#include "Date.h"


Date::Date( )
{
    setDate( 1, 1, 1600 );
}

Date::Date( int m, int d, int y )
{
    setDate( m, d, y );
}

Date::Date( const string & m, int d, int y )
{
    setDate( MonthInfo::getMonth( m ), d, y );
}

void Date::setDate( int m, int d, int y )
{
    if( m < 0 || m > 12 || y < 1600 || y > 2500 || d < 0 || d > MonthInfo::daysInMonth( m, y ) )
    {
        cerr << "Bad date!! (" << m << " " << d << " " << y << " " << endl;
        m = 1; d = 1; y = 1600;
    }
    month = m;
    day = d;
    year = y;
}

void Date::printDate( ostream & out ) const
{
    out << MonthInfo::getMonth( month ) << " " << day << ", " << year;
}

bool Date::equals( const Date & rhs ) const
{
    return month == rhs.month && day == rhs.day && year == rhs.year;
}

bool Date::lessThan( const Date & rhs ) const
{
    if( year != rhs.year )
        return year < rhs.year;

    if( month != rhs.month )
        return month < rhs.month;

    return day < rhs.day;
}

int Date::daysBetween( const Date & rhs ) const
{
    if( equals( rhs ) )
        return 0;
    if( lessThan( rhs ) )
        return - rhs.daysBetween( *this );

    // This is the later date!
    int answer;
    Date earlier = rhs;

    for( answer = 0; !equals( earlier ); answer++ )
        earlier = earlier.dateAfter( );

    return answer;
}

Date Date::dateAfter( ) const
{
    Date next = *this;

    if( next.day < MonthInfo::daysInMonth( next.month, next.year ) )
    {
        next.day++;
    }
    else
    {
        next.day = 1;
        if( next.month != 12 )
            next.month++;
        else
        {
            next.month = 1;
            next.year++;
        }
    }

    return next;
}

Date Date::futureDate( int numDays ) const
{
    Date future = *this;

    if( numDays < 0 )
        cerr << "numDays is negative; not the future." << endl;

    for( int i = 0; i < numDays; i++ )
        future = future.dateAfter( );

    return future;
}

bool MonthInfo::isLeapYear( int y )
{
    return ( y % 400 == 0 ) || ( y % 4 == 0 && y % 100 != 0 );
}

int MonthInfo::daysInMonth( int m, int y )
{
    switch( m )
    {
      case 2: return isLeapYear( y ) ? 29 : 28;

      case 1:
      case 3:
      case 5:
      case 7:
      case 8:
      case 10:
      case 12:
             return 31;

      default:
             return 30;
    }
}


const string MonthInfo::monthArray[ ] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun",
                                          "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };

int MonthInfo::getMonth( const string & m )
{
    int i;

    for( i = 0; i < 12; i++ )
        if( monthArray[ i ] == m )
            break;

    return i + 1;
}

string MonthInfo::getMonth( int m )
{
    if( m < 1 || m > 12 )
        return "???";
    else
        return monthArray[ m - 1 ];
}