/* - mode: c; c-basic-offset: 2; indent-tabs-mode: nil; -*-
 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
 *
 *  Copyright (C) 2008-2009 Sun Microsystems
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

/**
 * @file
 *
 * Defines the API for dealing with temporal data inside the server.
 *
 * The Temporal class is the base class for all data of any temporal
 * type.  A number of derived classes define specialized classes
 * representng various date, date-time, time, or timestamp types.
 *
 * All Temporal derived classes are ValueObjects.  That is to say that
 * Temporal class instances are not part of the Item hierarchy and serve
 * <em>only</em> to represent a time or date-related piece of data.
 *
 * @note
 *
 * Low-level calendrical calculations are done via routines in the
 * calendar.cc file.
 *
 * @see drizzled/calendar.cc
 */

#ifndef DRIZZLED_TEMPORAL_H
#define DRIZZLED_TEMPORAL_H

#define DRIZZLE_MAX_SECONDS 59
#define DRIZZLE_MAX_MINUTES 59
#define DRIZZLE_MAX_HOURS 23
#define DRIZZLE_MAX_DAYS 31
#define DRIZZLE_MAX_MONTHS 12
#define DRIZZLE_MAX_YEARS_SQL 9999
#define DRIZZLE_MAX_YEARS_EPOCH 2038
#define DRIZZLE_MIN_SECONDS 0
#define DRIZZLE_MIN_MINUTES 0
#define DRIZZLE_MIN_HOURS 0
#define DRIZZLE_MIN_DAYS 1
#define DRIZZLE_MIN_MONTHS 1
#define DRIZZLE_MIN_YEARS_SQL 1
#define DRIZZLE_MIN_YEARS_EPOCH 1970

#define DRIZZLE_SECONDS_IN_MINUTE 60
#define DRIZZLE_SECONDS_IN_HOUR (60*60)
#define DRIZZLE_SECONDS_IN_DAY (60*60*24)
#define DRIZZLE_NANOSECONDS_IN_MICROSECOND 1000

#define DRIZZLE_MAX_LENGTH_DATETIME_AS_STRING 40

#define DRIZZLE_YY_PART_YEAR  70

#include "drizzled/calendar.h"

#include <cassert>
#include <ostream>

/* Outside forward declarations */
class my_decimal;

namespace drizzled
{

/* Forward declaration needed */
class TemporalInterval;
class TemporalIntervalYear;
class TemporalIntervalDayOrLess;
class TemporalIntervalDayOrWeek;
class TemporalIntervalYearMonth;

/**
 * Base class for all temporal data classes.
 */
class Temporal
{
protected:
  enum calendar _calendar;
  uint32_t _years;
  uint32_t _months;
  uint32_t _days;
  uint32_t _hours;
  uint32_t _minutes;
  uint32_t _seconds;
  time_t _epoch_seconds;
  uint32_t _useconds;
  uint32_t _nseconds;
  /** Set on some operator overloads.  Indicates that an overflow occurred. */
  bool _overflow;
  /** Returns number of seconds in time components (hour + minute + second) */
  uint64_t _cumulative_seconds_in_time() const;
  /** Resets all temporal components to zero */
  inline void _reset()
  {
    _years= _months= _days= _hours= _minutes=
      _seconds= _epoch_seconds= _useconds= _nseconds= 0;
  }

