/**
    * Copyright 2010-2012 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.common.util;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.io.Reader;
  import java.io.Writer;
  import java.nio.charset.Charset;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.Enumeration;
  import java.util.List;
  import java.util.Map;
  import java.util.Properties;
  import java.util.Set;
  import java.util.TreeSet;
  
  import org.apache.commons.io.FileUtils;
  import org.apache.commons.io.IOUtils;
  import org.apache.commons.lang3.StringUtils;
  import org.kuali.common.util.property.Constants;
  import org.kuali.common.util.property.GlobalPropertiesMode;
  import org.kuali.common.util.property.processor.AddPropertiesProcessor;
  import org.kuali.common.util.property.processor.PropertyProcessor;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.util.PropertyPlaceholderHelper;
  
  /**
   * Simplify handling of <code>Properties</code> especially as it relates to storing and loading. <code>Properties</code> can be loaded from
   * any url Spring resource loading can understand. When storing and loading, locations ending in <code>.xml</code> are automatically handled
   * using <code>storeToXML()</code> and <code>loadFromXML()</code>, respectively. <code>Properties</code> are always stored in sorted order
   * with the <code>encoding</code> indicated via a comment.
   */
  public class PropertyUtils {
  
  	private static final Logger logger = LoggerFactory.getLogger(PropertyUtils.class);
  
  	private static final String XML_EXTENSION = ".xml";
  	private static final String ENV_PREFIX = "env";
  	private static final String DEFAULT_ENCODING = Charset.defaultCharset().name();
  	private static final String DEFAULT_XML_ENCODING = "UTF-8";
  
  	public static final Properties toEmpty(Properties properties) {
  		return properties == null ? new Properties() : properties;
  	}
  
  	public static final boolean isSingleUnresolvedPlaceholder(String string) {
  		return isSingleUnresolvedPlaceholder(string, Constants.DEFAULT_PLACEHOLDER_PREFIX, Constants.DEFAULT_PLACEHOLDER_SUFFIX);
  	}
  
  	public static final boolean isSingleUnresolvedPlaceholder(String string, String prefix, String suffix) {
  		int prefixMatches = StringUtils.countMatches(string, prefix);
  		int suffixMatches = StringUtils.countMatches(string, suffix);
  		boolean startsWith = StringUtils.startsWith(string, prefix);
  		boolean endsWith = StringUtils.endsWith(string, suffix);
  		return prefixMatches == 1 && suffixMatches == 1 && startsWith && endsWith;
  	}
  
  	public static final boolean containsUnresolvedPlaceholder2(String string) {
  		int beginIndex = StringUtils.indexOf(string, Constants.DEFAULT_PLACEHOLDER_PREFIX);
  		if (beginIndex == -1) {
  			return false;
  		}
  		int endIndex = StringUtils.indexOf(string, Constants.DEFAULT_PLACEHOLDER_SUFFIX, beginIndex);
  		if (endIndex == -1) {
  			return false;
  		}
  		String substring = StringUtils.substring(string, beginIndex, endIndex);
  		return StringUtils.indexOf(substring, Constants.DEFAULT_VALUE_SEPARATOR) == -1;
  	}
  
  	public static final boolean containsUnresolvedPlaceholder(String string) {
  		return containsUnresolvedPlaceholder(string, Constants.DEFAULT_PLACEHOLDER_PREFIX, Constants.DEFAULT_PLACEHOLDER_SUFFIX);
  	}
  
  	public static final boolean containsUnresolvedPlaceholder(String string, String prefix, String suffix) {
  		int beginIndex = StringUtils.indexOf(string, prefix);
  		if (beginIndex == -1) {
  			return false;
  		}
  		return StringUtils.indexOf(string, suffix) != -1;
  	}
 
 	/**
 	 * Return a new <code>Properties</code> object containing only those properties where the resolved value is different from the original
 	 * value. Using global properties to perform property resolution as indicated by <code>Constants.DEFAULT_GLOBAL_PROPERTIES_MODE</code>
 	 */
 	public static final Properties getResolvedProperties(Properties properties) {
 		return getResolvedProperties(properties, Constants.DEFAULT_PROPERTY_PLACEHOLDER_HELPER, Constants.DEFAULT_GLOBAL_PROPERTIES_MODE);
 	}
 
 	/**
 	 * Return a new <code>Properties</code> object containing only those properties where the resolved value is different from the original
 	 * value. Using global properties to perform property resolution as indicated by <code>globalPropertiesMode</code>
 	 */
 	public static final Properties getResolvedProperties(Properties properties, GlobalPropertiesMode globalPropertiesMode) {
 		return getResolvedProperties(properties, Constants.DEFAULT_PROPERTY_PLACEHOLDER_HELPER, globalPropertiesMode);
 	}
 
