/**

  * Copyright 2005-2011 The Kuali Foundation

  *

  * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php

  *

  * 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 org.kuali.rice.core.impl.config.property;

 import org.apache.commons.collections.CollectionUtils;

 import org.apache.commons.lang.StringUtils;

 import org.apache.log4j.Logger;

 import org.kuali.rice.core.api.config.ConfigurationException;

 import org.kuali.rice.core.api.config.property.Config;

 import org.kuali.rice.core.api.util.RiceUtilities;

 import org.kuali.rice.core.framework.config.property.AbstractBaseConfig;

 import org.kuali.rice.core.util.ImmutableProperties;

 import org.xml.sax.Attributes;

 import org.xml.sax.InputSource;

 import org.xml.sax.SAXException;

 import org.xml.sax.XMLFilter;

 import org.xml.sax.helpers.XMLFilterImpl;

 import javax.xml.bind.JAXBContext;

 import javax.xml.bind.JAXBException;

 import javax.xml.bind.Unmarshaller;

 import javax.xml.bind.UnmarshallerHandler;

 import javax.xml.parsers.ParserConfigurationException;

 import javax.xml.parsers.SAXParserFactory;

 import java.io.IOException;

 import java.io.InputStream;

 import java.util.ArrayList;

 import java.util.Collections;

 import java.util.HashSet;

 import java.util.LinkedHashMap;

 import java.util.List;

 import java.util.Map;

 import java.util.Properties;

 import java.util.Random;

 import java.util.Set;

 import java.util.SortedSet;

 import java.util.TreeSet;

 import java.util.regex.Matcher;

 import java.util.regex.Pattern;

 /**

  * This implementation of the Config interface uses JAXB to parse the config file and

  * maintains an internal copy of all properties in their "raw" form (without any nested

  * properties resolved).  This allows properties to be added in stages and still alter

  * values of properties previously read in.

  * It also has settings for whether system properties should override all properties or

  * only serve as default when the property has not been defined.

  * 

  * @author Kuali Rice Team (rice.collab@kuali.org)

  *

  */

 public class JAXBConfigImpl extends AbstractBaseConfig {

     private static final Logger LOG = Logger.getLogger(JAXBConfigImpl.class);

     private static final String IMPORT_NAME = "config.location";

     private static final String INDENT = "  ";

     private static final String PLACEHOLDER_REGEX = "\\$\\{([^{}]+)\\}";

     // keep the same random

     private static final Random RANDOM = new Random();

     private final List<String> fileLocs = new ArrayList<String>();

     private final Map<String, Object> objects = new LinkedHashMap<String, Object>();

     private final Properties rawProperties = new Properties();

     private final Properties resolvedProperties = new Properties();

     // compile pattern for regex once

     private final Pattern pattern = Pattern.compile(PLACEHOLDER_REGEX);

     private boolean systemOverride;

     public JAXBConfigImpl(){}

     public JAXBConfigImpl(Config config) {

             this.copyConfig(config);

     }

     public JAXBConfigImpl(String fileLoc, Config config) {

             this.copyConfig(config);

             this.fileLocs.add(fileLoc);

     }

         public JAXBConfigImpl(List<String> fileLocs, Config config) {

             this.copyConfig(config);

             this.fileLocs.addAll(fileLocs);

     }

     public JAXBConfigImpl(String fileLoc) {

         this.fileLocs.add(fileLoc);

     }

     public JAXBConfigImpl(List<String> fileLocs) {

         this.fileLocs.addAll(fileLocs);

     }

     public JAXBConfigImpl(Properties properties) {               

             this.putProperties(properties);

     }

     public JAXBConfigImpl(String fileLoc, Properties properties) {

         this.fileLocs.add(fileLoc);    

         this.putProperties(properties);

     }

     public JAXBConfigImpl(List<String> fileLocs, Properties properties) {

         this.fileLocs.addAll(fileLocs);        

         this.putProperties(properties);

     }

     /*****************************************************/

     /*

      * We need the ability to take a config object and copy the raw + cached data into

      * this config object. 

