/**
 * 扫描设备页面
 *
 * 新测点链路下此处只负责「连接蓝牙设备」：
 *   扫描 → 点击设备 → 询问设备名称（选填）→ 登记保存 → 交由常驻网关 gateway 接管 BLE 连接。
 * 设备不再需要配置弹窗（产品/MQTT 凭证统一在“我的”页配置），
 * 设备编号自动取自 BLE 广播名（无则退化为 BLE 地址归一化），
 * 设备名称仅作本地展示标签（可选填，留空沿用上次或退化为广播名/编号），不参与上报身份。
 */
const ble = require('../../../services/ble.js');
const storage = require('../../../utils/storage.js');
const { gateway } = require('../../../services/gateway.js');

Page({
  data: {
    scanning: false,
    connecting: false,
    scannedDevices: [],
    statusText: '准备扫描',
    statusHint: '点击下方按钮开始扫描 BLE 设备',
  },

  onLoad() {
    // 暂停正在跑的网关，避免常驻会话与扫描抢占同一 BLE 目标；
    // 返回首页后 index.onShow → gateway.ensureStarted() 会自动恢复。
    gateway.stop().then(() => this._initBluetooth());
  },

  onUnload() {
    // 停止扫描
    if (this.data.scanning) {
      ble.bleService.stopScan();
    }
  },

  /**
   * 初始化蓝牙
   */
  async _initBluetooth() {
    try {
      await ble.bleService.initBluetooth();
      this.setData({
        statusText: '蓝牙已就绪',
        statusHint: '点击下方按钮开始扫描 BLE 设备',
      });
    } catch (err) {
      console.error('[Scan] 初始化蓝牙失败:', err);
      this.setData({
        statusText: '蓝牙初始化失败',
        statusHint: err.message || '请确保已开启蓝牙',
      });
      wx.showModal({
        title: '蓝牙错误',
        content: err.message || '请确保已开启蓝牙权限',
        showCancel: false,
        success: () => {
          wx.navigateBack();
        },
      });
    }
  },

  /**
   * 开始扫描
   */
  async handleScan() {
    if (this.data.scanning) return;

    this.setData({
      scanning: true,
      scannedDevices: [],
      statusText: '正在扫描...',
      statusHint: '请确保设备已开机且在附近',
    });

    try {
      const devices = await ble.bleService.scanDevices();
      this.setData({
        scanning: false,
        scannedDevices: devices,
        statusText: devices.length > 0 ? `发现 ${devices.length} 个设备` : '扫描完成',
        statusHint: devices.length > 0 ? '点击设备连接，名称可选填' : '未发现设备，请确保设备已开机',
      });
    } catch (err) {
      console.error('[Scan] 扫描失败:', err);
      this.setData({
        scanning: false,
        statusText: '扫描失败',
        statusHint: err.message || '请重试',
      });
    }
  },

  /**
   * 停止扫描
   */
  async handleStopScan() {
    await ble.bleService.stopScan();
    this.setData({
      scanning: false,
      statusText: '已停止扫描',
    });
  },

  /**
   * 点击设备 - 询问设备名称（选填）后登记并交由网关连接
   *
   * 名称只是本地展示标签，serialNumber（上报身份）仍由 `_buildSerialNumber` 决定，
   * 所以留空也能直接连；这里用二次确认弹窗替代「点一下就连上」，
   * 便于顺手命名，也让误触有反悔余地。
   */
  async handleSelectDevice(e) {
    if (this.data.connecting) return;
    const index = e.currentTarget.dataset.index;
    const device = this.data.scannedDevices[index];
    if (!device) return;

    const serialNumber = this._buildSerialNumber(device);
    if (!serialNumber) {
      wx.showToast({ title: '无法识别该设备', icon: 'none' });
      return;
    }

    const existing = storage.getDevice(serialNumber);
    const inputName = await this._askDeviceName(device, serialNumber, existing);
    // 取消（或弹窗未能弹出）则不连接，否则用户没有退出路径
    if (inputName === null) return;

    this.setData({ connecting: true });
    wx.showLoading({ title: '连接中...', mask: true });

    try {
      // 登记设备（同名按 serialNumber 覆盖刷新 BLE 地址与信号）
      const deviceConfig = {
        deviceId: device.deviceId,
        serialNumber: serialNumber,
        name: this._resolveDeviceName(inputName, existing, device.name, serialNumber),
        bleName: device.name,
        RSSI: device.RSSI,
        enabled: true,
        connected: true,
        createTime: Date.now(),
      };

      storage.addDevice(deviceConfig);
      // 成为唯一启用设备（单 enabled 不变量）
      storage.activateDevice(serialNumber);

      const target = storage.getDevice(serialNumber);
      const hasMqtt = !!storage.getMqttConfig();

      wx.hideLoading();
      wx.showToast({
        title: hasMqtt ? '已连接设备' : '已连接，请在"我的"配置MQTT',
        icon: 'none',
        duration: hasMqtt ? 1500 : 2500,
      });

      // 由常驻网关接管 BLE 连接与采集
      gateway.start(target || deviceConfig);
      wx.navigateBack();
    } catch (err) {
      wx.hideLoading();
      console.error('[Scan] 连接设备失败:', err);
      wx.showToast({
        title: err.message || '连接失败',
        icon: 'none',
      });
    } finally {
      this.setData({ connecting: false });
    }
  },

  /**
   * 弹窗询问设备名称（选填）
   * @returns {Promise<string|null>} 确认返回输入内容（可能为空串）；取消/弹窗失败返回 null
   */
  _askDeviceName(device, serialNumber, existing) {
    const fallback = this._resolveDeviceName('', existing, device.name, serialNumber);
    const customized = this._isCustomizedName(existing);
    return new Promise((resolve) => {
      wx.showModal({
        title: '设置设备名称',
        editable: true,
        // 已自定义过则回填，方便改名；仍是广播名/编号说明用户没命名过，留空不干扰
        content: customized ? existing.name : '',
        placeholderText: `选填，留空用：${fallback}`,
        confirmText: '连接',
        cancelText: '取消',
        success: (res) => resolve(res.confirm ? (res.content || '').trim() : null),
        // 弹窗都没弹出来时不静默连接，按取消处理，避免「点一下就莫名连上了」
        fail: () => resolve(null),
      });
    });
  },

  /**
   * 解析最终展示名称：本次输入 > 既有名称 > BLE 广播名 > 设备编号
   * @returns {string}
   */
  _resolveDeviceName(inputName, existing, bleName, serialNumber) {
    return (inputName || '').trim()
      || (existing && existing.name)
      || (bleName || '').trim()
      || serialNumber;
  },

  /**
   * 判断既有名称是否为用户自定义（而非广播名/编号的自动兜底值）
   * @returns {boolean}
   */
  _isCustomizedName(existing) {
    const name = existing && existing.name;
    if (!name) return false;
    return name !== existing.bleName && name !== existing.serialNumber;
  },

  /**
   * 生成设备编号：优先 BLE 广播名，无名称时退化为 BLE 地址归一化（去冒号取后12位）
   * @param {Object} device - 扫描到的 BLE 设备
   * @returns {string}
   */
  _buildSerialNumber(device) {
    const rawName = (device.name || device.localName || '').trim();
    if (rawName) {
      return rawName;
    }
    const rawId = (device.deviceId || '').replace(/[:\-\s]/g, '').toUpperCase();
    return rawId ? rawId.slice(-12) : '';
  },
});