refactor(web): extract optimistic timeline reconciliation

apps/web/src/hooks/timelineOptimisticAllocations.ts

@@ -0,0 +1,51 @@
+export type OptimisticTimelineEntryLike = {
+  id: string;
+  startDate: Date | string;
+  endDate: Date | string;
+};
+
+export type OptimisticTimelineOverrideLike = {
+  startDate: Date;
+  endDate: Date;
+};
+
+export function reconcileOptimisticEntries(
+  optimisticAllocations: ReadonlyMap<string, OptimisticTimelineOverrideLike>,
+  entries: readonly OptimisticTimelineEntryLike[],
+  pendingOptimisticAllocationId: string | null,
+): {
+  optimisticAllocations: Map<string, OptimisticTimelineOverrideLike>;
+  pendingOptimisticAllocationId: string | null;
+  changed: boolean;
+} {
+  if (optimisticAllocations.size === 0) {
+    return {
+      optimisticAllocations: new Map(optimisticAllocations),
+      pendingOptimisticAllocationId,
+      changed: false,
+    };
+  }
+
+  const next = new Map(optimisticAllocations);
+  let nextPendingId = pendingOptimisticAllocationId;
+
+  for (const entry of entries) {
+    const override = next.get(entry.id);
+    if (!override) continue;
+
+    const startTime = new Date(entry.startDate).getTime();
+    const endTime = new Date(entry.endDate).getTime();
+    if (startTime === override.startDate.getTime() && endTime === override.endDate.getTime()) {
+      next.delete(entry.id);
+      if (nextPendingId === entry.id) {
+        nextPendingId = null;
+      }
+    }
+  }
+
+  return {
+    optimisticAllocations: next,
+    pendingOptimisticAllocationId: nextPendingId,
+    changed: next.size !== optimisticAllocations.size || nextPendingId !== pendingOptimisticAllocationId,
+  };
+}