From 0b2e3e07949fb0f2ff5ff1c6a935484957909011 Mon Sep 17 00:00:00 2001
From: Yorusaka Miyabi <23130178+ShadowRZ@users.noreply.github.com>
Date: Thu, 12 Jun 2025 15:29:40 +0800
Subject: [PATCH] feat(ffi): Expose legacy SSO support infomation

Currently Element X can't distinguish the cases where a homeserver only
supports legacy SSO without OIDC (and password login isn't avaliable),
and other server unreachable scenarios.

This patch exposes legacy SSO support infomation so that Element X side
can give a dedicated error message when it encounters a homeserver that
can only support legacy SSO.

Signed-off-by: Yorusaka Miyabi <23130178+ShadowRZ@users.noreply.github.com>
---
 bindings/matrix-sdk-ffi/CHANGELOG.md          |  7 ++++
 bindings/matrix-sdk-ffi/src/authentication.rs |  6 ++++
 bindings/matrix-sdk-ffi/src/client.rs         | 32 +++++++++++--------
 3 files changed, 32 insertions(+), 13 deletions(-)

diff --git a/bindings/matrix-sdk-ffi/CHANGELOG.md b/bindings/matrix-sdk-ffi/CHANGELOG.md
index 664ac6fdd22..f3671acffa5 100644
--- a/bindings/matrix-sdk-ffi/CHANGELOG.md
+++ b/bindings/matrix-sdk-ffi/CHANGELOG.md
@@ -6,6 +6,13 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased] - ReleaseDate
 
+### Features:
+
+- Add `HomeserverLoginDetails::supports_sso_login` for legacy SSO support infomation.
+  This is primarily for Element X to give a dedicated error message in case
+  it connects a homeserver with only this method avaliable.
+  ([#5222](https://github.com/matrix-org/matrix-rust-sdk/pull/5222))
+
 ### Breaking changes:
 
 - `Client::url_for_oidc` now allows requesting additional scopes for the OAuth2 authorization code grant.
diff --git a/bindings/matrix-sdk-ffi/src/authentication.rs b/bindings/matrix-sdk-ffi/src/authentication.rs
index cd04fff6558..1e7186f814c 100644
--- a/bindings/matrix-sdk-ffi/src/authentication.rs
+++ b/bindings/matrix-sdk-ffi/src/authentication.rs
@@ -23,6 +23,7 @@ pub struct HomeserverLoginDetails {
     pub(crate) sliding_sync_version: SlidingSyncVersion,
     pub(crate) supports_oidc_login: bool,
     pub(crate) supported_oidc_prompts: Vec<OidcPrompt>,
+    pub(crate) supports_sso_login: bool,
     pub(crate) supports_password_login: bool,
 }
 
@@ -43,6 +44,11 @@ impl HomeserverLoginDetails {
         self.supports_oidc_login
     }
 
+    /// Whether the current homeserver supports login using legacy SSO.
+    pub fn supports_sso_login(&self) -> bool {
+        self.supports_sso_login
+    }
+
     /// The prompts advertised by the authentication issuer for use in the login
     /// URL.
     pub fn supported_oidc_prompts(&self) -> Vec<OidcPrompt> {
diff --git a/bindings/matrix-sdk-ffi/src/client.rs b/bindings/matrix-sdk-ffi/src/client.rs
index 357b3412751..d569cd86836 100644
--- a/bindings/matrix-sdk-ffi/src/client.rs
+++ b/bindings/matrix-sdk-ffi/src/client.rs
@@ -341,7 +341,24 @@ impl Client {
             }
         };
 
-        let supports_password_login = self.supports_password_login().await.ok().unwrap_or(false);
+        let login_types = self.inner.matrix_auth().get_login_types().await.ok();
+        let supports_password_login = login_types
+            .as_ref()
+            .map(|login_types| {
+                login_types.flows.iter().any(|login_type| {
+                    matches!(login_type, get_login_types::v3::LoginType::Password(_))
+                })
+            })
+            .unwrap_or(false);
+        let supports_sso_login = login_types
+            .as_ref()
+            .map(|login_types| {
+                login_types
+                    .flows
+                    .iter()
+                    .any(|login_type| matches!(login_type, get_login_types::v3::LoginType::Sso(_)))
+            })
+            .unwrap_or(false);
         let sliding_sync_version = self.sliding_sync_version();
 
         Arc::new(HomeserverLoginDetails {
@@ -349,6 +366,7 @@ impl Client {
             sliding_sync_version,
             supports_oidc_login,
             supported_oidc_prompts,
+            supports_sso_login,
             supports_password_login,
         })
     }
@@ -808,18 +826,6 @@ impl Client {
     }
 }
 
-impl Client {
-    /// Whether or not the client's homeserver supports the password login flow.
-    pub(crate) async fn supports_password_login(&self) -> anyhow::Result<bool> {
-        let login_types = self.inner.matrix_auth().get_login_types().await?;
-        let supports_password = login_types
-            .flows
-            .iter()
-            .any(|login_type| matches!(login_type, get_login_types::v3::LoginType::Password(_)));
-        Ok(supports_password)
-    }
-}
-
 #[matrix_sdk_ffi_macros::export]
 impl Client {
     /// The sliding sync version.