chore(repo): initialize planarchy workspace

apps/web/src/hooks/useSelection.ts

@@ -0,0 +1,63 @@
+import { useState, useCallback } from "react";
+
+export interface UseSelectionReturn {
+  selectedIds: Set<string>;
+  toggle: (id: string) => void;
+  toggleAll: (ids: string[]) => void;
+  clear: () => void;
+  isAllSelected: (ids: string[]) => boolean;
+  isIndeterminate: (ids: string[]) => boolean;
+  count: number;
+  selectedArray: string[];
+}
+
+export function useSelection(): UseSelectionReturn {
+  const [selectedIds, setSelectedIds] = useState<Set<string>>(new Set());
+
+  const toggle = useCallback((id: string) => {
+    setSelectedIds((prev) => {
+      const next = new Set(prev);
+      if (next.has(id)) next.delete(id);
+      else next.add(id);
+      return next;
+    });
+  }, []);
+
+  const toggleAll = useCallback((ids: string[]) => {
+    setSelectedIds((prev) => {
+      const allSelected = ids.every((id) => prev.has(id));
+      if (allSelected) {
+        const next = new Set(prev);
+        ids.forEach((id) => next.delete(id));
+        return next;
+      } else {
+        const next = new Set(prev);
+        ids.forEach((id) => next.add(id));
+        return next;
+      }
+    });
+  }, []);
+
+  const clear = useCallback(() => setSelectedIds(new Set()), []);
+
+  const isAllSelected = useCallback(
+    (ids: string[]) => ids.length > 0 && ids.every((id) => selectedIds.has(id)),
+    [selectedIds],
+  );
+
+  const isIndeterminate = useCallback(
+    (ids: string[]) => ids.some((id) => selectedIds.has(id)) && !ids.every((id) => selectedIds.has(id)),
+    [selectedIds],
+  );
+
+  return {
+    selectedIds,
+    toggle,
+    toggleAll,
+    clear,
+    isAllSelected,
+    isIndeterminate,
+    count: selectedIds.size,
+    selectedArray: [...selectedIds],
+  };
+}