/**
 * uiUtil.js : Utility functions for the User Interface
 * 
 * Copyright 2013-2014 Mossroy and contributors
 * License GPL v3:
 * 
 * This file is part of Kiwix.
 * 
 * Kiwix 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.
 * 
 * Kiwix 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 Kiwix (file LICENSE-GPLv3.txt).  If not, see <http://www.gnu.org/licenses/>
 */
'use strict';
define([], function() {

    
    /**
     * Creates a Blob from the given content, then a URL from this Blob
     * And put this URL in the attribute of the DOM node
     * 
     * This is useful to inject images (and other dependencies) inside an article
     * 
     * @param {Object} jQueryNode
     * @param {String} nodeAttribute
     * @param {Uint8Array} content
     * @param {String} mimeType
     */
    function feedNodeWithBlob(jQueryNode, nodeAttribute, content, mimeType) {
        var blob = new Blob([content], {type: mimeType});
        var url = URL.createObjectURL(blob);
        jQueryNode.on('load', function () {
            URL.revokeObjectURL(url);
        });
        jQueryNode.attr(nodeAttribute, url);
    }

    /**
     * Replace the given CSS link (from the DOM) with an inline CSS of the given content
     * 
     * Due to CSP, Firefox OS does not accept <link> syntax with href="data:text/css..." or href="blob:..."
     * So we replace the tag with a <style type="text/css">...</style>
     * while copying some attributes of the original tag
     * Cf http://jonraasch.com/blog/javascript-style-node
     * 
     * @param {Element} link from the DOM
     * @param {String} cssContent
     */
    function replaceCSSLinkWithInlineCSS (link, cssContent) {
        var cssElement = document.createElement('style');
        cssElement.type = 'text/css';
        if (cssElement.styleSheet) {
            cssElement.styleSheet.cssText = cssContent;
        } else {
            cssElement.appendChild(document.createTextNode(cssContent));
        }
        var mediaAttributeValue = link.attr('media');
        if (mediaAttributeValue) {
            cssElement.media = mediaAttributeValue;
        }
        var disabledAttributeValue = link.attr('disabled');
        if (disabledAttributeValue) {
            cssElement.disabled = disabledAttributeValue;
        }
        link.replaceWith(cssElement);
    }
        
    var regexpRemoveUrlParameters = new RegExp(/([^?#]+)[?#].*$/);
    
    /**
     * Removes parameters and anchors from a URL
     * @param {type} url
     * @returns {String} same URL without its parameters and anchors
     */
    function removeUrlParameters(url) {
        return url.replace(regexpRemoveUrlParameters, "$1");
    }

    /**
     * Displays a Bootstrap warning alert with information about how to access content in a ZIM with unsupported active UI
     */
    function displayActiveContentWarning() {
        // We have to add the alert box in code, because Bootstrap removes it completely from the DOM when the user dismisses it
        var alertHTML =
            '<div id="activeContent" class="alert alert-warning alert-dismissible fade in">' +
                '<a href="#" class="close" data-dismiss="alert" aria-label="close">&times;</a>' +
                '<strong>Unable to display active content:</strong> This ZIM is not fully supported in jQuery mode.<br />' +
                'Content may be available by searching above (type a space or a letter of the alphabet), or else ' +
                '<a id="swModeLink" href="#contentInjectionModeDiv" class="alert-link">switch to Service Worker mode</a> ' +
                'if your platform supports it. &nbsp;[<a id="stop" href="#displaySettingsDiv" class="alert-link">Permanently hide</a>]' +
            '</div>';
        document.getElementById('alertBoxHeader').innerHTML = alertHTML;
        ['swModeLink', 'stop'].forEach(function(id) {
            // Define event listeners for both hyperlinks in alert box: these take the user to the Config tab and highlight
            // the options that the user needs to select
            document.getElementById(id).addEventListener('click', function () {
                var elementID = id === 'stop' ? 'hideActiveContentWarningCheck' : 'serviceworkerModeRadio';
                var thisLabel = document.getElementById(elementID).parentNode;
                thisLabel.style.borderColor = 'red';
                thisLabel.style.borderStyle = 'solid';
                var btnHome = document.getElementById('btnHome');
                [thisLabel, btnHome].forEach(function (ele) {
                    // Define event listeners to cancel the highlighting both on the highlighted element and on the Home tab
                    ele.addEventListener('mousedown', function () {
                        thisLabel.style.borderColor = '';
                        thisLabel.style.borderStyle = '';
                    });
                });
                document.getElementById('btnConfigure').click();
            });
        });
    }

    /**
     * Displays a Bootstrap alert box at the foot of the page to enable saving the content of the given title to the device's filesystem
     * and initiates download/save process if this is supported by the OS or Browser
     * 
     * @param {String} title The path and filename to the file to be extracted
     * @param {Boolean|String} download A Bolean value that will trigger download of title, or the filename that should
     *     be used to save the file in local FS
     * @param {String} contentType The mimetype of the downloadable file, if known
     * @param {Uint8Array} content The binary-format content of the downloadable file
     */
    function displayFileDownloadAlert(title, download, contentType, content) {
        // We have to create the alert box in code, because Bootstrap removes it completely from the DOM when the user dismisses it
        document.getElementById('alertBoxFooter').innerHTML =
        '<div id="downloadAlert" class="alert alert-info alert-dismissible">' +
        '    <a href="#" class="close" data-dismiss="alert" aria-label="close">&times;</a>' +
        '    <span id="alertMessage"></span>' +
        '</div>';
        // Download code adapted from https://stackoverflow.com/a/19230668/9727685 
        if (!contentType) {
            // DEV: Add more contentTypes here for downloadable files
            if (/\.epub$/.test(title)) contentType = 'application/epub+zip';
            if (/\.pdf$/.test(title)) contentType = 'application/pdf';
            if (/\.zip$/.test(title)) contentType = 'application/zip';
        }
        // Set default contentType if there has been no match
        if (!contentType) contentType = 'application/octet-stream';
        var a = document.createElement('a');
        var blob = new Blob([content], { 'type': contentType });
        // If the filename to use for saving has not been specified, construct it from title
        var filename = download === true ? title.replace(/^.*\/([^\/]+)$/, '$1') : download;
        // Make filename safe
        filename = filename.replace(/[\/\\:*?"<>|]/g, '_');
        a.href = window.URL.createObjectURL(blob);
        a.target = '_blank';
        a.type = contentType;
        a.download = filename;
        a.classList.add('alert-link');
        a.innerHTML = filename;
        var alertMessage = document.getElementById('alertMessage');
        alertMessage.innerHTML = '<strong>Download</strong> If the download does not start, please tap the following link: ';
        // We have to add the anchor to a UI element for Firefox to be able to click it programmatically: see https://stackoverflow.com/a/27280611/9727685
        alertMessage.appendChild(a);
        try { a.click(); }
        catch (err) {
            // If the click fails, user may be able to download by manually clicking the link
            // But for IE11 we need to force use of the saveBlob method with the onclick event 
            if (window.navigator && window.navigator.msSaveBlob) {
                a.addEventListener('click', function(e) {
                    window.navigator.msSaveBlob(blob, filename);
                    e.preventDefault();
                });
            }
        }
        $("#searchingArticles").hide();
    }

    /**
     * Functions and classes exposed by this module
     */
    return {
        feedNodeWithBlob: feedNodeWithBlob,
        replaceCSSLinkWithInlineCSS: replaceCSSLinkWithInlineCSS,
        removeUrlParameters: removeUrlParameters,
        displayActiveContentWarning: displayActiveContentWarning,
        displayFileDownloadAlert: displayFileDownloadAlert
    };
});