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

import '../../../core/localization/app_localizations.dart';
import '../../../core/theme/app_theme.dart';
import '../../../shared/services/toast_service.dart';
import '../services/usb_detection_service.dart';

/// U盘导入面板
///
/// 在设置页右侧主区域渲染 U盘检测与导入操作。
class UsbImportPanel extends ConsumerStatefulWidget {
  const UsbImportPanel({super.key});

  @override
  ConsumerState<UsbImportPanel> createState() => _UsbImportPanelState();
}

class _UsbImportPanelState extends ConsumerState<UsbImportPanel> {
  bool _detecting = false;

  Future<void> _detect() async {
    if (_detecting) return;
    setState(() => _detecting = true);
    final l10n = AppLocalizations.of(context);
    final connected = await UsbDetectionService.instance.detectUsb();
    if (!mounted) return;
    setState(() => _detecting = false);
    if (connected) {
      ToastService.showInfo(context, l10n?.detectingUsb ?? '正在检测U盘...');
    } else {
      ToastService.showWarning(context, l10n?.usbNotDetected ?? '未检测到U盘');
    }
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    final state = ref.watch(_usbStateProvider);
    final connected = state.maybeWhen(
      data: (s) => s.isConnected,
      orElse: () => UsbDetectionService.instance.isConnected,
    );
    final path = state.maybeWhen(
      data: (s) => s.path,
      orElse: () => UsbDetectionService.instance.usbPath,
    );

    return ListView(
      padding: EdgeInsets.zero,
      children: [
        Container(
          padding: const EdgeInsets.all(16),
          decoration: BoxDecoration(
            color: Colors.white,
            borderRadius: BorderRadius.circular(8),
            border: Border.all(color: AppTheme.borderSubtle),
          ),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              Row(
                children: [
                  Icon(
                    connected ? Icons.usb : Icons.usb_off,
                    color:
                        connected ? AppTheme.primaryColor : AppTheme.warningColor,
                    size: 28,
                  ),
                  const SizedBox(width: 12),
                  Expanded(
                    child: Text(
                      connected ? (l10n?.usbConnected ?? 'U盘已连接') : (l10n?.usbNotDetected ?? '未检测到U盘'),
                      style: TextStyle(
                        color: AppTheme.textPrimary,
                        fontSize: 16,
                        fontWeight: FontWeight.w600,
                      ),
                    ),
                  ),
                ],
              ),
              const SizedBox(height: 12),
              Text(
                connected
                    ? '${l10n?.mountPath ?? '挂载路径'}: ${path ?? "?"}'
                    : (l10n?.insertUsb ?? '请插入U盘后重试'),
                style: TextStyle(
                    color: AppTheme.textSecondary, fontSize: 13),
              ),
              const SizedBox(height: 20),
              Row(
                mainAxisAlignment: MainAxisAlignment.end,
                children: [
                  OutlinedButton.icon(
                    onPressed: _detecting ? null : _detect,
                    icon: _detecting
                        ? const SizedBox(
                            width: 14,
                            height: 14,
                            child: CircularProgressIndicator(strokeWidth: 2),
                          )
                        : const Icon(Icons.refresh, size: 18),
                    label: Text(l10n?.reDetect ?? '重新检测'),
                  ),
                  const SizedBox(width: 12),
                  ElevatedButton.icon(
                    onPressed: connected ? () => _import(path) : null,
                    icon: const Icon(Icons.download, size: 18),
                    label: Text(l10n?.importProgram ?? '导入程序'),
                  ),
                ],
              ),
            ],
          ),
        ),
        const SizedBox(height: 16),
        Container(
          padding: const EdgeInsets.all(16),
          decoration: BoxDecoration(
            color: Colors.white,
            borderRadius: BorderRadius.circular(8),
            border: Border.all(color: AppTheme.borderSubtle),
          ),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                l10n?.usageInstructions ?? '使用说明',
                style: TextStyle(
                  color: AppTheme.textPrimary,
                  fontSize: 14,
                  fontWeight: FontWeight.w600,
                ),
              ),
              const SizedBox(height: 8),
              _bullet(l10n?.usbUsageStep1 ?? '将程序文件 (.json) 放入 U盘根目录的 programs 文件夹'),
              _bullet(l10n?.usbUsageStep2 ?? '插入 U盘后点击"重新检测"'),
              _bullet(l10n?.usbUsageStep3 ?? '检测成功后点击"导入程序"加载程序列表'),
            ],
          ),
        ),
      ],
    );
  }

  void _import(String? path) {
    final l10n = AppLocalizations.of(context);
    if (path == null) {
      ToastService.showWarning(context, l10n?.usbPathInvalid ?? 'U盘路径无效');
      return;
    }
    ToastService.showInfo(context, l10n?.importingPrograms ?? '正在导入程序...');
    // TODO: 接入 program_import_service 实现真正的导入流程
  }

  Widget _bullet(String text) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 4),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Padding(
            padding: const EdgeInsets.only(top: 6, right: 8),
            child: Container(
              width: 4,
              height: 4,
              decoration: BoxDecoration(
                color: AppTheme.primaryColor,
                shape: BoxShape.circle,
              ),
            ),
          ),
          Expanded(
            child: Text(
              text,
              style: TextStyle(
                color: AppTheme.textSecondary,
                fontSize: 13,
                height: 1.5,
              ),
            ),
          ),
        ],
      ),
    );
  }
}

/// 监听 USB 状态变化的 Riverpod StreamProvider
final _usbStateProvider = StreamProvider<UsbState>((ref) {
  return UsbDetectionService.instance.stateStream;
});