/**
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 * @providesModule MetroListView
 * @flow
 */
'use strict';

const ListView = require('ListView');
const React = require('React');
const RefreshControl = require('RefreshControl');
const ScrollView = require('ScrollView');

const invariant = require('fbjs/lib/invariant');

type Item = any;

type NormalProps = {
  FooterComponent?: ReactClass<*>,
  renderItem: (info: Object) => ?React.Element<*>,
  renderSectionHeader?: ({section: Object}) => ?React.Element<*>,
  SeparatorComponent?: ?ReactClass<*>, // not supported yet

  // Provide either `items` or `sections`
  items?: ?Array<Item>, // By default, an Item is assumed to be {key: string}
  // $FlowFixMe - Something is a little off with the type Array<Item>
  sections?: ?Array<{key: string, data: Array<Item>}>,

  /**
   * If provided, a standard RefreshControl will be added for "Pull to Refresh" functionality. Make
   * sure to also set the `refreshing` prop correctly.
   */
  onRefresh?: ?Function,
  /**
   * Set this true while waiting for new data from a refresh.
   */
  refreshing?: boolean,
  /**
   * If true, renders items next to each other horizontally instead of stacked vertically.
   */
  horizontal?: ?boolean,
};
type DefaultProps = {
  keyExtractor: (item: Item, index: number) => string,
};
/* $FlowFixMe - the renderItem passed in from SectionList is optional there but
 * required here */
type Props = NormalProps & DefaultProps;

/**
 * This is just a wrapper around the legacy ListView that matches the new API of FlatList, but with
 * some section support tacked on. It is recommended to just use FlatList directly, this component
 * is mostly for debugging and performance comparison.
 */
class MetroListView extends React.Component {
  props: Props;
  scrollToEnd(params?: ?{animated?: ?boolean}) {
    throw new Error('scrollToEnd not supported in legacy ListView.');
  }
  scrollToIndex(params: {animated?: ?boolean, index: number, viewPosition?: number}) {
    throw new Error('scrollToIndex not supported in legacy ListView.');
  }
  scrollToItem(params: {animated?: ?boolean, item: Item, viewPosition?: number}) {
    throw new Error('scrollToItem not supported in legacy ListView.');
  }
  scrollToLocation() {
    throw new Error('scrollToLocation not supported in legacy ListView.');
  }
  scrollToOffset(params: {animated?: ?boolean, offset: number}) {
    const {animated, offset} = params;
    this._listRef.scrollTo(
      this.props.horizontal ? {x: offset, animated} : {y: offset, animated}
    );
  }
  getListRef() {
    return this._listRef;
  }

  setNativeProps(props: Object) {
    if (this._listRef) {
      this._listRef.setNativeProps(props);
    }
  }
  
  static defaultProps: DefaultProps = {
    keyExtractor: (item, index) => item.key || String(index),
    renderScrollComponent: (props: Props) => {
      if (props.onRefresh) {
        return (
          <ScrollView
            {...props}
            refreshControl={
              <RefreshControl
                refreshing={props.refreshing}
                onRefresh={props.onRefresh}
              />
            }
          />
        );
      } else {
        return <ScrollView {...props} />;
      }
    },
  };
  state = this._computeState(
    this.props,
    {
      ds: new ListView.DataSource({
        rowHasChanged: (itemA, itemB) => true,
        sectionHeaderHasChanged: () => true,
        getSectionHeaderData: (dataBlob, sectionID) => this.state.sectionHeaderData[sectionID],
      }),
      sectionHeaderData: {},
    },
  );
  componentWillReceiveProps(newProps: Props) {
    this.setState((state) => this._computeState(newProps, state));
  }
  render() {
    return (
      <ListView
        {...this.props}
        dataSource={this.state.ds}
        ref={this._captureRef}
        renderRow={this._renderRow}
        renderFooter={this.props.FooterComponent && this._renderFooter}
        renderSectionHeader={this.props.sections && this._renderSectionHeader}
        renderSeparator={this.props.SeparatorComponent && this._renderSeparator}
      />
    );
  }
  _listRef: ListView;
  _captureRef = (ref) => { this._listRef = ref; };
  _computeState(props: Props, state) {
    const sectionHeaderData = {};
    if (props.sections) {
      invariant(!props.items, 'Cannot have both sections and items props.');
      const sections = {};
      props.sections.forEach((sectionIn, ii) => {
        const sectionID = 's' + ii;
        sections[sectionID] = sectionIn.data;
        sectionHeaderData[sectionID] = sectionIn;
      });
      return {
        ds: state.ds.cloneWithRowsAndSections(sections),
        sectionHeaderData,
      };
    } else {
      invariant(!props.sections, 'Cannot have both sections and items props.');
      return {
        ds: state.ds.cloneWithRows(props.items),
        sectionHeaderData,
      };
    }
  }
  _renderFooter = () => <this.props.FooterComponent key="$footer" />;
  _renderRow = (item, sectionID, rowID, highlightRow) => {
    return this.props.renderItem({item, index: rowID});
  };
  _renderSectionHeader = (section, sectionID) => {
    const {renderSectionHeader} = this.props;
    invariant(renderSectionHeader, 'Must provide renderSectionHeader with sections prop');
    return renderSectionHeader({section});
  }
  _renderSeparator = (sID, rID) => <this.props.SeparatorComponent key={sID + rID} />;
}

module.exports = MetroListView;