Option<String>,
        scope: String,
    },
    Other(String),
}

/// Load a specific MCP credential from the session's config_toml.
async fn load_mcp_credential(
    state: &crate::ServerState,
    cred_name: &str,
) -> Result<McpCredentialInfo, AuthError> {
    let config_toml = state
        .config_toml
        .clone()
        .ok_or(AuthError::AuthNotConfigured)?;

    let config: toml::Value = toml::from_str(&config_toml)
        .map_err(|e| AuthError::OidcError(format!("Config parse error: {}", e)))?;

    let cred = config
        .get("mcp")
        .and_then(|m| m.get("credentials"))
        .and_then(|c| c.as_table())
        .and_then(|c| c.get(cred_name))
        .ok_or_else(|| AuthError::OidcError(format!("Credential '{}' not found", cred_name)))?;

    let cred_type = cred.get("type").and_then(|t| t.as_str()).unwrap_or("unknown");

    match cred_type {
        "web-interactive" => {
            let issuer_url = cred
                .get("issuer_url")
                .and_then(|v| v.as_str())
                .ok_or_else(|| AuthError::OidcError("Missing issuer_url".into()))?
                .to_string();
            let client_id = cred
                .get("client_id")
                .and_then(|v| v.as_str())
                .ok_or_else(|| AuthError::OidcError("Missing client_id".into()))?
                .to_string();
            let client_secret = cred
                .get("client_secret")
                .and_then(|v| v.as_str())
                .map(String::from);
            let scope = cred
                .get("scope")
                .and_then(|v| v.as_str())
                .unwrap_or("openid profile email")
                .to_string();

            Ok(McpCredentialInfo::WebInteractive {
                issuer_url,
                client_id,
                client_secret,
                scope,
            })
        }
        other => Ok(McpCredentialInfo::Other(other.to_string())),
    }
}

// ---------------------------------------------------------------------------
// Helpers
// ---------------------------------------------------------------------------

/// Create an HttpOnly auth cookie.
fn create_auth_cookie(name: &str, value: &str, max_age: StdDuration, secure: bool) -> Cookie<'static> {
    Cookie::build((name.to_string(), value.to_string()))
        .path("/")
        .http_only(true)
        .same_site(SameSite::Lax)
        .secure(secure)
        .max_age(TimeDuration::seconds(max_age.as_secs() as i64))
        .build()
}

// ---------------------------------------------------------------------------
// Error handling
// ---------------------------------------------------------------------------

/// Authentication errors.
#[derive(Debug)]
pub enum AuthError {
    MissingCode,
    MissingState,
    InvalidState,
    OidcError(String),
    TokenExchangeFailed(String),
    AuthNotConfigured,
}

impl IntoResponse for AuthError {
    fn into_response(self) -> Response {
        let (_status, msg) = match self {
            AuthError::MissingCode => (StatusCode::BAD_REQUEST, "Missing authorization code"),
            AuthError::MissingState => (StatusCode::BAD_REQUEST, "Missing state parameter"),
            AuthError::InvalidState => (StatusCode::BAD_REQUEST, "Invalid or expired state"),
            AuthError::OidcError(_) => (StatusCode::SERVICE_UNAVAILABLE, "Authentication service error"),
            AuthError::TokenExchangeFailed(_) => (StatusCode::BAD_REQUEST, "Token exchange failed"),
            AuthError::AuthNotConfigured => (StatusCode::NOT_IMPLEMENTED, "Authentication not configured"),
        };
        Redirect::temporary(&format!("/?error={}", urlencoding::encode(msg))).into_response()
    }
}