export async function startNfcScan() {
  const nfcAdapter = wx.getNFCAdapter();
  await nfcAdapter.startDiscovery();

  return new Promise((resolve, reject) => {
    try {
      nfcAdapter.onDiscovered((res) => {
        console.log("onDiscovered", res);
        const arr = Array.from(new Int8Array(res.id));
        resolve(arr);
      });
    } catch (e) {
      reject(e);
    }
  });
}

export class WeixinNfcUtil {
  nfcAdapter = null;
  discoveredListenerList = [];
  /**
   * @type {Function}
   */
  _discoveredHandler = null;

  constructor() {
    this.nfcAdapter = wx.getNFCAdapter();
    this._discoveredHandler = this.discoveredHandler.bind(this);
    this.nfcAdapter.onDiscovered(this._discoveredHandler);
  }

  /**
   * 是否开启NFC
   * NOTE 微信无法判断是否开启
   * @returns {boolean} true 已开启
   */
  static async isNfcEnabled() {
    try {
      wx.getNFCAdapter();
      return true;
    } catch (e) {
      console.error(e);
      return false;
    }
  }

  discoveredHandler(res) {
    console.log("onDiscovered", res);
    const arr = Array.from(new Int8Array(res.id));
    this.discoveredListenerList.forEach((cb) => {
      cb(arr);
    });
  }

  /**
   *
   * @param {Function} cb
   */
  addDiscoveredListener(cb) {
    this.discoveredListenerList.push(cb);
  }

  async startNfcScan() {
    return await this.nfcAdapter.startDiscovery();
  }

  async stopNfcScan() {
    this.nfcAdapter.offDiscovered(this._discoveredHandler);
    return await this.nfcAdapter.stopDiscovery();
  }

  static async scan() {
    const weixinNfcUtil = new WeixinNfcUtil();
    return await new Promise((resolve, reject) => {
      weixinNfcUtil
        .startNfcScan()
        .then(() => {
          weixinNfcUtil.addDiscoveredListener((res) => {
            weixinNfcUtil.stopNfcScan();
            resolve(res);
          });
        })
        .catch(reject);
    });
  }
}