(function () {

	if (typeof Prism === 'undefined' || typeof document === 'undefined') {
		return;
	}

	// https://developer.mozilla.org/en-US/docs/Web/API/Element/matches#Polyfill
	if (!Element.prototype.matches) {
		Element.prototype.matches = Element.prototype.msMatchesSelector || Element.prototype.webkitMatchesSelector;
	}

	var LOADING_MESSAGE = 'Loading…';
	var FAILURE_MESSAGE = function (status, message) {
		return '✖ Error ' + status + ' while fetching file: ' + message;
	};
	var FAILURE_EMPTY_MESSAGE = '✖ Error: File does not exist or is empty';

	var EXTENSIONS = {
		'js': 'javascript',
		'py': 'python',
		'rb': 'ruby',
		'ps1': 'powershell',
		'psm1': 'powershell',
		'sh': 'bash',
		'bat': 'batch',
		'h': 'c',
		'tex': 'latex'
	};

	var STATUS_ATTR = 'data-src-status';
	var STATUS_LOADING = 'loading';
	var STATUS_LOADED = 'loaded';
	var STATUS_FAILED = 'failed';

	var SELECTOR = 'pre[data-src]:not([' + STATUS_ATTR + '="' + STATUS_LOADED + '"])'
		+ ':not([' + STATUS_ATTR + '="' + STATUS_LOADING + '"])';

	var lang = /\blang(?:uage)?-([\w-]+)\b/i;

	/**
	 * Sets the Prism `language-xxxx` or `lang-xxxx` class to the given language.
	 *
	 * @param {HTMLElement} element
	 * @param {string} language
	 * @returns {void}
	 */
	function setLanguageClass(element, language) {
		var className = element.className;
		className = className.replace(lang, ' ') + ' language-' + language;
		element.className = className.replace(/\s+/g, ' ').trim();
	}


	Prism.hooks.add('before-highlightall', function (env) {
		env.selector += ', ' + SELECTOR;
	});

	Prism.hooks.add('before-sanity-check', function (env) {
		var pre = /** @type {HTMLPreElement} */ (env.element);
		if (pre.matches(SELECTOR)) {
			env.code = ''; // fast-path the whole thing and go to complete

			pre.setAttribute(STATUS_ATTR, STATUS_LOADING); // mark as loading

			// add code element with loading message
			var code = pre.appendChild(document.createElement('CODE'));
			code.textContent = LOADING_MESSAGE;

			var src = pre.getAttribute('data-src');

			var language = env.language;
			if (language === 'none') {
				// the language might be 'none' because there is no language set;
				// in this case, we want to use the extension as the language
				var extension = (/\.(\w+)$/.exec(src) || [, 'none'])[1];
				language = EXTENSIONS[extension] || extension;
			}

			// set language classes
			setLanguageClass(code, language);
			setLanguageClass(pre, language);

			// preload the language
			var autoloader = Prism.plugins.autoloader;
			if (autoloader) {
				autoloader.loadLanguages(language);
			}

			// load file
			var xhr = new XMLHttpRequest();
			xhr.open('GET', src, true);
			xhr.onreadystatechange = function () {
				if (xhr.readyState == 4) {
					if (xhr.status < 400 && xhr.responseText) {
						// mark as loaded
						pre.setAttribute(STATUS_ATTR, STATUS_LOADED);

						// highlight code
						code.textContent = xhr.responseText;
						Prism.highlightElement(code);

					} else {
						// mark as failed
						pre.setAttribute(STATUS_ATTR, STATUS_FAILED);

						if (xhr.status >= 400) {
							code.textContent = FAILURE_MESSAGE(xhr.status, xhr.statusText);
						} else {
							code.textContent = FAILURE_EMPTY_MESSAGE;
						}
					}
				}
			};
			xhr.send(null);
		}
	});

	Prism.plugins.fileHighlight = {
		/**
		 * Executes the File Highlight plugin for all matching `pre` elements under the given container.
		 *
		 * Note: Elements which are already loaded or currently loading will not be touched by this method.
		 *
		 * @param {ParentNode} [container=document]
		 */
		highlight: function highlight(container) {
			var elements = (container || document).querySelectorAll(SELECTOR);

			for (var i = 0, element; (element = elements[i++]);) {
				Prism.highlightElement(element);
			}
		}
	};

	var logged = false;
	/** @deprecated Use `Prism.plugins.fileHighlight.highlight` instead. */
	Prism.fileHighlight = function () {
		if (!logged) {
			console.warn('Prism.fileHighlight is deprecated. Use `Prism.plugins.fileHighlight.highlight` instead.');
			logged = true;
		}
		Prism.plugins.fileHighlight.highlight.apply(this, arguments);
	};

}());
