import * as types from '../constants/actionTypes';

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

import config from '../config';

// Utility function to delay effects

function delay(millis) {

    const promise = new Promise(resolve => {

        setTimeout(() => resolve(true), millis)

    });

    return promise;

}

function pingServer(client, token) {

  if(token) {

    const timeout = new Promise((resolve, reject) => {

      setTimeout(reject, config.networkStatusTimeout, 'request timed out');

    });

    return Promise

      .race([timeout, client.post('/api/auth/refresh/', { token })]);

  } else {

    return Promise.reject({ error: 'No token in the store'})

  }

}

// Fetch data every 20 seconds

function* pollData(context) {

  try {

    yield call(delay, config.networkStatusInterval);

    const token = yield select(state => state.token);

    const res = yield pingServer(context.client, token);

    yield call(context.callback, true);

    yield put({

      type: types.AUTH_STORE_TOKEN_ASYNC,

      token: res.token,

    });

  } catch (error) {

    yield call(context.callback, false);

    // if the error is that there is no token, then we know we have to wait for a login

    if(error.error && error.error === 'No token in the store') {

      yield take(types.AUTH_LOGIN_SUCCESS);

    }

  } finally {

    if (yield cancelled()) {

      // pollDate cancelled

      // if there is a token : this was a LOGIN, set status to ok

      // if there is no token : this was a LOGOUT, set status to ko and wait for login

      const token = yield select(state => state.token);

      if(token) {

        yield call(context.callback, true);

      } else {

        yield call(context.callback, false);

        yield take(types.AUTH_LOGIN_SUCCESS);

      }

    }

  }

}

// Wait for successful response, then fire another request

// Cancel polling if user logs out or log in

function* watchPollData(context) {

  while (true) {

    yield race([

      call(pollData, context),

      take(types.AUTH_LOGOUT),

      take(types.AUTH_LOGIN_SUCCESS)

    ]);

  }

}

// Daemonize tasks in parallel

export default function* root(baseContext) {

  const actionRes = yield take(types.OFFLINE_CONFIG_INITIALIZED);

  const context = {...baseContext, ...actionRes.additionalContext};

  yield all([

    fork(watchPollData, context)

    // other watchers here

  ]);

}