import 'package:flutter/material.dart';
import 'package:flutter/services.dart'; // 🟢 添加这一行
import 'package:flutter/services.dart' show rootBundle;
import 'package:flutter_markdown/flutter_markdown.dart';

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

  @override
  State<ChangelogPage> createState() => _ChangelogPageState();
}

class _ChangelogPageState extends State<ChangelogPage>
    with SingleTickerProviderStateMixin {
  // ---------- 数据 ----------
  String _markdownContent = '';
  bool _isLoading = true;
  String? _error;
  Widget? _cachedMarkdown;

  // ---------- 滚动 ----------
  final ScrollController _scrollController = ScrollController();
  double _scrollProgress = 0.0;
  bool _isScrolling = false;

  // ---------- 呼吸动画（维持高刷感知） ----------
  late AnimationController _breathController;
  late Animation<double> _breathAnimation;

  // ---------- 原生刷新率控制 ----------
  // 🟢 改用 static final（不是 const）
  static final _frameRateChannel = MethodChannel(
    'com.lxh.battery_health/frame_rate',
  );

  // ---------- 生命周期 ----------
  @override
  void initState() {
    super.initState();
    _loadChangelog();

    // 进入页面时申请高刷（原生层）
    _frameRateChannel.invokeMethod('setHighRefreshRate');

    // 呼吸动画：让进度条在滚动时轻微抖动，维持高刷感知
    _breathController = AnimationController(
      vsync: this,
      duration: const Duration(milliseconds: 500),
    )..repeat(reverse: true);

    _breathAnimation = Tween<double>(begin: 0.0, end: 0.03).animate(
      CurvedAnimation(parent: _breathController, curve: Curves.easeInOut),
    );

    _scrollController.addListener(() {
      _updateProgress();
      final isScrolling = _scrollController.position.isScrollingNotifier.value;
      if (isScrolling != _isScrolling) {
        setState(() {
          _isScrolling = isScrolling;
        });
        if (isScrolling) {
          _breathController.repeat(reverse: true);
        } else {
          _breathController.stop();
          _breathController.reset();
        }
      }
    });
  }

  @override
  void dispose() {
    // 离开页面时恢复默认刷新率
    _frameRateChannel.invokeMethod('clearRefreshRate');

    _scrollController.removeListener(_updateProgress);
    _scrollController.dispose();
    _breathController.dispose();
    super.dispose();
  }

  // ---------- 方法 ----------
  void _updateProgress() {
    if (!_scrollController.hasClients) return;
    final maxScroll = _scrollController.position.maxScrollExtent;
    final currentScroll = _scrollController.position.pixels;
    final progress = maxScroll > 0 ? currentScroll / maxScroll : 0.0;
    setState(() {
      _scrollProgress = progress;
    });
  }

  Future<void> _loadChangelog() async {
    try {
      final content = await rootBundle.loadString('assets/CHANGELOG.md');
      setState(() {
        _markdownContent = content;
        _isLoading = false;
        _cachedMarkdown = _buildMarkdown(content);
      });
    } catch (e) {
      setState(() {
        _error = '无法加载更新日志: $e';
        _isLoading = false;
      });
    }
  }

  Widget _buildMarkdown(String content) {
    return Markdown(
      data: content,
      shrinkWrap: true,
      physics: const NeverScrollableScrollPhysics(),
      styleSheet: MarkdownStyleSheet(
        h1: const TextStyle(
          fontFamily: 'HarmonyOS_Sans_SC',
          fontSize: 24,
          fontWeight: FontWeight.w700,
          color: Colors.black,
        ),
        h2: const TextStyle(
          fontFamily: 'HarmonyOS_Sans_SC',
          fontSize: 20,
          fontWeight: FontWeight.w600,
          color: Colors.black87,
        ),
        h3: const TextStyle(
          fontFamily: 'HarmonyOS_Sans_SC',
          fontSize: 18,
          fontWeight: FontWeight.w600,
          color: Colors.black87,
        ),
        p: const TextStyle(
          fontFamily: 'HarmonyOS_Sans_SC',
          fontSize: 16,
          color: Colors.black87,
        ),
        listBullet: const TextStyle(
          fontFamily: 'HarmonyOS_Sans_SC',
          fontSize: 16,
          color: Colors.black87,
        ),
        code: const TextStyle(
          fontFamily: 'HarmonyOS_Sans_SC',
          fontSize: 14,
          color: Colors.black87,
          backgroundColor: Color(0xFFF5F5F5),
        ),
      ),
    );
  }

  // ---------- Build ----------
  @override
  Widget build(BuildContext context) {
    final breathOffset = _isScrolling ? _breathAnimation.value : 0.0;
    final displayProgress = (_scrollProgress + breathOffset).clamp(0.0, 1.0);

    return Scaffold(
      backgroundColor: Colors.white,
      appBar: AppBar(
        title: const Text(
          '更新日志',
          style: TextStyle(
            fontFamily: 'HarmonyOS_Sans_SC',
            color: Colors.black,
          ),
        ),
        backgroundColor: Colors.white,
        elevation: 0,
        foregroundColor: Colors.black,
        iconTheme: const IconThemeData(color: Colors.black),
        bottom: PreferredSize(
          preferredSize: const Size.fromHeight(2.0),
          child: LinearProgressIndicator(
            value: displayProgress,
            backgroundColor: Colors.grey.shade200,
            valueColor: const AlwaysStoppedAnimation<Color>(
              Color.fromRGBO(157, 212, 237, 1.0),
            ),
            minHeight: 2.0,
          ),
        ),
      ),
      body: _isLoading
          ? const Center(child: CircularProgressIndicator())
          : _error != null
          ? Center(
              child: Text(
                _error!,
                style: const TextStyle(
                  fontFamily: 'HarmonyOS_Sans_SC',
                  color: Colors.grey,
                ),
              ),
            )
          : SingleChildScrollView(
              controller: _scrollController,
              padding: const EdgeInsets.all(16.0),
              child: _cachedMarkdown ?? const SizedBox.shrink(),
            ),
    );
  }
}