import 'package:flutter/material.dart';
import 'package:yx_only_office_flutter/yx_only_office_flutter.dart';

const _serverUrl = String.fromEnvironment(
  'ONLYOFFICE_SERVER_URL',
  defaultValue: '',
);
const _fileUrl = String.fromEnvironment(
  'ONLYOFFICE_FILE_URL',
  defaultValue: '',
);
const _jwtSecret = String.fromEnvironment(
  'ONLYOFFICE_JWT_SECRET',
  defaultValue: '',
);

void main() {
  runApp(const OnlyOfficeDemoApp());
}

class OnlyOfficeDemoApp extends StatelessWidget {
  const OnlyOfficeDemoApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'ONLYOFFICE Demo',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(colorSchemeSeed: Colors.blue, useMaterial3: true),
      home: const DemoHomePage(),
    );
  }
}

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

  @override
  State<DemoHomePage> createState() => _DemoHomePageState();
}

class _DemoHomePageState extends State<DemoHomePage> {
  String _mode = 'view'; // 'view' or 'edit'
  bool _allowDownload = true;
  bool _allowPrint = false;
  bool _lockNavigation = true;
  String? _lastError;
  bool _hasUnsavedChanges = false;

  @override
  Widget build(BuildContext context) {
    if (_serverUrl.isEmpty || _fileUrl.isEmpty) {
      return Scaffold(
        appBar: AppBar(title: const Text('ONLYOFFICE Demo')),
        body: const _MissingConfigHint(),
      );
    }

    return Scaffold(
      appBar: AppBar(
        title: Text('ONLYOFFICE Demo - ${_mode == 'edit' ? '编辑' : '查看'}模式'),
        actions: [
          if (_hasUnsavedChanges)
            Padding(
              padding: const EdgeInsets.only(right: 8),
              child: Chip(
                label: const Text('未保存', style: TextStyle(fontSize: 12)),
                backgroundColor: Colors.orange.shade100,
                avatar: const Icon(Icons.edit, size: 16),
              ),
            ),
          IconButton(
            tooltip: '刷新',
            onPressed: () => setState(() {}),
            icon: const Icon(Icons.refresh),
          ),
        ],
      ),
      body: Column(
        children: [
          _buildControls(),
          if (_lastError != null)
            Material(
              color: Theme.of(context).colorScheme.errorContainer,
              child: ListTile(
                leading: const Icon(Icons.error_outline),
                title: Text(
                  _lastError!,
                  style: TextStyle(
                    color: Theme.of(context).colorScheme.onErrorContainer,
                  ),
                ),
                trailing: IconButton(
                  icon: const Icon(Icons.close),
                  onPressed: () => setState(() => _lastError = null),
                ),
              ),
            ),
          Expanded(
            child: YxOnlyOfficeViewer.create(
              serverUrl: _serverUrl,
              fileUrl: _fileUrl,
              mode: _mode,
              allowDownload: _allowDownload,
              allowPrint: _allowPrint,
              user: const OnlyOfficeUser(
                id: 'demo-user-001',
                name: '演示用户',
                email: 'demo@example.com',
              ),
              customization: const OnlyOfficeCustomization(
                compactToolbar: true,
              ),
              tokenFactory: _jwtSecret.isNotEmpty ? const OnlyOfficeJwtSigner(_jwtSecret) : null,
              restrictNavigationToInitialPage: _lockNavigation,
              loadingBuilder: (_) => const ColoredBox(
                color: Colors.white,
                child: Center(child: CircularProgressIndicator()),
              ),
              onError: _handleError,
              onAppClose: () => _showSnackBar('用户请求关闭编辑器'),
              onDownloadAs: (type, url) => _showSnackBar('下载完成: $type -> $url'),
              onRequestSaveAs: (data) {
                _showSnackBar('用户请求另存为: $data');
                debugPrint('onRequestSaveAs: $data');
              },
              onRequestInsertImage: (data) {
                _showSnackBar('用户请求插入图片');
                debugPrint('onRequestInsertImage: $data');
                // 这里可以打开 Flutter 图片选择器
              },
              onDocumentStateChange: (data) {
                final isModified = data == true;
                setState(() => _hasUnsavedChanges = isModified);
                debugPrint('文档状态变化: ${isModified ? "已修改" : "未修改"}');
              },
              onMetaChange: (data) {
                debugPrint('文档元数据变化: $data');
              },
              onEvent: (event, data) {
                // 通用事件处理器
                debugPrint('📡 事件: $event, 数据: $data');
              },
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildControls() {
    return Card(
      margin: const EdgeInsets.all(8),
      child: Column(
        children: [
          ListTile(
            title: const Text('文档模式'),
            trailing: SegmentedButton<String>(
              segments: const [
                ButtonSegment(value: 'view', label: Text('查看'), icon: Icon(Icons.visibility)),
                ButtonSegment(value: 'edit', label: Text('编辑'), icon: Icon(Icons.edit)),
              ],
              selected: {_mode},
              onSelectionChanged: (Set<String> newSelection) {
                setState(() {
                  _mode = newSelection.first;
                  _hasUnsavedChanges = false;
                });
              },
            ),
          ),
          const Divider(height: 1),
          SwitchListTile(
            title: const Text('允许下载'),
            subtitle: Text(_mode == 'edit' ? '编辑模式下建议开启' : '控制下载按钮显示'),
            value: _allowDownload,
            onChanged: (value) => setState(() => _allowDownload = value),
          ),
          SwitchListTile.adaptive(
            title: const Text('允许打印'),
            subtitle: const Text('控制打印功能'),
            value: _allowPrint,
            onChanged: (value) => setState(() => _allowPrint = value),
          ),
          SwitchListTile.adaptive(
            title: const Text('限制导航'),
            subtitle: const Text('防止 WebView 跳转到其他页面'),
            value: _lockNavigation,
            onChanged: (value) => setState(() => _lockNavigation = value),
          ),
        ],
      ),
    );
  }

