import {loadCustomScript} from "@paypal/paypal-js";
import GooglepayButton from "./GooglepayButton";
import merge from "deepmerge";
import widgetBuilder from "../../../ppcp-button/resources/js/modules/Renderer/WidgetBuilder";

/**
 * Button manager instance; we usually only need a single instance of this object.
 *
 * @see buttonManager()
 */
let managerInstance = null;

/**
 * Default attributes for new buttons.
 */
const defaultAttributes = {
    button: {
        style: {
            type: 'pay',
            color: 'black',
            language: 'en'
        }
    }
};

/**
 * Accessor that creates and returns a single PreviewButtonManager instance.
 */
const buttonManager = () => {
    if (!managerInstance) {
        managerInstance = new PreviewButtonManager({
            // Internal, for logging.
            name: 'GooglePay',
            // WooCommerce configuration object.
            buttonConfig: window.wc_ppcp_googlepay_admin,
            // Internal widgetBuilder instance.
            widgetBuilder,
            // Default button styles.
            defaultAttributes,
            // Returns an async function that fetches the button configuration.
            cbFetchConfig: () => widgetBuilder?.paypal?.Googlepay()?.config,
            // Returns the CSS selector to render the given button.
            cbInitButton: (button) => {
                button.selector = `${button.wrapper}GooglePay`
                button.customClasses = 'ppcp-button-googlepay'
            }
        });
    }

    return managerInstance;
}


// ----------------------------------------------------------------------------


/**
 * Returns a new object which contains a copy of all public properties of the
 * input object.
 */
const cloneObject = obj => JSON.parse(JSON.stringify(obj));

/**
 * Convenience function to attach an event handler to the document node.
 * The callback handler will not receive the first argument (event), as this
 * argument is not used by our module.
 */
const onDocumentEvent = (name, handler) => jQuery(document).on(name, (ev, ...args) => handler(...args));


// ----------------------------------------------------------------------------


/**
 * A single GooglePay preview button instance.
 */
class PreviewButton {
    constructor({wrapperSelector, configResponse, defaultAttributes, cbInitButton}) {
        // Do not clone this object. It's generated by an API and might contain methods.
        this.configResponse = configResponse;

        this.defaultAttributes = cloneObject(defaultAttributes);
        this.buttonConfig = {};
        this.ppcpConfig = {};

        this.wrapper = wrapperSelector;
        this.selector = wrapperSelector + 'Button';
        this.customClasses = '';

        cbInitButton(this);

        this.domWrapper = jQuery(this.selector);
        this.payButton = null;
    }

    createNewWrapper() {
        const previewId = this.selector.replace('#', '')
        const previewClass = `ppcp-button-apm ${this.customClasses}`;

        return jQuery(`<div id="${previewId}" class="${previewClass}">`)
    }

    config(buttonConfig, ppcpConfig) {
        if (ppcpConfig) {
            this.ppcpConfig = cloneObject(ppcpConfig);
        }

        if (buttonConfig) {
            this.buttonConfig = merge(this.defaultAttributes, buttonConfig)
            this.buttonConfig.button.wrapper = this.selector
        }

        return this;
    }

    render() {
        this.remove();

        const newDomWrapper = this.createNewWrapper();

        if (this.domWrapper?.length) {
            this.domWrapper.replaceWith(newDomWrapper);
        } else {
            jQuery(this.ppcpConfig.button.wrapper).after(newDomWrapper);
        }
        this.domWrapper = newDomWrapper;

        this.payButton = new GooglepayButton(
            'preview',
            null,
            this.buttonConfig,
            this.ppcpConfig,
        );

        this.payButton.init(this.configResponse);
        return this;
    }

    remove() {
        // The payButton has no remove/cleanup function.
        this.payButton = null;

        if (this.domWrapper) {
            this.domWrapper.remove();
            this.domWrapper = null;
        }
    }
}

// ----------------------------------------------------------------------------

/**
 * Manages all GooglePay preview buttons on this page.
 */
class PreviewButtonManager {
    constructor({
        name,
        buttonConfig,
        widgetBuilder,
        defaultAttributes,
        cbFetchConfig,
        cbInitButton
    }) {
        this.name = name;
        this.buttonConfig = buttonConfig;
        this.widgetBuilder = widgetBuilder;
        this.defaultAttributes = defaultAttributes;
        this.cbInitButton = cbInitButton;
        this.cbFetchConfig = cbFetchConfig;

        this.state = 'enabled'
        this.buttons = {};
        this.configResponse = null;

