// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.

import React, {PureComponent} from 'react';
import PropTypes from 'prop-types';
import {intlShape} from 'react-intl';
import {
    Platform,
    View,
} from 'react-native';

import {debounce} from 'mattermost-redux/actions/helpers';
import {General} from 'mattermost-redux/constants';
import {filterProfilesMatchingTerm} from 'mattermost-redux/utils/user_utils';
import {filterChannelsMatchingTerm} from 'mattermost-redux/utils/channel_utils';
import {memoizeResult} from 'mattermost-redux/utils/helpers';

import CustomList, {FLATLIST, SECTIONLIST} from 'app/components/custom_list';
import UserListRow from 'app/components/custom_list/user_list_row';
import ChannelListRow from 'app/components/custom_list/channel_list_row';
import OptionListRow from 'app/components/custom_list/option_list_row';
import FormattedText from 'app/components/formatted_text';
import SearchBar from 'app/components/search_bar';
import StatusBar from 'app/components/status_bar';
import {ViewTypes} from 'app/constants';
import {createProfilesSections, loadingText} from 'app/utils/member_list';
import {changeOpacity, makeStyleSheetFromTheme, setNavigatorStyles} from 'app/utils/theme';
import {t} from 'app/utils/i18n';

export default class SelectorScreen extends PureComponent {
    static propTypes = {
        actions: PropTypes.shape({
            getProfiles: PropTypes.func.isRequired,
            getChannels: PropTypes.func.isRequired,
            searchProfiles: PropTypes.func.isRequired,
            searchChannels: PropTypes.func.isRequired,
        }),
        currentTeamId: PropTypes.string.isRequired,
        data: PropTypes.arrayOf(PropTypes.object),
        dataSource: PropTypes.string,
        navigator: PropTypes.object,
        onSelect: PropTypes.func.isRequired,
        theme: PropTypes.object.isRequired,
    };

    static contextTypes = {
        intl: intlShape.isRequired,
    };

    constructor(props) {
        super(props);

        this.searchTimeoutId = 0;
        this.page = -1;
        this.next = props.dataSource === ViewTypes.DATA_SOURCE_USERS || props.dataSource === ViewTypes.DATA_SOURCE_CHANNELS;

        let data = [];
        if (!props.dataSource) {
            data = props.data;
        }

        this.state = {
            data,
            loading: false,
            searchResults: [],
            term: '',
        };

        props.navigator.setOnNavigatorEvent(this.onNavigatorEvent);
    }

    componentDidMount() {
        const {dataSource} = this.props;
        this.mounted = true;
        if (dataSource === ViewTypes.DATA_SOURCE_USERS) {
            this.getProfiles();
        } else if (dataSource === ViewTypes.DATA_SOURCE_CHANNELS) {
            this.getChannels();
        }
    }

    componentWillUnmount() {
        this.mounted = false;
    }

    componentDidUpdate(prevProps) {
        if (this.props.theme !== prevProps.theme) {
            setNavigatorStyles(this.props.navigator, this.props.theme);
        }
    }

    clearSearch = () => {
        this.setState({term: '', searchResults: []});
    };

    close = () => {
        this.props.navigator.pop({animated: true});
    };

    handleSelectItem = (id, item) => {
        this.props.onSelect(item);
        this.close();
    };

    getChannels = debounce(() => {
        const {actions, currentTeamId} = this.props;
        const {loading, term} = this.state;
        if (this.next && !loading && !term) {
            this.setState({loading: true}, () => {
                actions.getChannels(
                    currentTeamId,
                    this.page += 1,
                    General.CHANNELS_CHUNK_SIZE
                ).then(this.loadedChannels);
            });
        }
    }, 100);

    getDataResults = () => {
        const {dataSource} = this.props;
        const {data, searchResults, term} = this.state;

        const result = {
            data,
            listType: FLATLIST};
        if (term) {
            result.data = filterSearchData(dataSource, searchResults, term);
        } else if (dataSource === ViewTypes.DATA_SOURCE_USERS) {
            result.data = createProfilesSections(data);
            result.listType = SECTIONLIST;
        }

        return result;
    };

    getProfiles = debounce(() => {
        const {loading, term} = this.state;
        if (this.next && !loading && !term) {
            this.setState({loading: true}, () => {
                const {actions} = this.props;

                actions.getProfiles(
                    this.page + 1,
                    General.PROFILE_CHUNK_SIZE
                ).then(this.loadedProfiles);
            });
        }
    }, 100);

    loadedChannels = ({data: channels}) => {
        const {data} = this.state;
        if (channels && !channels.length) {
            this.next = false;
        }

        this.page += 1;
        this.setState({loading: false, data: [...channels, ...data]});
    };

    loadedProfiles = ({data: profiles}) => {
        const {data} = this.state;
        if (profiles && !profiles.length) {
            this.next = false;
        }

        this.page += 1;
        this.setState({loading: false, data: [...profiles, ...data]});
    };

    loadMore = () => {
        const {dataSource} = this.props;

        if (dataSource === ViewTypes.DATA_SOURCE_USERS) {
            this.getProfiles();
        } else if (dataSource === ViewTypes.DATA_SOURCE_CHANNELS) {
            this.getChannels();
        }
    };

    onSearch = (text) => {
        const term = text.toLowerCase();

        if (term) {
            const {dataSource, data} = this.props;
            this.setState({term});
            clearTimeout(this.searchTimeoutId);

            this.searchTimeoutId = setTimeout(() => {
                if (!dataSource) {
                    this.setState({searchResults: filterSearchData(null, data, term)});
                    return;
                }

