import 'dart:async';
import 'dart:io' show Platform;

import 'package:device_info_plus/device_info_plus.dart';
import 'package:logger/logger.dart';
import 'package:permission_handler/permission_handler.dart';

import '../../constants.dart';
import '../../core/services/stoppable_service.dart';
import '../../core/util/logger.dart';

class PermissionService extends StoppableService {
  final Logger _logger = getLogger();

  Timer? _serviceCheckTimer;

  bool _devicePermissionDialogActive = false;

  bool _deviceInformationInitialized = false;
  bool _useStoragePermission = true;

  PermissionService();

  Future checkEnabledAndPermission() async {
    if (_devicePermissionDialogActive) {
      _logger.d('Device permission dialog active, skipping');
      return;
    }

    bool allGranted = false;
    bool anyPermanentlyDenied = false;

    // Since Android compileSdk >= 33, "storage" is deprecated
    // Instead, request access to all of
    // - Permission.photos
    // - Permission.videos
    // - Permission.audio
    //
    // For iOS and Android < 33, keep using "storage"
    if (_useStoragePermission) {
      PermissionStatus storagePermission = await Permission.storage.status;
      allGranted = PermissionStatus.granted == storagePermission;
      anyPermanentlyDenied =
          PermissionStatus.permanentlyDenied == storagePermission;
    } else {
      PermissionStatus photosPermission = await Permission.photos.status;
      PermissionStatus videosPermission = await Permission.videos.status;
      PermissionStatus audioPermission = await Permission.audio.status;

      allGranted = PermissionStatus.granted == photosPermission &&
          PermissionStatus.granted == videosPermission &&
          PermissionStatus.granted == audioPermission;
      anyPermanentlyDenied =
          PermissionStatus.permanentlyDenied == photosPermission ||
              PermissionStatus.permanentlyDenied == videosPermission ||
              PermissionStatus.permanentlyDenied == audioPermission;
    }

    // show warning to user to manually handle, don't enforce it over and over again
    if (anyPermanentlyDenied) {
      _logger.w(
          "At least one required permission has been denied permanently, stopping service");
      stop();
      return;
    }

    // all good, stop the permission service
    if (allGranted) {
      _logger.d("All permissions have been granted, stopping service");
      stop();
      return;
    }

    // not all have been granted, show OS dialog
    _logger.d(
        "Not all permissions have been granted yet, initializing permission dialog");
    _devicePermissionDialogActive = true;

    if (_useStoragePermission) {
      await [Permission.storage].request().whenComplete(() {
        _logger.d('Device request permission finished');
        _devicePermissionDialogActive = false;
      });
    } else {
      await [Permission.photos, Permission.videos, Permission.audio]
          .request()
          .whenComplete(() {
        _logger.d('Device request permission finished');
        _devicePermissionDialogActive = false;
      });
    }
  }

  @override
  Future start() async {
    super.start();
    await _determineDeviceInfo();
    await checkEnabledAndPermission();

    _serviceCheckTimer = Timer.periodic(
        const Duration(milliseconds: Constants.mediaPermissionCheckInterval),
        (serviceTimer) async {
      if (!super.serviceStopped) {
        await checkEnabledAndPermission();
      } else {
        serviceTimer.cancel();
      }
    });
    _logger.d('PermissionService started');
  }

  @override
  void stop() {
    _removeServiceCheckTimer();
    super.stop();
    _logger.d('PermissionService stopped');
  }

  Future _determineDeviceInfo() async {
    if (_deviceInformationInitialized) {
      _logger.d('Device information already initialized, skipping');
      return;
    }

    DeviceInfoPlugin deviceInfoPlugin = DeviceInfoPlugin();
    if (Platform.isAndroid) {
      final androidInfo = await deviceInfoPlugin.androidInfo;
      if (androidInfo.version.sdkInt >= 33) {
        _useStoragePermission = false;
      }
    }

    if (_useStoragePermission) {
      _logger.d('Device requires [storage] permission');
    } else {
      _logger.d('Device requires [photos,videos,audio] permission');
    }

    _deviceInformationInitialized = true;
  }

  void _removeServiceCheckTimer() {
    if (_serviceCheckTimer != null) {
      _serviceCheckTimer!.cancel();
      _serviceCheckTimer = null;
      _logger.d('Removed service check timer');
    }
  }
}