/*
 * Interval.h - TaskJuggler
 *
 * Copyright (c) 2001, 2002, 2003, 2004 by Chris Schlaeger <cs@kde.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * $Id$
 */

#ifndef _Interval_h_
#define _Interval_h_

#include <stdio.h>
#include "Utility.h"

class Interval
{
public:
    Interval(time_t s, time_t e) : start(s), end(e) { }
    Interval(time_t s) : start(s), end(s) { }
    Interval() : start(0), end(0) { }
    Interval(const Interval& iv) : start(iv.start), end(iv.end) { }
    virtual ~Interval() { }

    bool isNull() const { return !(start < end); }

    bool contains(time_t date) const
    {
        return (start <= date) && (date <= end);
    }

    bool contains(const Interval& i) const
    {
        return (start <= i.start) && (i.end <= end);
    }
    bool overlap(const Interval& i)
    {
        // Sets the interval to the overlapping interval.
        if (end <= i.start || start >= i.end)
        {
            // Intervals do not overlap.
            end = start - 1;
            return false;
        }
        if (start < i.start)
            start = i.start;
        if (end > i.end)
            end = i.end;
        return true;
    }
    bool overlaps(const Interval& i) const
    {
        return (start <= end && i.start <= i.end &&
                ((start <= i.start && i.start <= end) ||
                 (i.start <= start && start <= i.end)));
    }
    bool prepend(const Interval& i)
    {
        if (((i.end + 1) == start) && (i.start < start))
        {
            start = i.start;
            return true;
        }
        return false;
    }
    bool append(const Interval& i)
    {
        if (((end + 1) == i.start) && ((end + 1) <= i.end))
        {
            end = i.end;
            return true;
        }
        return false;
    }
    int compare(const Interval& i) const
    {
        if (end < i.start)
            return -1;  // interval is below i
        else if (i.end < start)
            return 1;   // interval above below i
        else
            return 0;   // interval overlap
    }
    bool operator==(const Interval& i) const
    {
        return start == i.start && end == i.end;
    }
    bool operator!=(const Interval& i) const
    {
        return start != i.start || end != i.end;
    } 

    time_t getStart() const { return start; }
    void setStart(time_t s) { start = s; }

    time_t getEnd() const { return end; }
    void setEnd(time_t e) { end = e; }

    time_t getDuration() const { return end >= start ? end - start + 1: 0; }

    const Interval& firstDay()
    {
        start = midnight(start);
        end = sameTimeNextDay(start) - 1;
        return *this;
    }

    const Interval& firstWeek(bool weekStartsMonday)
    {
        start = beginOfWeek(start, weekStartsMonday);
        end = sameTimeNextWeek(start) - 1;
        return *this;
    }

    const Interval& firstMonth()
    {
        start = beginOfMonth(start);
        end = sameTimeNextMonth(start) - 1;
        return *this;
    }

    const Interval& firstQuarter()
    {
        start = beginOfQuarter(start);
        end = sameTimeNextQuarter(start) - 1;
        return *this;
    }

    const Interval& firstYear()
    {
        start = beginOfYear(start);
        end = sameTimeNextYear(start) - 1;
        return *this;
    }

protected:
    /// The start of the time interval.
    time_t start;
    /// The end of the time interval. This value is part of the interval.
    time_t end;
} ;

#endif
