import { List as ImmutableList } from "immutable";

import {
  ALERT_SHOW,
  ALERT_DISMISS,
  ALERT_CLEAR,
} from "../actions/alerts";

const initialState = ImmutableList([]);

let id = 0;

const addAlert = (state, alert) =>
  state.push({
    key: id++,
    ...alert,
  });

export default function alerts(state = initialState, action) {
  switch(action.type) {
    case ALERT_SHOW:
      return addAlert(state, action.alert);
    case ALERT_DISMISS:
      return state.filterNot(item => item.key === action.alert.key);
    case ALERT_CLEAR:
      return state.clear();
    default:
      return state;
  }
}