      */

     private void copyConfig(Config config){

             if(config == null) {

                         return;

                 }

             this.putProperties(config.getProperties());

             if(config.getObjects() != null) {

                         this.objects.putAll(config.getObjects());

                 }

     }

     @Override

         public Object getObject(String key) {

         return objects.get(key);

     }

     @Override

         public Map<String, Object> getObjects() {

             return Collections.unmodifiableMap(objects);

     }

     @Override

         public Properties getProperties() {

             return new ImmutableProperties(resolvedProperties);

     }

     @Override

         public String getProperty(String key) {

         return resolvedProperties.getProperty(key);

     }

     /**

      * 

      * This overrided the property. Takes the place of the now depricated overrideProperty

      * 

      * @see Config#putProperty(java.lang.String, java.lang.String)

      */

         @Override

         public void putProperty(String key, String value) {

         this.setProperty(key, replaceVariable(key, value));

         resolveRawToCache();

         }

         @Override

         public void putProperties(Properties properties) {

         if (properties != null) {

             for(Object o : properties.keySet()) {

                     this.setProperty((String)o, replaceVariable((String)o, properties.getProperty((String)o)));

             }

                 resolveRawToCache();

         }

     }

     @Override

         public void parseConfig() throws IOException {

         if (!fileLocs.isEmpty()) {

             if (LOG.isInfoEnabled()) {

                 LOG.info("Loading Rice configs: " + StringUtils.join(fileLocs, ", "));

             }

             Unmarshaller unmarshaller;

             try {

                 JAXBContext jaxbContext = JAXBContext.newInstance(org.kuali.rice.core.impl.config.property.Config.class);

                 unmarshaller = jaxbContext.createUnmarshaller();

             } catch (Exception ex) {

                 throw new ConfigurationException("Error initializing JAXB for config", ex);

             }

             // add these first so they can be overridden

             configureBuiltIns();

             // parse all config files, but do not resolve any right hand side variables

             for (String s : fileLocs) {

                 parseConfig(s, unmarshaller, 0);

             }

             // now that all properties have been loaded, resolve the right hand side from

             // the raw properties into the resolved properties.  This will also replace properties

             // defined in the files with system properties if systemOverride==true.

             resolveRawToCache();

             if (LOG.isInfoEnabled()) {

                     final StringBuilder log = new StringBuilder();

                     log.append("\n");

                     log.append("####################################\n");

                     log.append("#\n");

                     log.append("# Properties used after config override/replacement\n");

                     log.append("# " + StringUtils.join(fileLocs, ", ") + "\n");

                     log.append("#\n");

                     log.append("####################################\n");

                 //commented out to backport to java 5

                 //SortedSet<String> sorted = new TreeSet<String>(properties.stringPropertyNames());

                 SortedSet<String> sorted = new TreeSet<String>();

                 CollectionUtils.addAll(sorted, rawProperties.propertyNames());

                 for (String s : sorted) {

                         log.append("Using config Prop ");

                     log.append(s);

                     log.append("=[");

                     log.append(ConfigLogger.getDisplaySafeValue(s, this.getProperty(s)));

                     log.append("]\n");

                 }

                 LOG.info(log);

             }

         } else {

             LOG.info("Loading Rice configs: No config files specified");

         }

     }

     protected void parseConfig(String filename, Unmarshaller unmarshaller, int depth) throws IOException {

         InputStream in = null;

         // have to check for empty filename because getResource will

         // return non-null if passed ""

         if (StringUtils.isNotEmpty(filename)) {

             in = RiceUtilities.getResourceAsStream(filename);

         }

         if (in == null) {

                 final StringBuilder log = new StringBuilder();

                 log.append("\n");

                 log.append("####################################\n");

                 log.append("#\n");

                 log.append("# Configuration file '" + filename + "' not found!\n");

                 log.append("#\n");

                 log.append("####################################\n");

                 LOG.warn(log);

         } else {

             final String prefix = StringUtils.repeat(INDENT, depth);            

