import 'dart:convert';
import 'dart:ui';
import 'dart:io';
import 'package:collection/collection.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:flutter/services.dart';
import 'package:win_text_editor/app/providers/editor_provider.dart';
import 'package:file_picker/file_picker.dart';

class TextTab extends StatefulWidget {
  final String tabId;

  const TextTab({super.key, required this.tabId});

  @override
  State<TextTab> createState() => TextTabState();
}

class TextTabState extends State<TextTab> {
  late TextEditingController _controller;
  late EditorProvider _provider;
  late FocusNode _focusNode;
  late ScrollController _scrollController;
  bool _isLoading = false;
  static const int maxFileSize = 1024 * 1024; // 1MB

  @override
  void initState() {
    super.initState();
    _provider = Provider.of<EditorProvider>(context, listen: false);
    _provider.registerTextTabController(widget.tabId, this);
    _controller = TextEditingController(text: _getCurrentContent());
    _focusNode = FocusNode();
    _scrollController = ScrollController();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      FocusScope.of(context).requestFocus(_focusNode);
    });
  }

  String _getCurrentContent() {
    return _provider.tabs.firstWhere((t) => t.id == widget.tabId).content;
  }

  @override
  void didUpdateWidget(TextTab oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (oldWidget.tabId != widget.tabId) {
      _controller.text = _getCurrentContent();
    }
  }

  @override
  void dispose() {
    _controller.dispose();
    _focusNode.dispose();
    _scrollController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final tab = _provider.tabs.firstWhereOrNull((t) => t.id == widget.tabId);
    if (tab == null) {
      return const Center(child: Text('选项卡不存在'));
    }

    String fileNameText =
        tab.fileName != null && tab.fileName!.isNotEmpty ? '${tab.fileName},' : '';

    return Column(
      children: [
        Container(
          height: 40,
          padding: const EdgeInsets.symmetric(horizontal: 16),
          decoration: BoxDecoration(
            color: Colors.grey[100],
            border: Border(bottom: BorderSide(color: Colors.grey[300]!)),
          ),
          child: Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: [
              Text(
                '源文本${tab.content.isEmpty ? '' : ' ($fileNameText${tab.content.length}字符)'}',
                style: const TextStyle(fontWeight: FontWeight.bold),
              ),
              Row(
                children: [
                  IconButton(
                    icon: const Icon(Icons.folder_open, size: 20),
                    tooltip: '打开文件',
                    onPressed: _isLoading ? null : () => _openFile(context),
                  ),
                  IconButton(
                    icon: const Icon(Icons.content_copy, size: 20),
                    tooltip: '复制内容',
                    onPressed:
                        tab.content.isEmpty ? null : () => _copyToClipboard(context, tab.content),
                  ),
                  IconButton(
                    icon: const Icon(Icons.save, size: 20),
                    tooltip: '保存到文件',
                    onPressed: tab.content.isEmpty ? null : () => _saveFile(context, tab.content),
                  ),
                  if (_isLoading)
                    const Padding(
                      padding: EdgeInsets.only(left: 8),
                      child: SizedBox(
                        width: 16,
                        height: 16,
                        child: CircularProgressIndicator(strokeWidth: 2),
                      ),
                    ),
                ],
              ),
            ],
          ),
        ),
        Expanded(
          child: ScrollConfiguration(
            behavior: ScrollConfiguration.of(context).copyWith(
              scrollbars: true,
              dragDevices: {PointerDeviceKind.touch, PointerDeviceKind.mouse},
            ),
            child: SingleChildScrollView(
              controller: _scrollController,
              child: Stack(
                children: [
                  TextField(
                    controller: _controller,
                    focusNode: _focusNode,
                    maxLines: null,
                    onChanged: (text) => _provider.updateContent(widget.tabId, text, tab.fileName),
                    decoration: const InputDecoration(
                      border: InputBorder.none,
                      contentPadding: EdgeInsets.all(16),
                    ),
                    style: TextStyle(
                      fontFamily: 'monospace',
                      fontSize: 14,
                      color: Theme.of(context).textTheme.bodyLarge?.color,
                    ),
                  ),
                ],
              ),
            ),
          ),
        ),
      ],
    );
  }

  Future<void> _openFile(BuildContext context) async {
    final result = await FilePicker.platform.pickFiles(type: FileType.any, allowMultiple: false);
    if (result != null && result.files.single.path != null) {
      await loadFile(context, result.files.single.path!);
    }
  }

