refactor: extract useAppNavigation hook from App.tsx — reduce god component churn (#194)

Co-authored-by: Test <test@test.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

src/hooks/useAppNavigation.ts

@@ -0,0 +1,89 @@
+import { useCallback, useEffect, useMemo, useRef } from 'react'
+import { useNavigationHistory } from './useNavigationHistory'
+import { useNavigationGestures } from './useNavigationGestures'
+import type { VaultEntry } from '../types'
+
+interface TabLike {
+  entry: { path: string }
+}
+
+interface UseAppNavigationParams {
+  entries: VaultEntry[]
+  tabs: TabLike[]
+  activeTabPath: string | null
+  onSelectNote: (entry: VaultEntry) => void
+  onSwitchTab: (path: string) => void
+}
+
+/**
+ * Encapsulates browser-style back/forward navigation for the app:
+ * - Navigation history (push on tab change, back/forward traversal)
+ * - Mouse button & trackpad gesture bindings
+ * - O(1) path→entry lookup map
+ */
+export function useAppNavigation({
+  entries,
+  tabs,
+  activeTabPath,
+  onSelectNote,
+  onSwitchTab,
+}: UseAppNavigationParams) {
+  const navHistory = useNavigationHistory()
+
+  // Push to navigation history whenever the active tab changes (user-initiated)
+  const navFromHistoryRef = useRef(false)
+  useEffect(() => {
+    if (activeTabPath && !navFromHistoryRef.current) {
+      navHistory.push(activeTabPath)
+    }
+    navFromHistoryRef.current = false
+  }, [activeTabPath]) // eslint-disable-line react-hooks/exhaustive-deps -- navHistory.push is stable
+
+  const isEntryExists = useCallback(
+    (path: string) => entries.some(e => e.path === path),
+    [entries],
+  )
+
+  const handleGoBack = useCallback(() => {
+    const target = navHistory.goBack(isEntryExists)
+    if (target) {
+      navFromHistoryRef.current = true
+      if (tabs.some(t => t.entry.path === target)) {
+        onSwitchTab(target)
+      } else {
+        const entry = entries.find(e => e.path === target)
+        if (entry) onSelectNote(entry)
+      }
+    }
+  }, [navHistory, isEntryExists, entries, tabs, onSelectNote, onSwitchTab])
+
+  const handleGoForward = useCallback(() => {
+    const target = navHistory.goForward(isEntryExists)
+    if (target) {
+      navFromHistoryRef.current = true
+      if (tabs.some(t => t.entry.path === target)) {
+        onSwitchTab(target)
+      } else {
+        const entry = entries.find(e => e.path === target)
+        if (entry) onSelectNote(entry)
+      }
+    }
+  }, [navHistory, isEntryExists, entries, tabs, onSelectNote, onSwitchTab])
+
+  useNavigationGestures({ onGoBack: handleGoBack, onGoForward: handleGoForward })
+
+  // O(1) path lookup map — rebuilt only when entries change
+  const entriesByPath = useMemo(() => {
+    const map = new Map<string, VaultEntry>()
+    for (const e of entries) map.set(e.path, e)
+    return map
+  }, [entries])
+
+  return {
+    handleGoBack,
+    handleGoForward,
+    canGoBack: navHistory.canGoBack,
+    canGoForward: navHistory.canGoForward,
+    entriesByPath,
+  }
+}