feat(base): add useViewDraft hook for local filter/sort drafts

apps/client/src/features/base/hooks/use-view-draft.ts

@@ -0,0 +1,156 @@
+import { useCallback, useMemo } from "react";
+import { useAtom } from "jotai";
+import { RESET } from "jotai/utils";
+import {
+  BaseViewDraft,
+  FilterGroup,
+  ViewConfig,
+  ViewSortConfig,
+} from "@/features/base/types/base.types";
+import { viewDraftAtomFamily } from "@/features/base/atoms/view-draft-atom";
+
+export type UseViewDraftArgs = {
+  userId: string | undefined;
+  baseId: string | undefined;
+  viewId: string | undefined;
+  baselineFilter: FilterGroup | undefined;
+  baselineSorts: ViewSortConfig[] | undefined;
+};
+
+export type ViewDraftState = {
+  draft: BaseViewDraft | null;
+  effectiveFilter: FilterGroup | undefined;
+  effectiveSorts: ViewSortConfig[] | undefined;
+  isDirty: boolean;
+  setFilter: (filter: FilterGroup | undefined) => void;
+  setSorts: (sorts: ViewSortConfig[] | undefined) => void;
+  reset: () => void;
+  buildPromotedConfig: (baseline: ViewConfig) => ViewConfig;
+};
+
+// JSON-stringify equality is good enough for FilterGroup (pure data tree)
+// and ViewSortConfig[] — V8 preserves non-numeric key insertion order so
+// the same object graph serializes identically. Avoids pulling in
+// lodash/fast-deep-equal for two known-shaped types. (Spec "Dirty check".)
+function filterEq(a: FilterGroup | undefined, b: FilterGroup | undefined) {
+  return JSON.stringify(a ?? null) === JSON.stringify(b ?? null);
+}
+function sortsEq(
+  a: ViewSortConfig[] | undefined,
+  b: ViewSortConfig[] | undefined,
+) {
+  return JSON.stringify(a ?? null) === JSON.stringify(b ?? null);
+}
+
+export function useViewDraft(args: UseViewDraftArgs): ViewDraftState {
+  const { userId, baseId, viewId, baselineFilter, baselineSorts } = args;
+  const ready = !!(userId && baseId && viewId);
+
+  // Always mount an atom with a stable shape so hook order is consistent.
+  // When not ready we still feed a key, but we won't read/write it.
+  const atomKey = useMemo(
+    () => ({
+      userId: userId ?? "",
+      baseId: baseId ?? "",
+      viewId: viewId ?? "",
+    }),
+    [userId, baseId, viewId],
+  );
+  const [storedDraft, setDraft] = useAtom(viewDraftAtomFamily(atomKey));
+
+  const draft = ready ? storedDraft : null;
+
+  const setFilter = useCallback(
+    (next: FilterGroup | undefined) => {
+      if (!ready) return;
+      const current = storedDraft ?? null;
+      const mergedFilter = next;
+      const mergedSorts = current?.sorts;
+      if (mergedFilter === undefined && (mergedSorts === undefined || mergedSorts === null)) {
+        setDraft(RESET);
+        return;
+      }
+      setDraft({
+        filter: mergedFilter,
+        sorts: mergedSorts,
+        updatedAt: new Date().toISOString(),
+      });
+    },
+    [ready, storedDraft, setDraft],
+  );
+
+  const setSorts = useCallback(
+    (next: ViewSortConfig[] | undefined) => {
+      if (!ready) return;
+      const current = storedDraft ?? null;
+      const mergedFilter = current?.filter;
+      const mergedSorts = next;
+      if (mergedFilter === undefined && (mergedSorts === undefined || mergedSorts === null)) {
+        setDraft(RESET);
+        return;
+      }
+      setDraft({
+        filter: mergedFilter,
+        sorts: mergedSorts,
+        updatedAt: new Date().toISOString(),
+      });
+    },
+    [ready, storedDraft, setDraft],
+  );
+
+  const reset = useCallback(() => {
+    if (!ready) return;
+    setDraft(RESET);
+  }, [ready, setDraft]);
+
+  const effectiveFilter = useMemo(
+    () => (draft?.filter !== undefined ? draft.filter : baselineFilter),
+    [draft?.filter, baselineFilter],
+  );
+  const effectiveSorts = useMemo(
+    () => (draft?.sorts !== undefined ? draft.sorts : baselineSorts),
+    [draft?.sorts, baselineSorts],
+  );
+
+  const isDirty = useMemo(() => {
+    if (!draft) return false;
+    const filterDirty =
+      draft.filter !== undefined && !filterEq(draft.filter, baselineFilter);
+    const sortsDirty =
+      draft.sorts !== undefined && !sortsEq(draft.sorts, baselineSorts);
+    return filterDirty || sortsDirty;
+  }, [draft, baselineFilter, baselineSorts]);
+
+  const buildPromotedConfig = useCallback(
+    (baseline: ViewConfig): ViewConfig => ({
+      ...baseline,
+      filter: draft?.filter ?? baseline.filter,
+      sorts: draft?.sorts ?? baseline.sorts,
+    }),
+    [draft],
+  );
+
+  if (!ready) {
+    return {
+      draft: null,
+      effectiveFilter: baselineFilter,
+      effectiveSorts: baselineSorts,
+      isDirty: false,
+      setFilter: () => {},
+      setSorts: () => {},
+      reset: () => {},
+      buildPromotedConfig: (baseline) => baseline,
+    };
+  }
+
+  return {
+    draft,
+    effectiveFilter,
+    effectiveSorts,
+    isDirty,
+    setFilter,
+    setSorts,
+    reset,
+    buildPromotedConfig,
+  };
+}