import 'dart:convert';

import 'package:yx_tracking_flutter/src/model/device_info.dart';
import 'package:yx_tracking_flutter/src/model/user_info.dart';

/// 统一事件模型。
class Event {
  /// 创建事件实例。
  const Event({
    required this.systemCode,
    required this.eventType,
    required this.userInfo,
    required this.clientType,
    required this.clientTimestamp,
    required this.timestamp,
    required this.deviceInfo,
    required this.eventParams,
    required this.customTags,
    required this.createTime,
    this.retryCount = 0,
  });

  /// 从序列化 payload 恢复事件。
  factory Event.fromPayload(
    String payload, {
    required DateTime createTime,
    required int retryCount,
  }) {
    final decoded = jsonDecode(payload);
    if (decoded is! Map<String, dynamic>) {
      throw const FormatException('事件 payload 不是合法的 JSON 对象');
    }
    return Event.fromJson(
      decoded,
      createTime: createTime,
      retryCount: retryCount,
    );
  }

  /// 从 JSON 恢复事件。
  factory Event.fromJson(
    Map<String, dynamic> json, {
    required DateTime createTime,
    required int retryCount,
  }) {
    final userJson = json['userInfo'];
    final deviceJson = json['deviceInfo'];

    if (deviceJson is! Map) {
      throw const FormatException('deviceInfo 缺失或格式错误');
    }

    return Event(
      systemCode: (json['system_code'] ?? '').toString(),
      eventType: (json['eventType'] ?? '').toString(),
      userInfo: userJson is Map
          ? UserInfo(
              userId: _toInt(userJson['userId']),
              userName: userJson['userName']?.toString(),
              account: userJson['account']?.toString(),
            )
          : null,
      clientType: _toInt(json['clientType']) ?? 0,
      clientTimestamp: _toInt(json['clientTimestamp']) ?? 0,
      timestamp: (json['timestamp'] ?? '').toString(),
      deviceInfo: DeviceInfo(
        os: deviceJson['os']?.toString() ?? 'unknown',
        model: deviceJson['model']?.toString() ?? 'unknown',
        screenResolution:
            deviceJson['screenResolution']?.toString() ?? 'unknown',
      ),
      eventParams: _toMap(json['eventParams']),
      customTags: _toMap(json['customTags']),
      createTime: createTime,
      retryCount: retryCount,
    );
  }

  /// 系统编码（system_code）。
  final String systemCode;

  /// 事件类型。
  final String eventType;

  /// 用户信息。
  final UserInfo? userInfo;

  /// 客户端类型（client_type）。
  final int clientType;

  /// 客户端时间戳（秒）。
  final int clientTimestamp;

  /// 业务时间戳字符串。
  final String timestamp;

  /// 设备信息。
  final DeviceInfo deviceInfo;

  /// 事件参数。
  final Map<String, dynamic>? eventParams;

  /// 自定义标签。
  final Map<String, dynamic>? customTags;

  /// 事件创建时间。
  final DateTime createTime;

  /// 当前重试次数。
  final int retryCount;

  /// 复制事件并覆盖部分字段。
  Event copyWith({
    UserInfo? userInfo,
    DeviceInfo? deviceInfo,
    Map<String, dynamic>? eventParams,
    Map<String, dynamic>? customTags,
    DateTime? createTime,
    int? retryCount,
  }) =>
      Event(
        systemCode: systemCode,
        eventType: eventType,
        userInfo: userInfo ?? this.userInfo,
        clientType: clientType,
        clientTimestamp: clientTimestamp,
        timestamp: timestamp,
        deviceInfo: deviceInfo ?? this.deviceInfo,
        eventParams: eventParams ?? this.eventParams,
        customTags: customTags ?? this.customTags,
        createTime: createTime ?? this.createTime,
        retryCount: retryCount ?? this.retryCount,
      );

  /// 转换为可序列化的 JSON。
  Map<String, dynamic> toJson() => <String, dynamic>{
        'system_code': systemCode,
        'eventType': eventType,
        'userInfo': userInfo?.toJson(),
        'clientType': clientType,
        'clientTimestamp': clientTimestamp,
        'timestamp': timestamp,
        'deviceInfo': deviceInfo.toJson(),
        'eventParams': eventParams,
        'customTags': customTags,
      };

  /// 转换为 payload 字符串。
  String toPayload() => jsonEncode(toJson());

  static int? _toInt(dynamic value) {
    if (value is int) {
      return value;
    }
    if (value is num) {
      return value.toInt();
    }
    if (value is String) {
      return int.tryParse(value);
    }
    return null;
  }

  static Map<String, dynamic>? _toMap(dynamic value) {
    if (value == null) {
      return null;
    }
    if (value is Map<String, dynamic>) {
      return value;
    }
    if (value is Map) {
      return value.map(
        (key, val) => MapEntry(key.toString(), val),
      );
    }
    return null;
  }
}

/// 带本地存储元数据的事件。
class StoredEvent {
  /// 创建带存储元数据的事件实例。
  const StoredEvent({
    required this.id,
    required this.event,
    required this.retryCount,
    required this.createTime,
  });

  /// 存储中的自增 ID。
  final int id;

  /// 事件本体。
  final Event event;

  /// 当前重试次数。
  final int retryCount;

  /// 事件创建时间。
  final DateTime createTime;

  /// 复制对象并覆盖部分字段。
  StoredEvent copyWith({
    int? id,
    Event? event,
    int? retryCount,
    DateTime? createTime,
  }) =>
      StoredEvent(
        id: id ?? this.id,
        event: event ?? this.event,
        retryCount: retryCount ?? this.retryCount,
        createTime: createTime ?? this.createTime,
      );
}