/*
 * 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.jmeter.functions;

import java.io.ObjectStreamException;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Random;

import org.apache.jmeter.engine.util.CompoundVariable;
import org.apache.jmeter.samplers.SampleResult;
import org.apache.jmeter.samplers.Sampler;
import org.apache.jmeter.threads.JMeterVariables;
import org.apache.jmeter.util.JMeterUtils;
import org.apache.jorphan.logging.LoggingManager;
import org.apache.log.Logger;
import org.apache.oro.text.MalformedCachePatternException;
import org.apache.oro.text.regex.MatchResult;
import org.apache.oro.text.regex.Pattern;
import org.apache.oro.text.regex.PatternMatcher;
import org.apache.oro.text.regex.PatternMatcherInput;
import org.apache.oro.text.regex.Perl5Compiler;
import org.apache.oro.text.regex.Util;
/**
 * Implements regular expression parsing of sample results and variables 
 */

// @see TestRegexFunction for unit tests

public class RegexFunction extends AbstractFunction implements Serializable {
	private static final Logger log = LoggingManager.getLoggerForClass();

	private static final long serialVersionUID = 232L;
	
	public static final String ALL = "ALL"; //$NON-NLS-1$

	public static final String RAND = "RAND"; //$NON-NLS-1$

	public static final String KEY = "__regexFunction"; //$NON-NLS-1$

	private Object[] values;// Parameters are stored here

	private static final Random rand = new Random();

	private static final List desc = new LinkedList();

	private transient Pattern templatePattern;// initialised to the regex \$(\d+)\$

	// Number of parameters expected - used to reject invalid calls
	private static final int MIN_PARAMETER_COUNT = 2;

	private static final int MAX_PARAMETER_COUNT = 7;
	static {
		desc.add(JMeterUtils.getResString("regexfunc_param_1"));// regex //$NON-NLS-1$
		desc.add(JMeterUtils.getResString("regexfunc_param_2"));// template //$NON-NLS-1$
		desc.add(JMeterUtils.getResString("regexfunc_param_3"));// which match //$NON-NLS-1$
		desc.add(JMeterUtils.getResString("regexfunc_param_4"));// between text //$NON-NLS-1$
		desc.add(JMeterUtils.getResString("regexfunc_param_5"));// default text //$NON-NLS-1$
		desc.add(JMeterUtils.getResString("function_name_paropt")); // output variable name //$NON-NLS-1$
        desc.add(JMeterUtils.getResString("regexfunc_param_7"));// input variable //$NON-NLS-1$
	}

	public RegexFunction() {
		initPattern();
	}

	private void initPattern() {
		templatePattern = JMeterUtils.getPatternCache().getPattern("\\$(\\d+)\\$",  //$NON-NLS-1$
				Perl5Compiler.READ_ONLY_MASK);
	}

    // For serialised objects, do the same work as the constructor:
    private Object readResolve() throws ObjectStreamException {
        initPattern();
        return this;
    }


	public synchronized String execute(SampleResult previousResult, Sampler currentSampler)
			throws InvalidVariableException {
		String valueIndex = "", defaultValue = "", between = ""; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
		String name = ""; //$NON-NLS-1$
		String inputVariable = ""; //$NON-NLS-1$
		Pattern searchPattern;
		Object[] tmplt;
		try {
			searchPattern = JMeterUtils.getPatternCache().getPattern(((CompoundVariable) values[0]).execute(),
					Perl5Compiler.READ_ONLY_MASK);
			tmplt = generateTemplate(((CompoundVariable) values[1]).execute());

			if (values.length > 2) {
				valueIndex = ((CompoundVariable) values[2]).execute();
			}
			if (valueIndex.length() == 0) {
				valueIndex = "1"; //$NON-NLS-1$
			}

			if (values.length > 3) {
				between = ((CompoundVariable) values[3]).execute();
			}

			if (values.length > 4) {
				String dv = ((CompoundVariable) values[4]).execute();
				if (dv.length() != 0) {
					defaultValue = dv;
				}
			}

			if (values.length > 5) {
				name = ((CompoundVariable) values[5]).execute();
			}

			if (values.length > 6) {
                inputVariable = ((CompoundVariable) values[6]).execute();
            }
		} catch (MalformedCachePatternException e) {
			throw new InvalidVariableException(e.toString());
		}

		// Relatively expensive operation, so do it once
		JMeterVariables vars = getVariables();
		
		if (name.length() > 0) {
		    vars.put(name, defaultValue);
		}
        
		String textToMatch=null;
		
		if (inputVariable.length() > 0){
		    textToMatch=vars.get(inputVariable);
		} else if (previousResult != null){
		    textToMatch = previousResult.getResponseDataAsString();		    
		}

        if (textToMatch == null || textToMatch.length() == 0) {
			return defaultValue;
		}