        // Empty promise that resolves instantly when called.
        this.bootstrapping = Promise.resolve();

        // Add the bootstrap logic to the Promise chain. More `then`s are added by createButton().
        this.bootstrapping = this.bootstrapping.then(() => this.bootstrap());

        this.registerEventListeners();
    }

    registerEventListeners() {
        onDocumentEvent('ppcp_paypal_render_preview', this.createButton.bind(this));
        onDocumentEvent('DOMContentLoaded', () => this.bootstrapping);
    }

    /**
     * Output an error message to the console, with a module-specific prefix.
     */
    error(message, ...args) {
        console.error(`${this.name} ${message}`, ...args)
    }

    /**
     * Load dependencies and bootstrap the module.
     * Returns a Promise that resolves once all dependencies were loaded and the module can be
     * used without limitation.
     *
     * @return {Promise<void>}
     */
    async bootstrap() {
        if (!this.buttonConfig || !this.widgetBuilder) {
            this.error('Button could not be configured.');
            return;
        }

        // Load the custom SDK script.
        const customScriptPromise = loadCustomScript({url: this.buttonConfig.sdk_url});

        // Wait until PayPal is ready.
        const paypalPromise = new Promise(resolve => {
            if (this.widgetBuilder.paypal) {
                resolve();
            } else {
                onDocumentEvent('ppcp-paypal-loaded', resolve);
            }
        });

        await Promise.all([customScriptPromise, paypalPromise]);

        const fetchConfig = this.cbFetchConfig()
        if (!fetchConfig) {
            this.error('Button could not be initialized');
            return;
        }

        this.configResponse = await fetchConfig();
    }

    /**
     * Creates a new preview button, that is rendered once the bootstrapping Promise resolves.
     */
    createButton(ppcpConfig) {
        if (!ppcpConfig.button.wrapper) {
            this.error('Button did not provide a selector', ppcpConfig)
            return;
        }

        const wrapper = ppcpConfig.button.wrapper;

        const createButtonInst = () => {
            if (!this.buttons[wrapper]) {
                this.buttons[wrapper] = new PreviewButton({
                    wrapperSelector: wrapper,
                    configResponse: this.configResponse,
                    defaultAttributes: this.defaultAttributes,
                    cbInitButton: this.cbInitButton
                });
            }

            this.buttons[wrapper].config(
                this.buttonConfig,
                ppcpConfig
            ).render()
        }

        if (this.bootstrapping) {
            this.bootstrapping.then(createButtonInst);
        } else {
            createButtonInst();
        }
    }

    /**
     * Changes the button configuration, and re-renders all buttons.
     */
    updateConfig(newConfig) {
        if (!newConfig || 'object' !== typeof newConfig) {
            return;
        }

        this.buttonConfig = merge(this.buttonConfig, newConfig)

        Object.values(this.buttons).forEach(button => button.config(this.buttonConfig))
        this.renderButtons()
    }


    /**
     * Refreshes all buttons using the latest buttonConfig.
     */
    renderButtons() {
        if ('enabled' === this.state) {
            Object.values(this.buttons).forEach(button => button.render())
        } else {
            Object.values(this.buttons).forEach(button => button.remove())
        }
    }

    /**
     * Enables this payment method, which re-creates or refreshes all buttons.
     */
    enable() {
        if ('enabled' === this.state) {
            return;
        }
        this.state = 'enabled';
        this.renderButtons()
    }

    /**
     * Disables this payment method, effectively removing all preview buttons.
     */
    disable() {
        if ('disabled' === this.state) {
            return;
        }

        this.state = 'disabled';
        this.renderButtons()
    }
}

// Initialize the preview button manager.
buttonManager().enable()

// todo - Expose button manager for testing. Remove this!
window.gpay = buttonManager()


/**

(function ({
   buttonConfig,
   jQuery
}) {

    let googlePayConfig;
    let buttonQueue = [];
    let activeButtons = {};
    let bootstrapped = false;

