import "dart:async";

import "package:flutter/material.dart";
import "package:logging/logging.dart";
import "package:photos/core/event_bus.dart";
import "package:photos/events/local_photos_updated_event.dart";
import "package:photos/models/file.dart";
import "package:photos/models/file_load_result.dart";
import "package:photos/models/selected_files.dart";
import "package:photos/theme/ente_theme.dart";
import "package:photos/ui/common/loading_widget.dart";
import "package:photos/ui/viewer/gallery/gallery.dart";

class MapPullUpGallery extends StatelessWidget {
  final StreamController<List<File>> visibleImages;
  final double bottomSheetDraggableAreaHeight;
  static const gridCrossAxisSpacing = 4.0;
  static const gridMainAxisSpacing = 4.0;
  static const gridPadding = 2.0;
  static const gridCrossAxisCount = 4;
  const MapPullUpGallery(
    this.visibleImages,
    this.bottomSheetDraggableAreaHeight, {
    Key? key,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    final Logger logger = Logger("_MapPullUpGalleryState");
    final textTheme = getEnteTextTheme(context);
    const double initialChildSize = 0.25;

    return DraggableScrollableSheet(
      expand: false,
      initialChildSize: initialChildSize,
      minChildSize: initialChildSize,
      maxChildSize: 0.8,
      snap: true,
      snapSizes: const [0.5],
      builder: (context, scrollController) {
        return Container(
          decoration: BoxDecoration(
            borderRadius: const BorderRadius.vertical(top: Radius.circular(12)),
            color: getEnteColorScheme(context).backgroundElevated,
          ),
          child: Column(
            mainAxisAlignment: MainAxisAlignment.start,
            children: [
              DraggableHeader(
                scrollController: scrollController,
                bottomSheetDraggableAreaHeight: bottomSheetDraggableAreaHeight,
              ),
              Expanded(
                child: AnimatedSwitcher(
                  duration: const Duration(milliseconds: 200),
                  switchInCurve: Curves.easeInOutExpo,
                  switchOutCurve: Curves.easeInOutExpo,
                  child: StreamBuilder<List<File>>(
                    stream: visibleImages.stream,
                    builder: (
                      BuildContext context,
                      AsyncSnapshot<List<File>> snapshot,
                    ) {
                      if (!snapshot.hasData) {
                        return SizedBox(
                          height: MediaQuery.of(context).size.height * 0.2,
                          child: const EnteLoadingWidget(),
                        );
                      }
                      final images = snapshot.data!;
                      logger.info("Visible images: ${images.length}");
                      if (images.isEmpty) {
                        return SizedBox(
                          height: MediaQuery.of(context).size.height * 0.2,
                          child: Center(
                            child: Column(
                              mainAxisSize: MainAxisSize.min,
                              children: [
                                Text(
                                  "No photos found here",
                                  style: textTheme.large,
                                ),
                                const SizedBox(height: 4),
                                Text(
                                  "Zoom out to see photos",
                                  style: textTheme.smallFaint,
                                )
                              ],
                            ),
                          ),
                        );
                      }

                      return Gallery(
                        asyncLoader: (
                          creationStartTime,
                          creationEndTime, {
                          limit,
                          asc,
                        }) async {
                          FileLoadResult result;
                          result = FileLoadResult(images, false);
                          return result;
                        },
                        reloadEvent: Bus.instance.on<LocalPhotosUpdatedEvent>(),
                        tagPrefix: "map_gallery",
                        showSelectAllByDefault: true,
                        selectedFiles: SelectedFiles(),
                      );
                    },
                  ),
                ),
              )
            ],
          ),
        );
      },
    );
  }
}

class DraggableHeader extends StatelessWidget {
  const DraggableHeader({
    Key? key,
    required this.scrollController,
    required this.bottomSheetDraggableAreaHeight,
  }) : super(key: key);
  static const indicatorHeight = 4.0;
  final ScrollController scrollController;
  final double bottomSheetDraggableAreaHeight;

  @override
  Widget build(BuildContext context) {
    return SingleChildScrollView(
      physics: const ClampingScrollPhysics(),
      controller: scrollController,
      child: Center(
        child: Padding(
          padding: EdgeInsets.symmetric(
            vertical: bottomSheetDraggableAreaHeight / 2 - indicatorHeight / 2,
          ),
          child: Container(
            height: indicatorHeight,
            width: 72,
            decoration: BoxDecoration(
              color: getEnteColorScheme(context).fillBase,
              borderRadius: const BorderRadius.all(Radius.circular(2)),
            ),
          ),
        ),
      ),
    );
  }
}