/**
* Copyright © Magento, Inc. All rights reserved.
* See COPYING.txt for license details.
*/

define([
'underscore'
], function (_) {
'use strict';

/**
* Checks if provided string is a valid DOM selector.
*
* @param {String} selector - Selector to be checked.
* @returns {Boolean}
*/
function isSelector(selector) {
try {
document.querySelector(selector);

return true;
} catch (e) {
return false;
}
}

/**
* Unescapes characters used in underscore templates.
*
* @param {String} str - String to be processed.
* @returns {String}
*/
function unescape(str) {
return str.replace(/&lt;%|%3C%/g, '<%').replace(/%&gt;|%%3E/g, '%>');
}

/**
* If 'tmpl' is a valid selector, returns target node's innerHTML if found.
* Else, returns empty string and emits console warning.
* If 'tmpl' is not a selector, returns 'tmpl' as is.
*
* @param {String} tmpl
* @returns {String}
*/
function getTmplString(tmpl) {
if (isSelector(tmpl)) {
tmpl = document.querySelector(tmpl);

if (tmpl) {
tmpl = tmpl.innerHTML.trim();
} else {
console.warn('No template was found by selector: ' + tmpl);

tmpl = '';
}
}

return unescape(tmpl);
}

/**
* Compiles or renders template provided either
* by selector or by the template string.
*
* @param {String} tmpl - Template string or selector.
* @param {(Object|Array|Function)} [data] - Data object with which to render template.
* @returns {String|Function}
*/
return function (tmpl, data) {
var render;

tmpl = getTmplString(tmpl);
render = _.template(tmpl);

return !_.isUndefined(data) ?
render(data) :
render;
};
});