import 'dart:async';

import 'package:device_plugin_interface/device_plugin_interface.dart';
import 'package:flutter/material.dart';
import 'package:flutter_screenutil/flutter_screenutil.dart';
import 'package:get/get.dart';

import '../../../core/theme/app_palette.dart';
import '../../../devices/device_hub.dart';
import '../../../devices/device_vendors.dart';
import '../../../routes/app_routes.dart';
import '../../main_tab/controllers/main_tab_controller.dart';

/// Smartcar（AI车载香薰）的扫描 / 连接页——走 [DeviceHub] 里的 Smartcar 插件。
///
/// 与支架那页结构一致，两点不同：
/// 1. **不需要后台自启动授权**：Smartcar 的连接是纯 GATT，没有向系统注册
///    「设备靠近就唤醒本应用」那种后台扫连，不构成自启动行为。
/// 2. 卡片上多显示一行 MAC —— 它来自 BLE 广播，是服务端确权的依据，
///    连不上时看一眼就知道是不是扫到了别的设备。
class SmartcarScanView extends StatefulWidget {
  const SmartcarScanView({super.key});

  @override
  State<SmartcarScanView> createState() => _SmartcarScanViewState();
}

class _SmartcarScanViewState extends State<SmartcarScanView> {
  DevicePlugin get _plugin => DeviceHub.to.plugin(DeviceVendors.smartcar)!;

  final RxList<DiscoveredDevice> _scanned = <DiscoveredDevice>[].obs;
  final RxBool _isScanning = false.obs;

  /// 附近**所有** BLE 设备（含没命中判定的），按 id 去重。
  /// 只在一台都没扫到时给人看——「扫不到」这个故障，
  /// 不摊开设备到底播了什么就只能靠反复出包猜。
  final RxMap<String, Map<String, Object?>> _nearby =
      <String, Map<String, Object?>>{}.obs;
  final RxBool _showDiag = false.obs;

  /// 扫描起不来时的原因。**必须显示出来**：第一版失败是静默的，
  /// 界面只会一直转圈，分不清「没扫到设备」和「压根没扫起来」。
  final RxnString _scanError = RxnString();
  StreamSubscription<DevicePluginEvent>? _sub;
  bool _connecting = false;

  @override
  void initState() {
    super.initState();
    _sub = _plugin.eventStream.listen((e) {
      switch (e.type) {
        case DevicePluginEventType.scanStarted:
          _isScanning.value = true;
          break;
        case DevicePluginEventType.scanStopped:
          _isScanning.value = false;
          break;
        case DevicePluginEventType.deviceDiscovered:
          final d = e.discovered;
          if (d == null || d.id.isEmpty) break;
          // 按 id 去重累积：BLE 扫描会对同一台设备反复上报
          final i = _scanned.indexWhere((x) => x.id == d.id);
          if (i >= 0) {
            _scanned[i] = d;
          } else {
            _scanned.add(d);
          }
          break;
        case DevicePluginEventType.customEvent:
          // 厂商插件转发的扫描诊断（业务层不能直接 import 厂商目录）
          if (e.customKey == 'smartcar.scan_diagnostic') {
            final d = e.customPayload;
            if (d is Map<String, Object?>) {
              final id = '${d['id']}';
              if (id.isNotEmpty) _nearby[id] = d;
            }
          }
          break;
        case DevicePluginEventType.error:
          _scanError.value = e.errorMessage ?? e.errorCode;
          _isScanning.value = false;
          break;
        default:
          break;
      }
    });
    WidgetsBinding.instance.addPostFrameCallback((_) => _startScan());
  }

  Future<void> _startScan() async {
    _scanned.clear();
    _nearby.clear();
    _scanError.value = null;
    if (!await _plugin.ensureReady()) return;
    await _plugin.startScan();
  }

  @override
  void dispose() {
    _sub?.cancel();
    _plugin.stopScan();
    super.dispose();
  }

  Future<void> _connect(DiscoveredDevice d) async {
    if (_connecting) return;
    setState(() => _connecting = true);

