/*
 * Copyright (C) 2016-2017  Alex Yatskov <alex@foosoft.net>
 * Author: Alex Yatskov <alex@foosoft.net>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

async function getOptionsArray() {
    const optionsFull = await apiOptionsGetFull();
    return optionsFull.profiles.map(profile => profile.options);
}

async function formRead(options) {
    options.general.enable = $('#enable').prop('checked');
    options.general.showGuide = $('#show-usage-guide').prop('checked');
    options.general.compactTags = $('#compact-tags').prop('checked');
    options.general.compactGlossaries = $('#compact-glossaries').prop('checked');
    options.general.resultOutputMode = $('#result-output-mode').val();
    options.general.debugInfo = $('#show-debug-info').prop('checked');
    options.general.showAdvanced = $('#show-advanced-options').prop('checked');
    options.general.maxResults = parseInt($('#max-displayed-results').val(), 10);
    options.general.popupDisplayMode = $('#popup-display-mode').val();
    options.general.popupHorizontalTextPosition = $('#popup-horizontal-text-position').val();
    options.general.popupVerticalTextPosition = $('#popup-vertical-text-position').val();
    options.general.popupWidth = parseInt($('#popup-width').val(), 10);
    options.general.popupHeight = parseInt($('#popup-height').val(), 10);
    options.general.popupHorizontalOffset = parseInt($('#popup-horizontal-offset').val(), 0);
    options.general.popupVerticalOffset = parseInt($('#popup-vertical-offset').val(), 10);
    options.general.popupHorizontalOffset2 = parseInt($('#popup-horizontal-offset2').val(), 0);
    options.general.popupVerticalOffset2 = parseInt($('#popup-vertical-offset2').val(), 10);
    options.general.popupTheme = $('#popup-theme').val();
    options.general.popupOuterTheme = $('#popup-outer-theme').val();
    options.general.customPopupCss = $('#custom-popup-css').val();
    options.general.customPopupOuterCss = $('#custom-popup-outer-css').val();

    options.audio.enabled = $('#audio-playback-enabled').prop('checked');
    options.audio.autoPlay = $('#auto-play-audio').prop('checked');
    options.audio.volume = parseFloat($('#audio-playback-volume').val());
    options.audio.customSourceUrl = $('#audio-custom-source').val();
    options.audio.textToSpeechVoice = $('#text-to-speech-voice').val();

    options.scanning.middleMouse = $('#middle-mouse-button-scan').prop('checked');
    options.scanning.touchInputEnabled = $('#touch-input-enabled').prop('checked');
    options.scanning.selectText = $('#select-matched-text').prop('checked');
    options.scanning.alphanumeric = $('#search-alphanumeric').prop('checked');
    options.scanning.autoHideResults = $('#auto-hide-results').prop('checked');
    options.scanning.deepDomScan = $('#deep-dom-scan').prop('checked');
    options.scanning.enablePopupSearch = $('#enable-search-within-first-popup').prop('checked');
    options.scanning.enableOnPopupExpressions = $('#enable-scanning-of-popup-expressions').prop('checked');
    options.scanning.enableOnSearchPage = $('#enable-scanning-on-search-page').prop('checked');
    options.scanning.delay = parseInt($('#scan-delay').val(), 10);
    options.scanning.length = parseInt($('#scan-length').val(), 10);
    options.scanning.modifier = $('#scan-modifier-key').val();
    options.scanning.popupNestingMaxDepth = parseInt($('#popup-nesting-max-depth').val(), 10);

    options.parsing.enableScanningParser = $('#parsing-scan-enable').prop('checked');
    options.parsing.enableMecabParser = $('#parsing-mecab-enable').prop('checked');
    options.parsing.readingMode = $('#parsing-reading-mode').val();

    const optionsAnkiEnableOld = options.anki.enable;
    options.anki.enable = $('#anki-enable').prop('checked');
    options.anki.tags = utilBackgroundIsolate($('#card-tags').val().split(/[,; ]+/));
    options.anki.sentenceExt = parseInt($('#sentence-detection-extent').val(), 10);
    options.anki.server = $('#interface-server').val();
    options.anki.screenshot.format = $('#screenshot-format').val();
    options.anki.screenshot.quality = parseInt($('#screenshot-quality').val(), 10);
    options.anki.fieldTemplates = $('#field-templates').val();

