// @flow

import React from 'react';
import {
    Alert,
    Modal,
    SafeAreaView,
    ScrollView,
    Switch,
    Text,
    TextInput,
    View
} from 'react-native';
import { connect } from 'react-redux';

import { translate } from '../../../base/i18n';
import { Header } from '../../../base/react';

import {
    AbstractSettingsView,
    _mapStateToProps
} from '../AbstractSettingsView';
import { setSettingsViewVisible } from '../../actions';
import BackButton from './BackButton';
import FormRow from './FormRow';
import FormSectionHeader from './FormSectionHeader';
import { normalizeUserInputURL } from '../../functions';
import styles from './styles';

/**
 * The native container rendering the app settings page.
 *
 * @extends AbstractSettingsView
 */
class SettingsView extends AbstractSettingsView {
    _urlField: Object;

    /**
     * Initializes a new {@code SettingsView} instance.
     *
     * @inheritdoc
     */
    constructor(props) {
        super(props);

        // Bind event handlers so they are only bound once per instance.
        this._onBlurServerURL = this._onBlurServerURL.bind(this);
        this._onRequestClose = this._onRequestClose.bind(this);
        this._setURLFieldReference = this._setURLFieldReference.bind(this);
        this._showURLAlert = this._showURLAlert.bind(this);
    }

    /**
     * Implements React's {@link Component#render()}, renders the settings page.
     *
     * @inheritdoc
     * @returns {ReactElement}
     */
    render() {
        return (
            <Modal
                animationType = 'slide'
                onRequestClose = { this._onRequestClose }
                presentationStyle = 'fullScreen'
                supportedOrientations = { [
                    'landscape',
                    'portrait'
                ] }
                visible = { this.props._visible }>
                <View style = { Header.pageStyle }>
                    { this._renderHeader() }
                    { this._renderBody() }
                </View>
            </Modal>
        );
    }

    _onBlurServerURL: () => void;

    /**
     * Handler the server URL lose focus event. Here we validate the server URL
     * and update it to the normalized version, or show an error if incorrect.
     *
     * @private
     * @returns {void}
     */
    _onBlurServerURL() {
        this._processServerURL(false /* hideOnSuccess */);
    }

    _onChangeDisplayName: (string) => void;

    _onChangeEmail: (string) => void;

    _onChangeServerURL: (string) => void;

    _onRequestClose: () => void;

    /**
     * Handles the back button. Also invokes normalizeUserInputURL to validate
     * the URL entered by the user.
     *
     * @returns {void}
     */
    _onRequestClose() {
        this._processServerURL(true /* hideOnSuccess */);
    }

    _onStartAudioMutedChange: (boolean) => void;

    _onStartVideoMutedChange: (boolean) => void;

    /**
     * Processes the server URL. It normalizes it and an error alert is
     * displayed in case it's incorrect.
     *
     * @param {boolean} hideOnSuccess - True if the dialog should be hidden if
     * normalization / validation succeeds, false otherwise.
     * @private
     * @returns {void}
     */
    _processServerURL(hideOnSuccess: boolean) {
        const { serverURL } = this.props._settings;
        const normalizedURL = normalizeUserInputURL(serverURL);

        if (normalizedURL === null) {
            this._showURLAlert();
        } else {
            this._onChangeServerURL(normalizedURL);
            if (hideOnSuccess) {
                this.props.dispatch(setSettingsViewVisible(false));
            }
        }
    }

    /**
     * Renders the body (under the header) of {@code SettingsView}.
     *
     * @private
     * @returns {React$Element}
     */
    _renderBody() {
        const { _settings } = this.props;

        return (
            <SafeAreaView style = { styles.settingsForm }>
                <ScrollView>
                    <FormSectionHeader
                        label = 'settingsView.profileSection' />
                    <FormRow
                        fieldSeparator = { true }
                        label = 'settingsView.displayName'>
                        <TextInput
                            autoCorrect = { false }
                            onChangeText = { this._onChangeDisplayName }
                            placeholder = 'John Doe'
                            value = { _settings.displayName } />
                    </FormRow>
                    <FormRow label = 'settingsView.email'>
                        <TextInput
                            autoCapitalize = 'none'
                            autoCorrect = { false }
                            keyboardType = { 'email-address' }
                            onChangeText = { this._onChangeEmail }
                            placeholder = 'email@example.com'
                            value = { _settings.email } />
                    </FormRow>
                    <FormSectionHeader
                        label = 'settingsView.conferenceSection' />
                    <FormRow
                        fieldSeparator = { true }
                        label = 'settingsView.serverURL'>
                        <TextInput
                            autoCapitalize = 'none'
                            autoCorrect = { false }
                            onBlur = { this._onBlurServerURL }
                            onChangeText = { this._onChangeServerURL }
                            placeholder = { this.props._serverURL }
                            value = { _settings.serverURL } />
                    </FormRow>
                    <FormRow
                        fieldSeparator = { true }
                        label = 'settingsView.startWithAudioMuted'>
                        <Switch
                            onValueChange = { this._onStartAudioMutedChange }
                            value = { _settings.startWithAudioMuted } />
                    </FormRow>
                    <FormRow label = 'settingsView.startWithVideoMuted'>
                        <Switch
                            onValueChange = { this._onStartVideoMutedChange }
                            value = { _settings.startWithVideoMuted } />
                    </FormRow>
                </ScrollView>
            </SafeAreaView>
        );
    }

    /**
     * Renders the header of {@code SettingsView}.
     *
     * @private
     * @returns {React$Element}
     */
    _renderHeader() {
        return (
            <Header>
                <BackButton onPress = { this._onRequestClose } />
                <Text
                    style = { [
                        styles.text,
                        Header.textStyle
                    ] }>
                    { this.props.t('settingsView.header') }
                </Text>
            </Header>
        );
    }

    _setURLFieldReference: (React$ElementRef<*> | null) => void;

    /**
     *  Stores a reference to the URL field for later use.
     *
     * @param {Object} component - The field component.
     * @protected
     * @returns {void}
     */
    _setURLFieldReference(component) {
        this._urlField = component;
    }

    _showURLAlert: () => void;

    /**
     * Shows an alert telling the user that the URL he/she entered was invalid.
     *
     * @returns {void}
     */
    _showURLAlert() {
        const { t } = this.props;

        Alert.alert(
            t('settingsView.alertTitle'),
            t('settingsView.alertURLText'),
            [
                {
                    onPress: () => this._urlField.focus(),
                    text: t('settingsView.alertOk')
                }
            ]
        );
    }
}

export default translate(connect(_mapStateToProps)(SettingsView));
