import { put, take, all, select, spawn, race, call} from 'redux-saga/effects'

import { delay } from 'redux-saga';

import { getLastSync, getOnline } from './selectors';

import { startSynchronize, endSynchronize, updateLastSync } from '../actions/syncActions';

import { forceSync } from '../actions/networkActions';

import config from '../config';

function* doSync(context) {

    const online = yield select(getOnline);

    if(!online) {

      yield put(endSynchronize());

      return;

    }

    yield put(startSynchronize());

}

function* watchDoSync(context) {

  while (true) {

    yield take(types.SYNC_DO_SYNC);

    yield spawn(doSync, context);

    yield take(types.SYNC_END_SYNC);

  }

}

function* delayPutDoSync() {

  yield put(forceSync());

  yield call(delay, config.syncInterval);

}

function* loopDoSync() {

  while(true) {

    const online = yield select(getOnline);

    if(!online) {

      yield take(types.STATUS_ONLINE);

    }

    yield race({

      delaySync: call(delayPutDoSync),

      offline: take(types.STATUS_OFFLINE)

    });

    watchDoSync(context),

    loopDoSync()