/*
 * 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.
 */
package org.apache.wicket.protocol.http.servlet;

import java.util.List;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

import javax.servlet.http.HttpServletRequest;

import org.apache.wicket.util.lang.Generics;
import org.apache.wicket.util.string.Strings;

/**
 * A factory of {@link HttpServletRequest} wrappers.
 * 
 * @author Juergen Donnerstag
 */
public abstract class AbstractRequestWrapperFactory
{
        /**
         * {@link Pattern} for a comma delimited string that support whitespace characters
         */
        private static final Pattern commaSeparatedValuesPattern = Pattern.compile("\\s*,\\s*");

        private boolean enabled = true;

        /**
         * Construct.
         */
        public AbstractRequestWrapperFactory()
        {
        }

        /**
         * 
         * @return {@code true} if filter is enabled
         */
        public final boolean isEnabled()
        {
                return enabled;
        }

        /**
         * Enable or disable the filter
         * 
         * @param enabled
         */
        public final void setEnabled(boolean enabled)
        {
                this.enabled = enabled;
        }

        /**
         * Wrap the given request.
         * 
         * @param request request to wrap
         * @return Either return the request itself, or if needed a wrapper for the request
         */
        public HttpServletRequest getWrapper(final HttpServletRequest request)
        {
                if (isEnabled() && needsWrapper(request))
                {
                        return newRequestWrapper(request);
                }
                return request;
        }

        /**
         * @param request
         * @return True, if a wrapper is needed
         */
        protected abstract boolean needsWrapper(final HttpServletRequest request);

        /**
         * @param request
         * @return Create a wrapper for the request
         */
        public abstract HttpServletRequest newRequestWrapper(HttpServletRequest request);

        /**
         * Convert a given comma delimited list of regular expressions into an array of compiled
         * {@link Pattern}
         * 
         * @param commaDelimitedPatterns
         * @return array of patterns (not <code>null</code>)
         */
        public static Pattern[] commaDelimitedListToPatternArray(
                final String commaDelimitedPatterns)
        {
                String[] patterns = commaDelimitedListToStringArray(commaDelimitedPatterns);
                List<Pattern> patternsList = Generics.newArrayList();
                for (String pattern : patterns)
                {
                        try
                        {
                                patternsList.add(Pattern.compile(pattern));
                        }
                        catch (PatternSyntaxException e)
                        {
                                throw new IllegalArgumentException("Illegal pattern syntax '" + pattern + "'", e);
                        }
                }
                return patternsList.toArray(new Pattern[patternsList.size()]);
        }

        /**
         * Convert a given comma delimited list of regular expressions into an array of String
         * 
         * @param commaDelimitedStrings
         * @return array of patterns (non <code>null</code>)
         */
        public static String[] commaDelimitedListToStringArray(final String commaDelimitedStrings)
        {
                if (Strings.isEmpty(commaDelimitedStrings))
                {
                        return new String[0];
                }
                else
                {
                        return commaSeparatedValuesPattern.split(commaDelimitedStrings);
                }
        }

        /**
         * Convert an array of strings in a comma delimited string
         * 
         * @param stringList
         * @return xxx
         */
        public static String listToCommaDelimitedString(final List<String> stringList)
        {
                return Strings.join(", ", stringList);
        }

        /**
         * 
         * @param str
         * @param patterns
         * @return Return <code>true</code> if the given <code>str</code> matches at least one of the
         *         given <code>patterns</code>.
         */
        public static boolean matchesOne(final String str, final Pattern... patterns)
        {
                for (Pattern pattern : patterns)
                {
                        if (pattern.matcher(str).matches())
                        {
                                return true;
                        }
                }
                return false;
        }
}