MAJOR UPDATE ALERT!!!!!

mobile/src/router.tsx

@@ -1,19 +1,43 @@
-import React, { createContext, useContext, useState } from "react";
+import React, { createContext, useCallback, useContext, useEffect, useRef, useState } from "react";
+import { BackHandler } from "react-native";
 
-export type Route = "home" | "text" | "image" | "datacards";
+export type Route = "home" | "text" | "image" | "datacards" | "settings";
 
 interface RouterContextValue {
   route: Route;
   navigate: (to: Route) => void;
+  goBack: () => boolean;
 }
 
 const RouterContext = createContext<RouterContextValue | null>(null);
 
 export function RouterProvider({ children }: { children: React.ReactNode }) {
   const [route, setRoute] = useState<Route>("home");
+  const history = useRef<Route[]>([]);
+
+  const navigate = useCallback((to: Route) => {
+    setRoute((prev) => {
+      history.current.push(prev);
+      return to;
+    });
+  }, []);
+
+  const goBack = useCallback((): boolean => {
+    const prev = history.current.pop();
+    if (prev !== undefined) {
+      setRoute(prev);
+      return true;
+    }
+    return false;
+  }, []);
+
+  useEffect(() => {
+    const sub = BackHandler.addEventListener("hardwareBackPress", goBack);
+    return () => sub.remove();
+  }, [goBack]);
 
   return (
-    <RouterContext.Provider value={{ route, navigate: setRoute }}>
+    <RouterContext.Provider value={{ route, navigate, goBack }}>
       {children}
     </RouterContext.Provider>
   );