import React, { Component, Fragment } from 'react';
import PropTypes from 'prop-types';
import Helmet from 'react-helmet';
import { graphql } from 'gatsby';
import { uniq } from 'lodash-es';
import { connect } from 'react-redux';
import { createSelector } from 'reselect';
import { bindActionCreators } from 'redux';
import { withTranslation } from 'react-i18next';
import { Grid, Row, Col } from '@freecodecamp/react-bootstrap';
import { configureAnchors } from 'react-scrollable-anchor';

import Login from '../../components/Header/components/Login';
import Map from '../../components/Map';
import CertChallenge from './components/CertChallenge';
import SuperBlockIntro from './components/SuperBlockIntro';
import Block from './components/Block';
import { Spacer } from '../../components/helpers';
import {
  currentChallengeIdSelector,
  userFetchStateSelector,
  isSignedInSelector,
  userSelector
} from '../../redux';
import { resetExpansion, toggleBlock } from './redux';
import { MarkdownRemark, AllChallengeNode, User } from '../../redux/propTypes';

import './intro.css';

const propTypes = {
  currentChallengeId: PropTypes.string,
  data: PropTypes.shape({
    markdownRemark: MarkdownRemark,
    allChallengeNode: AllChallengeNode
  }),
  expandedState: PropTypes.object,
  fetchState: PropTypes.shape({
    pending: PropTypes.bool,
    complete: PropTypes.bool,
    errored: PropTypes.bool
  }),
  isSignedIn: PropTypes.bool,
  location: PropTypes.shape({
    hash: PropTypes.string,
    state: PropTypes.shape({
      breadcrumbBlockClick: PropTypes.string
    })
  }),
  resetExpansion: PropTypes.func,
  t: PropTypes.func,
  toggleBlock: PropTypes.func,
  user: User
};

configureAnchors({ offset: -40, scrollDuration: 0 });

const mapStateToProps = state => {
  return createSelector(
    currentChallengeIdSelector,
    isSignedInSelector,
    userFetchStateSelector,
    userSelector,
    (currentChallengeId, isSignedIn, fetchState, user) => ({
      currentChallengeId,
      isSignedIn,
      fetchState,
      user
    })
  )(state);
};

const mapDispatchToProps = dispatch =>
  bindActionCreators(
    { resetExpansion, toggleBlock: b => toggleBlock(b) },
    dispatch
  );

class SuperBlockIntroductionPage extends Component {
  componentDidMount() {
    this.initializeExpandedState();

    setTimeout(() => {
      configureAnchors({ offset: -40, scrollDuration: 400 });
    }, 0);
  }

  componentWillUnmount() {
    configureAnchors({ offset: -40, scrollDuration: 0 });
  }

  getChosenBlock() {
    const {
      data: {
        allChallengeNode: { edges }
      },
      isSignedIn,
      currentChallengeId,
      location
    } = this.props;

    // if coming from breadcrumb click
    if (location.state && location.state.breadcrumbBlockClick) {
      return location.state.breadcrumbBlockClick;
    }

    // if the URL includes a hash
    if (location.hash) {
      const dashedBlock = location.hash.replace('#', '').replace('/', '');
      return dashedBlock;
    }

    let edge = edges[0];

    if (isSignedIn) {
      // see if currentChallenge is in this superBlock
      const currentChallengeEdge = edges.find(
        edge => edge.node.id === currentChallengeId
      );

      return currentChallengeEdge
        ? currentChallengeEdge.node.block
        : edge.node.block;
    }

    return edge.node.block;
  }

  initializeExpandedState() {
    const { resetExpansion, toggleBlock } = this.props;

    resetExpansion();
    return toggleBlock(this.getChosenBlock());
  }

  render() {
    const {
      data: {
        markdownRemark: {
          frontmatter: { superBlock, title }
        },
        allChallengeNode: { edges }
      },
      isSignedIn,
      t,
      user
    } = this.props;

    const nodesForSuperBlock = edges.map(({ node }) => node);
    const blockDashedNames = uniq(nodesForSuperBlock.map(({ block }) => block));
    const i18nSuperBlock = t(`intro:${superBlock}.title`);

    return (
      <>
        <Helmet>
          <title>{i18nSuperBlock} | freeCodeCamp.org</title>
        </Helmet>
        <Grid>
          <Row className='super-block-intro-page'>
            <Col md={8} mdOffset={2} sm={10} smOffset={1} xs={12}>
              <Spacer size={2} />
              <SuperBlockIntro superBlock={superBlock} />
              <Spacer size={2} />
              <h2 className='text-center big-subheading'>
                {t(`intro:misc-text.courses`)}
              </h2>
              <Spacer />
              <div className='block-ui'>
                {blockDashedNames.map(blockDashedName => (
                  <Fragment key={blockDashedName}>
                    <Block
                      blockDashedName={blockDashedName}
                      challenges={nodesForSuperBlock.filter(
                        node => node.block === blockDashedName
                      )}
                      superBlock={superBlock}
                    />
                    {blockDashedName !== 'project-euler' ? <Spacer /> : null}
                  </Fragment>
                ))}
                {superBlock !== 'coding-interview-prep' && (
                  <div>
                    <CertChallenge
                      superBlock={superBlock}
                      title={title}
                      user={user}
                    />
                  </div>
                )}
              </div>
              {!isSignedIn && (
                <div>
                  <Spacer size={2} />
                  <Login block={true}>{t('buttons.logged-out-cta-btn')}</Login>
                </div>
              )}
              <Spacer size={2} />
              <h3
                className='text-center big-block-title'
                style={{ whiteSpace: 'pre-line' }}
              >
                {t(`intro:misc-text.browse-other`)}
              </h3>
              <Spacer />
              <Map currentSuperBlock={superBlock} />
              <Spacer size={2} />
            </Col>
          </Row>
        </Grid>
      </>
    );
  }
}

SuperBlockIntroductionPage.displayName = 'SuperBlockIntroductionPage';
SuperBlockIntroductionPage.propTypes = propTypes;

export default connect(
  mapStateToProps,
  mapDispatchToProps
)(withTranslation()(SuperBlockIntroductionPage));

export const query = graphql`
  query SuperBlockIntroPageBySlug($slug: String!, $superBlock: String!) {
    markdownRemark(fields: { slug: { eq: $slug } }) {
      frontmatter {
        superBlock
        title
      }
    }
    allChallengeNode(
      sort: { fields: [superOrder, order, challengeOrder] }
      filter: { superBlock: { eq: $superBlock } }
    ) {
      edges {
        node {
          fields {
            slug
            blockName
          }
          id
          block
          challengeType
          title
          order
          superBlock
          dashedName
        }
      }
    }
  }
`;