import React from 'react';
import PropTypes from 'prop-types';
import ReactRouterPropTypes from 'react-router-prop-types';
import { Link } from 'react-router-dom';
import * as qs from 'query-string';
import moment from 'moment';

import Message from './Message';
import Spinner from './Spinner';

import { getMessages } from '../api';
import { UserType } from './Types';

export function Discover(props) {
  let search = qs.parse(props.location.search);
  const query = {
    baseUrl: '/messages',
    search: search,
    pageParam: search.search ? 'page' : 'before_mid'
  };
  return (<Feed authRequired={false} query={query} {...props} />);
}

export function Discussions(props) {
  const query = {
    baseUrl: '/messages/discussions',
    pageParam: 'to'
  };
  return (<Feed authRequired={true} query={query} {...props} />);
}

export function Blog(props) {
  const { user } = props.match.params;
  let search = qs.parse(props.location.search);
  search.uname = user;
  const query = {
    baseUrl: '/messages',
    search: search,
    pageParam: search.search ? 'page' : 'before_mid'
  };
  return (<Feed authRequired={false} query={query} {...props} />);
}

export function Tag(props) {
  const { tag } = props.match.params;
  const query = {
    baseUrl: '/messages',
    search: {
      tag: tag
    },
    pageParam: 'before_mid'
  };
  return (<Feed authRequired={false} query={query} {...props} />);
}

export function Home(props) {
  const query = {
    baseUrl: '/home',
    pageParam: 'before_mid'
  };
  return (<Feed authRequired={true} query={query} {...props} />);
}

class Feed extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      msgs: [],
      loading: false
    };
  }
  componentDidMount() {
    this.loadMessages(this.props.visitor.hash, this.props.location.search);
  }

  shouldComponentUpdate(nextProps, nextState) {
    return this.props.visitor.uid !== nextProps.visitor.uid
    || this.state !== nextState || this.props.location !== nextProps.location;
  }

  getSnapshotBeforeUpdate(prevProps) {
    return (this.props.location.search != prevProps.location.search
      || this.props.visitor != prevProps.visitor || this.props.query.search != prevProps.query.search);
  }
  componentDidUpdate(prevProps, prevState, shouldReload) {
    if (shouldReload) {
      this.loadMessages(this.props.visitor.hash, this.props.location.search);
    }
  }
  loadMessages = (hash = '', filter = '') => {
    document.body.scrollTop = 0;
    document.documentElement.scrollTop = 0;
    this.setState({ msgs: [], loading: true });
    const filterParams = qs.parse(filter);
    let params = Object.assign({}, filterParams || {}, this.props.query.search || {});
    let url = this.props.query.baseUrl;
    if (hash) {
      params.hash = hash;
    }
    if (!params.hash && this.props.authRequired) {
      this.props.history.push('/');
    }
    getMessages(url, params)
      .then(response => {
        const { data } = response;
        const { pageParam } = this.props.query;
        const lastMessage = data.slice(-1)[0] || {};
        const nextpage = this.getPageParam(pageParam, lastMessage, filterParams);
        this.setState({ msgs: data, loading: false, nextpage: nextpage });
      }).catch(ex => {
        this.setState({ error: true });
      });
  }

  getPageParam = (pageParam, lastMessage, filterParams) => {
    const pageValue = pageParam === 'before_mid' ? lastMessage.mid : pageParam === 'page' ? (Number(filterParams.page) || 0) + 1 : moment.utc(lastMessage.updated).valueOf();
    let newFilter = Object.assign({}, filterParams);
    newFilter[pageParam] = pageValue;
    return `?${qs.stringify(newFilter)}`;
  }

  render() {
    const { tag } = qs.parse(this.props.location.search || {});
    const nodes = (
      <React.Fragment>
        {
          tag && (
            <p className="page">
              <Link to={{ pathname: `/tag/${tag}` }}>
                <span>← All posts with tag&nbsp;</span><b>{tag}</b>
              </Link>
            </p>
          )
        }
        {
          this.state.msgs.map(msg =>
            <Message key={msg.mid} data={msg} visitor={this.props.visitor} />)
        }
        {
          this.state.msgs.length >= 20 && (
            <p className="page">
              <Link to={{ pathname: this.props.location.pathname, search: this.state.nextpage }} rel="prev">Next →</Link>
            </p>
          )
        }
      </React.Fragment>
    );
    return this.state.msgs.length > 0 ? (
      <div className="msgs">{nodes}</div>
    ) : this.state.error ? <div>error</div> : this.state.loading ? <div className="msgs"><Spinner /><Spinner /><Spinner /><Spinner /></div> : <div>No more messages</div>;
  }
}

Discover.propTypes = {
  location: ReactRouterPropTypes.location.isRequired,
  search: PropTypes.string
};

Blog.propTypes = {
  match: ReactRouterPropTypes.match.isRequired,
  location: ReactRouterPropTypes.location.isRequired,
  search: PropTypes.string
};

Tag.propTypes = {
  match: ReactRouterPropTypes.match.isRequired
};

Feed.propTypes = {
  authRequired: PropTypes.bool,
  visitor: UserType,
  history: ReactRouterPropTypes.history.isRequired,
  location: ReactRouterPropTypes.location.isRequired,
  msgs: PropTypes.array,
  query: PropTypes.shape({
    baseUrl: PropTypes.string.isRequired,
    search: PropTypes.object,
    pageParam: PropTypes.string.isRequired
  })
};