reducer.js

/* @flow */
import R from 'ramda';
import * as ActionTypes from './constants';
import type { State, Action } from '../../types';
import { setGrandchild } from '../../services/reducerHelpers';

const initialState = {};

/* eslint space-infix-ops: "off" */
const comparison = (state: State = initialState, action: Action): State => {
  const setState = setGrandchild(
    state,
    getProjectKey(action),
    getSegmentKey(action)
  );

  switch (action.type) {
    case ActionTypes.LOAD_COMPARISON:
      return setState({
        leftTaskId: action.payload.leftTaskId,
        rightTaskId: action.payload.rightTaskId
      });
    case ActionTypes.FETCH_COMPARISON_REQUEST:
      return setState({
        isFetching: true
      });
    case ActionTypes.FETCH_COMPARISON_SUCCESS:
      return setState({
        isFetching: false,
        leftTaskId: action.payload.leftTaskId,
        rightTaskId: action.payload.rightTaskId,
        [getComparisonKey(action)]: {
          payload: action.payload.comparison
        }
      });
    case ActionTypes.FETCH_COMPARISON_FAILURE:
      return setState({
        isFetching: false,
        leftTaskId: action.payload.leftTaskId,
        rightTaskId: action.payload.rightTaskId,
        error: action.payload.error
      });
    default:
      return state;
  }
};

const getProjectId = R.path(['payload', 'projectId']);
const getProjectKey = R.compose(R.concat('project'), getProjectId);

const getTaskLeftId = R.pathOr('All', ['payload', 'leftTaskId']);
const getTaskRightId = R.pathOr('All', ['payload', 'rightTaskId']);

const getSegmentId = R.pathOr('All', ['payload', 'segmentId']);
const getSegmentKey = R.compose(R.concat('segment'), getSegmentId);

const getComparisonKey = (action) => (
  `left${getTaskLeftId(action)}_right${getTaskRightId(action)}`
);

export default comparison;