import javax.servlet.http.*;
import java.io.IOException;
import javax.servlet.*;

import org.json.JSONException;
import org.json.JSONObject;

import java.io.PrintWriter;
import com.facebook.api.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;


public class SocialJavaTutorial extends HttpServlet {
	int count;

	//Application API Key and application secret from creating app in FB
	String appapikey = new String("7623a6ab94a7cc519b1fb73627afdda0");
	String appsecret = new String("90e48- your secret here - df6d957e");

	//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";
	String profilePage = "http://www.facebook.com/profile.php";

	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" );

		// do authentication  
		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 is logged on

			//get MockFBMLText from Profile as a parameter. If it exists, send it to servlet & skip the rest

			String mockfbmltext = req.getParameter("mockfbmltext");
			if (mockfbmltext!=null){
				servletOutput.println(mockfbmltext);
			}else{		// if MockFBMLText is set, don't do anything else
				facebook = new FacebookJsonRestClient(appapikey, appsecret,sessionKey);  // create Facebook Json Rest Client
				try{
					// Get user id as parameter 
					user = req.getParameter("fb_sig_user");  // get user as a string.  User info passed as request parameter
					Long userLong = new Long(user); // need user as a long for  API calls

					// get profiletext as parameter, if not null, then display on profile, redirect to profile page
					String displayText = req.getParameter("profiletext");
					if (displayText!=null){
						facebook.profile_setFBML(displayText, userLong);
						servletOutput.println("<fb:redirect url=" + profilePage + "/>");  // Facebook Redirect to login page
					}else{ 
						// render rest of page if displayText is not a parameter

						// Display User ID
						servletOutput.println("User is " + user +"<br>");  // displays numeric value

						// use JDBC to store and update the count
						Connection con;
						Statement stmt;
						try {
							Class.forName("com.mysql.jdbc.Driver").newInstance();
						} catch (Exception ex) {
							// handle the error
							servletOutput.println(ex +" error");
						}
						try {
							con = DriverManager.getConnection("jdbc:mysql://HOST/DATABASE?" +
							"user=USER_NAME&password=PASSWORD");
							String query;
							try {
								stmt = con.createStatement();
								query ="Select count from counter";  //counter is the table that contains count
								ResultSet rs = stmt.executeQuery(query);
								if (rs.next()) {
									int count = rs.getInt("count");
									count++;
									servletOutput.println("the count is " + count +" <br>");
									query ="UPDATE  counter SET count=" + count;  //update count in Database
									stmt.executeUpdate(query);

								} else { // if it is the first time access
									stmt = con.createStatement();
									query ="INSERT INTO counter (count) VALUES (1)";
									stmt.executeUpdate(query);
									servletOutput.println("You are number 1");
								}
								con.close(); 
							} catch(SQLException ex) {
								servletOutput.println("SQLException: " + ex.getMessage());
							}
						} catch (SQLException ex) {
							// handle any errors
							servletOutput.println("SQLException: " + ex.getMessage());
							servletOutput.println("SQLState: " + ex.getSQLState());
							servletOutput.println("VendorError: " + ex.getErrorCode());
						}

						// Try FQL to get name
						String query = "SELECT name FROM user WHERE uid=" + user;
						org.json.JSONArray resultArray = (org.json.JSONArray)facebook.fql_query(query); 
						try{
							JSONObject result = resultArray.getJSONObject(0);
							servletOutput.println("User Name is " + result.getString("name"));
							servletOutput.println("<br>");
						} catch(JSONException jex){
							servletOutput.println(">Error: JSON "  + jex );
						}

						// Set up input form on canvas page
						servletOutput.println("</pre>");
						servletOutput.println("<form action=\"\" method=\"post\">");
						servletOutput.println("<input name=\"profiletext\" type=\"text\" size=\"30\" value=\"\"><br>");
						servletOutput.println("<input name=\"submit\" type=\"submit\" value=\"Display text on profile\">");
						servletOutput.println("</form>");

						// Set up mockajax form on profile page
						String appCallBackUrl = "http://www.socialjava.com/servlet/SocialJavaTutorial/";
						String mockAjax;
						mockAjax="<form>";
						mockAjax+="<input name=\"mockfbmltext\" type=\"text\" size=\"30\">";
						mockAjax+="<br />";
						mockAjax+="<input type=\"submit\"";
						mockAjax+="  clickrewriteurl=\""+ appCallBackUrl +"\"";
						mockAjax+="  clickrewriteid=\"preview\" value=\"Draw text below\"";
						mockAjax+="/>";
						mockAjax+="<br />";
						mockAjax+="<div id=\"preview\" style=\"border-style: solid; border-color: black;";
						mockAjax+=" border-width: 1px; padding: 5px;\">";
						mockAjax+="</div>";
						mockAjax+="</form>";
						facebook.profile_setFBML(mockAjax.toString(), userLong);
					}			
				}//try 
				catch( FacebookException ex )
				{
					servletOutput.println(">Error: Couldn't talk to Facebook> "  + ex );
				}
			} //else user is logged in
		}//else mockajax

		servletOutput.close();
	}  // end doPost()
}