/* (c) 2014 - 2016 Open Source Geospatial Foundation - all rights reserved
 * (c) 2001 - 2013 OpenPlans
 * This code is licensed under the GPL 2.0 license, available at the root
 * application directory.
 */


package org.geoserver.security.cas;

import java.io.IOException;
import java.net.HttpCookie;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * A helper class for authentication against a Cas server
 * 
 * supported authentication mechanisms
 * 
 *  - Cas Form login
 * 
 * @author christian
 *
 */
public class CasFormAuthenticationHelper extends CasAuthenticationHelper{

    public final static String CAS_4_0_USER="casuser";
    public final static String CAS_4_0_PW="Mellon";
    
    String username,password;

    public CasFormAuthenticationHelper (URL casUrlPrefix,String username, String password) {
        super(casUrlPrefix);
        this.username=username;
        this.password=password;
    }

    
        
    public boolean ssoLogin() throws IOException{
        URL loginUrl = createURLFromCasURI("/login");
        HttpURLConnection conn = (HttpURLConnection) loginUrl.openConnection();
        String responseString = readResponse(conn);
        String loginTicket = extractFormParameter(responseString,"\"lt\"");
        if (loginTicket==null)
            throw new IOException (" No login ticket for: "+loginUrl.toString());
        String execution = extractFormParameter(responseString,"\"execution\"");
        if (execution==null)
            throw new IOException (" No hidden execution field for: "+loginUrl.toString());

        List<HttpCookie> cookies = getCookies(conn);
        HttpCookie sessionCookie = getCookieNamed(cookies, "JSESSIONID");        
        String sessionCookieSend=sessionCookie.toString();
        
        Map<String,String> paramMap = new HashMap<String,String>();
        paramMap.put("username",username);
        paramMap.put("password",password);
        paramMap.put("lt",loginTicket);
        paramMap.put("_eventId","submit");
        paramMap.put("submit","LOGIN");
        paramMap.put("execution",execution);
                
        conn = (HttpURLConnection) loginUrl.openConnection();
        
        conn.setRequestMethod("POST");
        conn.setDoOutput(true);
        conn.setDoInput(true);
        conn.setRequestProperty("Cookie", sessionCookieSend);
        
        writeParamsForPostAndSend(conn, paramMap);

        cookies = getCookies(conn);
        readResponse(conn);
        
        extractCASCookies(cookies,conn);
        
        return ticketGrantingCookie!=null && ticketGrantingCookie.getValue().startsWith("TGT-"); 
    }

    protected String extractFormParameter(String formLoginHtml, String searchString) {        
        int index = formLoginHtml.indexOf(searchString);
        index+=searchString.length();
        index = formLoginHtml.indexOf("\"", index);
        int index2 = formLoginHtml.indexOf("\"", index+1);
        return  formLoginHtml.substring(index+1,index2);        
    }

}