/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you 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.
 *
 */

/*
 *                        AT&T - PROPRIETARY
 *          THIS FILE CONTAINS PROPRIETARY INFORMATION OF
 *        AT&T AND IS NOT TO BE DISCLOSED OR USED EXCEPT IN
 *             ACCORDANCE WITH APPLICABLE AGREEMENTS.
 *
 *          Copyright (c) 2013 AT&T Knowledge Ventures
 *              Unpublished and Not for Publication
 *                     All Rights Reserved
 */
package org.apache.openaz.xacml.rest;

import java.io.IOException;
import java.util.Enumeration;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

import javax.servlet.ServletConfig;
import javax.servlet.http.HttpServletRequest;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.openaz.xacml.util.XACMLProperties;

/**
 * This static class is used by both the PDP and PAP servlet's. It contains some common static functions and
 * objects used by both the servlet's.
 */
public class XACMLRest {
    private static final Log logger = LogFactory.getLog(XACMLRest.class);
    private static Properties restProperties = new Properties();

    /**
     * This must be called during servlet initialization. It sets up the xacml.?.properties file as a system
     * property. If the System property is already set, then it does not do anything. This allows the
     * developer to specify their own xacml.properties file to be used. They can 1) modify the default
     * properties that comes with the project, or 2) change the WebInitParam annotation, or 3) specify an
     * alternative path in the web.xml, or 4) set the Java System property to point to their xacml.properties
     * file. The recommended way of overriding the default xacml.properties file is using a Java System
     * property: -Dxacml.properties=/opt/app/xacml/etc/xacml.admin.properties This way one does not change any
     * actual code or files in the project and can leave the defaults alone.
     *
     * @param config - The servlet config file passed from the javax servlet init() function
     */
    public static void xacmlInit(ServletConfig config) {
        //
        // Get the XACML Properties File parameter first
        //
        String propFile = config.getInitParameter("XACML_PROPERTIES_NAME");
        if (propFile != null) {
            //
            // Look for system override
            //
            String xacmlPropertiesName = System.getProperty(XACMLProperties.XACML_PROPERTIES_NAME);
            if (xacmlPropertiesName == null) {
                //
                // Set it to our servlet default
                //
                if (logger.isDebugEnabled()) {
                    logger.debug("Using Servlet Config Property for XACML_PROPERTIES_NAME:" + propFile);
                }
                System.setProperty(XACMLProperties.XACML_PROPERTIES_NAME, propFile);
            } else {
                if (logger.isDebugEnabled()) {
                    logger.debug("Using System Property for XACML_PROPERTIES_NAME:" + xacmlPropertiesName);
                }
            }
        }
        //
        // Setup the remaining properties
        //
        Enumeration<String> params = config.getInitParameterNames();
        while (params.hasMoreElements()) {
            String param = params.nextElement();
            if (!param.equals("XACML_PROPERTIES_NAME")) {
                String value = config.getInitParameter(param);
                logger.info(param + "=" + config.getInitParameter(param));
                restProperties.setProperty(param, value);
            }
        }
    }

    /**
     * Reset's the XACMLProperties internal properties object so we start in a fresh environment. Then adds
     * back in our Servlet init properties that were passed in the javax Servlet init() call. This function is
     * primarily used when a new configuration is passed in and the PDP servlet needs to load a new PDP engine
     * instance.
     *
     * @param pipProperties - PIP configuration properties
     * @param policyProperties - Policy configuration properties
     */
    public static void loadXacmlProperties(Properties policyProperties, Properties pipProperties) {
        try {
            //
            // Start fresh
            //
            XACMLProperties.reloadProperties();
            //
            // Now load our init properties
            //
            XACMLProperties.getProperties().putAll(XACMLRest.restProperties);
            //
            // Load our policy properties
            //
            if (policyProperties != null) {
                XACMLProperties.getProperties().putAll(policyProperties);
            }
            //
            // Load our pip config properties
            //
            if (pipProperties != null) {
                XACMLProperties.getProperties().putAll(pipProperties);
            }
        } catch (IOException e) {
            logger.error("Failed to put init properties into Xacml properties", e);
        }
        //
        // Dump them
        //
        if (logger.isDebugEnabled()) {
            try {
                logger.debug(XACMLProperties.getProperties().toString());
            } catch (IOException e) {
                logger.error("Cannot dump properties", e);
            }
        }
    }

    /**
     * Helper routine to dump the HTTP servlet request being serviced. Primarily for debugging.
     *
     * @param request - Servlet request (from a POST/GET/PUT/etc.)
     */
    public static void dumpRequest(HttpServletRequest request) {
        if (logger.isDebugEnabled()) {
            // special-case for receiving heartbeat - don't need to repeatedly output all of the information
            // in multiple lines
            if (request.getMethod().equals("GET") && "hb".equals(request.getParameter("type"))) {
                logger.debug("GET type=hb : heartbeat received");
                return;
            }
            logger.debug(request.getMethod() + ":" + request.getRemoteAddr() + " " + request.getRemoteHost()
                         + " " + request.getRemotePort());
            logger
                .debug(request.getLocalAddr() + " " + request.getLocalName() + " " + request.getLocalPort());
            Enumeration<String> en = request.getHeaderNames();
            logger.debug("Headers:");
            while (en.hasMoreElements()) {
                String element = en.nextElement();
                Enumeration<String> values = request.getHeaders(element);
                while (values.hasMoreElements()) {
                    String value = values.nextElement();
                    logger.debug(element + ":" + value);
                }
            }
            logger.debug("Attributes:");
            en = request.getAttributeNames();
            while (en.hasMoreElements()) {
                String element = en.nextElement();
                logger.debug(element + ":" + request.getAttribute(element));
            }
            logger.debug("ContextPath: " + request.getContextPath());
            if (request.getMethod().equals("PUT") || request.getMethod().equals("POST")) {
                // POST and PUT are allowed to have parameters in the content, but in our usage the parameters
                // are always in the Query string.
                // More importantly, there are cases where the POST and PUT content is NOT parameters (e.g. it
                // might contain a Policy file).
                // Unfortunately the request.getParameterMap method reads the content to see if there are any
                // parameters,
                // and once the content is read it cannot be read again.
                // Thus for PUT and POST we must avoid reading the content here so that the main code can read
                // it.
                logger.debug("Query String:" + request.getQueryString());
                try {
                    if (request.getInputStream() == null) {
                        logger.debug("Content: No content inputStream");
                    } else {
                        logger.debug("Content available: " + request.getInputStream().available());
                    }
                } catch (Exception e) {
                    logger.debug("Content: inputStream exception: " + e.getMessage()
                                 + ";  (May not be relevant)");
                }
            } else {
                logger.debug("Parameters:");
                Map<String, String[]> params = request.getParameterMap();
                Set<String> keys = params.keySet();
                for (String key : keys) {
                    String[] values = params.get(key);
                    logger.debug(key + "(" + values.length + "): " + (values.length > 0 ? values[0] : ""));
                }
            }
            logger.debug("Request URL:" + request.getRequestURL());
        }
    }
}