 	/**
 	 * Return a new <code>Properties</code> object containing only those properties where the resolved value is different from the original
 	 * value. Using global properties to perform property resolution as indicated by <code>Constants.DEFAULT_GLOBAL_PROPERTIES_MODE</code>
 	 */
 	public static final Properties getResolvedProperties(Properties properties, PropertyPlaceholderHelper helper) {
 		return getResolvedProperties(properties, helper, Constants.DEFAULT_GLOBAL_PROPERTIES_MODE);
 	}
 
 	/**
 	 * Return a new <code>Properties</code> object containing only those properties where the resolved value is different from the original
 	 * value. Using global properties to perform property resolution as indicated by <code>globalPropertiesMode</code>
 	 */
 	public static final Properties getResolvedProperties(Properties properties, PropertyPlaceholderHelper helper, GlobalPropertiesMode globalPropertiesMode) {
 		Properties global = PropertyUtils.getProperties(properties, globalPropertiesMode);
 		List<String> keys = PropertyUtils.getSortedKeys(properties);
 		Properties newProperties = new Properties();
 		for (String key : keys) {
 			String originalValue = properties.getProperty(key);
 			String resolvedValue = helper.replacePlaceholders(originalValue, global);
 			if (!resolvedValue.equals(originalValue)) {
 				logger.debug("Resolved property '" + key + "' [{}] -> [{}]", Str.flatten(originalValue), Str.flatten(resolvedValue));
 				newProperties.setProperty(key, resolvedValue);
 			}
 		}
 		return newProperties;
 	}
 
 	/**
 	 * Return the property values from <code>keys</code>
 	 */
 	public static final List<String> getValues(Properties properties, List<String> keys) {
 		List<String> values = new ArrayList<String>();
 		for (String key : keys) {
 			values.add(properties.getProperty(key));
 		}
 		return values;
 	}
 
 	/**
 	 * Return a sorted <code>List</code> of keys from <code>properties</code> that end with <code>suffix</code>.
 	 */
 	public static final List<String> getEndsWithKeys(Properties properties, String suffix) {
 		List<String> keys = getSortedKeys(properties);
 		List<String> matches = new ArrayList<String>();
 		for (String key : keys) {
 			if (StringUtils.endsWith(key, suffix)) {
 				matches.add(key);
 			}
 		}
 		return matches;
 	}
 
 	/**
 	 * Alter the <code>properties</code> passed in to contain only the desired property values. <code>includes</code> and
 	 * <code>excludes</code> are comma separated values.
 	 */
 	public static final void trim(Properties properties, String includesCSV, String excludesCSV) {
 		List<String> includes = CollectionUtils.getTrimmedListFromCSV(includesCSV);
 		List<String> excludes = CollectionUtils.getTrimmedListFromCSV(excludesCSV);
 		trim(properties, includes, excludes);
 	}
 
 	/**
 	 * Alter the <code>properties</code> passed in to contain only the desired property values.
 	 */
 	public static final void trim(Properties properties, List<String> includes, List<String> excludes) {
 		List<String> keys = getSortedKeys(properties);
 		for (String key : keys) {
 			boolean include = include(key, includes, excludes);
 			if (!include) {
 				logger.debug("Removing [{}]", key);
 				properties.remove(key);
 			}
 		}
 	}
 
 	/**
 	 * Return true if <code>value</code> should be included, false otherwise.<br>
 	 * If <code>excludes</codes> is not empty and contains <code>value</code> return false.<br>
 	 * If <code>value</code> has not been explicitly excluded, proceed with checking the <code>includes</code> list.<br>
 	 * If <code>includes</code> is empty return true.<br>
 	 * If <code>includes</code> is not empty, return true if, and only if, <code>value</code> appears in the list.
 	 */
 	public static final boolean include(String value, List<String> includes, List<String> excludes) {
 		if (!CollectionUtils.isEmpty(excludes) && excludes.contains(value)) {
 			return false;
 		} else {
 			return CollectionUtils.isEmpty(includes) || includes.contains(value);
 		}
 	}
 
 	/**
 	 * Return property keys that should be included as a sorted list.
 	 */
 	public static final List<String> getSortedKeys(Properties properties, List<String> includes, List<String> excludes) {
 		List<String> keys = getSortedKeys(properties);
 		List<String> includedKeys = new ArrayList<String>();
 		for (String key : keys) {
 			if (include(key, includes, excludes)) {
 				includedKeys.add(key);
 			}
 		}
 		return includedKeys;
 	}
 