    String? failReason;
    try {
      await _plugin.connect(
        d.id,
        // MAC 只在广播里有，连上就拿不到了。这里带过去给确权用，
        // 免得连上之后再回头找。
        options: DeviceConnectOptions(extra: {'mac': d.metadata['mac']}),
      );
      await _plugin.rememberDevice(d);
    } on DeviceException catch (e) {
      failReason = e.message ?? e.code;
    } catch (e) {
      failReason = '$e';
    }
    if (!mounted) return;
    setState(() => _connecting = false);

    if (failReason == null) {
      Get.snackbar('smartcarConnected'.tr, d.name,
          snackPosition: SnackPosition.TOP,
          duration: const Duration(seconds: 2));
      // BLE 通了不等于听得见：AI 回复和音乐走的是**经典蓝牙 A2DP**（见落地文档 7.0）。
      // 没接上时提示一次，别让用户以为"连上了却没声音"是坏了。
      unawaited(_hintClassicAudioIfNeeded(d.name));
      Get.offAllNamed(Routes.home);
      WidgetsBinding.instance.addPostFrameCallback((_) {
        if (Get.isRegistered<MainTabController>()) {
          MainTabController.to.changeTab(MainTabController.tabDevice);
        }
      });
    } else {
      // ⚠️ 失败原因**留在页面上**，不能只弹一下就没了：
      // 这些信息（设备实际暴露了哪些服务、握手卡在哪条命令）是排查的全部依据，
      // snackbar 几秒就消失，用户根本来不及看清更别说转述。
      _scanError.value = failReason;
      Get.snackbar('smartcarConnectFailed'.tr, failReason,
          snackPosition: SnackPosition.TOP,
          duration: const Duration(seconds: 5));
    }
  }

  /// 经典蓝牙没接上就提示一次。
  ///
  /// - Android：插件已经在连接后自动 `createBond` 试过一次，这里只兜底提示
  /// - iOS：**没有**发起经典蓝牙配对的公开 API，只能引导用户去系统设置
  Future<void> _hintClassicAudioIfNeeded(String name) async {
    try {
      final r = await _plugin.activeSession
          ?.invokeFeature('smartcar.a2dp_status');
      if (r == null || r['connected'] == true) return;
      Get.snackbar(
        'smartcarA2dpTitle'.tr,
        'smartcarA2dpHint'.tr.replaceAll('@name', name),
        snackPosition: SnackPosition.TOP,
        duration: const Duration(seconds: 6),
      );
    } catch (_) {
      // 查不到就不提示——这只是体验提示，不该把连接流程搅黄
    }
  }

  @override
  Widget build(BuildContext context) {
    final bool isDark = Theme.of(context).brightness == Brightness.dark;
    return Scaffold(
      backgroundColor: AppPalette.background(isDark),
      appBar: AppBar(
        backgroundColor: AppPalette.background(isDark),
        elevation: 0,
        title: Text('catCarAroma'.tr),
        actions: [
          Obx(() => _isScanning.value
              ? Padding(
                  padding: EdgeInsets.only(right: 16.w),
                  child: Center(
                    child: SizedBox(
                      width: 18.w,
                      height: 18.w,
                      child: const CircularProgressIndicator(strokeWidth: 2),
                    ),
                  ),
                )
              : IconButton(
                  icon: const Icon(Icons.refresh),
                  onPressed: _startScan,
                )),
        ],
      ),
      body: _connecting
          ? Center(
              child: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  const CircularProgressIndicator(),
                  SizedBox(height: 16.h),
                  Text('smartcarConnecting'.tr),
                ],
              ),
            )
          : Obx(() {
              final list = _scanned;
              if (list.isEmpty) return _empty(isDark);
              return ListView.separated(
                padding: EdgeInsets.symmetric(horizontal: 16.w, vertical: 16.h),
                itemCount: list.length,
                separatorBuilder: (_, __) => SizedBox(height: 12.h),
                itemBuilder: (context, i) => _card(list[i], isDark),
              );
            }),
    );
  }

  Widget _empty(bool isDark) => Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Icon(Icons.bluetooth_searching,
                size: 56.sp, color: AppPalette.brand300),
            SizedBox(height: 12.h),
            Obx(() => Text(
                  _isScanning.value
                      ? 'smartcarSearching'.tr
                      : 'smartcarNotFound'.tr,
                  style: TextStyle(
                      fontSize: 15.sp,
                      color: AppPalette.textSecondary(isDark)),
                )),
            SizedBox(height: 6.h),
            Text(
              'smartcarScanHint'.tr,
              textAlign: TextAlign.center,
              style: TextStyle(
                  fontSize: 12.sp, color: AppPalette.textHint(isDark)),
            ),
            SizedBox(height: 20.h),
            _diagnostics(isDark),
          ],
        ),
      );