                if (dataSource === ViewTypes.DATA_SOURCE_USERS) {
                    this.searchProfiles(term);
                } else if (dataSource === ViewTypes.DATA_SOURCE_CHANNELS) {
                    this.searchChannels(term);
                }
            }, General.SEARCH_TIMEOUT_MILLISECONDS);
        } else {
            this.clearSearch();
        }
    };

    searchChannels = (term) => {
        const {actions, currentTeamId} = this.props;

        actions.searchChannels(currentTeamId, term).then(({data}) => {
            this.setState({searchResults: data, loading: false});
        });
    };

    searchProfiles = (term) => {
        const {actions} = this.props;
        this.setState({loading: true});

        actions.searchProfiles(term).then(({data}) => {
            this.setState({searchResults: data, loading: false});
        });
    };

    renderLoading = () => {
        const {dataSource, theme} = this.props;
        const {loading} = this.state;
        const style = getStyleFromTheme(theme);

        if (!loading) {
            return null;
        }

        let text;
        switch (dataSource) {
        case ViewTypes.DATA_SOURCE_USERS:
            text = loadingText;
            break;
        case ViewTypes.DATA_SOURCE_CHANNELS:
            text = {
                id: t('mobile.loading_channels'),
                defaultMessage: 'Loading Channels...',
            };
            break;
        default:
            text = {
                id: t('mobile.loading_options'),
                defaultMessage: 'Loading Options...',
            };
            break;
        }

        return (
            <View style={style.loadingContainer}>
                <FormattedText
                    {...text}
                    style={style.loadingText}
                />
            </View>
        );
    };

    renderNoResults = () => {
        const {loading} = this.state;
        const {theme} = this.props;
        const style = getStyleFromTheme(theme);

        if (loading || this.page === -1) {
            return null;
        }

        return (
            <View style={style.noResultContainer}>
                <FormattedText
                    id='mobile.custom_list.no_results'
                    defaultMessage='No Results'
                    style={style.noResultText}
                />
            </View>
        );
    };

    render() {
        const {formatMessage} = this.context.intl;
        const {theme, dataSource} = this.props;
        const {loading, term} = this.state;
        const style = getStyleFromTheme(theme);

        const searchBarInput = {
            backgroundColor: changeOpacity(theme.centerChannelColor, 0.2),
            color: theme.centerChannelColor,
            fontSize: 15,
            ...Platform.select({
                android: {
                    marginBottom: -5,
                },
            }),
        };

        let rowComponent;
        if (dataSource === ViewTypes.DATA_SOURCE_USERS) {
            rowComponent = UserListRow;
        } else if (dataSource === ViewTypes.DATA_SOURCE_CHANNELS) {
            rowComponent = ChannelListRow;
        } else {
            rowComponent = OptionListRow;
        }

        const {data, listType} = this.getDataResults();

        return (
            <View style={style.container}>
                <StatusBar/>
                <View style={style.searchBar}>
                    <SearchBar
                        ref='search_bar'
                        placeholder={formatMessage({id: 'search_bar.search', defaultMessage: 'Search'})}
                        cancelTitle={formatMessage({id: 'mobile.post.cancel', defaultMessage: 'Cancel'})}
                        backgroundColor='transparent'
                        inputHeight={33}
                        inputStyle={searchBarInput}
                        placeholderTextColor={changeOpacity(theme.centerChannelColor, 0.5)}
                        tintColorSearch={changeOpacity(theme.centerChannelColor, 0.5)}
                        tintColorDelete={changeOpacity(theme.centerChannelColor, 0.5)}
                        titleCancelColor={theme.centerChannelColor}
                        onChangeText={this.onSearch}
                        onSearchButtonPress={this.onSearch}
                        onCancelButtonPress={this.clearSearch}
                        autoCapitalize='none'
                        value={term}
                    />
                </View>
                <CustomList
                    data={data}
                    key='custom_list'
                    listType={listType}
                    loading={loading}
                    loadingComponent={this.renderLoading()}
                    noResults={this.renderNoResults()}
                    onLoadMore={this.loadMore}
                    onRowPress={this.handleSelectItem}
                    renderItem={rowComponent}
                    theme={theme}
                />
            </View>
        );
    }
}

const getStyleFromTheme = makeStyleSheetFromTheme((theme) => {
    return {
        container: {
            flex: 1,
            backgroundColor: theme.centerChannelBg,
        },
        searchBar: {
            marginVertical: 5,
        },
        loadingContainer: {
            alignItems: 'center',
            backgroundColor: theme.centerChannelBg,
            height: 70,
            justifyContent: 'center',
        },
        loadingText: {
            color: changeOpacity(theme.centerChannelColor, 0.6),
        },
        noResultContainer: {
            flexGrow: 1,
            flexDirection: 'row',
            alignItems: 'center',
            justifyContent: 'center',
        },
        noResultText: {
            fontSize: 26,
            color: changeOpacity(theme.centerChannelColor, 0.5),
        },
    };
});

const filterSearchData = memoizeResult((dataSource, data, term) => {
    if (!data) {
        return [];
    }

    if (dataSource === ViewTypes.DATA_SOURCE_USERS) {
        return filterProfilesMatchingTerm(data, term);
    } else if (dataSource === ViewTypes.DATA_SOURCE_CHANNELS) {
        return filterChannelsMatchingTerm(data, term);
    }

    return data.filter((option) => option.text && option.text.toLowerCase().startsWith(term));
});