// Purpose.  Bridge - before
//
// Discussion.  Even though Date has
// a clean interface and a well encap-
// sulated implementation, the client
// still has to recompile if the class
// architect changes his/her mind.
// Instead, create a wrapper (or inter
// face) class that contains and dele-
// gates to a body (or implementation)
// class.  Client can now specify at
// run-time exactly what s/he wants.

#include <iostream>
#include <cstdio>
using std::cout;
using std::endl;

class Date {

public:
   Date( int y, int m, int d );
   void output();

private:

#ifdef OK
   int  year_, month_, day_;
#endif

#ifdef AA
   int        toJulian(int,int,int);
   char*      fromJulian(void);
   int        julian_;
   int        year_;
#endif

};

void main( void )
{
   Date  d1( 1996, 2, 29 );
   Date  d2( 1996, 2, 30 );
   d1.output();
   d2.output();
   cout << endl;
}

/////// OK //////
// 960229  960230

/////// AA //////
// 960229  960301

#ifdef OK
Date::Date( int y, int m, int d ) {
   year_ = y;
   month_ = m;
   day_ = d;
}
void Date::output() {
   char buf[20];
   int year = year_ - (year_/100*100);
   sprintf( buf, "%02d%02d%02d",
      year, month_, day_ );
   cout << buf << "  ";
}
#endif

#ifdef AA
Date::Date( int y, int m, int d ) {
   year_   = y;
   julian_ = toJulian( y, m, d );
}
void Date::output() {
   cout << fromJulian() << "  ";
}
int Date::toJulian( int year, int month, int day ) {
   static int dayTable_[2][13] = {
      {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
      {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31} };
   int  i, leap;
   leap = year % 4 == 0 && year % 100 != 0 || year % 400 == 0;
   for (i=1; i < month; i++) day += dayTable_[leap][i];
   return( day );
}
char* Date::fromJulian( void ) {
   static int dayTable_[2][13] = {
      {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
      {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31} };
   int          i, leap, year, month, day, jul = julian_;
   static char  buf[20];
   leap = year_ % 4 == 0 && year_ % 100 != 0 || year_ % 400 == 0;
   for (i=1; jul > dayTable_[leap][i]; i++)
      jul -= dayTable_[leap][i];
   year  = year_ - (year_/100 * 100);
   month = i;
   day   = jul;
   sprintf( buf, "%02d%02d%02d", year, month, day );
   return buf;
}
#endif




#if 0

// Purpose.  Bridge - after

#include <iostream>
#include <cstdio>
#include <cstring>
using std::cout;
using std::endl;

class DateImp;

class Date {
public:
   Date( int y, int m, int d );
   ~Date();
   void output();
   static void setImp( char* t ) {
      strcpy( impType_, t ); }
private:
   DateImp*    rep_;
   static char impType_[10];
};
char Date::impType_[] = "Ok";

class DateImp { public:
   virtual void output() = 0;
};

class DateOk : public DateImp {
public:
   DateOk( int y, int m, int d );
   void output();
private:
   int  year_, month_, day_;
};

class DateAA : public DateImp {
public:
   DateAA( int y, int m, int d );
   void output();
private:
   int        toJulian(int,int,int);
   char*      fromJulian(void);
   int        julian_;
   int        year_;
};

void main( void )
{
   Date  d1( 1996, 2, 29 );
   Date  d2( 1996, 2, 30 );
   Date::setImp( "AA" );
   Date  d3( 1996, 2, 29 );
   Date  d4( 1996, 2, 30 );
   d1.output();  d2.output();
   cout << endl;
   d3.output();  d4.output();
   cout << endl;
}

// 960229  960230
// 960229  960301


Date::Date( int y, int m, int d ) {
   if ( ! strcmp( impType_, "Ok" ))
      rep_ = new DateOk( y, m, d );
   else
      rep_ = new DateAA( y, m, d );
}
Date::~Date()       { delete rep_; }
void Date::output() { rep_->output(); }


DateOk::DateOk( int y, int m, int d ) {
   year_ = y;
   month_ = m;
   day_ = d;
}
void DateOk::output() {
   char buf[20];
   int year = year_ - (year_/100*100);
   sprintf( buf, "%02d%02d%02d",
      year, month_, day_ );
   cout << buf << "  ";
}


DateAA::DateAA( int y, int m, int d ) {
   year_   = y;
   julian_ = toJulian( y, m, d );
}
void DateAA::output() {
   cout << fromJulian() << "  ";
}
int DateAA::toJulian( int year, int month, int day ) {
   static int dayTable_[2][13] = {
      {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
      {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31} };
   int  i, leap;
   leap = year % 4 == 0 && year % 100 != 0 || year % 400 == 0;
   for (i=1; i < month; i++) day += dayTable_[leap][i];
   return( day );
}
char* DateAA::fromJulian( void ) {
   static int dayTable_[2][13] = {
      {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
      {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31} };
   int          i, leap, year, month, day, jul = julian_;
   static char  buf[20];
   leap = year_ % 4 == 0 && year_ % 100 != 0 || year_ % 400 == 0;
   for (i=1; jul > dayTable_[leap][i]; i++)
      jul -= dayTable_[leap][i];
   year  = year_ - (year_/100 * 100);
   month = i;
   day   = jul;
   sprintf( buf, "%02d%02d%02d", year, month, day );
   return buf;
}

#endif