import 'dart:collection';

import 'package:collection/collection.dart';
import 'package:quiver_hashcode/hashcode.dart';

class Embeddable {
  static const TYPE_KEY = '_type';
  static const INLINE_KEY = '_inline';
  final String type;
  final bool inline;
  final Map<String, dynamic> _data;

  Embeddable(this.type, this.inline, Map<String, dynamic> data)
      : assert(type != null),
        assert(inline != null),
        assert(!data.containsKey(TYPE_KEY)),
        assert(!data.containsKey(INLINE_KEY)),
        _data = Map.from(data);

  Map<String, dynamic> get data => UnmodifiableMapView(_data);

  Map<String, dynamic> toJson() {
    Map<String, dynamic> m = Map<String, dynamic>.from(_data);
    m[TYPE_KEY] = type;
    m[INLINE_KEY] = inline;
    return m;
  }

  static Embeddable fromJson(Map<String, dynamic> json) {
    String type = json[TYPE_KEY] as String;
    bool inline = json[INLINE_KEY] as bool;
    Map<String, dynamic> data = Map<String, dynamic>.from(json);
    data.remove(TYPE_KEY);
    data.remove(INLINE_KEY);
    if (inline) {
      return Span(type, data: data);
    }
    return BlockEmbed(type, data: data);
  }

  @override
  bool operator ==(dynamic other) {
    if (identical(this, other)) {
      return true;
    }
    if (other is! Embeddable) {
      return false;
    }
    final typedOther = other;
    return typedOther.type == type &&
        typedOther.inline == inline &&
        DeepCollectionEquality().equals(typedOther._data, _data);
  }

  @override
  int get hashCode {
    if (_data.isEmpty) {
      return hash2(type, inline);
    }

    final dataHash = hashObjects(
      _data.entries.map((e) => hash2(e.key, e.value)),
    );
    return hash3(type, inline, dataHash);
  }
}

class Span extends Embeddable {
  Span(
    String type, {
    Map<String, dynamic> data = const {},
  }) : super(type, true, data);
}

class BlockEmbed extends Embeddable {
  BlockEmbed(
    String type, {
    Map<String, dynamic> data = const {},
  }) : super(type, false, data);
}