// @flow

import * as React from 'react';
import {Image, KeyboardAvoidingView, StyleSheet, View} from "react-native";
import {Button, Card, HelperText, TextInput, withTheme} from 'react-native-paper';
import ConnectionManager from "../../managers/ConnectionManager";
import i18n from 'i18n-js';
import ErrorDialog from "../../components/Dialogs/ErrorDialog";
import type {CustomTheme} from "../../managers/ThemeManager";
import AsyncStorageManager from "../../managers/AsyncStorageManager";
import {StackNavigationProp} from "@react-navigation/stack";
import AvailableWebsites from "../../constants/AvailableWebsites";
import {MASCOT_STYLE} from "../../components/Mascot/Mascot";
import MascotPopup from "../../components/Mascot/MascotPopup";
import LinearGradient from "react-native-linear-gradient";
import CollapsibleScrollView from "../../components/Collapsible/CollapsibleScrollView";

type Props = {
    navigation: StackNavigationProp,
    route: { params: { nextScreen: string } },
    theme: CustomTheme
}

type State = {
    email: string,
    password: string,
    isEmailValidated: boolean,
    isPasswordValidated: boolean,
    loading: boolean,
    dialogVisible: boolean,
    dialogError: number,
    mascotDialogVisible: boolean,
}

const ICON_AMICALE = require('../../../assets/amicale.png');

const RESET_PASSWORD_PATH = "https://www.amicale-insat.fr/password/reset";

const emailRegex = /^.+@.+\..+$/;

class LoginScreen extends React.Component<Props, State> {

    state = {
        email: '',
        password: '',
        isEmailValidated: false,
        isPasswordValidated: false,
        loading: false,
        dialogVisible: false,
        dialogError: 0,
        mascotDialogVisible: AsyncStorageManager.getInstance().preferences.loginShowBanner.current === "1"
    };

    onEmailChange: (value: string) => null;
    onPasswordChange: (value: string) => null;
    passwordInputRef: { current: null | TextInput };

    nextScreen: string | null;

    constructor(props) {
        super(props);
        this.passwordInputRef = React.createRef();
        this.onEmailChange = this.onInputChange.bind(this, true);
        this.onPasswordChange = this.onInputChange.bind(this, false);
        this.props.navigation.addListener('focus', this.onScreenFocus);
    }

    onScreenFocus = () => {
        this.handleNavigationParams();
    };

    /**
     * Saves the screen to navigate to after a successful login if one was provided in navigation parameters
     */
    handleNavigationParams() {
        if (this.props.route.params != null) {
            if (this.props.route.params.nextScreen != null)
                this.nextScreen = this.props.route.params.nextScreen;
            else
                this.nextScreen = null;
        }
    }

    hideMascotDialog = () => {
        AsyncStorageManager.getInstance().savePref(
            AsyncStorageManager.getInstance().preferences.loginShowBanner.key,
            '0'
        );
        this.setState({mascotDialogVisible: false})
    };

    showMascotDialog = () => {
        this.setState({mascotDialogVisible: true})
    };

    /**
     * Shows an error dialog with the corresponding login error
     *
     * @param error The error given by the login request
     */
    showErrorDialog = (error: number) =>
        this.setState({
            dialogVisible: true,
            dialogError: error,
        });

    hideErrorDialog = () => this.setState({dialogVisible: false});

    /**
     * Navigates to the screen specified in navigation parameters or simply go back tha stack.
     * Saves in user preferences to not show the login banner again.
     */
    handleSuccess = () => {
        // Do not show the login banner again
        AsyncStorageManager.getInstance().savePref(
            AsyncStorageManager.getInstance().preferences.homeShowBanner.key,
            '0'
        );
        if (this.nextScreen == null)
            this.props.navigation.goBack();
        else
            this.props.navigation.replace(this.nextScreen);
    };