    if (optionsAnkiEnableOld && !ankiErrorShown()) {
        options.anki.terms.deck = $('#anki-terms-deck').val();
        options.anki.terms.model = $('#anki-terms-model').val();
        options.anki.terms.fields = utilBackgroundIsolate(ankiFieldsToDict($('#terms .anki-field-value')));
        options.anki.kanji.deck = $('#anki-kanji-deck').val();
        options.anki.kanji.model = $('#anki-kanji-model').val();
        options.anki.kanji.fields = utilBackgroundIsolate(ankiFieldsToDict($('#kanji .anki-field-value')));
    }
}

async function formWrite(options) {
    $('#enable').prop('checked', options.general.enable);
    $('#show-usage-guide').prop('checked', options.general.showGuide);
    $('#compact-tags').prop('checked', options.general.compactTags);
    $('#compact-glossaries').prop('checked', options.general.compactGlossaries);
    $('#result-output-mode').val(options.general.resultOutputMode);
    $('#show-debug-info').prop('checked', options.general.debugInfo);
    $('#show-advanced-options').prop('checked', options.general.showAdvanced);
    $('#max-displayed-results').val(options.general.maxResults);
    $('#popup-display-mode').val(options.general.popupDisplayMode);
    $('#popup-horizontal-text-position').val(options.general.popupHorizontalTextPosition);
    $('#popup-vertical-text-position').val(options.general.popupVerticalTextPosition);
    $('#popup-width').val(options.general.popupWidth);
    $('#popup-height').val(options.general.popupHeight);
    $('#popup-horizontal-offset').val(options.general.popupHorizontalOffset);
    $('#popup-vertical-offset').val(options.general.popupVerticalOffset);
    $('#popup-horizontal-offset2').val(options.general.popupHorizontalOffset2);
    $('#popup-vertical-offset2').val(options.general.popupVerticalOffset2);
    $('#popup-theme').val(options.general.popupTheme);
    $('#popup-outer-theme').val(options.general.popupOuterTheme);
    $('#custom-popup-css').val(options.general.customPopupCss);
    $('#custom-popup-outer-css').val(options.general.customPopupOuterCss);

    $('#audio-playback-enabled').prop('checked', options.audio.enabled);
    $('#auto-play-audio').prop('checked', options.audio.autoPlay);
    $('#audio-playback-volume').val(options.audio.volume);
    $('#audio-custom-source').val(options.audio.customSourceUrl);
    $('#text-to-speech-voice').val(options.audio.textToSpeechVoice).attr('data-value', options.audio.textToSpeechVoice);

    $('#middle-mouse-button-scan').prop('checked', options.scanning.middleMouse);
    $('#touch-input-enabled').prop('checked', options.scanning.touchInputEnabled);
    $('#select-matched-text').prop('checked', options.scanning.selectText);
    $('#search-alphanumeric').prop('checked', options.scanning.alphanumeric);
    $('#auto-hide-results').prop('checked', options.scanning.autoHideResults);
    $('#deep-dom-scan').prop('checked', options.scanning.deepDomScan);
    $('#enable-search-within-first-popup').prop('checked', options.scanning.enablePopupSearch);
    $('#enable-scanning-of-popup-expressions').prop('checked', options.scanning.enableOnPopupExpressions);
    $('#enable-scanning-on-search-page').prop('checked', options.scanning.enableOnSearchPage);
    $('#scan-delay').val(options.scanning.delay);
    $('#scan-length').val(options.scanning.length);
    $('#scan-modifier-key').val(options.scanning.modifier);
    $('#popup-nesting-max-depth').val(options.scanning.popupNestingMaxDepth);

    $('#parsing-scan-enable').prop('checked', options.parsing.enableScanningParser);
    $('#parsing-mecab-enable').prop('checked', options.parsing.enableMecabParser);
    $('#parsing-reading-mode').val(options.parsing.readingMode);