             LOG.info(prefix + "+ Parsing config: " + filename);            

             org.kuali.rice.core.impl.config.property.Config config;

             try {

                 config = unmarshal(unmarshaller, in);

             } catch (Exception ex) {

                 throw new ConfigurationException("Error parsing config file: " + filename, ex);

             }

             for (Param p : config.getParamList()) {

                 String name = p.getName();

                 if (name.equals(IMPORT_NAME)) {

                     String configLocation = parseValue(p.getValue(), new HashSet<String>());

                     // Remove new lines and white space.

                     if(configLocation != null){

                             configLocation = configLocation.trim();

                     }

                     parseConfig(configLocation, unmarshaller, depth + 1);

                 } else if(p.isSystem()){

                         if (p.isOverride() || System.getProperty(name) == null){

                                 if(p.isRandom()){

                                         String randStr = String.valueOf(generateRandomInteger(p.getValue()));

                                         System.setProperty(name, randStr);

                             this.setProperty(p.getName(), randStr); 

                                 if(LOG.isInfoEnabled())

                                 {        

                                         LOG.info("generating random string " + randStr + " for system property " + p.getName());

                                 }    

                                 }else{

                                         // resolve and set system params immediately so they can override

                             // existing system params. Add to rawProperties resolved as well to

                             // prevent possible mismatch

                             HashSet<String> set = new HashSet<String>();

                             set.add(p.getName());

                             String value = parseValue(p.getValue(), set);

                             System.setProperty(name, value);

                             this.setProperty(name, value);

                                 }

                         }

                 }

                 else if (p.isOverride() || !rawProperties.containsKey(name)) {

                         if (p.isRandom()) {

                             String randStr = String.valueOf(generateRandomInteger(p.getValue()));

                         this.setProperty(p.getName(), randStr); 

                             if(LOG.isInfoEnabled())

                             {        

                                     LOG.info("generating random string " + randStr + " for property " + p.getName());

                             }

                     } else {

                             /*

                              * myProp = dog

                              * We have a case where you might want myProp = ${myProp}:someOtherStuff:${foo}

                              * This would normally overwrite the existing myProp with ${myProp}:someOtherStuff:${foo}

                              * but what we want is:

                              * myProp = dog:someOtherStuff:${foo}

                              * so that we put the existing value of myProp into the new value. Basically how path works.

                              */

                             String value = replaceVariable(name, p.getValue());                       

                             this.setProperty(name, value);                            

                     }

                 }

             }

             LOG.info(prefix + "- Parsed config: " + filename);

         }

     }

     /*

      * This will set the property. No logic checking so what you pass in gets set.

      * We use this as a focal point for debugging the raw config changes.

      */

     protected void setProperty(String name, String value){

             if(LOG.isInfoEnabled()){

                     String oldProp = rawProperties.getProperty(name);

                     if(oldProp != null && !oldProp.equals(value)){

                             LOG.info("Raw Config Override: " + name + "=[" + ConfigLogger.getDisplaySafeValue(name,oldProp) +"]->[" + ConfigLogger.getDisplaySafeValue(name,value) +"]");

                     }

             }

             rawProperties.setProperty(name, value);

     }    

     protected String resolve(String key) {

             return resolve(key, null);

     }

     /**

      * This method will determine the value for a property by looking it up in the raw properties.  If the

      * property value contains a nested property (foo=${nested}) it will start the recursion by

      * calling parseValue().

      * It will also check for a system property of the same name and, based on the value of systemOverride,

      * 'override with' the system property or 'default to' the system property if not found in the raw properties.

      * This method only determines the resolved value, it does not modify the properties in the resolved or raw

      * properties objects.

      * 

      * @param key they key of the property for which to determine the value

      * @param keySet contains all keys used so far in this recursion.  used to check for circular references.

