;'use strict';(function(exports){function Version(str){str=str||'0.0';var parts=str.split('.');this.major=parts[0];this.minor=parts[1];this.toString=function(){return''+str;};}
function InfoResult(current,previous){this.current=current;this.previous=previous;}
InfoResult.prototype.isUpgrade=function(){var prev=this.previous,curr=this.current,isUpgrade=false;if(prev&&curr){isUpgrade=curr.major>prev.major||curr.minor>prev.minor;}
return isUpgrade;};InfoResult.prototype.delta=function(){var prev=this.previous,curr=this.current;var delta='';if(prev){delta+=prev.major+'.'+prev.minor;}
delta+='..';if(curr){delta+=curr.major+'.'+curr.minor;}
return delta;};function getSetting(setting,cb,errback){var req=navigator.mozSettings.createLock().get(setting);req.onsuccess=function(){var value=req.result[setting];if(typeof cb==='function'){cb(value);}};req.onerror=function(){if(typeof errback==='function'){errback(req.error);}};}
function getCurrent(){return new Promise(function(resolve,reject){getSetting('deviceinfo.os',function(value){resolve(value?new Version(value):null);},function(err){reject(err);});});}
function getPrevious(){return new Promise(function(resolve,reject){getSetting('deviceinfo.previous_os',function(value){resolve(value?new Version(value):null);},function(err){resolve(null);});});}
function updatePrevious(str){var currentPromise=str?Promise.resolve(new Version(str)):getCurrent();var setPromise=new Promise(function(resolve,reject){currentPromise.then(function(version){if(version){var req=navigator.mozSettings.createLock().set({'deviceinfo.previous_os':version.toString()});req.onsuccess=function(){resolve(version);};req.onerror=function(){var reason=req.error;reject(reason);};}else{resolve(null);}},function(err){reject('Error getting previous version: ',err);});});return setPromise;}
function getVersionInfo(){var info=new InfoResult();var infoPromise=new Promise(function(resolve,reject){Promise.all([getCurrent().then(function(version){info.current=version;}),getPrevious().then(function(version){info.previous=version;})]).then(function(){resolve(info);},reject);});return infoPromise;}
exports.VersionHelper={updatePrevious:updatePrevious,getVersionInfo:getVersionInfo};})(window);