    // React to PayPal config changes.
    jQuery(document).on('ppcp_paypal_render_preview', (ev, ppcpConfig) => {
        if (bootstrapped) {
            createButton(ppcpConfig);
        } else {
            buttonQueue.push({
                ppcpConfig: JSON.parse(JSON.stringify(ppcpConfig))
            });
        }
    });

    // React to GooglePay config changes.
    jQuery([
        '#ppcp-googlepay_button_enabled',
        '#ppcp-googlepay_button_type',
        '#ppcp-googlepay_button_color',
        '#ppcp-googlepay_button_language',
        '#ppcp-googlepay_button_shipping_enabled'
    ].join(',')).on('change', () => {
        for (const [selector, ppcpConfig] of Object.entries(activeButtons)) {
            createButton(ppcpConfig);
        }
    });

    // Maybe we can find a more elegant reload method when transitioning from styling modes.
    jQuery([
        '#ppcp-smart_button_enable_styling_per_location'
    ].join(',')).on('change', () => {
        setTimeout(() => {
            for (const [selector, ppcpConfig] of Object.entries(activeButtons)) {
                createButton(ppcpConfig);
            }
        }, 100);
    });

    const shouldDisplayPreviewButton = function() {
        // TODO - original condition, which is wrong.
        return jQuery('#ppcp-googlepay_button_enabled').is(':checked');
    }

    const applyConfigOptions = function (buttonConfig) {
        buttonConfig.button = buttonConfig.button || {};
        buttonConfig.button.style = buttonConfig.button.style || {};
        buttonConfig.button.style.type = jQuery('#ppcp-googlepay_button_type').val();
        buttonConfig.button.style.color = jQuery('#ppcp-googlepay_button_color').val();
        buttonConfig.button.style.language = jQuery('#ppcp-googlepay_button_language').val();
    }

    const createButton = function (ppcpConfig) {
        const selector = ppcpConfig.button.wrapper + 'GooglePay';

        if (!shouldDisplayPreviewButton()) {
            jQuery(selector).remove();
            return;
        }

        buttonConfig = JSON.parse(JSON.stringify(buttonConfig));
        buttonConfig.button.wrapper = selector;
        applyConfigOptions(buttonConfig);

        const wrapperElement = `<div id="${selector.replace('#', '')}" class="ppcp-button-apm ppcp-button-googlepay"></div>`;

        if (!jQuery(selector).length) {
            jQuery(ppcpConfig.button.wrapper).after(wrapperElement);
        } else {
            jQuery(selector).replaceWith(wrapperElement);
        }

        const button = new GooglepayButton(
            'preview',
            null,
            buttonConfig,
            ppcpConfig,
        );

        button.init(googlePayConfig);

        activeButtons[selector] = ppcpConfig;
    }

    const bootstrap = async function () {
        if (!widgetBuilder.paypal) {
            return;
        }

        googlePayConfig = await widgetBuilder.paypal.Googlepay().config();

        // We need to set bootstrapped here otherwise googlePayConfig may not be set.
        bootstrapped = true;

        let options;
        while (options = buttonQueue.pop()) {
            createButton(options.ppcpConfig);
        }
    };

    document.addEventListener(
        'DOMContentLoaded',
        () => {

            if (typeof (buttonConfig) === 'undefined') {
                console.error('PayPal button could not be configured.');
                return;
            }

            let paypalLoaded = false;
            let googlePayLoaded = false;

            const tryToBoot = () => {
                if (!bootstrapped && paypalLoaded && googlePayLoaded) {
                    bootstrap();
                }
            }

            // Load GooglePay SDK
            loadCustomScript({ url: buttonConfig.sdk_url }).then(() => {
                googlePayLoaded = true;
                tryToBoot();
            });

            // Wait for PayPal to be loaded externally
            if (typeof widgetBuilder.paypal !== 'undefined') {
                paypalLoaded = true;
                tryToBoot();
            }

            jQuery(document).on('ppcp-paypal-loaded', () => {
                paypalLoaded = true;
                tryToBoot();
            });
        },
    );

})({
    buttonConfig: window.wc_ppcp_googlepay_admin,
    jQuery: window.jQuery
});

// */