import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../models/device.dart';
import '../services/device_service.dart';
import '../services/org_service.dart';
import '../utils/session_org_scope.dart';
import 'devices_provider.dart';

/// 仪表盘统计数据。
class DashboardStats {
  const DashboardStats({
    this.deviceTotal = 0,
    this.storeTotal = 0,
    this.onlineCount = 0,
    this.offlineCount = 0,
  });

  final int deviceTotal;
  final int storeTotal;
  final int onlineCount;
  final int offlineCount;

  DashboardStats copyWith({
    int? deviceTotal,
    int? storeTotal,
    int? onlineCount,
    int? offlineCount,
  }) {
    return DashboardStats(
      deviceTotal: deviceTotal ?? this.deviceTotal,
      storeTotal: storeTotal ?? this.storeTotal,
      onlineCount: onlineCount ?? this.onlineCount,
      offlineCount: offlineCount ?? this.offlineCount,
    );
  }
}

/// 仪表盘统计状态。
class DashboardStatsNotifier extends StateNotifier<DashboardStats> {
  DashboardStatsNotifier(this._deviceService, this._orgService)
      : super(const DashboardStats());

  final DeviceService _deviceService;
  final OrgService _orgService;

  Future<void> load() async {
    try {
      int deviceTotal = 0;
      int onlineCount = 0;
      int offlineCount = 0;

      if (SessionOrgScope.instance.enabled) {
        // 受限账号：仅统计其组织子树内的设备。
        // 设备接口可能忽略 orgId，故改为「拉取列表 + 按 storeId 在范围内收敛」，
        // 杜绝跨组织设备越权统计（只会少计、不会多计或泄露其他组织数据）。
        final ids = await _orgService.scopedOrgIdSet();
        if (ids.isNotEmpty) {
          final devices = await _deviceService.fetchDevices(limit: 1000);
          final scoped =
              devices.where((d) => ids.contains(d.storeId)).toList();
          deviceTotal = scoped.length;
          onlineCount =
              scoped.where((d) => d.status == DeviceStatus.online).length;
          offlineCount =
              scoped.where((d) => d.status == DeviceStatus.offline).length;
        }
      } else {
        deviceTotal = await _deviceService.fetchDeviceTotalCount();
        // 若后端未返回 totalCount，则拉取一页列表用其长度兜底。
        if (deviceTotal <= 0) {
          final devices = await _deviceService.fetchDevices(limit: 100);
          deviceTotal = devices.length;
        }
        // 在线/离线：分别按 status 拉 totalCount（O(1)，无需遍历全量设备）。
        final results = await Future.wait<int>([
          _deviceService.fetchDeviceCountByStatus(status: 'online'),
          _deviceService.fetchDeviceCountByStatus(status: 'offline'),
        ]);
        onlineCount = results[0];
        offlineCount = results[1];
      }

      // 门店总数：优先组织树，失败回退门店接口（fetchStoreCount 内部已含回退链）。
      final storeTotal = await _orgService.fetchStoreCount();

      state = state.copyWith(
        deviceTotal: deviceTotal,
        storeTotal: storeTotal,
        onlineCount: onlineCount,
        offlineCount: offlineCount,
      );
    } catch (_) {
      // 统计失败不阻断页面，保持旧值或 0。
    }
  }
}

final orgServiceProvider = Provider<OrgService>((ref) => OrgService());

final dashboardStatsProvider =
    StateNotifierProvider<DashboardStatsNotifier, DashboardStats>(
  (ref) => DashboardStatsNotifier(
    ref.watch(deviceServiceProvider),
    ref.watch(orgServiceProvider),
  ),
);