// 精臣打印机原生插件。插件由 DCloud 账号绑定，账号未购买/未打入基座时不能抛错，
// 否则页面一加载就白屏，所以这里做容错加载，缺失时打印功能给出提示而不是崩溃。
let jcapi = null;
let pluginMissing = false;
try {
  jcapi = uni.requireNativePlugin("JCSDK-JCApiModule");
  if (!jcapi) {
    pluginMissing = true;
  }
} catch (e) {
  pluginMissing = true;
}

const PLUGIN_MISSING_MSG = "未检测到精臣打印插件，请确认打包时已购买并勾选该原生插件";

function requirePlugin() {
  if (pluginMissing || !jcapi) {
    uni.showToast({ title: PLUGIN_MISSING_MSG, icon: "none", duration: 3000 });
    return null;
  }
  return jcapi;
}

let state = {
  connectedDevice: null,
  connectionStatus: "disconnected", // disconnected | connecting | connected
  listeners: [],
};

/** 通知所有订阅页面 */
function notify() {
  state.listeners.forEach(fn => fn({
    connectedDevice: state.connectedDevice,
    connectionStatus: state.connectionStatus,
  }));
}

/** 页面订阅蓝牙状态 */
function onChange(fn) {
  state.listeners.push(fn);
  fn({
    connectedDevice: state.connectedDevice,
    connectionStatus: state.connectionStatus,
  });
}

/** 初始化（全局只需一次） */
function init() {
  const api = requirePlugin();
  if (!api) return;

  api.initSDK();

  const saved = uni.getStorageSync("bluetoothConnection");
  if (saved) {
    state.connectedDevice = saved;
    state.connectionStatus = "connected";
  }

  // 断开监听
  api.didReadPrintErrorInfo((r) => {
    if (r.code === 23) {
      state.connectedDevice = null;
      state.connectionStatus = "disconnected";
      uni.removeStorageSync("bluetoothConnection");
      notify();
    }
  });
}

/** 搜索设备 */
function searchDevices() {
  return new Promise((resolve, reject) => {
    const api = requirePlugin();
    if (!api) {
      return reject(new Error(PLUGIN_MISSING_MSG));
    }
    uni.openBluetoothAdapter({
      success() {
        api.getBluetoothDevices(list => {
          resolve(list || []);
        });
      },
      fail: reject
    });
  });
}

/** 连接设备 */
function connect(device) {
  return new Promise((resolve, reject) => {
    const api = requirePlugin();
    if (!api) {
      return reject(new Error(PLUGIN_MISSING_MSG));
    }
    state.connectionStatus = "connecting";
    notify();

    api.openPrinterByDevice({
      address: device.address,
      name: device.name,
      deviceType: 0,
    }, (r) => {
      if (r.code === 0) {
        state.connectedDevice = device;
        state.connectionStatus = "connected";
        uni.setStorageSync("bluetoothConnection", device);
        notify();
        resolve(device);
      } else {
        state.connectionStatus = "disconnected";
        notify();
        reject(r);
      }
    });
  });
}

function isConnected() {
  return state.connectionStatus === "connected";
}

function getCurrentDevice() {
  return state.connectedDevice;
}

export default {
  init,
  onChange,
  searchDevices,
  connect,
  isConnected,
  getCurrentDevice,
};