    /**
     * Navigates to the Amicale website screen with the reset password link as navigation parameters
     */
    onResetPasswordClick = () => this.props.navigation.navigate("website", {
        host: AvailableWebsites.websites.AMICALE,
        path: RESET_PASSWORD_PATH,
        title: i18n.t('screens.websites.amicale')
    });

    /**
     * The user has unfocused the input, his email is ready to be validated
     */
    validateEmail = () => this.setState({isEmailValidated: true});

    /**
     * Checks if the entered email is valid (matches the regex)
     *
     * @returns {boolean}
     */
    isEmailValid() {
        return emailRegex.test(this.state.email);
    }

    /**
     * Checks if we should tell the user his email is invalid.
     * We should only show this if his email is invalid and has been checked when un-focusing the input
     *
     * @returns {boolean|boolean}
     */
    shouldShowEmailError() {
        return this.state.isEmailValidated && !this.isEmailValid();
    }

    /**
     * The user has unfocused the input, his password is ready to be validated
     */
    validatePassword = () => this.setState({isPasswordValidated: true});

    /**
     * Checks if the user has entered a password
     *
     * @returns {boolean}
     */
    isPasswordValid() {
        return this.state.password !== '';
    }

    /**
     * Checks if we should tell the user his password is invalid.
     * We should only show this if his password is invalid and has been checked when un-focusing the input
     *
     * @returns {boolean|boolean}
     */
    shouldShowPasswordError() {
        return this.state.isPasswordValidated && !this.isPasswordValid();
    }

    /**
     * If the email and password are valid, and we are not loading a request, then the login button can be enabled
     *
     * @returns {boolean}
     */
    shouldEnableLogin() {
        return this.isEmailValid() && this.isPasswordValid() && !this.state.loading;
    }

    /**
     * Called when the user input changes in the email or password field.
     * This saves the new value in the State and disabled input validation (to prevent errors to show while typing)
     *
     * @param isEmail True if the field is the email field
     * @param value The new field value
     */
    onInputChange(isEmail: boolean, value: string) {
        if (isEmail) {
            this.setState({
                email: value,
                isEmailValidated: false,
            });
        } else {
            this.setState({
                password: value,
                isPasswordValidated: false,
            });
        }
    }

    /**
     * Focuses the password field when the email field is done
     *
     * @returns {*}
     */
    onEmailSubmit = () => {
        if (this.passwordInputRef.current != null)
            this.passwordInputRef.current.focus();
    }

    /**
     * Called when the user clicks on login or finishes to type his password.
     *
     * Checks if we should allow the user to login,
     * then makes the login request and enters a loading state until the request finishes
     *
     */
    onSubmit = () => {
        if (this.shouldEnableLogin()) {
            this.setState({loading: true});
            ConnectionManager.getInstance().connect(this.state.email, this.state.password)
                .then(this.handleSuccess)
                .catch(this.showErrorDialog)
                .finally(() => {
                    this.setState({loading: false});
                });
        }
    };

    /**
     * Gets the form input
     *
     * @returns {*}
     */
    getFormInput() {
        return (
            <View>
                <TextInput
                    label={i18n.t("screens.login.email")}
                    mode='outlined'
                    value={this.state.email}
                    onChangeText={this.onEmailChange}
                    onBlur={this.validateEmail}
                    onSubmitEditing={this.onEmailSubmit}
                    error={this.shouldShowEmailError()}
                    textContentType={'emailAddress'}
                    autoCapitalize={'none'}
                    autoCompleteType={'email'}
                    autoCorrect={false}
                    keyboardType={'email-address'}
                    returnKeyType={'next'}
                    secureTextEntry={false}
                />
                <HelperText
                    type="error"
                    visible={this.shouldShowEmailError()}
                >
                    {i18n.t("screens.login.emailError")}
                </HelperText>
                <TextInput
                    ref={this.passwordInputRef}
                    label={i18n.t("screens.login.password")}
                    mode='outlined'
                    value={this.state.password}
                    onChangeText={this.onPasswordChange}
                    onBlur={this.validatePassword}
                    onSubmitEditing={this.onSubmit}
                    error={this.shouldShowPasswordError()}
                    textContentType={'password'}
                    autoCapitalize={'none'}
                    autoCompleteType={'password'}
                    autoCorrect={false}
                    keyboardType={'default'}
                    returnKeyType={'done'}
                    secureTextEntry={true}
                />
                <HelperText
                    type="error"
                    visible={this.shouldShowPasswordError()}
                >
                    {i18n.t("screens.login.passwordError")}
                </HelperText>
            </View>
        );
    }

