/**
 * 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.camel.converter;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.camel.Converter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Converter from String syntax to milli seconds.
 */
@Converter
public final class TimePatternConverter {   
    private static final Logger LOG = LoggerFactory.getLogger(TimePatternConverter.class);
    private static final String NUMBERS_ONLY_STRING_PATTERN = "^[-]?(\\d)+$";
    private static final String REPLACEMENT_PATTERN = "[our|inute|econd](s)?";
    private static final String HOUR_REGEX_PATTERN = "((\\d)*(\\d))[h|H]";
    private static final String MINUTES_REGEX_PATTERN = "((\\d)*(\\d))[m|M]";
    private static final String SECONDS_REGEX_PATTERN = "((\\d)*(\\d))[s|S]";

    /**
     * Utility classes should not have a public constructor.
     */
    private TimePatternConverter() {
    }
    
    @Converter
    public static long toMilliSeconds(String source) throws IllegalArgumentException {
        long milliseconds = 0;
        boolean foundFlag = false;
        Matcher matcher;

        matcher = createMatcher(NUMBERS_ONLY_STRING_PATTERN, source);
        if (matcher.find()) {
            // Note: This will also be used for regular numeric strings. 
            //       This String -> long converter will be used for all strings.
            milliseconds = Long.valueOf(source).longValue();
        } else {            
            matcher = createMatcher(REPLACEMENT_PATTERN, source);
            String replacedSource = matcher.replaceAll(""); 
            
            LOG.trace("Replaced original source {} to {}", source, replacedSource);
            
            matcher = createMatcher(HOUR_REGEX_PATTERN, replacedSource);
            if (matcher.find()) {
                milliseconds = milliseconds + (3600000 * Long.valueOf(matcher.group(1)).longValue());
                foundFlag = true;
            }
            
            matcher = createMatcher(MINUTES_REGEX_PATTERN, replacedSource);            
            if (matcher.find()) {
                long minutes = Long.valueOf(matcher.group(1)).longValue();
                if ((minutes > 59) && foundFlag) {
                    throw new IllegalArgumentException("Minutes should contain a valid value between 0 and 59: " + source);
                }
                foundFlag = true;
                milliseconds = milliseconds + (60000 * minutes);
            }
               
            matcher = createMatcher(SECONDS_REGEX_PATTERN, replacedSource);
            if (matcher.find()) {
                long seconds = Long.valueOf(matcher.group(1)).longValue();
                if ((seconds > 59) && foundFlag) {
                    throw new IllegalArgumentException("Seconds should contain a valid value between 0 and 59: " + source);
                }
                foundFlag = true;
                milliseconds = milliseconds + (1000 * seconds);
            }      
            
            // No pattern matched... initiating fallback check and conversion (if required). 
            // The source at this point may contain illegal values or special characters 
            if (!foundFlag) {
                milliseconds = Long.valueOf(source).longValue();
            }
        }       
        
        LOG.trace("source: {} milliseconds: ", source, milliseconds);
        
        return milliseconds;
    }

    private static Matcher createMatcher(String regexPattern, String source) {
        Pattern pattern = Pattern.compile(regexPattern, Pattern.CASE_INSENSITIVE);
        return pattern.matcher(source);        
    }    
}
