import 'dart:async';
import 'dart:io';

import 'package:flutter/material.dart';
import 'package:lottie/lottie.dart';
import 'package:photos/core/event_bus.dart';
import 'package:photos/ente_theme_data.dart';
import 'package:photos/events/local_import_progress.dart';
import 'package:photos/events/sync_status_update_event.dart';
import "package:photos/generated/l10n.dart";
import 'package:photos/services/local_sync_service.dart';
import 'package:photos/ui/backup_folder_selection_page.dart';
import 'package:photos/ui/common/bottom_shadow.dart';
import 'package:photos/utils/navigation_util.dart';

class LoadingPhotosWidget extends StatefulWidget {
  const LoadingPhotosWidget({Key? key}) : super(key: key);

  @override
  State<LoadingPhotosWidget> createState() => _LoadingPhotosWidgetState();
}

class _LoadingPhotosWidgetState extends State<LoadingPhotosWidget> {
  late StreamSubscription<SyncStatusUpdate> _firstImportEvent;
  late StreamSubscription<LocalImportProgressEvent> _importProgressEvent;
  int _currentPage = 0;
  String _loadingMessage = "Loading your photos...";
  final PageController _pageController = PageController(
    initialPage: 0,
  );
  final List<String> _messages = [];

  @override
  void initState() {
    super.initState();
    _firstImportEvent =
        Bus.instance.on<SyncStatusUpdate>().listen((event) async {
      if (mounted && event.status == SyncStatus.completedFirstGalleryImport) {
        if (LocalSyncService.instance.hasGrantedLimitedPermissions()) {
          // Do nothing, let HomeWidget refresh
        } else {
          routeToPage(
            context,
            const BackupFolderSelectionPage(
              isOnboarding: true,
              buttonText: "Start backup",
            ),
          );
        }
      }
    });
    _importProgressEvent =
        Bus.instance.on<LocalImportProgressEvent>().listen((event) {
      if (Platform.isAndroid) {
        _loadingMessage = 'Processing ${event.folderName}...';
        if (mounted) {
          setState(() {});
        }
      }
    });
    Timer.periodic(const Duration(seconds: 5), (Timer timer) {
      if (!mounted) {
        return;
      }
      if (_currentPage < _messages.length - 1) {
        _currentPage++;
      } else {
        _currentPage = 0;
      }

      _pageController.animateToPage(
        _currentPage,
        duration: const Duration(milliseconds: 300),
        curve: Curves.easeIn,
      );
    });
  }

  @override
  void dispose() {
    _firstImportEvent.cancel();
    _importProgressEvent.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    _setupLoadingMessages(context);
    final isLightMode =
        MediaQuery.of(context).platformBrightness == Brightness.light;
    return Scaffold(
      body: SingleChildScrollView(
        child: Center(
          child: Padding(
            padding: const EdgeInsets.symmetric(horizontal: 20),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.center,
              children: [
                Stack(
                  alignment: Alignment.center,
                  children: [
                    isLightMode
                        ? Image.asset(
                            'assets/loading_photos_background.png',
                            color: Colors.white.withOpacity(0.5),
                            colorBlendMode: BlendMode.modulate,
                          )
                        : Image.asset(
                            'assets/loading_photos_background_dark.png',
                            color: Colors.white.withOpacity(0.25),
                            colorBlendMode: BlendMode.modulate,
                          ),
                    Column(
                      children: [
                        const SizedBox(height: 24),
                        Lottie.asset(
                          'assets/loadingGalleryLottie.json',
                          height: 400,
                        ),
                      ],
                    )
                  ],
                ),
                Text(
                  _loadingMessage,
                  style: TextStyle(
                    color: Theme.of(context).colorScheme.subTextColor,
                  ),
                ),
                const SizedBox(height: 54),
                Column(
                  children: [
                    Row(
                      mainAxisAlignment: MainAxisAlignment.start,
                      children: [
                        Text(
                          S.of(context).didYouKnow,
                          style: Theme.of(context)
                              .textTheme
                              .headline6!
                              .copyWith(
                                color: Theme.of(context).colorScheme.greenText,
                              ),
                        ),
                      ],
                    ),
                    const SizedBox(
                      height: 16,
                    ),
                    SizedBox(
                      height: 175,
                      child: Stack(
                        children: [
                          PageView.builder(
                            scrollDirection: Axis.vertical,
                            controller: _pageController,
                            itemBuilder: (context, index) {
                              return _getMessage(_messages[index]);
                            },
                            itemCount: _messages.length,
                            physics: const NeverScrollableScrollPhysics(),
                          ),
                          const Positioned(
                            bottom: 0,
                            left: 0,
                            right: 0,
                            child: BottomShadowWidget(),
                          )
                        ],
                      ),
                    ),
                  ],
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }

  void _setupLoadingMessages(BuildContext context) {
    _messages.add(S.of(context).loadMessage1);
    _messages.add(S.of(context).loadMessage2);
    _messages.add(S.of(context).loadMessage3);
    _messages.add(S.of(context).loadMessage4);
    _messages.add(S.of(context).loadMessage5);
    _messages.add(S.of(context).loadMessage6);
    _messages.add(S.of(context).loadMessage7);
    _messages.add(S.of(context).loadMessage8);
    _messages.add(S.of(context).loadMessage9);
  }

  Widget _getMessage(String text) {
    return Text(
      text,
      textAlign: TextAlign.start,
      style: Theme.of(context)
          .textTheme
          .headline5!
          .copyWith(color: Theme.of(context).colorScheme.defaultTextColor),
    );
  }
}