/*
 Live.js - One script closer to Designing in the Browser
 Written for Handcraft.com by Martin Kool (@mrtnkl).

 Version 4.
 Recent change: Made stylesheet and mimetype checks case insensitive.

 http://livejs.com
 http://livejs.com/license (MIT)  
 @livejs

 Include live.js#css to monitor css changes only.
 Include live.js#js to monitor js changes only.
 Include live.js#html to monitor html changes only.
 Mix and match to monitor a preferred combination such as live.js#html,css  

 By default, just include live.js to monitor all css, js and html changes.

 Live.js can also be loaded as a bookmarklet. It is best to only use it for CSS then,
 as a page reload due to a change in html or css would not re-include the bookmarklet.
 To monitor CSS and be notified that it has loaded, include it as: live.js#css,notify

*/ (function () {

var headers = { "Etag": 1, "Last-Modified": 1, "Content-Length": 1, "Content-Type": 1 },
    resources = {},
    pendingRequests = {},
    currentLinkElements = {},
    oldLinkElements = {},
    interval = {{ page.live-reload-time | default: site.live-reload-time | default: 5000 }},
    loaded = false,
    active = { "html": 1, "css": 1, "js": 1 };
var Live = {
  // performs a cycle per interval
  heartbeat: function () {      
    if (document.body) {        
      // make sure all resources are loaded on first activation
      if (!loaded) Live.loadresources();
      Live.checkForChanges();
    }
    setTimeout(Live.heartbeat, interval);
  },
  // loads all local css and js resources upon first activation
  loadresources: function () {
    // helper method to assert if a given url is local
    function isLocal(url) {
      var loc = document.location,
          reg = new RegExp("^\\.|^\/(?!\/)|^[\\w]((?!://).)*$|" + loc.protocol + "//" + loc.host);
      return url.match(reg);
    }
    // gather all resources
    var scripts = document.getElementsByTagName("script"),
        links = document.getElementsByTagName("link"),
        uris = [];
    // track local js urls
    for (var i = 0; i < scripts.length; i++) {
      var script = scripts[i], src = script.getAttribute("src");
      if (src && isLocal(src))
        uris.push(src);
      if (src && src.match(/\blive.js#/)) {
        for (var type in active)
          active[type] = src.match("[#,|]" + type) != null
        if (src.match("notify")) 
          alert("Live.js is loaded.");
      }
    }
    if (!active.js) uris = [];
    if (active.html) uris.push(document.location.href);
    // track local css urls
    for (var i = 0; i < links.length && active.css; i++) {
      var link = links[i], rel = link.getAttribute("rel"), href = link.getAttribute("href", 2);
      if (href && rel && rel.match(new RegExp("stylesheet", "i")) && isLocal(href)) {
        uris.push(href);
        currentLinkElements[href] = link;
      }
    }
    // initialize the resources info
    for (var i = 0; i < uris.length; i++) {
      var url = uris[i];
      Live.getHead(url, function (url, info) {
        resources[url] = info;
      });
    }
    // add rule for morphing between old and new css files
    var head = document.getElementsByTagName("head")[0],
        style = document.createElement("style"),
        rule = "transition: all .3s ease-out;"
    css = [".livejs-loading * { ", rule, " -webkit-", rule, "-moz-", rule, "-o-", rule, "}"].join('');
    style.setAttribute("type", "text/css");
    head.appendChild(style);
    style.styleSheet ? style.styleSheet.cssText = css : style.appendChild(document.createTextNode(css));
    // yep
    loaded = true;
  },
  // check all tracking resources for changes
  checkForChanges: function () {
    for (var url in resources) {
      if (pendingRequests[url])
        continue;
      Live.getHead(url, function (url, newInfo) {
        var oldInfo = resources[url],
            hasChanged = false;
        resources[url] = newInfo;
        for (var header in oldInfo) {
          // do verification based on the header type
          var oldValue = oldInfo[header],
              newValue = newInfo[header],
              contentType = newInfo["Content-Type"];
          switch (header.toLowerCase()) {
            case "etag":
              if (!newValue) break;
              // fall through to default
            default:
              hasChanged = oldValue != newValue;
              break;
          }
          // if changed, act
          if (hasChanged) {
            Live.refreshResource(url, contentType);
            break;
          }
        }
      });
    }
  },
  // act upon a changed url of certain content type
  refreshResource: function (url, type) {
    switch (type.toLowerCase()) {
      // css files can be reloaded dynamically by replacing the link element                               
      case "text/css":
        var link = currentLinkElements[url],
            html = document.body.parentNode,
            head = link.parentNode,
            next = link.nextSibling,
            newLink = document.createElement("link");
        html.className = html.className.replace(/\s*livejs\-loading/gi, '') + ' livejs-loading';
        newLink.setAttribute("type", "text/css");
        newLink.setAttribute("rel", "stylesheet");
        newLink.setAttribute("href", url + "?now=" + new Date() * 1);
        next ? head.insertBefore(newLink, next) : head.appendChild(newLink);
        currentLinkElements[url] = newLink;
        oldLinkElements[url] = link;
        // schedule removal of the old link
        Live.removeoldLinkElements();
        break;
      // check if an html resource is our current url, then reload                               
      case "text/html":
        if (url != document.location.href)
          return;
        // local javascript changes cause a reload as well
      case "text/javascript":
      case "application/javascript":
      case "application/x-javascript":
        document.location.reload();
    }
  },
  // removes the old stylesheet rules only once the new one has finished loading
  removeoldLinkElements: function () {
    var pending = 0;
    for (var url in oldLinkElements) {
      // if this sheet has any cssRules, delete the old link
      try {
        var link = currentLinkElements[url],
            oldLink = oldLinkElements[url],
            html = document.body.parentNode,
            sheet = link.sheet || link.styleSheet,
            rules = sheet.rules || sheet.cssRules;
        if (rules.length >= 0) {
          oldLink.parentNode.removeChild(oldLink);
          delete oldLinkElements[url];
          setTimeout(function () {
            html.className = html.className.replace(/\s*livejs\-loading/gi, '');
          }, 100);
        }
      } catch (e) {
        pending++;
      }
      if (pending) setTimeout(Live.removeoldLinkElements, 50);
    }
  },
  // performs a HEAD request and passes the header info to the given callback
  getHead: function (url, callback) {
    pendingRequests[url] = true;
    var xhr = window.XMLHttpRequest ? new XMLHttpRequest() : new ActiveXObject("Microsoft.XmlHttp");
    xhr.open("HEAD", url + "?reloadtime=" + new Date().getTime(), true);
    xhr.setRequestHeader("Cache-Control", "no-cache");
    xhr.onreadystatechange = function () {
      delete pendingRequests[url];
      if (xhr.readyState == 4 && xhr.status != 304) {
        xhr.getAllResponseHeaders();
        var info = {};
        for (var h in headers) {
          var value = xhr.getResponseHeader(h);
          // adjust the simple Etag variant to match on its significant part
          if (h.toLowerCase() == "etag" && value) value = value.replace(/^W\//, '');
          if (h.toLowerCase() == "content-type" && value) value = value.replace(/^(.*?);.*?$/i, "$1");
          info[h] = value;
        }
        callback(url, info);
      }
    }
    xhr.send();
  }
};
// start listening
if (document.location.protocol != "file:") {
  if (!window.liveJsLoaded)
    Live.heartbeat();
  window.liveJsLoaded = true;
}
else if (window.console)
  console.log("Live.js doesn't support the file protocol. It needs http.");

})();