From 55497e1428c4eb8443f368df86eb79f3f117cbdb Mon Sep 17 00:00:00 2001
From: dawn <90008@gaze.systems>
Date: Fri, 27 Mar 2026 04:28:43 +0300
Subject: [PATCH] [api] implement getLatestCommit

---
 README.md                         |  1 +
 src/api/xrpc/get_latest_commit.rs | 58 +++++++++++++++++++++++++++++++
 src/api/xrpc/mod.rs               |  3 ++
 3 files changed, 62 insertions(+)
 create mode 100644 src/api/xrpc/get_latest_commit.rs

diff --git a/README.md b/README.md
index 9846523..17fd550 100644
--- a/README.md
+++ b/README.md
@@ -314,6 +314,7 @@ the following are implemented currently:
 - `com.atproto.sync.listHosts`
 - `com.atproto.sync.getRepoStatus`
 - `com.atproto.sync.listRepos`
+- `com.atproto.sync.getLatestCommit`
 
 ### systems.gaze.hydrant.*
 
diff --git a/src/api/xrpc/get_latest_commit.rs b/src/api/xrpc/get_latest_commit.rs
new file mode 100644
index 0000000..7e6f10e
--- /dev/null
+++ b/src/api/xrpc/get_latest_commit.rs
@@ -0,0 +1,58 @@
+use jacquard_api::com_atproto::sync::get_latest_commit::{
+    GetLatestCommitError, GetLatestCommitOutput, GetLatestCommitRequest, GetLatestCommitResponse,
+};
+use jacquard_common::{CowStr, types::cid::Cid};
+
+use crate::types::RepoStatus;
+
+use super::*;
+
+pub async fn handle(
+    State(hydrant): State<Hydrant>,
+    ExtractXrpc(req): ExtractXrpc<GetLatestCommitRequest>,
+) -> XrpcResult<Json<GetLatestCommitOutput<'static>>, GetLatestCommitError<'static>> {
+    let nsid = GetLatestCommitResponse::NSID;
+
+    let Some(state) = hydrant
+        .repos
+        .get(&req.did)
+        .state()
+        .await
+        .map_err(|e| internal_error(nsid, e))?
+    else {
+        return Err(XrpcErrorResponse {
+            status: StatusCode::NOT_FOUND,
+            error: XrpcError::Xrpc(GetLatestCommitError::RepoNotFound(None)),
+        });
+    };
+
+    // return specific errors for inactive account states
+    let xrpc_err = match &state.status {
+        RepoStatus::Takendown => Some(GetLatestCommitError::RepoTakendown(None)),
+        RepoStatus::Suspended => Some(GetLatestCommitError::RepoSuspended(None)),
+        RepoStatus::Deactivated => Some(GetLatestCommitError::RepoDeactivated(None)),
+        _ => None,
+    };
+    if let Some(err) = xrpc_err {
+        return Err(XrpcErrorResponse {
+            status: StatusCode::FORBIDDEN,
+            error: XrpcError::Xrpc(err),
+        });
+    }
+
+    // return whatever we last recorded; if we haven't synced at all yet, we have nothing to give
+    let (Some(data), Some(rev_db)) = (state.data, state.rev) else {
+        return Err(XrpcErrorResponse {
+            status: StatusCode::NOT_FOUND,
+            error: XrpcError::Xrpc(GetLatestCommitError::RepoNotFound(Some(CowStr::Borrowed(
+                "repo still backfilling",
+            )))),
+        });
+    };
+
+    Ok(Json(GetLatestCommitOutput {
+        cid: Cid::from(data),
+        rev: rev_db.to_tid(),
+        extra_data: None,
+    }))
+}
diff --git a/src/api/xrpc/mod.rs b/src/api/xrpc/mod.rs
index 2b2a4a0..38e517c 100644
--- a/src/api/xrpc/mod.rs
+++ b/src/api/xrpc/mod.rs
@@ -10,6 +10,7 @@ use jacquard_api::com_atproto::repo::{
     list_records::{ListRecordsOutput, ListRecordsRequest, Record as RepoRecord},
 };
 use jacquard_api::com_atproto::sync::get_host_status::GetHostStatusRequest;
+use jacquard_api::com_atproto::sync::get_latest_commit::GetLatestCommitRequest;
 use jacquard_api::com_atproto::sync::get_repo_status::GetRepoStatusRequest;
 use jacquard_api::com_atproto::sync::list_hosts::ListHostsRequest;
 use jacquard_api::com_atproto::sync::list_repos::ListReposRequest;
@@ -28,6 +29,7 @@ use std::fmt::Display;
 mod count_records;
 mod describe_repo;
 mod get_host_status;
+mod get_latest_commit;
 mod get_record;
 mod get_repo_status;
 mod list_hosts;
@@ -42,6 +44,7 @@ pub fn router() -> Router<Hydrant> {
         .route(DescribeRepo::PATH, get(describe_repo::handle))
         .route(GetHostStatusRequest::PATH, get(get_host_status::handle))
         .route(ListHostsRequest::PATH, get(list_hosts::handle))
+        .route(GetLatestCommitRequest::PATH, get(get_latest_commit::handle))
         .route(GetRepoStatusRequest::PATH, get(get_repo_status::handle))
         .route(ListReposRequest::PATH, get(list_repos::handle))
 }
-- 
2.51.2