      * @return

      */

     protected String resolve(String key, Set<String> keySet) {

         // check if we have already resolved this key and have circular reference

         if (keySet != null && keySet.contains(key)) {

             throw new ConfigurationException("Circular reference in config: " + key);

         }

         String value = this.rawProperties.getProperty(key);

         if ((value == null || systemOverride) && System.getProperties().containsKey(key)) {

             value = System.getProperty(key);

         }

         if (value != null && value.contains("${")) {

                 if(keySet == null) {

                         keySet = new HashSet<String>();

                 }

             keySet.add(key);

             value = parseValue(value, keySet);

             keySet.remove(key);

         }

         if(value == null) {

                 value = "";

                 LOG.warn("Property key: '" + key + "' is not available and hence set to empty");

         }

         return value;

     }

     /**

      * This method parses the value string to find all nested properties (foo=${nested}) and

      * replaces them with the value returned from calling resolve().  It does this in a new

      * string and does not modify the raw or resolved properties objects.

      * 

      * @param value the string to search for nest properties

      * @param keySet contains all keys used so far in this recursion.  used to check for circular references.

      * @return

      */

     protected String parseValue(String value, Set<String> keySet) {

         String result = value;

         Matcher matcher = pattern.matcher(value);

         while (matcher.find()) {

             // get the first, outermost ${} in the string.  removes the ${} as well.

             String key = matcher.group(1);

             String resolved = resolve(key, keySet);

             result = matcher.replaceFirst(Matcher.quoteReplacement(resolved));

             matcher = matcher.reset(result);

         }

         return result;

     }

     /**

      * This method is used when reading in new properties to check if there is a direct reference to the

      * key in the value.  This emulates operating system environment variable setting behavior 

      * and replaces the reference in the value with the current value of the property from the rawProperties.

      * <pre>

      * ex:

      * path=/usr/bin;${someVar}

      * path=${path};/some/other/path

      * 

      * resolves to:

      * path=/usr/bin;${someVar};/some/other/path

      * </pre>

      * 

      * It does not resolve the the value from rawProperties as it could contain nested properties that might change later.

      * If the property does not exist in the rawProperties it will check for a default system property now to

      * prevent a circular reference error.

      * 

      * @param name the property name

      * @param value the value to check for nested property of the same name

      * @return

      */

     protected String replaceVariable(String name, String value){

             String regex = "(?:\\$\\{"+ name +"\\})";

             String temporary = null;

             // Look for a property in the map first and use that.  If system override is true

             // then it will get overridden during the resolve phase.  If the value is null

             // we need to check the system now so we don't throw an error.

             if(value.contains("${" + name + "}")) {

                     if( (temporary = rawProperties.getProperty(name)) == null ) {

                             temporary = System.getProperty(name);

                     }

                     if(temporary != null) {

                             return value.replaceAll(regex,  Matcher.quoteReplacement(temporary));

                     }

             }   

             return value;

     }

     /**

      * This method iterates through the raw properties and stores their resolved values in the

      * resolved properties map, which acts as a cache so we don't have to run the recursion every

      * time getProperty() is called.

      */

     protected void resolveRawToCache() {

             if(rawProperties.size() > 0) {

                     Properties oldProps = new Properties(new ImmutableProperties(resolvedProperties));

                     //oldProps.putAll(new ImmutableProperties(resolvedProperties));

                     resolvedProperties.clear();

                     for(Object o : rawProperties.keySet()) {                            

                             String resolved = resolve((String)o);

                             if(LOG.isInfoEnabled()){

                                     String oldResolved = oldProps.getProperty((String)o);

                                     if(oldResolved != null && !oldResolved.equals(resolved)){

                                             String key = (String)o;

                                             String unResolved = rawProperties.getProperty(key);

                                             if(unResolved.contains("$")){

                                                     LOG.info("Resolved Config Override: " + key + "(" + unResolved +")=[" + ConfigLogger.getDisplaySafeValue(key,oldResolved) +"]->[" + ConfigLogger.getDisplaySafeValue(key,resolved) +"]");                                             

                                             }else{

                                                     LOG.info("Resolved Config Override: " + key + "=[" + ConfigLogger.getDisplaySafeValue(key,oldResolved) +"]->[" + ConfigLogger.getDisplaySafeValue(key,resolved) +"]"); 

                                             }                                            

                                     }

                             }                            

                             resolvedProperties.setProperty((String)o, resolved);

                     }

             }

     }

     /**

      * Configures built-in properties.

