import { Observable } from 'rx';

import types from './types';
import {
  moveToNextChallenge,
  clearSavedCode
} from './actions';

import { challengeSelector } from './selectors';
import { randomCompliment } from '../../../utils/get-words';
import {
  createErrorObservable,
  updateUserPoints,
  updateUserChallenge
} from '../../../redux/actions';
import { backEndProject } from '../../../utils/challengeTypes';
import { makeToast } from '../../../toasts/redux/actions';
import { postJSON$ } from '../../../../utils/ajax-stream';

function postChallenge(url, username, _csrf, challengeInfo) {
  const body = { ...challengeInfo, _csrf };
  const saveChallenge$ = postJSON$(url, body)
    .retry(3)
    .flatMap(({ points, lastUpdated, completedDate }) => {
      return Observable.of(
        updateUserPoints(username, points),
        updateUserChallenge(
          username,
          { ...challengeInfo, lastUpdated, completedDate }
        ),
        clearSavedCode()
      );
    })
    .catch(createErrorObservable);
  const challengeCompleted$ = Observable.of(moveToNextChallenge());
  return Observable.merge(saveChallenge$, challengeCompleted$);
}

function submitModern(type, state) {
  const { tests } = state.challengesApp;
  if (tests.length > 0 && tests.every(test => test.pass && !test.err)) {
    if (type === types.checkChallenge) {
      return Observable.of(
        makeToast({
          message: `${randomCompliment()} Go to your next challenge.`,
          action: 'Submit',
          actionCreator: 'submitChallenge',
          timeout: 10000
        })
      );
    }

    if (type === types.submitChallenge) {
      const { challenge: { id } } = challengeSelector(state);
      const {
        app: { user, csrfToken },
        challengesApp: { files }
      } = state;
      const challengeInfo = { id, files };
      return postChallenge(
        '/modern-challenge-completed',
        user,
        csrfToken,
        challengeInfo
      );
    }
  }
  return Observable.just(
    makeToast({ message: 'Keep trying.' })
  );
}

function submitProject(type, state, { solution, githubLink }) {
  const {
    challenge: { id, challengeType }
  } = challengeSelector(state);
  const {
    app: { user, csrfToken }
  } = state;
  const challengeInfo = { id, challengeType, solution };
  if (challengeType === backEndProject) {
    challengeInfo.githubLink = githubLink;
  }
  return postChallenge(
    '/project-completed',
    user,
    csrfToken,
    challengeInfo
  );
}

function submitSimpleChallenge(type, state) {
  const {
    challenge: { id }
  } = challengeSelector(state);
  const {
    app: { user, csrfToken }
  } = state;
  const challengeInfo = { id };
  return postChallenge(
    '/challenge-completed',
    user,
    csrfToken,
    challengeInfo
  );
}

const submitTypes = {
  tests: submitModern,
  step: submitSimpleChallenge,
  video: submitSimpleChallenge,
  'project.frontEnd': submitProject,
  'project.backEnd': submitProject,
  'project.simple': submitSimpleChallenge
};

export default function completionSaga(actions$, getState) {
  return actions$
    .filter(({ type }) => (
      type === types.checkChallenge ||
      type === types.submitChallenge
    ))
    .flatMap(({ type, payload }) => {
      const state = getState();
      const { submitType } = challengeSelector(state);
      const submitter = submitTypes[submitType] ||
        (() => Observable.just(null));
      return submitter(type, state, payload);
    });
}