    $('#anki-enable').prop('checked', options.anki.enable);
    $('#card-tags').val(options.anki.tags.join(' '));
    $('#sentence-detection-extent').val(options.anki.sentenceExt);
    $('#interface-server').val(options.anki.server);
    $('#screenshot-format').val(options.anki.screenshot.format);
    $('#screenshot-quality').val(options.anki.screenshot.quality);
    $('#field-templates').val(options.anki.fieldTemplates);

    onAnkiTemplatesValidateCompile();
    await onDictionaryOptionsChanged(options);

    try {
        await ankiDeckAndModelPopulate(options);
    } catch (e) {
        ankiErrorShow(e);
    }

    formUpdateVisibility(options);
}

function formSetupEventListeners() {
    $('input, select, textarea').not('.anki-model').not('.ignore-form-changes *').change((e) => onFormOptionsChanged(e));
    $('.anki-model').change((e) => onAnkiModelChanged(e));
}

function formUpdateVisibility(options) {
    document.documentElement.dataset.optionsAnkiEnable = `${!!options.anki.enable}`;
    document.documentElement.dataset.optionsGeneralDebugInfo = `${!!options.general.debugInfo}`;
    document.documentElement.dataset.optionsGeneralShowAdvanced = `${!!options.general.showAdvanced}`;
    document.documentElement.dataset.optionsGeneralResultOutputMode = `${options.general.resultOutputMode}`;

    if (options.general.debugInfo) {
        const temp = utilIsolate(options);
        temp.anki.fieldTemplates = '...';
        const text = JSON.stringify(temp, null, 4);
        $('#debug').text(text);
    }
}

async function onFormOptionsChanged(e) {
    if (!e.originalEvent && !e.isTrigger) {
        return;
    }

    const optionsContext = getOptionsContext();
    const options = await apiOptionsGet(optionsContext);
    const optionsAnkiEnableOld = options.anki.enable;
    const optionsAnkiServerOld = options.anki.server;

    await formRead(options);
    await settingsSaveOptions();
    formUpdateVisibility(options);

    try {
        const ankiUpdated =
            options.anki.enable !== optionsAnkiEnableOld ||
            options.anki.server !== optionsAnkiServerOld;

        if (ankiUpdated) {
            ankiSpinnerShow(true);
            await ankiDeckAndModelPopulate(options);
            ankiErrorShow();
        }
    } catch (error) {
        ankiErrorShow(error);
    } finally {
        ankiSpinnerShow(false);
    }
}

async function onReady() {
    showExtensionInformation();

    formSetupEventListeners();
    appearanceInitialize();
    await audioSettingsInitialize();
    await profileOptionsSetup();
    await dictSettingsInitialize();
    ankiTemplatesInitialize();

    storageInfoInitialize();

    chrome.runtime.onMessage.addListener(onMessage);
}

$(document).ready(() => onReady());


/*
 * Page exit prevention
 */

class PageExitPrevention {
    constructor() {
    }

    start() {
        PageExitPrevention._addInstance(this);
    }

    end() {
        PageExitPrevention._removeInstance(this);
    }

    static _addInstance(instance) {
        const size = PageExitPrevention._instances.size;
        PageExitPrevention._instances.set(instance, true);
        if (size === 0) {
            window.addEventListener('beforeunload', PageExitPrevention._onBeforeUnload);
        }
    }

    static _removeInstance(instance) {
        if (
            PageExitPrevention._instances.delete(instance) &&
            PageExitPrevention._instances.size === 0
        ) {
            window.removeEventListener('beforeunload', PageExitPrevention._onBeforeUnload);
        }
    }

    static _onBeforeUnload(e) {
        if (PageExitPrevention._instances.size === 0) {
            return;
        }

        e.preventDefault();
        e.returnValue = '';
        return '';
    }
}
PageExitPrevention._instances = new Map();


