#ifndef _utl_UTCDate_h_
#define _utl_UTCDate_h_

#include <iostream>
#include <ctime>
#include <utl/SafeBoolCast.h>


namespace utl {


  /**
    \class UTCDate UTCDate.h utl/UTCDate.h

    \author Darko Veberic
    \date 22 Jul 2009
    \version $Id$
    \ingroup time
  */

  class UTCDate : public SafeBoolCast<UTCDate> {
  public:
    enum Month {
      eJan = 1,
      eFeb = 2,
      eMar = 3,
      eApr = 4,
      eMay = 5,
      eJun = 6,
      eJul = 7,
      eAug = 8,
      eSep = 9,
      eOct = 10,
      eNov = 11,
      eDec = 12
    };

    UTCDate() : fYear(0), fMonth(0), fDay(0) { }

    /// Jan = 1, Dec = 12
    UTCDate(const int year, const int month, const int day)
    { Set(year, month, day); }

    void Set(const int year, const int month, const int day);

    int GetYear() const { return fYear; }

    int GetMonth() const { return fMonth; }

    int GetDay() const { return fDay; }

    std::string GetInAugerFormat() const;

    std::string GetInXMLFormat() const
    { return GetInXMLFormatZone("Z"); }

    bool BoolCast() const { return fYear && fMonth && fDay; }

    bool operator==(const UTCDate& d) const
    { return fYear == d.fYear && fMonth == d.fMonth && fDay == d.fDay; }

    bool operator!=(const UTCDate& d) const
    { return !operator==(d); }

    static UTCDate GetGPSEpoch() { return UTCDate(1980, eJan, 6); }

    static UTCDate GetUnixEpoch() { return UTCDate(1970, eJan, 1); }

    /// Relative to Unix epoch (1 Jan 1970 00:00:00 UTC) without leap corrections
    std::time_t GetUnixSecond() const
    { return GetUnixSecond(fYear, fMonth, fDay, 0, 0, 0); }

  protected:
    static const char* const fgMonthNames[];

    static std::time_t GetUnixSecond(const int year, const int month, const int day,
                                     const int hour, const int minute, const int second);

    std::string GetInXMLFormatZone(const char* const zone) const;

    std::istream& Parse(std::istream& is, const bool zone = true);

  private:
    static bool IsLeapYear(const int year)
    { return (!(year%4) && (year%100)) || !(year%400); }

    static
    int
    NumberOfDaysInMonth(const int year, const int month)
    {
      switch (month) {
      case eJan:
      case eMar:
      case eMay:
      case eJul:
      case eAug:
      case eOct:
      case eDec:
        return 31;
      case eFeb:
        return IsLeapYear(year) ? 29 : 28;
      case eApr:
      case eJun:
      case eSep:
      case eNov:
        return 30;
      default:
        return 0;
      }
    }

    int fYear;
    int fMonth;
    int fDay;

    friend std::istream& operator>>(std::istream&, UTCDate&);
  };


  /// output in XML schema type "Date" (UTC) compliant format
  inline std::ostream& operator<<(std::ostream& os, const UTCDate& date)
  { return os << date.GetInXMLFormat(); }


  /// read from XML schema type "Date" (any timezone) compliant format
  inline std::istream& operator>>(std::istream& is, UTCDate& date)
  { return date.Parse(is); }


}


#endif