using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Net;
using System.IO;
using System.Text;
using System.Xml;
using System.Collections.Specialized;
using System.Diagnostics;

/// <summary>
/// Summary description for GoogleAnalytics
/// </summary>
public class GoogleAnalytics
{
    //Oauth not implemented yet, check out API docs for more
    public enum mode { ClientLogin, AuthSub }
    
    //used when you want to manage email/pass from within your app
    public static string getSessionTokenClientLogin(string email, string password)
    { 
        //Google analytics requires certain variables to be POSTed
        string postData = "Email=" + email + "&Passwd=" + password;

        //defined - should not channge much
        postData = postData + "&accountType=HOSTED_OR_GOOGLE" + "&service=analytics" + "&source=akamarketing-testapp-1";

        ASCIIEncoding encoding = new ASCIIEncoding();
        byte[] data = encoding.GetBytes(postData);

        HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create("https://www.google.com/accounts/ClientLogin");
        myRequest.Method = "POST";
        myRequest.ContentType = "application/x-www-form-urlencoded";
        myRequest.ContentLength = data.Length;
        Stream newStream = myRequest.GetRequestStream();

        // Send the data.
        newStream.Write(data, 0, data.Length);
        newStream.Close();

        HttpWebResponse myResponse = (HttpWebResponse)myRequest.GetResponse();
        Stream responseBody = myResponse.GetResponseStream();

        Encoding encode = System.Text.Encoding.GetEncoding("utf-8");
        StreamReader readStream = new StreamReader(responseBody, encode);

        //returned from Google Analytics API
        string response = readStream.ReadToEnd();

        //get the data we need
        string[] auth = response.Split(new string[] { "Auth=" }, StringSplitOptions.None);
        
        //return it (the authorization token)
        return auth[1];
    }

    //used when you have authenticated on Google (via AuthSub & query params) & have a temp token
    public static string getSessionTokenAuthSub(string tempToken)
    {
        string response = GArequestResponseHelper("https://www.google.com/accounts/AuthSubSessionToken", tempToken, mode.AuthSub);

        //temp (once off) token will have been exchanged for session token, return it
        return response.Split('=')[1];
    }

    public static NameValueCollection getAccountInfo(string sessionToken, mode mode)
    {
        string response = GArequestResponseHelper("https://www.google.com/analytics/feeds/accounts/default", sessionToken, mode);

        //response will contain an XML formatted string similar to
        //http://code.google.com/p/ga-api-http-samples/source/browse/trunk/src/v1/accountFeedResponse.xml

        //we need to convert it to proper XML for parsing
        XmlDocument accountinfoXML = new XmlDocument(); accountinfoXML.LoadXml(response);

        //each account/profile combo the current user is authorized for will an 'entry' element
        XmlNodeList entries = accountinfoXML.GetElementsByTagName("entry");

        NameValueCollection profiles = new NameValueCollection();
        for (int i = 0; i < entries.Count; i++)
        {
            //profile name, profile ID - profile ID is needed for ID what data you want from the API
            profiles.Add(entries.Item(i).ChildNodes[2].InnerText,entries.Item(i).ChildNodes[6].Attributes["value"].Value);
        }

        return profiles;
    }

    public static string getData(string sessionToken, string profileID, mode mode)
    {
        //we'll also want to pass in non hardcoded dates and report specifiers
        //month in format yyyy-mm-dd etc. alternatively we could have static
        //metrics for each of the tasks our system needs to do, eg. getTopContent(),
        //getTopBrowswer() etc. 
        
        //At the moment we just getting pageview metric for our sites URLs
        //so for the purposes of demostration the URL in this method is
        //almost fully hardcoded

        string response = GArequestResponseHelper("https://www.google.com/analytics/feeds/data?ids=ga:" + profileID + "&dimensions=ga:pageTitle&metrics=ga:pageviews&sort=-ga:pageviews&start-date=2009-03-01&end-date=2009-03-31&prettyprint=true&max-results=20", sessionToken, mode);

        //response will contain an XML formatted string similar to
        //http://code.google.com/p/ga-api-http-samples/source/browse/trunk/src/v1/dataFeedResponse.xml

        return response;
    }

    public static string GArequestResponseHelper(string url, string token, mode mode)
    {
        HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(url);
        
        //will always be a token of some sort required in the header but the format
        //it is passed in will depend on what type of authorization is being used
        if (mode == mode.ClientLogin)
        { 
            myRequest.Headers.Add("Authorization: GoogleLogin auth=" + token);
        }
        else if (mode == mode.AuthSub)
        { 
            myRequest.Headers.Add("Authorization: AuthSub token=" + token);
        }

        //obviously you need some kind of try/catch here
        //but OK to bubble auth/connection failures up for demo
        HttpWebResponse myResponse = (HttpWebResponse)myRequest.GetResponse();
        Stream responseBody = myResponse.GetResponseStream();

        Encoding encode = System.Text.Encoding.GetEncoding("utf-8");
        StreamReader readStream = new StreamReader(responseBody, encode);

        //return string itself (easier to work with)
        return readStream.ReadToEnd();
    }
}