import 'dart:async';

import 'package:flutter/cupertino.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter_screenutil/flutter_screenutil.dart';

class AutoScrollListView extends StatefulWidget {
  final NullableIndexedWidgetBuilder itemBuilder;

  final int itemCount;

  final Axis scrollDirection;

  final EdgeInsetsGeometry? padding;

  final bool isAutoScrolling;

  const AutoScrollListView({
    super.key,
    required this.itemBuilder,
    required this.itemCount,
    this.padding,
    this.isAutoScrolling = true,
    this.scrollDirection = Axis.horizontal,
  });

  @override
  State<AutoScrollListView> createState() => _AutoScrollListViewState();
}

class _AutoScrollListViewState extends State<AutoScrollListView> {
  final ScrollController scrollController = ScrollController();
  Timer? _timer;
  bool _isUserScrolling = true;

  @override
  void initState() {
    super.initState();
    _isUserScrolling = widget.isAutoScrolling;
    _startAutoScroll();
  }

  @override
  void dispose() {
    super.dispose();
    scrollController.dispose();
    _timer?.cancel();
  }


  void _startAutoScroll() {
    _timer = Timer.periodic(Duration(milliseconds: 50), (timer) {
      if (!_isUserScrolling || !scrollController.hasClients) return;

      final maxScrollExtent = scrollController.position.maxScrollExtent;
      final current = scrollController.position.pixels;

      double next = current + 1;

      if (next >= maxScrollExtent) {

        next = 0;
      }

      scrollController.jumpTo(next);
    });
  }

  void _onUserScroll() {
    if (!_isUserScrolling) {
      return;
    }
    _timer?.cancel();
    _timer = Timer(Duration(seconds: 1), () {
      setState(() {
        _isUserScrolling = widget.isAutoScrolling;
      });
      _startAutoScroll();
    });
  }

  @override
  Widget build(BuildContext context) {
    return NotificationListener<UserScrollNotification>(
      onNotification: (notification) {
        if (notification.direction != ScrollDirection.idle) {
          _onUserScroll(); // 用户滑动时暂停自动滚动
        }
        return false; // 不阻止子组件的事件传递
      },

      child: ListView.builder(
        padding: widget.padding,
        scrollDirection: widget.scrollDirection,
        itemCount: 1000000,
        itemBuilder: (context, index) {
          return widget.itemBuilder(context, index % widget.itemCount);
        },
        controller: scrollController,
      ),
    );
  }
}


// 多行横向自动滚动列表
/// 一个支持自动滚动的多行横向列表，每一行自动向右滚动（模拟跑马灯效果）
class StaggeredAutoScrollListView extends StatefulWidget {
  /// 子项构建器（需根据 itemIndex 构建对应组件）
  final NullableIndexedWidgetBuilder itemBuilder;

  /// 实际数据项数量（不是扩展后的数量）
  final int itemCount;

  /// 每行的内边距
  final EdgeInsetsGeometry? padding;

  /// 是否启用自动滚动
  final bool isAutoScrolling;

  const StaggeredAutoScrollListView({
    super.key,
    required this.itemBuilder,
    required this.itemCount,
    this.padding,
    this.isAutoScrolling = true,
  });

  @override
  State<StaggeredAutoScrollListView> createState() => _StaggeredAutoScrollListViewState();
}

class _StaggeredAutoScrollListViewState extends State<StaggeredAutoScrollListView> {
  final int rowCount = 3; // 列表的总行数
  final List<ScrollController> _controllers = []; // 每一行的滚动控制器
  final List<Timer?> _timers = []; // 每一行对应的自动滚动定时器
  final int loopFactor = 3; // 每行内容扩展的倍数，防止滚动过短

  @override
  void initState() {
    super.initState();

    // 初始化每一行的滚动控制器
    for (int i = 0; i < rowCount; i++) {
      final controller = ScrollController();
      _controllers.add(controller);
    }

    // 如果启用自动滚动，则在渲染后启动滚动逻辑
    if (widget.isAutoScrolling) {
      WidgetsBinding.instance.addPostFrameCallback((_) {
        _startAllScrolls();
      });
    }
  }

  @override
  void dispose() {
    // 销毁滚动控制器
    for (final controller in _controllers) {
      controller.dispose();
    }

    // 取消所有定时器
    for (final timer in _timers) {
      timer?.cancel();
    }

    super.dispose();
  }

  /// 启动所有行的自动滚动
  void _startAllScrolls() {
    for (int i = 0; i < rowCount; i++) {
      final controller = _controllers[i];

      // 每 50ms 滚动一次，实现平滑向右滚动效果
      final timer = Timer.periodic(const Duration(milliseconds: 50), (_) {
        if (!controller.hasClients) return;

        final maxExtent = controller.position.maxScrollExtent;
        final current = controller.position.pixels;
        final next = current + 1;

        if (next >= maxExtent) {
          // 若滚动到底部，则跳转到中间，避免突然回到顶部产生视觉跳变
          controller.jumpTo(maxExtent / 2);
        } else {
          controller.jumpTo(next);
        }
      });

      _timers.add(timer);
    }
  }

  @override
  Widget build(BuildContext context) {
    // 每一行应显示的实际数据项数（取整向上）
    final actualItemsPerRow = (widget.itemCount / rowCount).ceil();

    // 每一行扩展后的 item 数量（用于循环滚动）
    final extendedItemsPerRow = actualItemsPerRow * loopFactor;

    return Column(
      children: List.generate(rowCount, (rowIndex) {
        return SizedBox(
          height: 50.w, // 每行高度，单位为屏幕适配宽度
          child: ListView.builder(
            controller: _controllers[rowIndex], // 设置对应行的滚动控制器
            scrollDirection: Axis.horizontal,
            padding: widget.padding,
            itemCount: extendedItemsPerRow, // 扩展后的数量，制造无限滚动感
            itemBuilder: (context, index) {
              // 计算实际要展示的数据项索引
              final itemIndex = (rowIndex * actualItemsPerRow + index) % widget.itemCount;
              return widget.itemBuilder(context, itemIndex);
            },
          ),
        );
      }),
    );
  }
}