/*
 * © Copyright IBM Corp. 2012
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); 
 * you may not use this file except in compliance with the License. 
 * You may obtain a copy of the License at:
 * 
 * http://www.apache.org/licenses/LICENSE-2.0 
 * 
 * Unless required by applicable law or agreed to in writing, software 
 * distributed under the License is distributed on an "AS IS" BASIS, 
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or 
 * implied. See the License for the specific language governing 
 * permissions and limitations under the License.
 */

package com.ibm.sbt.security.authentication.oauth.consumer.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.ibm.commons.runtime.Context;
import com.ibm.commons.util.StringUtil;
import com.ibm.sbt.core.configuration.Configuration;
import com.ibm.sbt.security.authentication.oauth.consumer.OAuthHandler;
import com.ibm.sbt.service.core.handlers.AbstractServiceHandler;
import com.ibm.sbt.service.core.servlet.ServiceServlet;
import com.ibm.sbt.services.client.ClientServicesException;
import com.ibm.sbt.services.endpoints.Endpoint;
import com.ibm.sbt.services.endpoints.EndpointFactory;

/**
 * OAuth client authentication.
 * <p>
 * This servlet gets is used to trigger the authentication from a Javascript client, generally in a pop-up
 * window.
 * </p>
 * 
 * @author Philippe Riand
 */
public class OAClientAuthentication extends AbstractServiceHandler {

	public static final String	URL_PATH			= "oauth_jsauth";

	public static final String	MODE_MAINWINDOW		= "main";
	public static final String	MODE_POPUP			= "popup";
	public static final String	MODE_DIALOG			= "dialog";

	@SuppressWarnings("unused")
	private static final long	serialVersionUID	= 1L;

	@Override
	public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		// The URL to call the service should be of the form:
		// .../oauth_jsauth/[endpoint]
		int len = URL_PATH.length() + 2;
		String pathInfo = req.getPathInfo();
		if (pathInfo.length() <= len) {
			ServiceServlet.service500(req, resp, "Empty endpoint name");
			return;
		}
		String epName = pathInfo.substring(len);
		Endpoint ep = EndpointFactory.getEndpoint(epName);
		if (ep == null) {
			ServiceServlet.service500(req, resp, "Cannot find endpoint {0}", epName);
			return;
		}

		try {
			// If the endpoint is not authenticated, then authenticate
			// else redirect the main page
			if (!ep.isAuthenticationValid()) {
				ep.authenticate(true);
			} else {
				generateCloseScript(req, resp);
			}
		} catch (ClientServicesException ex) {
			throw new ServletException(ex);
		}
	}

	protected void generateCloseScript(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		String mode = req.getParameter("loginUi");

		PrintWriter pw = resp.getWriter();
		/*
		 * Fix : Adding content type in response. Not setting this, results in
		 * the html being rendered as text/plain.
		 */
		resp.setContentType("text/html");
		try {
			pw.println("<html>");
			pw.println("<head>");
			pw.println("</head>");
			pw.println("<body>");
			pw.println("<script>");
			if (StringUtil.isEmpty(mode) || mode.equalsIgnoreCase(MODE_MAINWINDOW)) {
				String redirect = req.getParameter("oaredirect");
				pw.println("  window.location.href = '" + redirect + "';");
			} else if (mode.equalsIgnoreCase(MODE_POPUP)) {
				pw.println("  if (window.opener && !window.opener.closed) {");
				pw.println("window.opener.require(['sbt/config'], function(config){");
				pw.println("    window.opener.location.reload();"); 
					pw.println("  if (config.callback) {");
						pw.println("config.callback();");
						pw.println("delete config.callback;");
					pw.println("  }");
				pw.println("});");
				pw.println("  }");
				pw.println("  window.close();");
			} else if (mode.equalsIgnoreCase(MODE_DIALOG)) {
				//
				// pw.println("  if (window.opener && !window.opener.closed) {");
				// pw.println("    window.opener.location.reload();");
				// pw.println("  }");
				// pw.println("  window.close();");
			} else {
				throw new ServletException(StringUtil.format("Invalid mode {0}", mode));
			}
			pw.println("</script>");
			pw.println("</body>");
			pw.println("</html>");
		} finally {
			pw.flush();
		}
	}
}