package util;

import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;

import org.apache.http.HttpResponse;
import org.apache.http.ParseException;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.util.EntityUtils;
import org.apache.log4j.Logger;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonSyntaxException;

import edu.kit.scc.dei.ecplean.ECPAuthenticationException;
import edu.kit.scc.dei.ecplean.ECPAuthenticator;


public class ShibbolethECP {

	/**
	 * Logger instance for this class
	 */
	private final static Logger LOGGER = Logger.getLogger(ShibbolethECP.class);

	/**
	 * Static gson object for (de)serialization
	 */
	private static final Gson GSON = new GsonBuilder().create();
	
	/**
	 * Static URI to the SP.
	 */
	private final static URI BWLP_SP;
	static {
		URI tmp;
		try {
			tmp = new URI("https://bwlp-masterserver.ruf.uni-freiburg.de/secure-all/test.php");
		} catch (URISyntaxException e) {
			// should never happen!
			LOGGER.error("Bad URI syntax of the service provider, see trace: ", e);
			tmp = null;
		}
		BWLP_SP = tmp;
	}

	/**
	 * Fetches the resource
	 *
	 * @param idpUrl
	 *            URL of the identity provider to authenticate against, as String.
	 * @param user
	 *            Username as String.
	 * @param pass
	 *            Password as String.
	 * @return
	 * 						true if login worked, false otherwise.
	 */
	public static Boolean doLogin(final String idpUrl, final String user, final String pass) {

		// first lets do some sanity checks
		if (BWLP_SP == null) {
			LOGGER.error("URI to service provider is not set. Check the initialization of 'BWLP_SP'.");
			return false;
		}
		if (idpUrl == null) {
			LOGGER.error("Identity provider is not set, did you initialize this class correctly?");
			return false;
		}
		if (user == null) {
			LOGGER.error("No username given, aborting...");
			return false;
		}
		if (pass == null) {
			LOGGER.error("No password given, aborting...");
			return false;
		}

		// now init the authenticator for that idp and our static sp
    ECPAuthenticator auth = null;
		try {
			auth = new ECPAuthenticator(user, pass, new URI(idpUrl), BWLP_SP);
		} catch (URISyntaxException e) {
			LOGGER.error("Bad URI syntax, see trace: ", e);
			return false;
		}
    if (auth == null) {
			LOGGER.error("Initialising ECP authentication failed, aborting...");
			return false;
    }
    try {
			auth.authenticate();
    } catch (ECPAuthenticationException e) {
			LOGGER.error("ECP Authentication Exception, see trace: ", e);
			return false;
    }
    // here test again for the SPURL
    HttpGet testSp = new HttpGet("https://bwlp-masterserver.ruf.uni-freiburg.de/test.json");
    HttpResponse response = null;
    try {
			response = auth.getHttpClient().execute(testSp);
		} catch (ClientProtocolException e) {
			LOGGER.error("Bad protocol, see trace: ", e);
			return false;
		} catch (IOException e) {
			LOGGER.error("I/O error, see trace: ", e);
			return false;
		}
    LOGGER.debug("SP request returned: " + response.getStatusLine());
    String responseBody = null;
    try {
			responseBody = EntityUtils.toString(response.getEntity());
		} catch (ParseException e) {
			LOGGER.error("Parsing error, see trace: ", e);
			return false;
		} catch (IOException e) {
			LOGGER.error("I/O error, see trace: ", e);
			return false;
		}
    ServiceProviderResponse spr = null;
    try {
    	spr = GSON.fromJson(responseBody, ServiceProviderResponse.class);
    } catch (JsonSyntaxException e) {
    	LOGGER.error("Bad JSON syntax, see trace: ", e);
    	return false;
    }
    LOGGER.debug("SP JSON STATUS: " + spr.getStatus());
    // TODO: here we will need to parse the answer accordingly.
    // no errors, meaning everything worked fine.
    return spr.getStatus().equals("funzt") ? true : false;
	}
}