  Future<void> _copyToClipboard(BuildContext context, String content) async {
    await Clipboard.setData(ClipboardData(text: content));
    if (context.mounted) {
      ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('已复制到剪贴板')));
    }
  }

  Future<void> _saveFile(BuildContext context, String content) async {
    try {
      String? outputPath = await FilePicker.platform.saveFile(
        dialogTitle: '保存文件',
        fileName: 'untitled.txt',
        allowedExtensions: ['txt'],
        type: FileType.any,
      );

      if (outputPath == null) return;

      final file = File(outputPath);

      if (await file.exists()) {
        final shouldOverwrite = await showDialog<bool>(
          context: context,
          builder:
              (context) => AlertDialog(
                title: const Text('文件已存在'),
                content: const Text('要覆盖现有文件吗？'),
                actions: [
                  TextButton(
                    onPressed: () => Navigator.pop(context, false),
                    child: const Text('取消'),
                  ),
                  TextButton(
                    onPressed: () => Navigator.pop(context, true),
                    child: const Text('覆盖'),
                  ),
                ],
              ),
        );

        if (shouldOverwrite != true) return;
      }

      await file.writeAsString(content);

      if (context.mounted) {
        ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('已保存到: ${file.path}')));
      }
    } on FileSystemException catch (e) {
      if (context.mounted) {
        ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('保存失败: ${e.message}')));
      }
    } catch (e) {
      if (context.mounted) {
        ScaffoldMessenger.of(
          context,
        ).showSnackBar(SnackBar(content: Text('保存失败: ${e.toString()}')));
      }
    }
  }

  // 新增公共方法，处理文件加载逻辑
  Future<void> loadFile(BuildContext context, String filePath) async {
    try {
      setState(() => _isLoading = true);
      final file = File(filePath);
      final fileSize = await file.length();

      // 检查文件大小
      if (fileSize > maxFileSize) {
        if (context.mounted) {
          ScaffoldMessenger.of(
            context,
          ).showSnackBar(const SnackBar(content: Text('文件过大(超过1MB)，无法处理')));
        }
        return;
      }

      // 判断活动的文本编辑框中是否有内容
      final activeTab = _provider.getTabById(widget.tabId);
      if (activeTab != null && activeTab.content.isNotEmpty) {
        final confirm = await showDialog<bool>(
          context: context,
          builder:
              (context) => AlertDialog(
                title: const Text('确认提示'),
                content: const Text('确认是否打开新的文件？打开后将覆盖当前内容'),
                actions: [
                  TextButton(
                    onPressed: () => Navigator.pop(context, false),
                    child: const Text('取消'),
                  ),
                  TextButton(
                    onPressed: () => Navigator.pop(context, true),
                    child: const Text('确认'),
                  ),
                ],
              ),
        );

        if (confirm != true) {
          return;
        }
      }

      final _fileName = file.path.split('\\').last;

      // 清空当前内容
      _provider.updateContent(widget.tabId, '', _fileName);
      _controller.text = '';

      // 逐行读取文件
      final stream = file.openRead();
      final lines = stream.transform(utf8.decoder).transform(const LineSplitter());

      await for (final line in lines) {
        if (!mounted) break; // 如果组件已卸载，停止处理

        setState(() {
          _controller.text += '$line\n';
          _provider.updateContent(widget.tabId, _controller.text, _fileName);
        });

        // 自动滚动到底部
        WidgetsBinding.instance.addPostFrameCallback((_) {
          _scrollController.jumpTo(_scrollController.position.maxScrollExtent);
        });

        // 添加微小延迟，让用户能看到逐行加载效果
        await Future.delayed(const Duration(milliseconds: 10));
      }

      if (context.mounted) {
        ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('已加载: ${file.path}')));
      }
    } on FormatException {
      if (context.mounted) {
        ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('这不是可读的文本文件')));
      }
    } on FileSystemException catch (e) {
      if (context.mounted) {
        ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('文件访问错误: ${e.message}')));
      }
    } catch (e) {
      if (context.mounted) {
        ScaffoldMessenger.of(
          context,
        ).showSnackBar(SnackBar(content: Text('读取失败: ${e.toString()}')));
      }
    } finally {
      if (mounted) {
        setState(() => _isLoading = false);
      }
    }
  }
}