/*
 * Appearance
 */

function appearanceInitialize() {
    let previewVisible = false;
    $('#settings-popup-preview-button').on('click', () => {
        if (previewVisible) { return; }
        showAppearancePreview();
        previewVisible = true;
    });
}

function showAppearancePreview() {
    const container = $('#settings-popup-preview-container');
    const buttonContainer = $('#settings-popup-preview-button-container');
    const settings = $('#settings-popup-preview-settings');
    const text = $('#settings-popup-preview-text');
    const customCss = $('#custom-popup-css');
    const customOuterCss = $('#custom-popup-outer-css');

    const frame = document.createElement('iframe');
    frame.src = '/bg/settings-popup-preview.html';
    frame.id = 'settings-popup-preview-frame';

    window.wanakana.bind(text[0]);

    text.on('input', () => {
        const action = 'setText';
        const params = {text: text.val()};
        frame.contentWindow.postMessage({action, params}, '*');
    });
    customCss.on('input', () => {
        const action = 'setCustomCss';
        const params = {css: customCss.val()};
        frame.contentWindow.postMessage({action, params}, '*');
    });
    customOuterCss.on('input', () => {
        const action = 'setCustomOuterCss';
        const params = {css: customOuterCss.val()};
        frame.contentWindow.postMessage({action, params}, '*');
    });

    container.append(frame);
    buttonContainer.remove();
    settings.css('display', '');
}


/*
 * Audio
 */

let audioSourceUI = null;

async function audioSettingsInitialize() {
    const optionsContext = getOptionsContext();
    const options = await apiOptionsGet(optionsContext);
    audioSourceUI = new AudioSourceUI.Container(options.audio.sources, $('.audio-source-list'), $('.audio-source-add'));
    audioSourceUI.save = () => settingsSaveOptions();

    textToSpeechInitialize();
}

function textToSpeechInitialize() {
    if (typeof speechSynthesis === 'undefined') { return; }

    speechSynthesis.addEventListener('voiceschanged', () => updateTextToSpeechVoices(), false);
    updateTextToSpeechVoices();

    $('#text-to-speech-voice-test').on('click', () => textToSpeechTest());
}

function updateTextToSpeechVoices() {
    const voices = Array.prototype.map.call(speechSynthesis.getVoices(), (voice, index) => ({voice, index}));
    voices.sort(textToSpeechVoiceCompare);
    if (voices.length > 0) {
        $('#text-to-speech-voice-container').css('display', '');
    }

    const select = $('#text-to-speech-voice');
    select.empty();
    select.append($('<option>').val('').text('None'));
    for (const {voice} of voices) {
        select.append($('<option>').val(voice.voiceURI).text(`${voice.name} (${voice.lang})`));
    }

    select.val(select.attr('data-value'));
}

function languageTagIsJapanese(languageTag) {
    return (
        languageTag.startsWith('ja-') ||
        languageTag.startsWith('jpn-')
    );
}

function textToSpeechVoiceCompare(a, b) {
    const aIsJapanese = languageTagIsJapanese(a.voice.lang);
    const bIsJapanese = languageTagIsJapanese(b.voice.lang);
    if (aIsJapanese) {
        if (!bIsJapanese) { return -1; }
    } else {
        if (bIsJapanese) { return 1; }
    }

    const aIsDefault = a.voice.default;
    const bIsDefault = b.voice.default;
    if (aIsDefault) {
        if (!bIsDefault) { return -1; }
    } else {
        if (bIsDefault) { return 1; }
    }

    if (a.index < b.index) { return -1; }
    if (a.index > b.index) { return 1; }
    return 0;
}

function textToSpeechTest() {
    try {
        const text = $('#text-to-speech-voice-test').attr('data-speech-text') || '';
        const voiceURI = $('#text-to-speech-voice').val();
        const voice = audioGetTextToSpeechVoice(voiceURI);
        if (voice === null) { return; }

        const utterance = new SpeechSynthesisUtterance(text);
        utterance.lang = 'ja-JP';
        utterance.voice = voice;
        utterance.volume = 1.0;

        speechSynthesis.speak(utterance);
    } catch (e) {
        // NOP
    }
}


/*
 * Remote options updates
 */

function settingsGetSource() {
    return new Promise((resolve) => {
        chrome.tabs.getCurrent((tab) => resolve(`settings${tab ? tab.id : ''}`));
    });
}

async function settingsSaveOptions() {
    const source = await settingsGetSource();
    await apiOptionsSave(source);
}

async function onOptionsUpdate({source}) {
    const thisSource = await settingsGetSource();
    if (source === thisSource) { return; }

    const optionsContext = getOptionsContext();
    const options = await apiOptionsGet(optionsContext);
    await formWrite(options);
}

function onMessage({action, params}, sender, callback) {
    switch (action) {
        case 'optionsUpdate':
            onOptionsUpdate(params);
            break;
        case 'getUrl':
            callback({url: window.location.href});
            break;
    }
}


