import PropTypes from "prop-types";

import { defineMessages, injectIntl, FormattedMessage } from "react-intl";

import { Helmet } from "react-helmet";

import ImmutablePropTypes from "react-immutable-proptypes";
import ImmutablePureComponent from "react-immutable-pure-component";
import { connect } from "react-redux";
import { createSelector } from "reselect";

import { fetchLists } from "mastodon/actions/lists";
import Column from "mastodon/components/column";
import ColumnHeader from "mastodon/components/column_header";
import { LoadingIndicator } from "mastodon/components/loading_indicator";
import ScrollableList from "mastodon/components/scrollable_list";
import ColumnLink from "mastodon/features/ui/components/column_link";
import ColumnSubheading from "mastodon/features/ui/components/column_subheading";

import NewListForm from "./components/new_list_form";

const messages = defineMessages({
  heading: { id: "column.lists", defaultMessage: "Lists" },
  subheading: { id: "lists.subheading", defaultMessage: "Your lists" },
});

const getOrderedLists = createSelector([state => state.get("lists")], lists => {
  if (!lists) {
    return lists;
  }

  return lists.toList().filter(item => !!item).sort((a, b) => a.get("title").localeCompare(b.get("title")));
});

const mapStateToProps = state => ({
  lists: getOrderedLists(state),
});

class Lists extends ImmutablePureComponent {

  static propTypes = {
    params: PropTypes.object.isRequired,
    dispatch: PropTypes.func.isRequired,
    lists: ImmutablePropTypes.list,
    intl: PropTypes.object.isRequired,
    multiColumn: PropTypes.bool,
  };

  UNSAFE_componentWillMount () {
    this.props.dispatch(fetchLists());
  }

  render () {
    const { intl, lists, multiColumn } = this.props;

    if (!lists) {
      return (
        <Column>
          <LoadingIndicator />
        </Column>
      );
    }

    const emptyMessage = <FormattedMessage id='empty_column.lists' defaultMessage="You don't have any lists yet. When you create one, it will show up here." />;

    return (
      <Column bindToDocument={!multiColumn} label={intl.formatMessage(messages.heading)}>
        <ColumnHeader title={intl.formatMessage(messages.heading)} icon='list-ul' multiColumn={multiColumn} />

        <NewListForm />

        <ScrollableList
          scrollKey='lists'
          emptyMessage={emptyMessage}
          prepend={<ColumnSubheading text={intl.formatMessage(messages.subheading)} />}
          bindToDocument={!multiColumn}
        >
          {lists.map(list =>
            <ColumnLink key={list.get("id")} to={`/lists/${list.get("id")}`} icon='list-ul' text={list.get("title")} />,
          )}
        </ScrollableList>

        <Helmet>
          <title>{intl.formatMessage(messages.heading)}</title>
          <meta name='robots' content='noindex' />
        </Helmet>
      </Column>
    );
  }

}

export default connect(mapStateToProps)(injectIntl(Lists));