 	/**
 	 * Return a sorted <code>List</code> of keys from <code>properties</code> that start with <code>prefix</code>
 	 */
 	public static final List<String> getStartsWithKeys(Properties properties, String prefix) {
 		List<String> keys = getSortedKeys(properties);
 		List<String> matches = new ArrayList<String>();
 		for (String key : keys) {
 			if (StringUtils.startsWith(key, prefix)) {
 				matches.add(key);
 			}
 		}
 		return matches;
 	}
 
 	/**
 	 * Return the property keys as a sorted list.
 	 */
 	public static final List<String> getSortedKeys(Properties properties) {
 		List<String> keys = new ArrayList<String>(properties.stringPropertyNames());
 		Collections.sort(keys);
 		return keys;
 	}
 
 	public static final void show(Properties properties) {
 		List<String> keys = getSortedKeys(properties);
 		for (String key : keys) {
 			String value = Str.flatten(properties.getProperty(key));
 			logger.info(key + "=" + value);
 		}
 	}
 
 	/**
 	 * Store the properties to the indicated file using the platform default encoding.
 	 */
 	public static final void store(Properties properties, File file) {
 		store(properties, file, null);
 	}
 
 	/**
 	 * Store the properties to the indicated file using the indicated encoding.
 	 */
 	public static final void store(Properties properties, File file, String encoding) {
 		store(properties, file, encoding, null);
 	}
 
 	/**
 	 * Store the properties to the indicated file using the indicated encoding with the indicated comment appearing at the top of the file.
 	 */
 	public static final void store(Properties properties, File file, String encoding, String comment) {
 		OutputStream out = null;
 		Writer writer = null;
 		try {
 			out = FileUtils.openOutputStream(file);
 			String path = file.getCanonicalPath();
 			boolean xml = isXml(path);
 			Properties sorted = getSortedProperties(properties);
 			comment = getComment(encoding, comment, xml);
 			if (xml) {
 				logger.info("Storing XML properties - [{}] encoding={}", path, StringUtils.defaultIfBlank(encoding, DEFAULT_ENCODING));
 				if (encoding == null) {
 					sorted.storeToXML(out, comment);
 				} else {
 					sorted.storeToXML(out, comment, encoding);
 				}
 			} else {
 				writer = LocationUtils.getWriter(out, encoding);
 				logger.info("Storing properties - [{}] encoding={}", path, StringUtils.defaultIfBlank(encoding, DEFAULT_ENCODING));
 				sorted.store(writer, comment);
 			}
 		} catch (IOException e) {
 			throw new IllegalStateException("Unexpected IO error", e);
 		} finally {
 			IOUtils.closeQuietly(writer);
 			IOUtils.closeQuietly(out);
 		}
 	}
 
 	/**
 	 * Return a new properties object containing the properties from <code>getEnvAsProperties()</code> and
 	 * <code>System.getProperties()</code>. Properties from <code>System.getProperties()</code> override properties from
 	 * <code>getEnvAsProperties</code> if there are duplicates.
 	 */
 	public static final Properties getGlobalProperties() {
 		return getProperties(Constants.DEFAULT_GLOBAL_PROPERTIES_MODE);
 	}
 
 	/**
 	 * Return a new properties object containing the properties passed in, plus any properties returned by <code>getEnvAsProperties()</code>
 	 * and <code>System.getProperties()</code>. Properties from <code>getEnvAsProperties()</code> override <code>properties</code> and
 	 * properties from <code>System.getProperties()</code> override everything.
 	 */
 	public static final Properties getGlobalProperties(Properties properties) {
 		return getProperties(properties, Constants.DEFAULT_GLOBAL_PROPERTIES_MODE);
 	}
 
 	/**
 	 * Return a new properties object containing the properties passed in, plus any global properties as requested. If <code>mode</code> is
 	 * <code>NONE</code> the new properties are a duplicate of the properties passed in. If <code>mode</code> is <code>ENVIRONMENT</code>
 	 * the new properties contain the original properties plus any properties returned by <code>getEnvProperties()</code>. If
 	 * <code>mode</code> is <code>SYSTEM</code> the new properties contain the original properties plus <code>System.getProperties()</code>.
 	 * If <code>mode</code> is <code>BOTH</code> the new properties contain the original properties plus <code>getEnvProperties()</code> and
 	 * <code>System.getProperties()</code>.
 	 */
 	public static final Properties getProperties(Properties properties, GlobalPropertiesMode mode) {
 		Properties newProperties = duplicate(properties);
 		List<PropertyProcessor> modifiers = getPropertyProcessors(mode);
 		for (PropertyProcessor modifier : modifiers) {
 			modifier.process(newProperties);
 		}
 		return newProperties;
 	}
 
