From a713d72ae60594e7848c3613b6fc5e24dc91aa89 Mon Sep 17 00:00:00 2001
From: Seongmin Lee <git@boltless.me>
Date: Tue, 2 Dec 2025 11:55:51 +0900
Subject: [PATCH] wip: knot2: xrpc.git.keepCommit

Signed-off-by: Seongmin Lee <git@boltless.me>
---
 knot2/server/handler/xrpc_git_keep_commit.go | 87 ++++++++++++++++++++
 knot2/server/routes.go                       |  7 +-
 2 files changed, 91 insertions(+), 3 deletions(-)
 create mode 100644 knot2/server/handler/xrpc_git_keep_commit.go

diff --git a/knot2/server/handler/xrpc_git_keep_commit.go b/knot2/server/handler/xrpc_git_keep_commit.go
new file mode 100644
index 00000000..a7c8ab3e
--- /dev/null
+++ b/knot2/server/handler/xrpc_git_keep_commit.go
@@ -0,0 +1,87 @@
+package handler
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"os/exec"
+	"path"
+
+	"github.com/bluesky-social/indigo/atproto/syntax"
+	"github.com/go-git/go-git/v5"
+	"github.com/go-git/go-git/v5/plumbing"
+	"tangled.org/core/api/tangled"
+	"tangled.org/core/knot2/config"
+	"tangled.org/core/log"
+	xrpcerr "tangled.org/core/xrpc/errors"
+)
+
+func XrpcGitKeepCommit(cfg *config.Config) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		ctx := r.Context()
+		l := log.FromContext(ctx).With("handler", "XrpcGitKeepCommit")
+
+		// TODO: get session did
+		actorDid := syntax.DID("")
+
+		var input tangled.GitKeepCommit_Input
+		if err := json.NewDecoder(r.Body).Decode(&input); err != nil {
+			l.Error("failed to decode body", "err", err)
+			panic("unimplemented")
+		}
+
+		repoAt, err := syntax.ParseATURI(input.Repo)
+		if err != nil {
+			l.Error("failed to decode body", "err", err)
+			panic("unimplemented")
+		}
+		repoPath := repoPathFromAtUri(cfg, repoAt)
+
+		// ensure repo exist (if not, clone it)
+		repo, err := git.PlainOpen(repoPath)
+		if err != nil {
+			// TODO: clone the ref from source repo if repo doesn't exist in this knot yet
+			l.Info("repo missing in knot", "err", err)
+			panic("unimplemented")
+		}
+
+		commitId, err := repo.ResolveRevision(plumbing.Revision(input.Ref))
+		if err != nil {
+			l.Error("failed to resolve revision", "ref", input.Ref, "err", err)
+			panic("unimplemented")
+		}
+
+		// set keep-ref for given commit
+		refspec := fmt.Sprintf("refs/knot/%s/keep/%s", actorDid, commitId)
+		updateRefCmd := exec.Command("git", "-C", repoPath, "update-ref", refspec, commitId.String())
+		if err := updateRefCmd.Run(); err != nil {
+			writeError(w, xrpcerr.GenericError(err), http.StatusBadRequest)
+			return
+		}
+
+		output := tangled.GitKeepCommit_Output{
+			CommitId: commitId.String(),
+		}
+
+		w.WriteHeader(http.StatusOK)
+		writeJson(w, output)
+	}
+}
+
+func repoPathFromAtUri(cfg *config.Config, repoAt syntax.ATURI) string {
+	return path.Join(cfg.RepoDir, repoAt.Authority().String(), repoAt.RecordKey().String())
+}
+
+func writeError(w http.ResponseWriter, e xrpcerr.XrpcError, status int) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	json.NewEncoder(w).Encode(e)
+}
+
+func writeJson(w http.ResponseWriter, response any) {
+	w.Header().Set("Content-Type", "application/json")
+	if err := json.NewEncoder(w).Encode(response); err != nil {
+		writeError(w, xrpcerr.GenericError(err), http.StatusInternalServerError)
+		return
+	}
+}
diff --git a/knot2/server/routes.go b/knot2/server/routes.go
index cdf28624..0c512170 100644
--- a/knot2/server/routes.go
+++ b/knot2/server/routes.go
@@ -7,6 +7,7 @@ import (
 	"github.com/bluesky-social/indigo/atproto/auth/oauth"
 	"github.com/go-chi/chi/v5"
 	"github.com/gorilla/sessions"
+	"tangled.org/core/api/tangled"
 	"tangled.org/core/knot2/config"
 	"tangled.org/core/knot2/server/handler"
 	"tangled.org/core/knot2/server/middleware"
@@ -43,9 +44,9 @@ func Routes(
 
 	r.Get("/events", handler.Events())
 
-	// r.Route("/xrpc", func(r chi.Router) {
-	// 	r.Post("/"+tangled.GitKeepRefNSID, handler.GitKeepRef())
-	// })
+	r.Route("/xrpc", func(r chi.Router) {
+		r.Post("/"+tangled.GitKeepCommitNSID, handler.XrpcGitKeepCommit(cfg))
+	})
 
 	return r
 }
-- 
2.51.2