Coursemology/coursemology2

import actions from '../constants';

export default function (state = {}, action) {
  switch (action.type) {
    case actions.FETCH_SUBMISSION_SUCCESS:
    case actions.FINALISE_SUCCESS:
    case actions.UNSUBMIT_SUCCESS:
    case actions.SAVE_ALL_GRADE_SUCCESS:
    case actions.SAVE_GRADE_SUCCESS:
    case actions.MARK_SUCCESS:
    case actions.UNMARK_SUCCESS:
    case actions.PUBLISH_SUCCESS:
      return {
        ...state,
        ...action.payload.answers.reduce(
          (obj, answer) => ({
            ...obj,
            [answer.questionId]: answer.explanation,
          }),
          {},
        ),
      };
    case actions.SAVE_ANSWER_SUCCESS:
    case actions.REEVALUATE_SUCCESS:
    case actions.AUTOGRADE_SUCCESS:
    case actions.RESET_SUCCESS: {
      const { questionId } = action.payload;
      return Object.keys(state).reduce(
        (obj, key) => {
          if (key !== questionId.toString()) {
            return { ...obj, [key]: state[key] };
          }
          return obj;
        },
        { [questionId]: action.payload.explanation },
      );
    }
    case actions.REEVALUATE_FAILURE:
    case actions.AUTOGRADE_FAILURE: {
      const { questionId } = action;
      return {
        ...state,
        [questionId]: {
          correct: null,
          explanations: [],
        },
      };
    }
    default:
      return state;
  }
}