Flutter pageView animation

.dart

class Home extends StatefulWidget {
  const Home({super.key});

  @override
  State<Home> createState() => _HomeState();
}

class _HomeState extends State<Home> {
  final pageController = PageController(viewportFraction: 0.8, initialPage: 1);
  int currentIndex = 1;
  int totalItem = 5;
  late final Timer timer;
  @override
  void initState() {
    timer = Timer.periodic(const Duration(milliseconds: 2000), (t) {
      if (currentIndex == totalItem - 1) {
        pageController.animateToPage(0,
            duration: const Duration(seconds: 1), curve: Curves.ease);
      } else {
        pageController.nextPage(
            duration: const Duration(seconds: 1), curve: Curves.ease);
      }
    });
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        body: SafeArea(
      child: Column(
        children: [
          Expanded(
            child: PageView.builder(
              controller: pageController,
              itemCount: 5,
              onPageChanged: (value) => setState(() => currentIndex = value),
              itemBuilder: (context, i) => AnimatedContainer(
                padding: const EdgeInsets.all(16),
                // This is where the magic happens
                margin: EdgeInsets.symmetric(
                    horizontal: 8, vertical: currentIndex == i ? 100 : 150),
                decoration: BoxDecoration(
                    border: Border.all(),
                    borderRadius: BorderRadius.circular(12),
                    color: currentIndex == i
                        ? Colors.black
                        : const Color(0xfff5f8ff)),
                width: 200,
                duration: const Duration(milliseconds: 800),
                child: Center(
                  child: Text(
                    'item $i',
                    style: TextStyle(
                      fontWeight: FontWeight.w800,
                      color: currentIndex == i ? Colors.white : Colors.black,
                      fontSize: 22,
                    ),
                  ),
                ),
              ),
            ),
          ),
        ],
      ),
    ));
  }
}