		List collectAllMatches = new ArrayList();
		try {
			PatternMatcher matcher = JMeterUtils.getMatcher();
			PatternMatcherInput input = new PatternMatcherInput(textToMatch);
			while (matcher.contains(input, searchPattern)) {
				MatchResult match = matcher.getMatch();
				collectAllMatches.add(match);
			}
		} catch (NumberFormatException e) {//TODO: can this occur?
			log.error("", e); //$NON-NLS-1$
			return defaultValue;
		} finally {
		    if (name.length() > 0){
		        vars.put(name + "_matchNr", "" + collectAllMatches.size()); //$NON-NLS-1$ //$NON-NLS-2$
		    }
		}

		if (collectAllMatches.size() == 0) {
			return defaultValue;
		}

		if (valueIndex.equals(ALL)) {
			StringBuffer value = new StringBuffer();
			Iterator it = collectAllMatches.iterator();
			boolean first = true;
			while (it.hasNext()) {
				if (!first) {
					value.append(between);
				} else {
					first = false;
				}
				value.append(generateResult((MatchResult) it.next(), name, tmplt, vars));
			}
			return value.toString();
		} else if (valueIndex.equals(RAND)) {
			MatchResult result = (MatchResult) collectAllMatches.get(rand.nextInt(collectAllMatches.size()));
			return generateResult(result, name, tmplt, vars);
		} else {
			try {
				int index = Integer.parseInt(valueIndex) - 1;
				MatchResult result = (MatchResult) collectAllMatches.get(index);
				return generateResult(result, name, tmplt, vars);
			} catch (NumberFormatException e) {
				float ratio = Float.parseFloat(valueIndex);
				MatchResult result = (MatchResult) collectAllMatches
						.get((int) (collectAllMatches.size() * ratio + .5) - 1);
				return generateResult(result, name, tmplt, vars);
			} catch (IndexOutOfBoundsException e) {
				return defaultValue;
			}
		}

	}

	private void saveGroups(MatchResult result, String namep, JMeterVariables vars) {
		if (result != null) {
			for (int x = 0; x < result.groups(); x++) {
				vars.put(namep + "_g" + x, result.group(x)); //$NON-NLS-1$
			}
		}
	}

	public List getArgumentDesc() {
		return desc;
	}

	private String generateResult(MatchResult match, String namep, Object[] template, JMeterVariables vars) {
		saveGroups(match, namep, vars);
		StringBuffer result = new StringBuffer();
		for (int a = 0; a < template.length; a++) {
			if (template[a] instanceof String) {
				result.append(template[a]);
			} else {
				result.append(match.group(((Integer) template[a]).intValue()));
			}
		}
		if (namep.length() > 0){
		    vars.put(namep, result.toString());
		}
		return result.toString();
	}

	public String getReferenceKey() {
		return KEY;
	}

	public synchronized void setParameters(Collection parameters) throws InvalidVariableException {
		checkParameterCount(parameters, MIN_PARAMETER_COUNT, MAX_PARAMETER_COUNT);
		values = parameters.toArray();
	}

	private Object[] generateTemplate(String rawTemplate) {
		List pieces = new ArrayList();
		List combined = new LinkedList();
		PatternMatcher matcher = JMeterUtils.getMatcher();
		Util.split(pieces, matcher, templatePattern, rawTemplate);
		PatternMatcherInput input = new PatternMatcherInput(rawTemplate);
		Iterator iter = pieces.iterator();
		boolean startsWith = isFirstElementGroup(rawTemplate);
		while (iter.hasNext()) {
			boolean matchExists = matcher.contains(input, templatePattern);
			if (startsWith) {
				if (matchExists) {
					combined.add(new Integer(matcher.getMatch().group(1)));
				}
				combined.add(iter.next());
			} else {
				combined.add(iter.next());
				if (matchExists) {
					combined.add(new Integer(matcher.getMatch().group(1)));
				}
			}
		}
		if (matcher.contains(input, templatePattern)) {
			combined.add(new Integer(matcher.getMatch().group(1)));
		}
		return combined.toArray();
	}

	private boolean isFirstElementGroup(String rawData) {
		Pattern pattern = JMeterUtils.getPatternCache().getPattern("^\\$\\d+\\$",  //$NON-NLS-1$
				Perl5Compiler.READ_ONLY_MASK);
		return JMeterUtils.getMatcher().contains(rawData, pattern);
	}

}
