feat(auth): add authentication integration

Signed-off-by: kjuulh <contact@kjuulh.io>

como_auth/src/introspection.rs

@@ -1,12 +1,16 @@
-use std::sync::Arc;
+use std::{ops::Deref, sync::Arc};
 
 use async_trait::async_trait;
 use axum::extract::FromRef;
+use oauth2::TokenIntrospectionResponse;
 use openidconnect::IntrospectionUrl;
 use zitadel::{
     axum::introspection::IntrospectionStateBuilderError,
     credentials::Application,
-    oidc::{discovery::discover, introspection::AuthorityAuthentication},
+    oidc::{
+        discovery::discover,
+        introspection::{introspect, AuthorityAuthentication},
+    },
 };
 
 use crate::AuthClap;
@@ -14,10 +18,10 @@ use crate::AuthClap;
 #[async_trait]
 pub trait Introspection {
     async fn get_user(&self) -> anyhow::Result<()>;
+    async fn get_id_token(&self, token: &str) -> anyhow::Result<String>;
 }
 
 pub struct IntrospectionService(Arc<dyn Introspection + Send + Sync + 'static>);
-
 impl IntrospectionService {
     pub async fn new_zitadel(config: &AuthClap) -> anyhow::Result<Self> {
         let res = IntrospectionStateBuilder::new(&config.zitadel.authority_url.clone().unwrap())
@@ -34,6 +38,14 @@ impl IntrospectionService {
     }
 }
 
+impl Deref for IntrospectionService {
+    type Target = Arc<dyn Introspection + Send + Sync + 'static>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
 pub struct ZitadelIntrospection {
     state: IntrospectionState,
 }
@@ -49,6 +61,21 @@ impl Introspection for ZitadelIntrospection {
     async fn get_user(&self) -> anyhow::Result<()> {
         Ok(())
     }
+    async fn get_id_token(&self, token: &str) -> anyhow::Result<String> {
+        let config = &self.state.config;
+        let res = introspect(
+            &config.introspection_uri,
+            &config.authority,
+            &config.authentication,
+            token,
+        )
+        .await?;
+
+        Ok(res
+            .sub()
+            .ok_or(anyhow::anyhow!("could not find a userid (sub) in token"))?
+            .to_string())
+    }
 }
 
 #[derive(Clone, Debug)]