import 'dart:convert';
import 'dart:typed_data';

import 'package:shared_preferences/shared_preferences.dart';

import '../models/contact.dart';

class ContactStore {
  static const String _key = 'contacts';

  Future<List<Contact>> loadContacts() async {
    final prefs = await SharedPreferences.getInstance();
    final jsonStr = prefs.getString(_key);
    if (jsonStr == null) return [];

    try {
      final jsonList = jsonDecode(jsonStr) as List<dynamic>;
      return jsonList.map((entry) => _fromJson(entry as Map<String, dynamic>)).toList();
    } catch (_) {
      return [];
    }
  }

  Future<void> saveContacts(List<Contact> contacts) async {
    final prefs = await SharedPreferences.getInstance();
    final jsonList = contacts.map(_toJson).toList();
    await prefs.setString(_key, jsonEncode(jsonList));
  }

  Map<String, dynamic> _toJson(Contact contact) {
    return {
      'publicKey': base64Encode(contact.publicKey),
      'name': contact.name,
      'type': contact.type,
      'pathLength': contact.pathLength,
      'path': base64Encode(contact.path),
      'latitude': contact.latitude,
      'longitude': contact.longitude,
      'lastSeen': contact.lastSeen.millisecondsSinceEpoch,
    };
  }

  Contact _fromJson(Map<String, dynamic> json) {
    return Contact(
      publicKey: Uint8List.fromList(base64Decode(json['publicKey'] as String)),
      name: json['name'] as String? ?? 'Unknown',
      type: json['type'] as int? ?? 0,
      pathLength: json['pathLength'] as int? ?? -1,
      path: json['path'] != null
          ? Uint8List.fromList(base64Decode(json['path'] as String))
          : Uint8List(0),
      latitude: (json['latitude'] as num?)?.toDouble(),
      longitude: (json['longitude'] as num?)?.toDouble(),
      lastSeen: DateTime.fromMillisecondsSinceEpoch(json['lastSeen'] as int? ?? 0),
    );
  }
}