/*
 * Anki
 */

function ankiSpinnerShow(show) {
    const spinner = $('#anki-spinner');
    if (show) {
        spinner.show();
    } else {
        spinner.hide();
    }
}

function ankiErrorShow(error) {
    const dialog = $('#anki-error');
    if (error) {
        dialog.show().text(error);
    }
    else {
        dialog.hide();
    }
}

function ankiErrorShown() {
    return $('#anki-error').is(':visible');
}

function ankiFieldsToDict(selection) {
    const result = {};
    selection.each((index, element) => {
        result[$(element).data('field')] = $(element).val();
    });

    return result;
}

async function ankiDeckAndModelPopulate(options) {
    const ankiFormat = $('#anki-format').hide();

    const deckNames = await utilAnkiGetDeckNames();
    const ankiDeck = $('.anki-deck');
    ankiDeck.find('option').remove();
    deckNames.sort().forEach(name => ankiDeck.append($('<option/>', {value: name, text: name})));

    const modelNames = await utilAnkiGetModelNames();
    const ankiModel = $('.anki-model');
    ankiModel.find('option').remove();
    modelNames.sort().forEach(name => ankiModel.append($('<option/>', {value: name, text: name})));

    $('#anki-terms-deck').val(options.anki.terms.deck);
    await ankiFieldsPopulate($('#anki-terms-model').val(options.anki.terms.model), options);

    $('#anki-kanji-deck').val(options.anki.kanji.deck);
    await ankiFieldsPopulate($('#anki-kanji-model').val(options.anki.kanji.model), options);

    ankiFormat.show();
}

function ankiCreateFieldTemplate(name, value, markers) {
    const template = document.querySelector('#anki-field-template').content;
    const content = document.importNode(template, true).firstChild;

    content.querySelector('.anki-field-name').textContent = name;

    const field = content.querySelector('.anki-field-value');
    field.dataset.field = name;
    field.value = value;

    content.querySelector('.anki-field-marker-list').appendChild(ankiGetFieldMarkersHtml(markers));

    return content;
}

function ankiGetFieldMarkersHtml(markers, fragment) {
    const template = document.querySelector('#anki-field-marker-template').content;
    if (!fragment) {
        fragment = new DocumentFragment();
    }
    for (const marker of markers) {
        const markerNode = document.importNode(template, true).firstChild;
        markerNode.querySelector('.marker-link').textContent = marker;
        fragment.appendChild(markerNode);
    }
    return fragment;
}

function ankiGetFieldMarkers(type) {
    switch (type) {
        case 'terms':
            return [
                'audio',
                'cloze-body',
                'cloze-prefix',
                'cloze-suffix',
                'dictionary',
                'expression',
                'furigana',
                'furigana-plain',
                'glossary',
                'glossary-brief',
                'reading',
                'screenshot',
                'sentence',
                'tags',
                'url'
            ];
        case 'kanji':
            return [
                'character',
                'dictionary',
                'glossary',
                'kunyomi',
                'onyomi',
                'screenshot',
                'sentence',
                'tags',
                'url'
            ];
        default:
            return [];
    }
}

async function ankiFieldsPopulate(element, options) {
    const modelName = element.val();
    if (!modelName) {
        return;
    }

    const tab = element.closest('.tab-pane');
    const tabId = tab.attr('id');
    const container = tab.find('tbody').empty();
    const markers = ankiGetFieldMarkers(tabId);

    for (const name of await utilAnkiGetModelFieldNames(modelName)) {
        const value = options.anki[tabId].fields[name] || '';
        const html = ankiCreateFieldTemplate(name, value, markers);
        container.append($(html));
    }

