Rocket.Chat.ReactNative/app/views/PickerView.tsx

import React from 'react';
import { FlatList, StyleSheet, Text, View } from 'react-native';

import { IBaseScreen } from '../definitions';
import I18n from '../i18n';
import { TSupportedThemes, withTheme } from '../theme';
import { themes } from '../lib/constants';
import debounce from '../utils/debounce';
import * as List from '../containers/List';
import SearchBox from '../containers/SearchBox';
import SafeAreaView from '../containers/SafeAreaView';
import sharedStyles from './Styles';
import { ChatsStackParamList } from '../stacks/types';
import { IOptionsField } from './NotificationPreferencesView/options';

const styles = StyleSheet.create({
	search: {
		width: '100%',
		height: 56
	},
	noResult: {
		fontSize: 16,
		paddingVertical: 56,
		...sharedStyles.textSemibold,
		...sharedStyles.textAlignCenter
	},
	listNoHeader: {
		marginTop: 32
	}
});

interface IItem {
	item: IOptionsField;
	selected: boolean;
	onItemPress: () => void;
	theme: TSupportedThemes;
}

interface IRenderSearch {
	hasSearch: boolean;
	onChangeText: (text: string) => void;
}

interface IPickerViewState {
	data: IOptionsField[];
	value: string;
	total: number;
	searchText: string;
}

type IPickerViewProps = IBaseScreen<ChatsStackParamList, 'PickerView'>;

const Item = React.memo(({ item, selected, onItemPress, theme }: IItem) => (
	<List.Item
		title={I18n.t(item.label, { defaultValue: item.label, second: item?.second })}
		right={() => (selected ? <List.Icon name='check' color={themes[theme].tintColor} /> : null)}
		onPress={onItemPress}
		translateTitle={false}
	/>
));

const RenderSearch = ({ hasSearch, onChangeText }: IRenderSearch) => {
	if (!hasSearch) {
		return <List.Separator style={styles.listNoHeader} />;
	}
	return (
		<>
			<View style={styles.search}>
				<SearchBox onChangeText={onChangeText} />
			</View>
			<List.Separator />
		</>
	);
};

class PickerView extends React.PureComponent<IPickerViewProps, IPickerViewState> {
	private onSearch?: (text?: string) => Promise<any>;

	static navigationOptions = ({ route }: IPickerViewProps) => ({
		title: route.params?.title ?? I18n.t('Select_an_option')
	});

	constructor(props: IPickerViewProps) {
		super(props);
		const data = props.route.params?.data ?? [];
		const value = props.route.params?.value ?? '';
		const total = props.route.params?.total ?? 0;
		this.state = { data, value, total, searchText: '' };
		this.onSearch = props.route.params?.onSearch;
	}

	onChangeValue = (value: string) => {
		const { navigation, route } = this.props;
		const goBack = route.params?.goBack ?? true;
		const onChange = route.params?.onChangeValue ?? (() => {});
		onChange(value);
		if (goBack) {
			navigation.goBack();
		}
	};

	onChangeText = debounce(async (searchText: string) => {
		if (this.onSearch) {
			const data = await this.onSearch(searchText);
			if (data?.data) {
				this.setState({ ...data, searchText });
			}
		}
	}, 500);

	onEndReached = async () => {
		const { route } = this.props;
		const { data, total, searchText } = this.state;
		const onEndReached = route.params?.onEndReached;
		if (onEndReached && data.length < total) {
			const val = await onEndReached(searchText, data.length);
			if (val?.data) {
				this.setState({ ...val, data: [...data, ...val.data] });
			}
		}
	};

	render() {
		const { data, value } = this.state;
		const { theme } = this.props;

		return (
			<SafeAreaView>
				<FlatList
					data={data}
					keyExtractor={item => item.value as string}
					renderItem={({ item }) => (
						<Item
							item={item}
							theme={theme}
							selected={!this.onSearch && (value || data[0]?.value) === item.value}
							onItemPress={() => this.onChangeValue(item.value as string)}
						/>
					)}
					onEndReached={() => this.onEndReached()}
					onEndReachedThreshold={0.5}
					ItemSeparatorComponent={List.Separator}
					ListHeaderComponent={<RenderSearch hasSearch={!!this.onSearch} onChangeText={this.onChangeText} />}
					ListFooterComponent={List.Separator}
					ListEmptyComponent={() => (
						<Text style={[styles.noResult, { color: themes[theme].titleText }]}>{I18n.t('No_results_found')}</Text>
					)}
				/>
			</SafeAreaView>
		);
	}
}

export default withTheme(PickerView);