// Thanks for doing your part to liber(IE)t the world from IE6!
// Here's to the "Support but Discourage" approach :)
// Original copy written by Jonathan Howard.
// jon@StaringIsPolite.com // twitter.com/staringispolite
//
// GNU LGPL License v3
// SevenUp 0.3 is released into the wild under a GNU LGPL v3
//
// Browser sniffing technique lovingly adapted from http://www.thefutureoftheweb.com/
// Simple CSS Lightbox technique adapted equally lovingly from http://www.emanueleferonato.com/
// Go read their blogs :)

// Constructor technique advocated by Doug Crockford (of LSlint, JSON) in his recent Google tech talk.
var sevenUp = function() {
  // Define 'private vars' here.
	var osSupportsUpgrade = /(Windows NT 5.1|Windows NT 6.0|Windows NT 6.1|)/i.test(navigator.userAgent); // XP, Vista, Win7
  var options = {  // Change these to fit your color scheme via the 'options' arg for test().
	enableClosing: true,
	enableQuitBuggingMe: true,
	overlayColor: "#000000",  
	lightboxColor: "#ffffff",
	borderColor: "#6699ff",
	downloadLink: osSupportsUpgrade ? 
				  "http://www.microsoft.com/windows/internet-explorer" :
				  "http://getfirefox.com",
	overrideLightbox: false,
	lightboxHTML: null,
	showToAllBrowsers: false,
	usePlugin: false
  };
  function mergeInOptions(newOptions) {
	if (newOptions) {
	  for (var i in options) {
		if (newOptions[i] !== undefined) {
		  options[i] = newOptions[i];
		}
	  }
	}
  }
  function isCookieSet() {
	if (document.cookie.length > 0) {
	  var i = document.cookie.indexOf("sevenup=");
	  return (i != -1);
	}
	return false;
  }
  
  // Return object literal and public methods here.
  return {
	// Hate to define CSS this way, but trying to keep to one file.
	// I'll keep it as pretty as possible.
	overlayCSS: function() {
	  return "display: block; position: absolute; top: 0%; left: 0%;" +
	  "width: 100%; height: 100%; background-color: " + options.overlayColor + "; " +
	  "filter: alpha(opacity: 80); z-index:1001;";
	},
	lightboxCSS: function() {
	  return "display: block; position: absolute; top: 25%; left: 25%; width: 50%; " +
	  "padding: 16px; border: 8px solid " + options.borderColor + "; " +
	  "background-color:" + options.lightboxColor + "; " +
	  "z-index:1002; overflow: hidden;";
	},
	lightboxContents: function() {
	  var html = options.lightboxHTML;
	  if (!html) {
		html =
		"<div style='width: 100%; height: 95%'>" +
		  "<h2 style='text-align: center;'>Your web browser is outdated and unsupported</h2>" +
		  "<div class='upgrade_msg' style='text-align: center;'>" +
			"You can easily upgrade to the latest version at<br> " +
			"<a style='color: #0000EE' href='" + options.downloadLink + "'>" +
			  options.downloadLink +
			"</a>" +
		  "</div>" +
		  "<h3 style='margin-top: 40px'>Why should I upgrade?</h3>" +
		  "<ul>" +
			"<li><b>Websites load faster</b>, often double the speed of this older version</li>" +
			"<li><b>Websites look better</b>, so you see sites they way they were intended</li>" +
			"<li><b>Tabs</b> let you view multiple sites in one window</li>" +
			"<li><b>Safer browsing</b> with phishing protection</li>" +
		  "</ul>" +
		"</div>";
		if (options.enableClosing) {
		  html += "<div style='font-size: 11px; text-align: right;'>";
		  html += options.enableQuitBuggingMe ?
		  ("<a href='#' onclick='sevenUp.quitBuggingMe();' " +
			  "style='color: #0000EE'>" +
			  "Quit bugging me" +
		  "</a>") :
		  ("<a href='#' onclick='sevenUp.close();' " +
			  "style='color: #0000EE'>" +
			  "close" +
			"</a>");
		  html += "</div>";
		}
	  }
	  return html;
	},
	test: function(newOptions, callback) {
	  mergeInOptions(newOptions);
	  if (!isCookieSet()) {
		// Write layer into the document.
		var layerHTML = "<div id='sevenUpCallbackSignal'></div>";
		if (options.overrideLightbox) {
		  layerHTML += options.lightboxHTML;
		} else {
		  layerHTML += "<div id='sevenUpOverlay' style='" + overlayCSS() + "'>" +
			"</div>" +
			"<div id='sevenUpLightbox' style='" + lightboxCSS() + "'>" +
			  lightboxContents() +
			"</div>";
		}
		if (options.showToAllBrowsers !== true) {
		  layerHTML = "<!--[if lt IE 7]>" + layerHTML + "<![endif]-->";
		}
		var layer = document.createElement('div');
		layer.innerHTML = layerHTML;
		document.body.appendChild(layer);
		// Fire callback.
		// I don't like this hack but IE6 seems to restrict dynamically created <script> tags to <head> only, 
		// and I don't see a way to add conditional comments around the script tag or its contents.
		// So for now, we write a 'signal' div inside the CC. If anyone has a better way please let me know.
		if (callback && document.getElementById('sevenUpCallbackSignal')) {
		  callback(options);
		}
	  }  
	},
	quitBuggingMe: function() {
	  var exp = new Date();
	  exp.setTime(exp.getTime()+(7*24*3600000));
	  document.cookie = "sevenup=dontbugme; expires="+exp.toUTCString();
	  this.close();
	},
	close: function() {
	  var overlay = document.getElementById('sevenUpOverlay');
	  var lightbox = document.getElementById('sevenUpLightbox');
	  if (overlay) { overlay.style.display = 'none'; }
	  if (lightbox) { lightbox.style.display = 'none'; }
	},
	plugin: {}
  };
}();