    tab.find('.anki-field-value').change((e) => onFormOptionsChanged(e));
    tab.find('.marker-link').click((e) => onAnkiMarkerClicked(e));
}

function onAnkiMarkerClicked(e) {
    e.preventDefault();
    const link = e.target;
    $(link).closest('.input-group').find('.anki-field-value').val(`{${link.text}}`).trigger('change');
}

async function onAnkiModelChanged(e) {
    try {
        if (!e.originalEvent) {
            return;
        }

        const element = $(this);
        const tab = element.closest('.tab-pane');
        const tabId = tab.attr('id');

        const optionsContext = getOptionsContext();
        const options = await apiOptionsGet(optionsContext);
        await formRead(options);
        options.anki[tabId].fields = utilBackgroundIsolate({});
        await settingsSaveOptions();

        ankiSpinnerShow(true);
        await ankiFieldsPopulate(element, options);
        ankiErrorShow();
    } catch (error) {
        ankiErrorShow(error);
    } finally {
        ankiSpinnerShow(false);
    }
}

function onAnkiFieldTemplatesReset(e) {
    e.preventDefault();
    $('#field-template-reset-modal').modal('show');
}

async function onAnkiFieldTemplatesResetConfirm(e) {
    try {
        e.preventDefault();

        $('#field-template-reset-modal').modal('hide');

        const optionsContext = getOptionsContext();
        const options = await apiOptionsGet(optionsContext);
        const fieldTemplates = profileOptionsGetDefaultFieldTemplates();
        options.anki.fieldTemplates = fieldTemplates;
        $('#field-templates').val(fieldTemplates);
        onAnkiTemplatesValidateCompile();
        await settingsSaveOptions();
    } catch (error) {
        ankiErrorShow(error);
    }
}

function ankiTemplatesInitialize() {
    const markers = new Set(ankiGetFieldMarkers('terms').concat(ankiGetFieldMarkers('kanji')));
    const fragment = ankiGetFieldMarkersHtml(markers);

    const list = document.querySelector('#field-templates-list');
    list.appendChild(fragment);
    for (const node of list.querySelectorAll('.marker-link')) {
        node.addEventListener('click', onAnkiTemplateMarkerClicked, false);
    }

    $('#field-templates').on('change', (e) => onAnkiTemplatesValidateCompile(e));
    $('#field-template-render').on('click', (e) => onAnkiTemplateRender(e));
    $('#field-templates-reset').on('click', (e) => onAnkiFieldTemplatesReset(e));
    $('#field-templates-reset-confirm').on('click', (e) => onAnkiFieldTemplatesResetConfirm(e));
}

const ankiTemplatesValidateGetDefinition = (() => {
    let cachedValue = null;
    let cachedText = null;

    return async (text, optionsContext) => {
        if (cachedText !== text) {
            const {definitions} = await apiTermsFind(text, {}, optionsContext);
            if (definitions.length === 0) { return null; }

            cachedValue = definitions[0];
            cachedText = text;
        }
        return cachedValue;
    };
})();

async function ankiTemplatesValidate(infoNode, field, mode, showSuccessResult, invalidateInput) {
    const text = document.querySelector('#field-templates-preview-text').value || '';
    const exceptions = [];
    let result = `No definition found for ${text}`;
    try {
        const optionsContext = getOptionsContext();
        const definition = await ankiTemplatesValidateGetDefinition(text, optionsContext);
        if (definition !== null) {
            const options = await apiOptionsGet(optionsContext);
            result = await dictFieldFormat(field, definition, mode, options, exceptions);
        }
    } catch (e) {
        exceptions.push(e);
    }

    const hasException = exceptions.length > 0;
    infoNode.hidden = !(showSuccessResult || hasException);
    infoNode.textContent = hasException ? exceptions.map(e => `${e}`).join('\n') : (showSuccessResult ? result : '');
    infoNode.classList.toggle('text-danger', hasException);
    if (invalidateInput) {
        const input = document.querySelector('#field-templates');
        input.classList.toggle('is-invalid', hasException);
    }
}

function onAnkiTemplatesValidateCompile() {
    const infoNode = document.querySelector('#field-template-compile-result');
    ankiTemplatesValidate(infoNode, '{expression}', 'term-kanji', false, true);
}

function onAnkiTemplateMarkerClicked(e) {
    e.preventDefault();
    document.querySelector('#field-template-render-text').value = `{${e.target.textContent}}`;
}

function onAnkiTemplateRender(e) {
    e.preventDefault();

    const field = document.querySelector('#field-template-render-text').value;
    const infoNode = document.querySelector('#field-template-render-result');
    infoNode.hidden = true;
    ankiTemplatesValidate(infoNode, field, 'term-kanji', true, false);
}


