import 'package:flutter/material.dart';
import 'package:photos/models/memory.dart';
import 'package:photos/services/memories_service.dart';
import "package:photos/ui/home/memories/memory_cover_widget.dart";

class MemoriesWidget extends StatelessWidget {
  const MemoriesWidget({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return FutureBuilder<List<Memory>>(
      future: MemoriesService.instance.getMemories(),
      builder: (context, snapshot) {
        if (snapshot.hasError || !snapshot.hasData || snapshot.data!.isEmpty) {
          return const SizedBox.shrink();
        } else {
          return Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              _buildMemories(snapshot.data!),
              const Divider(),
            ],
          );
        }
      },
    );
  }

  Widget _buildMemories(List<Memory> memories) {
    final collatedMemories = _collateMemories(memories);
    final List<Widget> memoryWidgets = [];
    for (final memories in collatedMemories) {
      memoryWidgets.add(MemoryCovertWidget(memories: memories));
    }
    return SingleChildScrollView(
      scrollDirection: Axis.horizontal,
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: memoryWidgets,
      ),
    );
  }

  List<List<Memory>> _collateMemories(List<Memory> memories) {
    final List<Memory> yearlyMemories = [];
    final List<List<Memory>> collatedMemories = [];
    for (int index = 0; index < memories.length; index++) {
      if (index > 0 &&
          !_areMemoriesFromSameYear(memories[index - 1], memories[index])) {
        final List<Memory> collatedYearlyMemories = [];
        collatedYearlyMemories.addAll(yearlyMemories);
        collatedMemories.add(collatedYearlyMemories);
        yearlyMemories.clear();
      }
      yearlyMemories.add(memories[index]);
    }
    if (yearlyMemories.isNotEmpty) {
      collatedMemories.add(yearlyMemories);
    }
    return collatedMemories.reversed.toList();
  }

  bool _areMemoriesFromSameYear(Memory first, Memory second) {
    final firstDate =
        DateTime.fromMicrosecondsSinceEpoch(first.file.creationTime!);
    final secondDate =
        DateTime.fromMicrosecondsSinceEpoch(second.file.creationTime!);
    return firstDate.year == secondDate.year;
  }
}