import 'dart:async';
import 'dart:io';
import 'dart:ui' as ui;
import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/scheduler.dart';
import 'package:image_gallery_saver/image_gallery_saver.dart';
import 'package:permission_handler/permission_handler.dart';

class ImageSaveService {
  /// 保存图片到相册 - 改进版本，避免 debugNeedsPaint 错误
  static Future<bool> saveImageToGallery(
    GlobalKey repaintBoundaryKey, {
    String? fileName,
  }) async {
    try {
      // 1. 检查权限
      final hasPermission = await _requestPermission();
      if (!hasPermission) {
        debugPrint('没有相册访问权限');
        return false;
      }

      // 2. 使用调度器确保在正确的时机捕获
      final completer = Completer<bool>();

      SchedulerBinding.instance.addPostFrameCallback((_) async {
        try {
          // 额外等待确保所有绘制完成
          await Future.delayed(const Duration(milliseconds: 100));

          final result = await _captureAndSave(repaintBoundaryKey, fileName);
          completer.complete(result);
        } catch (e) {
          debugPrint('捕获图片失败: $e');
          completer.complete(false);
        }
      });

      return await completer.future;
    } catch (e) {
      debugPrint('保存图片失败: $e');
      return false;
    }
  }

  /// 内部方法：捕获并保存图片
  static Future<bool> _captureAndSave(
    GlobalKey repaintBoundaryKey,
    String? fileName,
  ) async {
    try {
      // 获取 RepaintBoundary
      final boundary =
          repaintBoundaryKey.currentContext?.findRenderObject()
              as RenderRepaintBoundary?;

      if (boundary == null) {
        debugPrint('无法获取RepaintBoundary');
        return false;
      }

      // 多次尝试捕获，避免绘制冲突
      ui.Image? image;
      int attempts = 0;
      const maxAttempts = 5;

      while (attempts < maxAttempts) {
        try {
          // 检查是否正在绘制
          if (boundary.debugNeedsPaint) {
            debugPrint(
              'RepaintBoundary 正在绘制中，等待... (尝试 ${attempts + 1}/$maxAttempts)',
            );
            await Future.delayed(Duration(milliseconds: 200 * (attempts + 1)));
            attempts++;
            continue;
          }

          // 尝试捕获图片
          image = await boundary.toImage(pixelRatio: 3.0);
          break;
        } catch (e) {
          debugPrint('捕获尝试 ${attempts + 1} 失败: $e');
          attempts++;
          if (attempts < maxAttempts) {
            await Future.delayed(Duration(milliseconds: 300 * attempts));
          }
        }
      }

      if (image == null) {
        debugPrint('所有捕获尝试都失败了');
        return false;
      }

      // 转换为字节数据
      final byteData = await image.toByteData(format: ui.ImageByteFormat.png);
      if (byteData == null) {
        debugPrint('无法转换图片数据');
        return false;
      }

      final pngBytes = byteData.buffer.asUint8List();

      // 保存到相册
      final result = await ImageGallerySaver.saveImage(
        pngBytes,
        name: fileName ?? 'MoodCanvas_${DateTime.now().millisecondsSinceEpoch}',
        quality: 100,
      );

      debugPrint('保存结果: $result');
      return result['isSuccess'] == true;
    } catch (e) {
      debugPrint('_captureAndSave 失败: $e');
      return false;
    }
  }

  /// 请求相册访问权限
  static Future<bool> _requestPermission() async {
    if (Platform.isIOS) {
      // iOS 14+ 需要 photos 权限
      final status = await Permission.photos.request();
      return status.isGranted;
    } else if (Platform.isAndroid) {
      // Android 需要存储权限
      final status = await Permission.storage.request();
      return status.isGranted;
    }
    return false;
  }

  /// 检查权限状态
  static Future<bool> checkPermission() async {
    if (Platform.isIOS) {
      final status = await Permission.photos.status;
      return status.isGranted;
    } else if (Platform.isAndroid) {
      final status = await Permission.storage.status;
      return status.isGranted;
    }
    return false;
  }

  /// 打开应用设置页面
  static Future<void> openSettings() async {
    await openAppSettings();
  }
}