/*
 * Copyright (C) 2018 Guido Berhoerster <guido+feed-preview@berhoerster.name>
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

'use strict';

function updateFeedReaders(feedReaders) {
    let feedReaderSelectionElement = document.forms['feed-subscription']
            .elements['feed-reader-selection'];
    for (let optionElement of
            feedReaderSelectionElement.querySelectorAll('option')) {
        optionElement.remove();
    }

    for (let feedReader of feedReaders) {
        let optionElement = document.createElement('option');
        optionElement.value = feedReader.urlTemplate;
        optionElement.textContent = feedReader.title;
        feedReaderSelectionElement.append(optionElement);
    }

    document.forms['feed-subscription'].elements['main'].disabled =
            feedReaders.length === 0;
}

document.addEventListener('submit', ev => {
    if (ev.target.id !== 'feed-subscription') {
        return;
    }

    ev.preventDefault();
    let subscribeUrl = ev.target.elements['feed-reader-selection'].value
            .replace('%s', encodeURIComponent(document.documentURI));
    console.log(`subscribing to feed using ${subscribeUrl}`);
    window.location.href = subscribeUrl;
});

function onStorageChanged(changes, areaName) {
    if (areaName !== 'sync' || changes.feedReaders === 'undefined') {
        return;
    }

    // stored feed readers have been changed or deleted
    let feedReaders = typeof changes.feedReaders.newValue !== 'undefined' ?
            changes.feedReaders.newValue : [];
    console.log('feedReaders changed to', feedReaders);
    updateFeedReaders(feedReaders);
}

(async () => {
    // initialize subscription form
    let {feedReaders = []} = await browser.storage.sync.get('feedReaders');
    updateFeedReaders(feedReaders);

    browser.storage.onChanged.addListener(onStorageChanged);
})();