Documentação

lib/auth_gate.dart

@@ -0,0 +1,53 @@
+import 'package:firebase_auth/firebase_auth.dart';
+import 'package:flutter/material.dart';
+
+import 'home_screen.dart';
+import 'logged_home.dart';
+
+final ValueNotifier<bool> forceHomeScreen = ValueNotifier<bool>(false);
+
+class AuthGate extends StatelessWidget {
+  const AuthGate({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return ValueListenableBuilder<bool>(
+      valueListenable: forceHomeScreen,
+      builder: (context, forcedHome, _) {
+        return StreamBuilder<User?>(
+          stream: FirebaseAuth.instance.authStateChanges(),
+          builder: (context, snapshot) {
+            final user = snapshot.data;
+
+            final Widget child;
+            if (snapshot.connectionState == ConnectionState.waiting) {
+              child = const SizedBox.shrink();
+            } else if (forcedHome || user == null) {
+              child = const HomeScreen(key: ValueKey('home_screen'));
+            } else {
+              child = const LoggedHomeScreen(key: ValueKey('logged_home_screen'));
+            }
+
+            return AnimatedSwitcher(
+              duration: const Duration(milliseconds: 280),
+              reverseDuration: const Duration(milliseconds: 240),
+              switchInCurve: Curves.easeOutCubic,
+              switchOutCurve: Curves.easeInCubic,
+              transitionBuilder: (child, animation) {
+                final fade = CurvedAnimation(parent: animation, curve: Curves.easeOut);
+                return FadeTransition(
+                  opacity: fade,
+                  child: ScaleTransition(
+                    scale: Tween<double>(begin: 0.985, end: 1.0).animate(fade),
+                    child: child,
+                  ),
+                );
+              },
+              child: child,
+            );
+          },
+        );
+      },
+    );
+  }
+}