// ==UserScript==
// @name           SocialGraphAPIValidator
// @namespace      api.kurrik@google.com
// @description    Validates the current page against the social graph API
// @include        *
// ==/UserScript==

function bind(func, obj) {
  return function() {
    func.apply(obj, arguments);
  };
};

var sg = function() {
};

sg.prototype = {
  dom_html : null,
  out_window : null,

  encodePost : function(data) {
    var key = null,
        out = [],
        tempout = [];
    for (key in data) {
      if (data.hasOwnProperty(key)) {
        tempout = [];
        tempout.push(encodeURIComponent(key));
        tempout.push(encodeURIComponent(data[key]));
        out.push(tempout.join("="));
      }
    }
    return out.join("&");
  },

  makeOutWindow : function() {
    this.out_window = window.open("", "", "scrollbars=yes,resizable=yes,toolbar=no,width=400,height=300");
    this.out_window.document.write("<h2>Social Graph API Validation Results</h2>"); 
  },

  print : function(msg) {
    GM_log(msg);
    if (!this.out_window) {
      alert("Please disable your popup blocker");
    } else {
      this.out_window.document.write(msg);
      this.out_window.document.close();
    }
  },

  request : function() {
    var metas = document.getElementsByTagName("meta"),
        meta = null,
        content_type = "text/html; charset=utf-8",
        body_text = "",
        data = null,
        i = 0;
 
    this.makeOutWindow();

    this.dom_html = document.getElementsByTagName("html")[0] ||
                    document.getElementsByTagName("RDF")[0];
    
    if (!this.dom_html) {
      this.print("Could not find HTML or RDF data", true);
    }

    for (i = 0; meta = metas[i]; i++){
      if (meta.getAttribute("http-equiv") &&
          meta.getAttribute("http-equiv").toLowerCase() == "content-type") {
        if (meta.getAttribute("content")) {
          content_type = meta.getAttribute("content");
        }
      }
    }

    body_text = this.dom_html.innerHTML;
    if (!body_text) {
      body_text = [ "<?xml version=\"1.0\"?>\n", 
                    new XMLSerializer().serializeToString(this.dom_html) ].join("");
      content_type = "application/rdf+xml; charset=utf-8";
    }

    data = {
      "url" : window.location.href,
      "body" : body_text,
      "contentType" : content_type,
      "urlFormat" : "base"
    };

    if (console && console.log) {
      console.log("Validating", data);
    }

    GM_xmlhttpRequest({
      method: "POST",
      url: "http://socialgraph.apis.google.com/testparse",
      headers: {
        "Content-type" : "application/x-www-form-urlencoded",
        "User-agent": "Mozilla/4.0 (compatible) Greasemonkey"
      },
      data : this.encodePost(data),
      onload: bind(this.response, this),
      onerror: bind(this.errorHappened, this)
    });
  },

  response : function(data) {
    var msg = data.responseText.replace(/ /g, "&nbsp;&nbsp;&nbsp;").replace(/\n/g, "<br />"); 
    if (data.status == "200") {
      this.print(msg, true);
    } else {
      this.print([ "Problem fetching data!  Response code = ", data.status ].join(""), true);
    }
  },

  errorHappened : function(data) {
    this.print([ "Problem fetching data!  Response code = ",
                 data.status,
                 " status text = ",
                 data.statusText ].join(""), true);
  }
}

var instance = new sg();
GM_registerMenuCommand("Validate on Social Graph API", bind(instance.request, instance));