  void _handleError(String message) {
    setState(() => _lastError = message);
    _showSnackBar('错误: $message');
  }

  void _showSnackBar(String message) {
    if (!mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text(message),
        behavior: SnackBarBehavior.floating,
      ),
    );
  }
}

class _MissingConfigHint extends StatelessWidget {
  const _MissingConfigHint();

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.all(24),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          const Text(
            '⚠️ 尚未配置 Document Server',
            style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
          ),
          const SizedBox(height: 16),
          const Text(
            '运行示例前请通过 --dart-define 传入以下环境变量：',
            style: TextStyle(fontSize: 14),
          ),
          const SizedBox(height: 12),
          _buildConfigItem('ONLYOFFICE_SERVER_URL', 'ONLYOFFICE 服务器地址', required: true),
          _buildConfigItem('ONLYOFFICE_FILE_URL', '文档文件地址', required: true),
          _buildConfigItem('ONLYOFFICE_JWT_SECRET', 'JWT 签名密钥（可选）', required: false),
          const SizedBox(height: 20),
          const Text(
            '示例命令：',
            style: TextStyle(fontSize: 14, fontWeight: FontWeight.bold),
          ),
          const SizedBox(height: 8),
          Container(
            padding: const EdgeInsets.all(12),
            decoration: BoxDecoration(
              color: Colors.grey.shade100,
              borderRadius: BorderRadius.circular(8),
              border: Border.all(color: Colors.grey.shade300),
            ),
            child: const SelectableText(
              'flutter run \\\n'
              '  --dart-define ONLYOFFICE_SERVER_URL=https://doc.example.com \\\n'
              '  --dart-define ONLYOFFICE_FILE_URL=https://doc.example.com/demo.docx \\\n'
              '  --dart-define ONLYOFFICE_JWT_SECRET=your-secret-key',
              style: TextStyle(fontFamily: 'monospace', fontSize: 12),
            ),
          ),
          const SizedBox(height: 20),
          const Divider(),
          const SizedBox(height: 12),
          const Text(
            '📚 参考文档：',
            style: TextStyle(fontSize: 14, fontWeight: FontWeight.bold),
          ),
          const SizedBox(height: 8),
          _buildLink('ONLYOFFICE Docs API', 'https://api.onlyoffice.com/docs/docs-api/'),
          _buildLink('Android 官方项目', 'https://github.com/ONLYOFFICE/documents-app-android'),
          _buildLink('iOS 官方项目', 'https://github.com/ONLYOFFICE/documents-app-ios'),
        ],
      ),
    );
  }

  Widget _buildConfigItem(String key, String description, {required bool required}) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 8),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Icon(
            required ? Icons.check_circle : Icons.info_outline,
            size: 16,
            color: required ? Colors.red : Colors.blue,
          ),
          const SizedBox(width: 8),
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  key,
                  style: const TextStyle(fontWeight: FontWeight.bold, fontFamily: 'monospace'),
                ),
                Text(
                  description,
                  style: TextStyle(fontSize: 12, color: Colors.grey.shade700),
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildLink(String title, String url) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 4),
      child: Row(
        children: [
          const Icon(Icons.link, size: 14),
          const SizedBox(width: 4),
          Expanded(
            child: SelectableText(
              '$title: $url',
              style: const TextStyle(fontSize: 12, color: Colors.blue),
            ),
          ),
        ],
      ),
    );
  }
}