    /**
     * Gets the card containing the input form
     * @returns {*}
     */
    getMainCard() {
        return (
            <View style={styles.card}>
                <Card.Title
                    title={i18n.t("screens.login.title")}
                    titleStyle={{color: "#fff"}}
                    subtitle={i18n.t("screens.login.subtitle")}
                    subtitleStyle={{color: "#fff"}}
                    left={(props) => <Image
                        {...props}
                        source={ICON_AMICALE}
                        style={{
                            width: props.size,
                            height: props.size,
                        }}/>}
                />
                <Card.Content>
                    {this.getFormInput()}
                    <Card.Actions style={{flexWrap: "wrap"}}>
                        <Button
                            icon="lock-question"
                            mode="contained"
                            onPress={this.onResetPasswordClick}
                            color={this.props.theme.colors.warning}
                            style={{marginRight: 'auto', marginBottom: 20}}>
                            {i18n.t("screens.login.resetPassword")}
                        </Button>
                        <Button
                            icon="send"
                            mode="contained"
                            disabled={!this.shouldEnableLogin()}
                            loading={this.state.loading}
                            onPress={this.onSubmit}
                            style={{marginLeft: 'auto'}}>
                            {i18n.t("screens.login.title")}
                        </Button>

                    </Card.Actions>
                    <Card.Actions>
                        <Button
                            icon="help-circle"
                            mode="contained"
                            onPress={this.showMascotDialog}
                            style={{
                                marginLeft: 'auto',
                                marginRight: 'auto',
                            }}>
                            {i18n.t("screens.login.mascotDialog.title")}
                        </Button>
                    </Card.Actions>
                </Card.Content>
            </View>
        );
    }

    render() {
        return (
            <LinearGradient
                style={{
                    height: "100%"
                }}
                colors={['#9e0d18', '#530209']}
                start={{x: 0, y: 0.1}}
                end={{x: 0.1, y: 1}}>
                <KeyboardAvoidingView
                    behavior={"height"}
                    contentContainerStyle={styles.container}
                    style={styles.container}
                    enabled
                    keyboardVerticalOffset={100}
                >
                    <CollapsibleScrollView>
                        <View style={{height: "100%"}}>
                            {this.getMainCard()}
                        </View>
                        <MascotPopup
                            visible={this.state.mascotDialogVisible}
                            title={i18n.t("screens.login.mascotDialog.title")}
                            message={i18n.t("screens.login.mascotDialog.message")}
                            icon={"help"}
                            buttons={{
                                action: null,
                                cancel: {
                                    message: i18n.t("screens.login.mascotDialog.button"),
                                    icon: "check",
                                    onPress: this.hideMascotDialog,
                                }
                            }}
                            emotion={MASCOT_STYLE.NORMAL}
                        />
                        <ErrorDialog
                            visible={this.state.dialogVisible}
                            onDismiss={this.hideErrorDialog}
                            errorCode={this.state.dialogError}
                        />
                    </CollapsibleScrollView>
                </KeyboardAvoidingView>
            </LinearGradient>
        );
    }
}

const styles = StyleSheet.create({
    container: {
        flex: 1,
    },
    card: {
        marginTop: 'auto',
        marginBottom: 'auto',
    },
    header: {
        fontSize: 36,
        marginBottom: 48
    },
    textInput: {},
    btnContainer: {
        marginTop: 5,
        marginBottom: 10,
    }
});

export default withTheme(LoginScreen);