  /// 诊断面板：把附近扫到的 BLE 设备摊开。
  ///
  /// 判据（厂商 ID 0x8505 / 名字含 smartcar）对不对，看这里最快：
  /// - 列表里根本没有目标设备 → 设备没在播，或不在范围内
  /// - 有、但 mfg 那栏的厂商 ID 不是 0x8505 → 判据要按实际值改
  /// - 有、厂商 ID 对但长度不足 22 → 广播段布局和文档对不上
  Widget _diagnostics(bool isDark) => Obx(() {
        final list = _nearby.values.toList();
        final err = _scanError.value;
        // ⚠️ 0 台也要显示。「附近 0 台」和「面板不出现」是两回事：
        // 前者说明扫描跑了但什么都没收到，后者说明扫描压根没起来。
        return Padding(
          padding: EdgeInsets.symmetric(horizontal: 24.w),
          child: Column(
            children: [
              if (err != null)
                Container(
                  width: double.infinity,
                  margin: EdgeInsets.only(bottom: 8.h),
                  padding: EdgeInsets.all(10.w),
                  decoration: BoxDecoration(
                    color: Colors.red.withValues(alpha: 0.08),
                    borderRadius: BorderRadius.circular(8.r),
                  ),
                  child: SelectableText('失败详情：$err',
                      style: TextStyle(fontSize: 11.sp, color: Colors.red)),
                ),
              TextButton.icon(
                onPressed: () => _showDiag.value = !_showDiag.value,
                icon: Icon(
                    _showDiag.value ? Icons.expand_less : Icons.expand_more,
                    size: 18.sp),
                label: Text('附近 ${list.length} 台蓝牙设备',
                    style: TextStyle(fontSize: 12.sp)),
              ),
              if (_showDiag.value && list.isEmpty)
                Text('一台都没收到 —— 蓝牙可能没开、权限被拒，或周围确实没有设备',
                    textAlign: TextAlign.center,
                    style: TextStyle(
                        fontSize: 11.sp, color: AppPalette.textHint(isDark))),
              if (_showDiag.value && list.isNotEmpty)
                Container(
                  constraints: BoxConstraints(maxHeight: 260.h),
                  padding: EdgeInsets.all(10.w),
                  decoration: BoxDecoration(
                    color: AppPalette.surface(isDark),
                    borderRadius: BorderRadius.circular(10.r),
                    border: Border.all(color: AppPalette.border(isDark)),
                  ),
                  child: ListView.builder(
                    shrinkWrap: true,
                    itemCount: list.length,
                    itemBuilder: (_, i) {
                      final d = list[i];
                      final matched = d['matched'] == true;
                      final name = '${d['name']}';
                      return Padding(
                        padding: EdgeInsets.symmetric(vertical: 4.h),
                        child: Column(
                          crossAxisAlignment: CrossAxisAlignment.start,
                          children: [
                            Text(
                              '${matched ? '✓ ' : ''}'
                              '${name.isEmpty ? '(无名)' : name}  ${d['rssi']}dBm',
                              style: TextStyle(
                                fontSize: 11.sp,
                                fontWeight: matched
                                    ? FontWeight.w700
                                    : FontWeight.w400,
                                color: AppPalette.textPrimary(isDark),
                              ),
                            ),
                            // 可长按复制：MAC 解错时要把这串原始字节发出来分析
                            SelectableText(
                              'mfg=${d['mfg']}\n'
                              '解出MAC=${d['parsedMac']}\n'
                              'svc=${d['services']}',
                              style: TextStyle(
                                  fontSize: 10.sp,
                                  color: AppPalette.textHint(isDark)),
                            ),
                          ],
                        ),
                      );
                    },
                  ),
                ),
            ],
          ),
        );
      });

  Widget _card(DiscoveredDevice d, bool isDark) {
    final mac = '${d.metadata['mac'] ?? ''}';
    return GestureDetector(
      behavior: HitTestBehavior.opaque,
      onTap: () => _connect(d),
      child: Container(
        padding: EdgeInsets.all(14.w),
        decoration: BoxDecoration(
          color: AppPalette.surface(isDark),
          borderRadius: BorderRadius.circular(14.r),
          border: Border.all(color: AppPalette.border(isDark)),
        ),
        child: Row(
          children: [
            Icon(Icons.air, size: 26.sp, color: AppPalette.brand500),
            SizedBox(width: 12.w),
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(
                    d.name,
                    maxLines: 1,
                    overflow: TextOverflow.ellipsis,
                    style: TextStyle(
                      fontSize: 15.sp,
                      fontWeight: FontWeight.w600,
                      color: AppPalette.textPrimary(isDark),
                    ),
                  ),
                  if (mac.isNotEmpty) ...[
                    SizedBox(height: 3.h),
                    Text(
                      mac,
                      style: TextStyle(
                        fontSize: 11.sp,
                        color: AppPalette.textHint(isDark),
                      ),
                    ),
                  ],
                ],
              ),
            ),
            if (d.rssi != null)
              Text(
                '${d.rssi} dBm',
                style: TextStyle(
                    fontSize: 11.sp, color: AppPalette.textHint(isDark)),
              ),
            SizedBox(width: 6.w),
            Icon(Icons.chevron_right,
                size: 20.sp, color: AppPalette.textHint(isDark)),
          ],
        ),
      ),
    );
  }
}