refactor(frontend): Split friends.ts store into focused modules

apps/frontend/src/lib/shortcuts/handlers/navigation.ts

@@ -1,6 +1,6 @@
 import { get } from 'svelte/store';
 import { goto } from '$app/navigation';
-import { friendListFilter } from '$lib/stores/friends';
+import { buildSearchParams, friendListFilter } from '$lib/stores/friends';
 import { NAVIGATION_PATHS } from '../config.js';
 import type { HandlerContext } from '../types.js';
 
@@ -13,7 +13,7 @@ export function handleNavigation(e: KeyboardEvent, ctx: HandlerContext): boolean
   if (e.key === 'f') {
     // Restore filter state from store when navigating to friends
     const filterState = get(friendListFilter);
-    const params = friendListFilter.buildSearchParams(filterState);
+    const params = buildSearchParams(filterState);
     const queryString = params.toString();
     goto(queryString ? `/friends?${queryString}` : '/friends');
     return true;

apps/frontend/src/lib/stores/friendListFilter.ts

@@ -0,0 +1,102 @@
+import { derived, writable } from 'svelte/store';
+import type { FacetFilters } from '$shared';
+
+export interface FriendListFilterState {
+  query: string;
+  filters: FacetFilters;
+}
+
+const initialFilterState: FriendListFilterState = {
+  query: '',
+  filters: {},
+};
+
+function createFriendListFilterStore() {
+  const { subscribe, set, update } = writable<FriendListFilterState>(initialFilterState);
+
+  return {
+    subscribe,
+
+    setQuery: (query: string) => {
+      update((state) => ({ ...state, query }));
+    },
+
+    setFilters: (filters: FacetFilters) => {
+      update((state) => ({ ...state, filters }));
+    },
+
+    setState: (query: string, filters: FacetFilters) => {
+      set({ query, filters });
+    },
+
+    clear: () => {
+      set(initialFilterState);
+    },
+  };
+}
+
+export const friendListFilter = createFriendListFilterStore();
+
+export const friendListQuery = derived(friendListFilter, ($filter) => $filter.query);
+
+export const hasFriendListFilters = derived(
+  friendListFilter,
+  ($filter) =>
+    $filter.query.trim().length > 0 ||
+    Object.values($filter.filters).some((arr) => arr && arr.length > 0),
+);
+
+/**
+ * Build URL search params from filter state.
+ * Pure utility — does not read the store; pass a state snapshot.
+ */
+export function buildSearchParams(state: FriendListFilterState): URLSearchParams {
+  const params = new URLSearchParams();
+
+  if (state.query.trim()) {
+    params.set('q', state.query.trim());
+  }
+
+  for (const [key, values] of Object.entries(state.filters)) {
+    if (values && values.length > 0) {
+      params.set(key, values.join(','));
+    }
+  }
+
+  return params;
+}
+
+/**
+ * Parse URL search params into filter state.
+ * Pure utility — does not read the store.
+ */
+export function parseSearchParams(params: URLSearchParams): FriendListFilterState {
+  const query = params.get('q') ?? '';
+  const filters: FacetFilters = {};
+
+  const stringArrayKeys = [
+    'country',
+    'city',
+    'organization',
+    'job_title',
+    'department',
+    'circles',
+  ] as const;
+  for (const key of stringArrayKeys) {
+    const value = params.get(key);
+    if (value) {
+      filters[key] = value.split(',');
+    }
+  }
+
+  const relationshipCategory = params.get('relationship_category');
+  if (relationshipCategory) {
+    filters.relationship_category = relationshipCategory.split(',') as (
+      | 'family'
+      | 'professional'
+      | 'social'
+    )[];
+  }
+
+  return { query, filters };
+}