/*
 * Storage
 */

function storageBytesToLabeledString(size) {
    const base = 1000;
    const labels = [' bytes', 'KB', 'MB', 'GB'];
    let labelIndex = 0;
    while (size >= base) {
        size /= base;
        ++labelIndex;
    }
    const label = labelIndex === 0 ? `${size}` : size.toFixed(1);
    return `${label}${labels[labelIndex]}`;
}

async function storageEstimate() {
    try {
        return (storageEstimate.mostRecent = await navigator.storage.estimate());
    } catch (e) { }
    return null;
}
storageEstimate.mostRecent = null;

async function isStoragePeristent() {
    try {
        return await navigator.storage.persisted();
    } catch (e) { }
    return false;
}

async function storageInfoInitialize() {
    storagePersistInitialize();
    const {browser, platform} = await apiGetEnvironmentInfo();
    document.documentElement.dataset.browser = browser;
    document.documentElement.dataset.operatingSystem = platform.os;

    await storageShowInfo();

    document.querySelector('#storage-refresh').addEventListener('click', () => storageShowInfo(), false);
}

async function storageUpdateStats() {
    storageUpdateStats.isUpdating = true;

    const estimate = await storageEstimate();
    const valid = (estimate !== null);

    if (valid) {
        // Firefox reports usage as 0 when persistent storage is enabled.
        const finite = (estimate.usage > 0 || !(await isStoragePeristent()));
        if (finite) {
            document.querySelector('#storage-usage').textContent = storageBytesToLabeledString(estimate.usage);
            document.querySelector('#storage-quota').textContent = storageBytesToLabeledString(estimate.quota);
        }
        document.querySelector('#storage-use-finite').classList.toggle('storage-hidden', !finite);
        document.querySelector('#storage-use-infinite').classList.toggle('storage-hidden', finite);
    }

    storageUpdateStats.isUpdating = false;
    return valid;
}
storageUpdateStats.isUpdating = false;

async function storageShowInfo() {
    storageSpinnerShow(true);

    const valid = await storageUpdateStats();
    document.querySelector('#storage-use').classList.toggle('storage-hidden', !valid);
    document.querySelector('#storage-error').classList.toggle('storage-hidden', valid);

    storageSpinnerShow(false);
}

function storageSpinnerShow(show) {
    const spinner = $('#storage-spinner');
    if (show) {
        spinner.show();
    } else {
        spinner.hide();
    }
}

async function storagePersistInitialize() {
    if (!(navigator.storage && navigator.storage.persist)) {
        // Not supported
        return;
    }

    const info = document.querySelector('#storage-persist-info');
    const button = document.querySelector('#storage-persist-button');
    const checkbox = document.querySelector('#storage-persist-button-checkbox');

    info.classList.remove('storage-hidden');
    button.classList.remove('storage-hidden');

    let persisted = await isStoragePeristent();
    checkbox.checked = persisted;

    button.addEventListener('click', async () => {
        if (persisted) {
            return;
        }
        let result = false;
        try {
            result = await navigator.storage.persist();
        } catch (e) {
            // NOP
        }

        if (result) {
            persisted = true;
            checkbox.checked = true;
            storageShowInfo();
        } else {
            $('.storage-persist-fail-warning').removeClass('storage-hidden');
        }
    }, false);
}


/*
 * Information
 */

function showExtensionInformation() {
    const node = document.getElementById('extension-info');
    if (node === null) { return; }

    const manifest = chrome.runtime.getManifest();
    node.textContent = `${manifest.name} v${manifest.version}`;
}