import { inRuntime, bridgeAsync } from "../bridge/appbridge";
import { isSupportWebScan, startScanForWeb, stopScanForWeb, isSupportImageScan, startScanForImage } from "../web";
import { isSupportWxScan, startScanForWx } from "../wx";
import { startScanner, stopScanner } from "../scanner";
import { getConfig } from "../config";

let _scan_status = "closed";
let _scan_status_listener = null;
let _scan_listener_list = [];
let _scan_resolve = null;
let _scan_closing = false;
let _scan_next_start_time = 0;

const SCAN_RESTART_DELAY = 2000;

function __checkScanner() {
  if (_scan_listener_list.length > 0) {
    startScanner((result) => {
      __scannerResult(result);
    });
  } else {
    stopScanner();
  }
}

function __match(result, match) {
  let reg = null;
  if (!!match && typeof match === "string") {
    reg = new RegExp(match);
  }
  if (!!reg) {
    return reg.test(result);
  }
  return true;
}


function __result(result) {
  let matched = false;
  for (let i = 0; i < _scan_listener_list.length; i++) {
    const item = _scan_listener_list[i];
    if (item.listener && __match(result, item.match)) {
      matched = true;
      item.listener({ result, key: item.key });
      break;
    }
  }
  if (matched) {
    _scan_next_start_time = Date.now() + SCAN_RESTART_DELAY;
  }
  return matched;
}

function __hasMatchedListener(result) {
  for (let i = 0; i < _scan_listener_list.length; i++) {
    const item = _scan_listener_list[i];
    if (item.listener && __match(result, item.match)) {
      return true;
    }
  }
  return false;
}

function __scanning() {
  if (_scan_status !== "scanning") {
    _scan_status = "scanning";
    if (_scan_status_listener) {
      _scan_status_listener({ status: "scanning" });
    }
  }
}

function __closed() {
  if (_scan_status !== "closed") {
    _scan_status = "closed";
    if (_scan_status_listener) {
      _scan_status_listener({ status: "closed" });
    }
  }
}

function __finishScan() {
  const resolve = _scan_resolve;
  _scan_resolve = null;
  __closed();
  return resolve;
}

function __stopCurrentScan() {
  if (inRuntime()) {
    return bridgeAsync("stopScan").catch(() => {
      // no thing
    });
  } else if (isSupportWebScan()) {
    return stopScanForWeb().catch(() => {
      // no thing
    });
  }
  return Promise.resolve();
}

function __scannerResult(result) {
  if (!__hasMatchedListener(result)) {
    return;
  }
  if (isScanning()) {
    const resolve = __finishScan();
    _scan_closing = true;
    __stopCurrentScan().then(() => {
      setTimeout(() => {
        _scan_closing = false;
      }, 0);
    });
    __result(result);
    resolve && resolve({
      result
    });
    return;
  }
  __result(result);
}

function __startBridgeScan() {
  return bridgeAsync("startScan", {
    closeable: true
  }).then(resp => {
    if (!isScanning()) {
      return resp;
    }
    if (!resp || !resp.result) {
      return resp;
    }
    if (__result(resp.result)) {
      return resp;
    }
    if (isScanning()) {
      return __startBridgeScan();
    }
    return resp;
  }).catch(err => {
    if (!isScanning()) {
      return err;
    }
    if (!err || !err.result) {
      return err;
    }
    if (__result(err.result)) {
      return err;
    }
    if (isScanning()) {
      return __startBridgeScan();
    }
    return err;
  });
}

function __startWxScan() {
  return startScanForWx({
    needResult: 1,
    scanType: ["qrCode", "barCode"]
  }).then(resp => {
    if (!isScanning()) {
      return resp;
    }
    if (!resp || !resp.result) {
      return resp;
    }
    if (__result(resp.result)) {
      return resp;
    }
    if (isScanning()) {
      return __startWxScan();
    }
    return resp;
  }).catch(err => {
    if (!isScanning()) {
      return err;
    }
    if (!err || !err.result) {
      return err;
    }
    if (__result(err.result)) {
      return err;
    }
    if (isScanning()) {
      return __startWxScan();
    }
    return err;
  });
}

function __startImageScan() {
  return startScanForImage().then(resp => {
    if (!isScanning()) {
      return resp;
    }
    if (!resp || !resp.result) {
      return resp;
    }
    if (__result(resp.result)) {
      return resp;
    }
    if (isScanning()) {
      return __startImageScan();
    }
    return resp;
  }).catch(err => {
    if (!isScanning()) {
      return err;
    }
    if (!err || !err.result) {
      return err;
    }
    if (__result(err.result)) {
      return err;
    }
    if (isScanning()) {
      return __startImageScan();
    }
    return err;
  });
}

export function isScanning() {
  return _scan_status === "scanning";
}

export function clear() {
  for (let i = 0; i < _scan_listener_list.length; i++) {
    const item = _scan_listener_list[i];
    item.cancel();
  }
  _scan_listener_list.length = 0;
  __checkScanner();
}

export function onScanListener(listener, key, match, level) {
  if (typeof listener !== 'function') {
    return;
  }
  let item = null;
  for (let i = 0; i < _scan_listener_list.length; i++) {
    const _i = _scan_listener_list[i];
    if (_i.listener === listener) {
      item = _i;
      break;
    }
  }
  if (item) {
    item.key = key;
    item.level = level;
    item.match = match;
  } else {
    item = {
      key,
      match,
      level,
      listener,
      cancel: () => {
        const index = _scan_listener_list.indexOf(item);
        if (index !== -1) {
          const items = _scan_listener_list.splice(index, 1);
          for (let i = 0; i < items.length; i++) {
            const item = items[i];
            item.listener && item.listener({ cancel: 1 });
          }
        }
      }
    };
    _scan_listener_list.push(item);
  }
  // 根据level排序
  _scan_listener_list.sort((a, b) => b.level - a.level);
  __checkScanner();
  return item;
}

export function offScanListener(listener) {
  for (let i = 0; i < _scan_listener_list.length; i++) {
    const _i = _scan_listener_list[i];
    if (typeof listener === 'string') {
      if (_i.key === listener) {
        _i.cancel();
        break;
      }
    } else if (_i.listener === listener) {
      _i.cancel();
      break;
    }
  }
  __checkScanner();
}

export function setStatusListener(listener) {
  if (typeof listener !== 'function') {
    return;
  }
  _scan_status_listener = listener;
}

export function getStatus() {
  return _scan_status;
}

export function stopScan() {
  if (!isScanning()) {
    return;
  }
  __stopCurrentScan().then(() => {
    __closed();
  });
}

export function startScan() {
  if (isScanning() || _scan_closing || Date.now() < _scan_next_start_time) {
    return;
  }
  Promise.resolve().then(() => {
    __scanning();
    let scannerPromise = new Promise(resolve => {
      _scan_resolve = resolve;
    });
    let scanPromise = Promise.resolve();
    if (inRuntime()) {
      console.log("startScanForBridge");
      scanPromise = __startBridgeScan();
    } else if (isSupportWxScan()) {
      console.log("startScanForWx");
      scanPromise = __startWxScan();
    } else if (isSupportWebScan()) {
      console.log("startScanForWeb");
      scanPromise = startScanForWeb(getConfig("webCanvasStyle"), __result);
    } else if (isSupportImageScan()) {
      console.log("startScanForImage");
      scanPromise = __startImageScan();
    } else {
      console.log("not support scanner");
    }
    return Promise.race([scanPromise, scannerPromise]);
  }).finally(() => {
    _scan_resolve = null;
    __closed();
  });
}