import 'dart:io';
import 'package:dio/dio.dart';
import 'package:flutter/material.dart';
import 'package:get/get.dart';
import 'package:path_provider/path_provider.dart';
import 'package:open_file/open_file.dart';
import 'package:package_info_plus/package_info_plus.dart';
import 'package:permission_handler/permission_handler.dart';

class UpgraderService extends GetxService {
  final Dio _dio = Dio();
  final String _versionUrl =
      'http://xhota.anxincloud.cn/problem/version.json'; // 您的版本信息 JSON 地址

  var isUpdateAvailable = false.obs;
  var updateInfo = {}.obs;
  var downloadProgress = '0'.obs;
  var totalSize = '0'.obs;
  var isDownloading = false.obs;

  @override
  void onInit() {
    super.onInit();
    checkForUpdate();
  }

  // 检查更新
  Future<void> checkForUpdate() async {
    try {
      // 获取当前应用版本信息
      PackageInfo packageInfo = await PackageInfo.fromPlatform();
      String currentVersion = packageInfo.version;

      final response = await _dio.get(_versionUrl);
      if (response.statusCode == 200) {
        final latestVersion = response.data['version'];
        if (latestVersion.compareTo(currentVersion) > 0) {
          isUpdateAvailable.value = true;
          updateInfo.value = response.data;
          showUpdateDialog();
        }
      }
    } catch (e) {
      Get.log('检查更新失败: $e');
    }
  }

  // 显示更新提示对话框
  void showUpdateDialog() {
    Get.dialog(
      AlertDialog(
        title: Text('发现新版本'),
        content: Text(updateInfo['description'] ?? '有新的更新可用。'),
        actions: [
          TextButton(onPressed: () => Get.back(), child: Text('稍后')),
          TextButton(
            onPressed: () {
              Get.back();
              startDownload();
            },
            child: Text('立即更新'),
          ),
        ],
      ),
      barrierDismissible: false,
    );
  }

  // 开始下载
  Future<void> startDownload() async {
    isDownloading.value = true;
    showDownloadProgressDialog();

    try {
      Directory? dir = await getExternalStorageDirectory();

      if (dir == null) {
        Get.back(); // 关闭进度对话框
        Get.snackbar('错误', '无法获取外部存储目录。');
        print('错误: getExternalStorageDirectory() 返回 null');
        isDownloading.value = false;
        return; // 提前退出
      }

      String savePath = '${dir.path}/app-release.apk';
      print('--- 调试信息 ---');
      print('目标下载路径: $savePath');
      print('--- 调试信息 ---');

      // 确保父目录存在
      final file = File(savePath);
      if (!await file.parent.exists()) {
        await file.parent.create(recursive: true);
        print('--- 调试信息 ---');
        print('已尝试创建父目录: ${file.parent.path}');
        print('--- 调试信息 ---');
      }

      await _dio.download(
        updateInfo['url'],
        savePath,
        onReceiveProgress: (received, total) {
          if (total != -1) {
            downloadProgress.value = (received / 1024 / 1024).toStringAsFixed(
              2,
            );
            totalSize.value = (total / 1024 / 1024).toStringAsFixed(2);
            // 在进度回调中也打印路径，确保一直有效
            // print('下载进度 - 目标路径: $savePath');
          }
        },
        options: Options(
          receiveTimeout: const Duration(seconds: 30), // 增加超时时间
          sendTimeout: const Duration(seconds: 30),
        ),
      );

      isDownloading.value = false;
      Get.back(); // 关闭下载进度对话框

      // 再次验证文件是否存在
      if (await file.exists()) {
        final fileSize = await file.length();
        Get.log('文件验证成功！路径: $savePath');
        Get.log('文件大小: ${(fileSize / 1024 / 1024).toStringAsFixed(2)} MB');
        installApk(savePath);
      } else {
        Get.snackbar('下载失败', '文件下载完毕但未找到，请联系管理员。');
        Get.log('错误：文件下载完毕但未找到！');
      }
    } on DioException catch (e) {
      // 使用 DioException 捕获更具体的 Dio 错误
      isDownloading.value = false;
      Get.back();
      String errorMessage = '下载失败: 网络或服务器问题。';
      if (e.type == DioExceptionType.badResponse) {
        errorMessage = '下载失败: 服务器响应错误 (${e.response?.statusCode})';
        Get.log('Dio响应错误: ${e.response?.data}');
      } else if (e.type == DioExceptionType.connectionError) {
        errorMessage = '下载失败: 连接错误，请检查网络。';
      } else if (e.type == DioExceptionType.unknown) {
        // 可能是文件系统错误、权限错误等
        errorMessage = '下载失败: 未知错误。请检查存储权限或设备空间。';
        Get.log('Dio未知错误: $e');
      }
      Get.snackbar('下载失败', errorMessage);
      Get.log('下载失败 (DioException): $e');
    } catch (e) {
      isDownloading.value = false;
      Get.back();
      Get.snackbar('下载失败', '发生未知错误。');
      Get.log('下载失败 (通用异常): $e');
    }
  }

  // 显示下载进度对话框
  void showDownloadProgressDialog() {
    Get.dialog(
      AlertDialog(
        title: Text('正在下载更新...'),
        content: Obx(
          () => Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              LinearProgressIndicator(
                value: totalSize.value == '0'
                    ? null
                    : double.parse(downloadProgress.value) /
                          double.parse(totalSize.value),
              ),
              SizedBox(height: 16),
              Text('${downloadProgress.value} MB / ${totalSize.value} MB'),
            ],
          ),
        ),
      ),
      barrierDismissible: false,
    );
  }

  // 安装 APK
  Future<void> installApk(String path) async {
    // 检查安装权限
    var status = await Permission.requestInstallPackages.status;
    if (status.isGranted) {
      // 权限已授予，直接安装
      _openApkFile(path);
    } else {
      // 权限未授予，发起请求
      // 这会打开系统设置页面，让用户手动授权
      status = await Permission.requestInstallPackages.request();
      if (status.isGranted) {
        _openApkFile(path);
      } else {
        // 如果用户拒绝了权限，给出提示
        Get.snackbar(
          '权限被拒绝',
          '需要授权才能安装更新。请在系统设置中为本应用开启“安装未知应用”的权限。',
          duration: Duration(seconds: 5),
        );
      }
    }
  }

  // 抽离出打开文件的逻辑
  Future<void> _openApkFile(String path) async {
    final result = await OpenFile.open(path);
    print('OpenFile result: ${result.type}, message: ${result.message}');
    if (result.type != ResultType.done) {
      Get.snackbar('安装失败', '无法启动安装程序: ${result.message}');
    }
  }
}