nc-photos/lib/entity/album/item.dart

import 'dart:math';

import 'package:equatable/equatable.dart';
import 'package:logging/logging.dart';
import 'package:nc_photos/entity/file.dart';
import 'package:nc_photos/list_extension.dart';

List<AlbumItem> makeDistinctAlbumItems(List<AlbumItem> items) =>
    items.distinctIf(
        (a, b) =>
            a is AlbumFileItem &&
            b is AlbumFileItem &&
            a.file.path == b.file.path, (a) {
      if (a is AlbumFileItem) {
        return a.file.path.hashCode;
      } else {
        return Random().nextInt(0xFFFFFFFF);
      }
    });

abstract class AlbumItem {
  AlbumItem();

  factory AlbumItem.fromJson(Map<String, dynamic> json) {
    final type = json["type"];
    final content = json["content"];
    switch (type) {
      case AlbumFileItem._type:
        return AlbumFileItem.fromJson(content.cast<String, dynamic>());
      default:
        _log.shout("[fromJson] Unknown type: $type");
        throw ArgumentError.value(type, "type");
    }
  }

  Map<String, dynamic> toJson() {
    String getType() {
      if (this is AlbumFileItem) {
        return AlbumFileItem._type;
      } else {
        throw StateError("Unknwon subtype");
      }
    }

    return {
      "type": getType(),
      "content": toContentJson(),
    };
  }

  Map<String, dynamic> toContentJson();

  static final _log = Logger("entity.album.AlbumItem");
}

class AlbumFileItem extends AlbumItem with EquatableMixin {
  AlbumFileItem({this.file});

  @override
  // ignore: hash_and_equals
  bool operator ==(Object other) => equals(other, isDeep: true);

  bool equals(Object other, {bool isDeep = false}) {
    if (other is AlbumFileItem) {
      return super == other &&
          (file == null) == (other.file == null) &&
          (file?.equals(other.file, isDeep: isDeep) ?? true);
    } else {
      return false;
    }
  }

  factory AlbumFileItem.fromJson(Map<String, dynamic> json) {
    return AlbumFileItem(
      file: File.fromJson(json["file"].cast<String, dynamic>()),
    );
  }

  @override
  toString() {
    return "$runtimeType {"
        "file: $file"
        "}";
  }

  @override
  toContentJson() {
    return {
      "file": file.toJson(),
    };
  }

  @override
  get props => [
        // file is handled separately, see [equals]
      ];

  final File file;

  static const _type = "file";
}