chore(repo): initialize planarchy workspace

apps/web/src/hooks/useRowOrder.ts

@@ -0,0 +1,65 @@
+import { useMemo, useCallback } from "react";
+import type { ViewPrefsHandle } from "./useViewPrefs.js";
+
+/**
+ * Manages manual drag-to-reorder row ordering for a table.
+ *
+ * - When a column sort is active (sortField !== null), row order is suppressed —
+ *   the sorted rows are returned unchanged and dragging is disabled.
+ * - When no column sort is active and a saved rowOrder exists, rows are sorted
+ *   by their position in rowOrder; rows without a saved position go to the end.
+ * - Calling reorder() saves the new order and clears any active column sort.
+ *
+ * Each user's rowOrder is persisted independently via useViewPrefs.
+ */
+export function useRowOrder<T extends { id: string }>(
+  rows: T[],
+  prefs: Pick<ViewPrefsHandle, "rowOrder" | "setRowOrder">,
+  activeSortField: string | null,
+  resetSort: () => void,
+) {
+  const { rowOrder, setRowOrder } = prefs;
+
+  const orderedRows = useMemo((): T[] => {
+    // Column sort takes precedence — ignore manual order while sorting
+    if (activeSortField !== null) return rows;
+    if (rowOrder.length === 0) return rows;
+
+    const indexMap = new Map(rowOrder.map((id, i) => [id, i]));
+    return [...rows].sort((a, b) => {
+      const ai = indexMap.get(a.id) ?? Infinity;
+      const bi = indexMap.get(b.id) ?? Infinity;
+      return ai - bi;
+    });
+  }, [rows, rowOrder, activeSortField]);
+
+  const reorder = useCallback(
+    (draggedId: string, targetId: string) => {
+      if (draggedId === targetId) return;
+
+      // Build current ordered ID list from the current orderedRows snapshot
+      // (works correctly even when rowOrder is empty / partial)
+      const currentIds = orderedRows.map((r) => r.id);
+      const fromIdx = currentIds.indexOf(draggedId);
+      const toIdx = currentIds.indexOf(targetId);
+      if (fromIdx === -1 || toIdx === -1) return;
+
+      const next = [...currentIds];
+      next.splice(fromIdx, 1);
+      next.splice(toIdx, 0, draggedId);
+
+      // Clear any active column sort (mutual exclusion)
+      resetSort();
+      setRowOrder(next);
+    },
+    [orderedRows, resetSort, setRowOrder],
+  );
+
+  const resetOrder = useCallback(() => {
+    setRowOrder([]);
+  }, [setRowOrder]);
+
+  const isCustomOrder = rowOrder.length > 0 && activeSortField === null;
+
+  return { orderedRows, reorder, isCustomOrder, resetOrder };
+}