import 'dart:convert';

enum SessionFreshness { fresh, stale, expired }

class SessionEntity {
  const SessionEntity({
    required this.id,
    required this.expiresOn,
    required this.token,
    required this.modelJson,
  });

  factory SessionEntity.fromMap(Map<String, dynamic> map) => SessionEntity(
        id: map['id'],
        expiresOn: DateTime.fromMillisecondsSinceEpoch(
          map['expiresOn'] as int,
        ),
        token: map['token'] as String,
        modelJson: map['modelJson'],
      );

  factory SessionEntity.fromJson(String source) => SessionEntity.fromMap(
        json.decode(source) as Map<String, dynamic>,
      );

  final String id;
  final DateTime expiresOn;
  final String token;
  final Map<String, dynamic> modelJson;

  SessionFreshness get freshness {
    final now = DateTime.now();
    if (now.isAfter(expiresOn)) return SessionFreshness.expired;
    if (expiresOn.difference(now) < const Duration(days: 30)) {
      return SessionFreshness.stale;
    }
    return SessionFreshness.fresh;
  }

  Map<String, dynamic> toMap() => <String, dynamic>{
        'id': id,
        'expiresOn': expiresOn.millisecondsSinceEpoch,
        'token': token,
        'modelJson': modelJson,
      };

  String toJson() => json.encode(toMap());
}