 	/**
 	 * Return a new properties object containing global properties as requested. If <code>mode</code> is <code>NONE</code> the new
 	 * properties are empty. If <code>mode</code> is <code>ENVIRONMENT</code> the new properties contain the properties returned by
 	 * <code>getEnvProperties()</code>. If <code>mode</code> is <code>SYSTEM</code> the new properties contain
 	 * <code>System.getProperties()</code>. If <code>mode</code> is <code>BOTH</code> the new properties contain
 	 * <code>getEnvProperties</code> plus <code>System.getProperties()</code> with system properties overriding environment variables if the
 	 * same case sensitive property key is supplied in both places.
 	 */
 	public static final Properties getProperties(GlobalPropertiesMode mode) {
 		return getProperties(new Properties(), mode);
 	}
 
 	/**
 	 * Search global properties to find a value for <code>key</code> according to the mode passed in.
 	 */
 	public static final String getProperty(String key, GlobalPropertiesMode mode) {
 		return getProperty(key, new Properties(), mode);
 	}
 
 	/**
 	 * Search <code>properties</code> plus global properties to find a value for <code>key</code> according to the mode passed in. If the
 	 * property is present in both, the value from the global properties is returned.
 	 */
 	public static final String getProperty(String key, Properties properties, GlobalPropertiesMode mode) {
 		return getProperties(properties, mode).getProperty(key);
 	}
 
 	/**
 	 * Return modifiers that add environment variables, system properties, or both, according to the mode passed in.
 	 */
 	public static final List<PropertyProcessor> getPropertyProcessors(GlobalPropertiesMode mode) {
 		List<PropertyProcessor> processors = new ArrayList<PropertyProcessor>();
 		switch (mode) {
 		case NONE:
 			return processors;
 		case ENVIRONMENT:
 			processors.add(new AddPropertiesProcessor(getEnvAsProperties()));
 			return processors;
 		case SYSTEM:
 			processors.add(new AddPropertiesProcessor(System.getProperties()));
 			return processors;
 		case BOTH:
 			processors.add(new AddPropertiesProcessor(getEnvAsProperties()));
 			processors.add(new AddPropertiesProcessor(System.getProperties()));
 			return processors;
 		default:
 			throw new IllegalStateException(mode + " is unknown");
 		}
 	}
 
 	/**
 	 * Convert the <code>Map</code> to a <code>Properties</code> object.
 	 */
 	public static final Properties convert(Map<String, String> map) {
 		Properties props = new Properties();
 		for (String key : map.keySet()) {
 			String value = map.get(key);
 			props.setProperty(key, value);
 		}
 		return props;
 	}
 
 	/**
 	 * Return a new properties object that duplicates the properties passed in.
 	 */
 	public static final Properties duplicate(Properties properties) {
 		Properties newProperties = new Properties();
 		newProperties.putAll(properties);
 		return newProperties;
 	}
 
 	/**
 	 * Return a new properties object containing environment variables as properties prefixed with <code>env</code>
 	 */
 	public static Properties getEnvAsProperties() {
 		return getEnvAsProperties(ENV_PREFIX);
 	}
 
 	/**
 	 * Return a new properties object containing environment variables as properties prefixed with <code>prefix</code>
 	 */
 	public static Properties getEnvAsProperties(String prefix) {
 		Properties properties = convert(System.getenv());
 		return getPrefixedProperties(properties, prefix);
 	}
 
 	/**
 	 * Return true if, and only if, location ends with <code>.xml</code> (case insensitive).
 	 */
 	public static final boolean isXml(String location) {
 		return StringUtils.endsWithIgnoreCase(location, XML_EXTENSION);
 	}
 
 	/**
 	 * Return a new <code>Properties</code> object loaded from <code>location</code>.
 	 */
 	public static final Properties load(String location) {
 		return load(location, null);
 	}
 
 	/**
 	 * Return a new <code>Properties</code> object loaded from <code>location</code> using <code>encoding</code>.
 	 */
 	public static final Properties load(String location, String encoding) {
 		InputStream in = null;
 		Reader reader = null;
 		try {
 			Properties properties = new Properties();
 			boolean xml = isXml(location);
 			if (xml) {
 				in = LocationUtils.getInputStream(location);
 				logger.info("Loading XML properties - [{}]", location);
 				properties.loadFromXML(in);
 			} else {
 				logger.info("Loading properties - [{}] encoding={}", location, StringUtils.defaultIfBlank(encoding, DEFAULT_ENCODING));
 				reader = LocationUtils.getBufferedReader(location, encoding);
 				properties.load(reader);
 			}
 			return properties;
 		} catch (IOException e) {
 			throw new IllegalStateException("Unexpected IO error", e);
 		} finally {
 			IOUtils.closeQuietly(in);
 			IOUtils.closeQuietly(reader);
 		}
 	}
 