      */

     protected void configureBuiltIns() {

             this.setProperty("host.ip", RiceUtilities.getIpNumber());

             this.setProperty("host.name", RiceUtilities.getHostName());

     }

     /**

      * Generates a random integer in the range specified by the specifier, in the format: min-max

      * 

      * @param rangeSpec

      *            a range specification, 'min-max'

      * @return a random integer in the range specified by the specifier, in the format: min-max

      */

     protected int generateRandomInteger(String rangeSpec) {

         String[] range = rangeSpec.split("-");

         if (range.length != 2) {

             throw new RuntimeException("Invalid range specifier: " + rangeSpec);

         }

         int from = Integer.parseInt(range[0].trim());

         int to = Integer.parseInt(range[1].trim());

         if (from > to) {

             int tmp = from;

             from = to;

             to = tmp;

         }

         int num;

         // not very random huh...

         if (from == to) {

             num = from;

             if(LOG.isInfoEnabled())

             {

                     LOG.info("from==to, so not generating random value for property.");

             }

         } else {

             num = from + RANDOM.nextInt((to - from) + 1);

         }

         return num;

     }

     public boolean isSystemOverride() {

         return systemOverride;

     }

     /**

      * If set to true then system properties will always be checked first, disregarding

      * any values in the config.

      * 

      * The default is false.

      * 

      * @param systemOverride

      */

     public void setSystemOverride(boolean systemOverride) {

         this.systemOverride = systemOverride;

     }

     protected org.kuali.rice.core.impl.config.property.Config unmarshal(Unmarshaller unmarshaller, InputStream in) throws SAXException, JAXBException, ParserConfigurationException, IOException {

         SAXParserFactory spf = SAXParserFactory.newInstance();

         spf.setNamespaceAware(true);

         XMLFilter filter = new ConfigNamespaceURIFilter();

         filter.setParent(spf.newSAXParser().getXMLReader());

         UnmarshallerHandler handler = unmarshaller.getUnmarshallerHandler();

         filter.setContentHandler(handler);

         filter.parse(new InputSource(in));

         return (org.kuali.rice.core.impl.config.property.Config)handler.getResult();

     }

     /**

      *  This is a SAX filter that adds the config xml namespace to the document if the document

      *  does not have a namespace (for backwards compatibility).  This filter assumes unqualified

      *  attributes and does not modify their namespace (if any).

      *  

      *   This could be broken out into a more generic class if Rice makes more use of JAXB.

      * 

      * @author Kuali Rice Team (kuali-rice@googlegroups.com)

      *

      */

     public class ConfigNamespaceURIFilter extends XMLFilterImpl {

         public static final String CONFIG_URI="http://rice.kuali.org/core/impl/config";

         @Override

                 public void startElement(String uri, String localName, String qName, Attributes atts) throws SAXException {

             if(StringUtils.isBlank(uri)) {

                 uri = CONFIG_URI;

             }

             super.startElement(uri, localName, qName, atts);

         }

         @Override

                 public void endElement(String uri, String localName, String qName) throws SAXException {

             if(StringUtils.isBlank(uri)) {

                 uri = CONFIG_URI;

             }

             super.endElement(uri, localName, qName);

         }

     }

         @Override

         public void putObject(String key, Object value) {

                 this.objects.put(key, value);                

         }

         @Override

         public void putObjects(Map<String, Object> objects) {

                 this.objects.putAll(objects);        

         }

         @Override

         public void removeObject(String key){

                 this.objects.remove(key);

         }

         @Override

         public void removeProperty(String key){

                 this.rawProperties.remove(key);

             resolveRawToCache();

         }

         @Override

         public void putConfig(Config config) {

                 this.copyConfig(config);

         }

 }