/***********************************
*       Implementation File (Date.cpp)
*
*  Private members of the class
 const int MAX_APPOINTMENTS = 10;
 float JDN;
 int numberAppointments;
 string appointments [MAX_APPOINTMENTS];
***********************************/
#include "Date.h"

// prototypes for helper functions
float today();
float jdn(int , int , int);
void mailThis( string subject, string addr, string message);

Date::Date()
// constructor. JDN is set to today
// numberAppointments = 0
{
	JDN = today();
	numberAppointments = 0;
}

Date::Date(int mm, int dd, int yyyy)
// constructor JDN is set to correspond to date specified by 
// mm dd yyyy, if it is a valid date. Otherwise JDN is set 
// for today. numberAppointments = 0;
{ // under construction
	JDN = 100.5;
	numberAppointments = 0;
}

void Date::setDate( int mm, int dd, int yyyy)
// set JDN to appropriate value
// precondition mm dd yyyy is a valid date
// otherwise set to today
{
	//under construction
	JDN = jdn(mm,dd,yyyy);
}
void Date::setDate( float jdn)
// set JDN of Date object that activeted the method to jdn.
{
	JDN=jdn;
}

float Date::getJDN()
// returns the Julian day number of the date object that activates the
// method
{
	return JDN;
}

int Date::getDayOfWeek()
// return int 0..6 representing the day of the week
{
	return int(JDN + 1.5) %7; 
}

void Date::getMonthDayYear(int & m, int &d, int &y)
// return ints representing the month, day, and year of a Date
{
int p, s1, n, s2, i,s3, q,e,s4;

    //(Eq. 3) p = int(JDN + 0.5) 
	p = int(JDN+0.5);
    //(Eq. 4) s1 = p + 68569 
	s1 = p + 68569;
    //(Eq. 5) n =int(4*s1/146097) 
	n =int(4*s1/146097);
    //(Eq. 6) s2 = s1 - (146097*n + 3)/4 
	 s2 = s1 - (146097*n + 3)/4;
    //(Eq. 7) i = 4000*(s2 + 1)/1461001. 
	i = 4000*(s2 + 1)/1461001;
    //(Eq. 8) s3 = s2 - 1461*i/4 + 31 
	s3 = s2 - 1461*i/4 + 31;
    //(Eq. 9) q = 80*s3/2447 
	q = 80*s3/2447;
    //(Eq. 10) e = s3 - 2447*q/80 
	e = s3 - 2447*q/80;
    //(Eq. 11) s4 = q/11 
	s4 = q/11;
    //(Eq. 12) m = q + 2 - 12*s4 
	m = q + 2 - 12*s4;
    //(Eq. 13) y = 100*(n - 49) + i + s4 
	y = 100*(n - 49) + i + s4;
    //(Eq. 14) d = e + J - p + 0.5 
	d = e + JDN - p + 0.5;

//The date is then day d in month m in year y. 
// taken from "Astronomy Answers Julian Day Number"
// http://www.astro.uu.nl/~strous/AA/en/reken/juliaansedag.html
}

int Date::numAppointments()
// return the number of appointments 
{
        return(numberAppointments);
}

string Date::ShowAppointment( int n)
// if 0 <= n < numberAppointments
// then return Appointment[n]
// Otherwise return "Invalid Appointment Number" + n
{
	// under construction
	return "Under Construction "+ n;
}

bool  Date::SetAppointment( string appt)
        // if  numberAppointments < MAX_APPOINTMENTS
        // then add appt as Appointment[numberAppointments++]
        // return true
        // Otherwise return false.
{
	if (numberAppointments < MAX_APPOINTMENTS) {
		appointments[numberAppointments++] = appt;	
		return true;
	}
	return false;
}



bool Date::equals(Date N)
// Suppose this is activated by a date object D as 
// D.equals(N). This returns true if and only if
// D.JDN = N.JDN, 
{
	// under construction
	return true;
}

bool Date::lessThan(Date N)
// returns true only if D.JDN < N.JDN
{
	// under construction
	return true;
}

bool Date::greaterThan(Date N)
// returns true only if D.JDN > N.JDN
{
	// under construction
	return true;
}

void Date::mailAppointments( string  subject, string sendTo )
// send the appointments for the object that activated this method as email
// parameters
//    subject holds the subject of the email sent
//    sendTo holds the email address that will receive the appointments
// if there are no appointments then no email is sent, otherwise the
// appointments are sent as one message
{
	int curAppointment; // points to current appointment
	string allAppointments; // holds all appointments

	if (numberAppointments == 0) return;

	// build the message
	allAppointments = "";
	for (curAppointment =0; curAppointment < numberAppointments;
	     curAppointment ++) {
		allAppointments = allAppointments + 
				  appointments[curAppointment] +
				  "\n";
	}

	//send the email
	mailThis(subject, sendTo, allAppointments);

	//that's it!
}


// Helper functions

float today()
{
#include <time.h>
  time_t rawtime;
  struct tm * timeinfo;
  int mm, dd, yyyy;
  float julian;

  time ( &rawtime );
  timeinfo = localtime ( &rawtime );
  yyyy = timeinfo->tm_year + 1900;
  mm = timeinfo->tm_mon+1;
  dd =	timeinfo->tm_mday;
  julian = jdn(mm,dd,yyyy);
  return julian;
}

float jdn( int m, int d, int y)
{
	int A, B, C, E, F;
	// under construction 
	// got the algorthim at
	//http://quasar.as.utexas.edu/BillInfo/JulianDatesG.html
	// assume the date is valid
	if (m < 3) {
		m = m + 12;
		y = y -1;
	}

	// assume that we are using this for the modern era
	A = y/100;
	B = A/4;
	C = 2 - A + B;
	// convert years to days
	E = 365.25 * y;
	// do the thing with the month
	F = 30.6001 * (m + 1);

	return C+d+E+F+1720994.5;
}

#include <cstdio>
#include <string.h>

void mailThis( string subject, string sendto, string body)
{
        FILE *fin;
        string complete;
        char * mailstr;
        complete = "mailx -s '" + subject + "' " + sendto;
        mailstr = complete.c_str();

        if ((fin = popen(mailstr, "w")) == NULL) {
                fprintf(stderr, " can't run %s\n", body);
                exit(1);
        }
        fprintf(fin,"%s",body.c_str());
        fflush(fin);
        pclose(fin);
}