import {createStore, combineReducers, applyMiddleware, compose} from 'redux';
import thunk from 'redux-thunk';
import mainReducer from '../reducers';
import {getClient} from './client';

let listeners = [];

export function injectReducers(reducers) {
  const store = getStore();
  store.coralReducers = {...store.coralReducers, ...reducers};
  store.replaceReducer(combineReducers(store.coralReducers));
}

/**
 * Add a action listener to the redux store.
 * The action is passed as the first argument to the callback.
 */
export function addListener(cb) {
  listeners.push(cb);
}

export function getStore() {
  if (window.coralStore) {
    return window.coralStore;
  }

  const apolloErrorReporter = () => (next) => (action) => {
    if (action.type === 'APOLLO_QUERY_ERROR') {
      console.error(action.error);
    }
    return next(action);
  };

  const customListener = () => (next) => (action) => {
    listeners.forEach((cb) => {cb(action);});
    return next(action);
  };

  const middlewares = [
    applyMiddleware(
      getClient().middleware(),
      thunk,
      apolloErrorReporter,
      customListener,
    ),
  ];

  if (window.devToolsExtension) {

    // we can't have the last argument of compose() be undefined
    middlewares.push(window.devToolsExtension());
  }

  const coralReducers = {
    ...mainReducer,
    apollo: getClient().reducer()
  };

  window.coralStore = createStore(
    combineReducers(coralReducers),
    {},
    compose(...middlewares)
  );

  window.coralStore.coralReducers = coralReducers;

  return window.coralStore;
}