package source;
import javax.servlet.http.*;
import java.io.IOException;
import javax.servlet.*;
import java.io.PrintWriter;
import com.facebook.api.*;

public class SocialJavaAPIIntroApp extends HttpServlet {

	//Application API Key and application secret from creating app in FB
	String appapikey = new String("00b0049fc7cf0d1e4a4ba2ea3e55b269");
	String appsecret = new String("8ad-secret key goes here-");

	//Facebook loginPage to this application.  Parameter canvas=true shows the result in Facebook canvas
	String loginPage = "http://www.facebook.com/login.php?api_key="+"00b0049fc7cf0d1e4a4ba2ea3e55b269"+"&v=1.0&canvas=true";
	FacebookJsonRestClient facebook;  // the facebook client, talks to REST Server
	PrintWriter servletOutput;  // output of servlet. HTML or FBML out

	public void doGet( HttpServletRequest req, HttpServletResponse res ) throws ServletException, IOException{
		servletOutput = res.getWriter(); // response is sent to ServletOutput
		res.setContentType( "text/html" );
		servletOutput.println("This is the doGet method");
	}

	public void doPost(HttpServletRequest req, 
			HttpServletResponse res) 
	throws ServletException, IOException {

		servletOutput = res.getWriter(); // response is sent to ServletOutput
		res.setContentType( "text/html" );
		servletOutput.println("This is the doPost method");
		servletOutput.println("<br>");

		String user =null;
		String sessionKey=null;
		sessionKey = req.getParameter(FacebookParam.SESSION_KEY.toString());  // Session Key passed as request parameter
		if (sessionKey==null) { // If there is not session key, they user not logged in
			servletOutput.println("<fb:redirect url=" + loginPage + "/>");  // Facebook Redirect to login page
		}
		else{
			user = req.getParameter("fb_sig_user");  // get user as a string.  User info passed as request parameter
			servletOutput.println("User is " + user);  // displays numeric value
			servletOutput.println("<br>");
			facebook = new FacebookJsonRestClient(appapikey, appsecret,sessionKey);  // create Facebook Json Rest Client
			servletOutput.println("Facebook Client created");
			servletOutput.println("<br>");
			
			// with Facebook client created, now Facebook API calls can be made
			// In this case, a call to FQL to get username
			
			try{
				String query = "SELECT name FROM user WHERE uid=" + user;
				org.json.JSONArray resultArray = (org.json.JSONArray)facebook.fql_query(query); // query return an object.  Casting it as a String
				servletOutput.println("User Name is " + resultArray); 
			}
			catch( FacebookException ex )
			{
				servletOutput.println(">Error: Couldn't talk to Facebook> "  + ex );
			}
		} //else user is logged in
		servletOutput.close();
	}  // end doPost()
}