 	/**
 	 * Return a new <code>Properties</code> object containing properties prefixed with <code>prefix</code>. If <code>prefix</code> is blank,
 	 * the new properties object duplicates the properties passed in.
 	 */
 	public static final Properties getPrefixedProperties(Properties properties, String prefix) {
 		if (StringUtils.isBlank(prefix)) {
 			return duplicate(properties);
 		}
 		Properties newProperties = new Properties();
 		for (String key : properties.stringPropertyNames()) {
 			String value = properties.getProperty(key);
 			String newKey = StringUtils.startsWith(key, prefix + ".") ? key : prefix + "." + key;
 			newProperties.setProperty(newKey, value);
 		}
 		return newProperties;
 	}
 
 	/**
 	 * Return a new properties object where the keys have been converted to upper case and periods have been replaced with an underscore.
 	 */
 	public static final Properties reformatKeysAsEnvVars(Properties properties) {
 		Properties newProperties = new Properties();
 		for (String key : properties.stringPropertyNames()) {
 			String value = properties.getProperty(key);
 			String newKey = StringUtils.upperCase(StringUtils.replace(key, ".", "-"));
 			newProperties.setProperty(newKey, value);
 		}
 		return newProperties;
 	}
 
 	/**
 	 * Before setting the newValue, check to see if there is a conflict with an existing value. If there is no existing value, add the
 	 * property. If there is a conflict, check <code>propertyOverwriteMode</code> to make sure we have permission to override the value.
 	 */
 	public static final void addOrOverrideProperty(Properties properties, String key, String newValue, Mode propertyOverwriteMode) {
 		String oldValue = properties.getProperty(key);
 		boolean newEqualsOld = StringUtils.equals(newValue, oldValue);
 		if (newEqualsOld) {
 			// Nothing to do! New value is the same as old value.
 			return;
 		}
 		boolean overwrite = !StringUtils.isBlank(oldValue);
 		if (overwrite) {
 			// This property already has a value, and it is different from the new value
 			// Check to make sure we are allowed to override the old value before doing so
 			ModeUtils.validate(propertyOverwriteMode, "Overriding [{}]", key, "Override of existing property [" + key + "] is not allowed.");
 		} else {
 			// There is no existing value for this key
 			logger.debug("Adding property {}=[{}]", key, Str.flatten(newValue));
 		}
 		properties.setProperty(key, newValue);
 	}
 
 	private static final String getDefaultComment(String encoding, boolean xml) {
 		if (encoding == null) {
 			if (xml) {
 				// Java defaults XML properties files to UTF-8 if no encoding is provided
 				return "encoding.default=" + DEFAULT_XML_ENCODING;
 			} else {
 				// For normal properties files the platform default encoding is used
 				return "encoding.default=" + DEFAULT_ENCODING;
 			}
 		} else {
 			return "encoding.specified=" + encoding;
 		}
 	}
 
 	private static final String getComment(String comment, String encoding, boolean xml) {
 		if (StringUtils.isBlank(comment)) {
 			return getDefaultComment(encoding, xml);
 		} else {
 			return comment + "\n#" + getDefaultComment(encoding, xml);
 		}
 	}
 
 	/**
 	 * This is private because <code>SortedProperties</code> does not fully honor the contract for <code>Properties</code>
 	 */
 	private static final SortedProperties getSortedProperties(Properties properties) {
 		SortedProperties sp = new PropertyUtils().new SortedProperties();
 		sp.putAll(properties);
 		return sp;
 	}
 
 	/**
 	 * This is private since it does not honor the full contract for <code>Properties</code>. <code>PropertyUtils</code> uses it internally
 	 * to store properties in sorted order.
 	 */
 	private class SortedProperties extends Properties {
 
 		private static final long serialVersionUID = 1330825236411537386L;
 
 		/**
 		 * <code>Properties.storeToXML()</code> uses <code>keySet()</code>
 		 */
 		@Override
 		public Set<Object> keySet() {
 			return Collections.unmodifiableSet(new TreeSet<Object>(super.keySet()));
 		}
 
 		/**
 		 * <code>Properties.store()</code> uses <code>keys()</code>
 		 */
 		@Override
 		public synchronized Enumeration<Object> keys() {
 			return Collections.enumeration(new TreeSet<Object>(super.keySet()));
 		}
 	}
 
 }