var windows = require("sdk/windows").browserWindows;
var tabs = require("sdk/tabs");
var Request = require("sdk/request").Request;
var prefs = require("sdk/simple-prefs").prefs;
var XMLHttpRequest = require("sdk/net/xhr").XMLHttpRequest;

function log(url, title){
    var data = JSON.stringify({
        url: url, time: Date.now(),
        title: title, key: prefs.key
    });
    var xhr = new XMLHttpRequest();
    xhr.open("POST", prefs.callback);
    xhr.send(data);
}

function logTab(tab) {
    if (tab.id === tabs.activeTab.id) {
        log(tab.url, tab.title);
    }
}

tabs.on("activate", function () { logTab(tabs.activeTab) });
tabs.on("pageshow", logTab );
windows.on("activate", function () { logTab(tabs.activeTab) });
windows.on("deactivate", function () { log(null, null) });