/*
 * Copyright 2005 the original author or authors.
 * 
 * Licensed 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.wamblee.crawler.kiss;

/**
 * Time interval. 
 */
public class TimeInterval {

    /**
     * Begin time. 
     */
    private Time _begin;

    /**
     * End time. 
     */
    private Time _end;

    /**
     * Construts the interval. 
     * @param aBegin Start time. 
     * @param aEnd End time. 
     */
    public TimeInterval(Time aBegin, Time aEnd) {
        _begin = aBegin;
        _end = aEnd;
    }

    /**
     * Gets the begin time. 
     * @return Begin time.  
     */
    public Time getBegin() {
        return _begin;
    }

    /**
     * Gets the end time. 
     * @return End time. 
     */
    public Time getEnd() {
        return _end;
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.lang.Object#toString()
     */
    @Override
    public String toString() {
        return _begin + " - " + _end;
    }

    /**
     * Determines if there is an overlap between the current interval and given
     * one.
     * 
     * @param aInterval
     *            Interval to compare with.
     * @return True iff there is overlap
     */
    public boolean overlap(TimeInterval aInterval) {

        if (isUncertain() || aInterval.isUncertain()) {
            // Optimistic assume there is no overlap if one of the intervals is
            // uncertain.
            return false;
        }

        if (_end.asFloat() <= aInterval._begin.asFloat()
                || aInterval._end.asFloat() <= _begin.asFloat()) {
            return false;
        }

        return true;
    }

    /**
     * Determines if the actual time that the program corresponds to is
     * uncertain due to the representation of a period of more than 24 hours
     * using a 24 hour clock.
     * 
     * @return True iff the interval is uncertain.
     */
    boolean isUncertain() {
        return _begin.asFloat() > _end.asFloat();
    }
    
    /* (non-Javadoc)
     * @see java.lang.Object#equals(java.lang.Object)j
     */
    @Override
    public boolean equals(Object obj) {
        if ( !(obj instanceof TimeInterval)) { 
            return false; 
        } 
        return obj.toString().equals(obj.toString());
    }
    
    /* (non-Javadoc)
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        return _begin.hashCode();
    }
}