fix(vector): harden runtime embedding sync

runtime/vector-sync-coalescer.js

@@ -0,0 +1,133 @@
+export function normalizeVectorSyncRange(range = null) {
+  if (
+    range &&
+    Number.isFinite(Number(range.start)) &&
+    Number.isFinite(Number(range.end))
+  ) {
+    const start = Math.floor(Number(range.start));
+    const end = Math.floor(Number(range.end));
+    return {
+      start: Math.min(start, end),
+      end: Math.max(start, end),
+    };
+  }
+  return null;
+}
+
+export function mergeVectorSyncRange(current = null, next = null) {
+  const currentRange = normalizeVectorSyncRange(current);
+  const nextRange = normalizeVectorSyncRange(next);
+  if (!currentRange || !nextRange) return null;
+  return {
+    start: Math.min(currentRange.start, nextRange.start),
+    end: Math.max(currentRange.end, nextRange.end),
+  };
+}
+
+function createTaskRecord(task = {}) {
+  const id = String(task.id || `vector-sync:${Date.now()}`);
+  return {
+    id,
+    chatId: String(task.chatId || "").trim(),
+    modelScope: String(task.modelScope || "").trim(),
+    range: normalizeVectorSyncRange(task.range),
+    reason:
+      String(task.reason || "background-vector-sync").trim() ||
+      "background-vector-sync",
+    mode: String(task.mode || "balanced").trim() || "balanced",
+    stale: false,
+    requestedAt: Date.now(),
+    updatedAt: Date.now(),
+  };
+}
+
+function canMergeTask(left = null, right = null) {
+  return Boolean(
+    left &&
+      right &&
+      !left.stale &&
+      left.chatId === right.chatId &&
+      left.modelScope === right.modelScope,
+  );
+}
+
+function mergeTaskInto(target, incoming) {
+  target.range = mergeVectorSyncRange(target.range, incoming.range);
+  target.reason =
+    target.reason === incoming.reason
+      ? target.reason
+      : `${target.reason}+${incoming.reason}`;
+  target.mode = incoming.mode || target.mode;
+  target.updatedAt = Date.now();
+  return target;
+}
+
+function markStale(task = null, reason = "stale") {
+  if (!task) return;
+  task.stale = true;
+  task.clearReason = String(reason || "stale");
+}
+
+export function createVectorSyncCoalescer() {
+  let active = null;
+  let pending = null;
+
+  return {
+    clear(reason = "clear") {
+      markStale(active, reason);
+      markStale(pending, reason);
+      active = null;
+      pending = null;
+    },
+    getActive() {
+      return active;
+    },
+    getPending() {
+      return pending;
+    },
+    enqueue(task = {}) {
+      const incoming = createTaskRecord(task);
+      if (canMergeTask(active, incoming)) {
+        if (canMergeTask(pending, incoming)) {
+          mergeTaskInto(pending, incoming);
+          return { scheduled: false, coalesced: true, task: pending };
+        }
+        markStale(pending, "replaced");
+        pending = incoming;
+        return { scheduled: true, coalesced: false, task: pending };
+      }
+      if (canMergeTask(pending, incoming)) {
+        mergeTaskInto(pending, incoming);
+        return { scheduled: false, coalesced: true, task: pending };
+      }
+      markStale(pending, "replaced");
+      pending = incoming;
+      return { scheduled: true, coalesced: false, task: pending };
+    },
+    start(task = null) {
+      if (!task || task.stale) return false;
+      if (pending === task) pending = null;
+      active = task;
+      return true;
+    },
+    complete(task = null) {
+      if (task && active !== task) return false;
+      active = null;
+      return true;
+    },
+    drop(task = null, reason = "dropped") {
+      if (!task) return false;
+      const target = pending === task ? pending : active === task ? active : null;
+      if (!target) return false;
+      markStale(target, reason);
+      if (pending === task) pending = null;
+      if (active === task) active = null;
+      return true;
+    },
+    isStale(task = null, chatId = "") {
+      if (!task || task.stale) return true;
+      const currentChatId = String(chatId || "").trim();
+      return Boolean(currentChatId && task.chatId && currentChatId !== task.chatId);
+    },
+  };
+}