flutter_integrated_whb/lib/customWidget/remote_file_page.dart

import 'dart:async';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:pdfx/pdfx.dart';
import 'package:path_provider/path_provider.dart';
import 'package:qhd_prevention/customWidget/toast_util.dart';
import 'package:qhd_prevention/pages/my_appbar.dart';
import 'package:qhd_prevention/customWidget/custom_button.dart';
import 'package:dio/dio.dart';
import 'package:qhd_prevention/tools/tools.dart';

class RemoteFilePage extends StatefulWidget {
  final String fileUrl;
  final int countdownSeconds;

  const RemoteFilePage({
    Key? key,
    required this.fileUrl,
    this.countdownSeconds = 3,
  }) : super(key: key);

  @override
  _RemoteFilePageState createState() => _RemoteFilePageState();
}

class _RemoteFilePageState extends State<RemoteFilePage> {
  String? _localPath;
  bool _isLoading = true;
  bool _hasScrolledToBottom = false;
  bool _timerFinished = false;
  late int _secondsRemaining;
  Timer? _countdownTimer;
  late PdfControllerPinch _pdfController;
  int _totalPages = 0;

  // 用于短文档(<=3页)的停留计时器兜底
  Timer? _pageViewTimer;

  @override
  void initState() {
    super.initState();
    _secondsRemaining = widget.countdownSeconds;
    _startCountdown();
    _downloadAndLoad();
    LoadingDialogHelper.hide();
  }

  Future<void> _downloadAndLoad() async {
    try {
      final url = widget.fileUrl;
      final filename = url.split('/').last;
      final dir = await getTemporaryDirectory();
      final filePath = '${dir.path}/$filename';

      final dio = Dio();
      final response = await dio.get<List<int>>(
        url,
        options: Options(responseType: ResponseType.bytes),
      );
      final file = File(filePath);
      await file.writeAsBytes(response.data!);

      // 加载 PDF 控制器
      _pdfController = PdfControllerPinch(
        document: PdfDocument.openFile(filePath),
      );

      setState(() {
        _localPath = filePath;
        _isLoading = false;
      });
    } catch (e) {
      // 下载或加载失败
      setState(() {
        _isLoading = false;
      });

      ToastUtil.showNormal(context, '文件加载失败: $e');
    }
  }

  void _startCountdown() {
    _countdownTimer = Timer.periodic(const Duration(seconds: 1), (timer) {
      setState(() {
        if (_secondsRemaining > 1) {
          _secondsRemaining--;
        } else {
          _secondsRemaining = 0;
          _timerFinished = true;
          _countdownTimer?.cancel();
        }
      });
    });
  }

  @override
  void dispose() {
    _countdownTimer?.cancel();
    _pageViewTimer?.cancel();
    if (!_isLoading) {
      _pdfController.dispose();
    }
    super.dispose();
  }

  // 当页面改变时调用（pdfx 的 page 是 1-based）
  void _onPageChanged(int page) {
    // 取消可能存在的短页面计时器（重新开始）
    _pageViewTimer?.cancel();

    // 如果到达最后一页（注意页码从 1 开始）
    if (_totalPages > 0 && page >= _totalPages) {
      // 直接标记为已翻到底
      setState(() => _hasScrolledToBottom = true);
      return;
    }

    // 对于特别短的文档（例如 <=3 页），我们做一个停留计时器：如果用户停留在最后一页一小段时间，也视为已浏览完毕
    if (_totalPages > 0 && _totalPages <= 3) {
      // 如果当前页已经是最后一页（page == _totalPages），启动短计时器
      if (page == _totalPages) {
        _pageViewTimer = Timer(const Duration(seconds: 1), () {
          if (mounted) setState(() => _hasScrolledToBottom = true);
        });
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final isButtonEnabled = _timerFinished && _hasScrolledToBottom;
    return Scaffold(
      appBar: MyAppbar(title: '资料学习'),
      backgroundColor: Colors.white,
      body: SafeArea(
        child: Column(
          children: [
            Expanded(
              child: _isLoading
                  ? const Center(child: CircularProgressIndicator())
                  : PdfViewPinch(
                controller: _pdfController,
                scrollDirection: Axis.vertical,
                onDocumentLoaded: (document) {
                  setState(() {
                    _totalPages = document.pagesCount;
                    // 如果文档只有 1 页，直接视为已看完
                    if (_totalPages <= 1) {
                      _hasScrolledToBottom = true;
                    }
                  });
                },
                onPageChanged: (page) {
                  _onPageChanged(page);
                },
              ),
            ),
            Padding(
              padding: const EdgeInsets.all(16),
              child: CustomButton(
                backgroundColor: isButtonEnabled ? Colors.blue : Colors.grey,
                text: isButtonEnabled
                    ? '我已学习完毕'
                    : _secondsRemaining == 0 ? '我已学习完毕' : '（$_secondsRemaining s）我已学习完毕',
                onPressed: isButtonEnabled
                    ? () {
                  // TODO: 完成回调
                  Navigator.pop(context, true);
                }
                    : null,
              ),
            ),
          ],
        ),
      ),
    );
  }
}