public:
  Temporal();
  virtual ~Temporal() {}

  /** Returns the calendar component. */
  inline enum calendar calendar() const {return _calendar;}
  /** Sets the nseconds component. */
  inline void set_nseconds(const uint32_t nsecond) {_nseconds= nsecond;}
  /** Returns the nanoseconds component. */
  inline uint32_t nseconds() const {return _nseconds;}
  /** Sets the useconds component. */
  inline void set_useconds(const uint32_t usecond) {_useconds= usecond;}
  /** Returns the microsseconds component. */
  inline uint32_t useconds() const {return _useconds;}
  /**
   * Sets the epoch_seconds component automatically,
   * based on the temporal's components.
   */
  void set_epoch_seconds();
  /** Sets the epch_seconds component manually. */
  inline void set_epoch_seconds(const uint32_t epoch_second)
  {_epoch_seconds= epoch_second;}
  /** Returns the UNIX epoch seconds component. */
  inline time_t epoch_seconds() const {return _epoch_seconds;}
  /** Sets the seconds component. */
  inline void set_seconds(const uint32_t second) {_seconds= second;}
  /** Returns the seconds component. */
  inline uint32_t seconds() const {return _seconds;}
  /** Sets the days component. */
  inline void set_minutes(const uint32_t minute) {_minutes= minute;}
  /** Returns the minutes component. */
  inline uint32_t minutes() const {return _minutes;}
  /** Sets the hours component. */
  inline void set_hours(const uint32_t hour) {_hours= hour;}
  /** Returns the hours component. */
  inline uint32_t hours() const {return _hours;}
  /** Sets the days component. */
  inline void set_days(const uint32_t day) {_days= day;}
  /** Returns the days component. */
  inline uint32_t days() const {return _days;}
  /** Sets the months component. */
  inline void set_months(const uint32_t month) {_months= month;}
  /** Returns the months component. */
  inline uint32_t months() const {return _months;}
  /** Sets the years component. */
  inline void set_years(const uint32_t year) {_years= year;}
  /** Returns the years component. */
  inline uint32_t years() const {return _years;}
  /** Returns whether the overflow flag was set
   *  (which can occur during an overloaded operator's execution) */
  inline bool overflow() const {return _overflow;}

  /** Returns whether the temporal value is valid as a date. */
  virtual bool is_valid_date() const= 0;
  /** Returns whether the temporal value is valid as a datetime. */
  virtual bool is_valid_datetime() const= 0;
  /** Returns whether the temporal value is valid as a time. */
  virtual bool is_valid_time() const= 0;
  /** Returns whether the temporal value is valid as a UNIX timestamp. */
  virtual bool is_valid_timestamp() const= 0;

  /**
   * Returns whether the temporal
   * value is valid. Each subclass defines what is
   * valid for the range of temporal data it contains.
   */
  virtual bool is_valid() const= 0;

  /**
   * All Temporal derived classes must implement
   * conversion routines for converting to and from
   * a string. Subclasses implement other conversion
   * routines, but should always follow these notes:
   *
   * 1) Ensure that ALL from_xxx methods call is_valid()
   * 2) Ensure that ALL to_xxx methods are void returns and
   *    do not call is_valid()
   *
   * This minimizes the repeated bounds-checking to
   * just the conversion from_xxx routines.
   */
  friend class TemporalFormat;
};

/* Forward declaration needed */
class DateTime;
class Timestamp;
class Time;

/**
 * Class representing temporal components in a valid
 * SQL date range, with no time component
 */
class Date: public Temporal
{
public:
  Date() :Temporal() {}
  /**
   * Comparison operator overloads to compare a Date against
   * another Date value.
   *
   * @param Date to compare against.
   */
  virtual bool operator==(const Date &rhs);
  virtual bool operator!=(const Date &rhs);
  virtual bool operator>(const Date &rhs);
  virtual bool operator>=(const Date &rhs);
  virtual bool operator<(const Date &rhs);
  virtual bool operator<=(const Date &rhs);

  /**
   * Comparison operator overloads to compare a Date against
   * a DateTime value.
   *
   * @param DateTime to compare against.
   */
  virtual bool operator==(const DateTime &rhs);
  virtual bool operator!=(const DateTime &rhs);
  virtual bool operator>(const DateTime &rhs);
  virtual bool operator>=(const DateTime &rhs);
  virtual bool operator<(const DateTime &rhs);
  virtual bool operator<=(const DateTime &rhs);

  /**
   * Comparison operator overloads to compare this against
   * a Timestamp value.
   *
   * @param Timestamp to compare against.
   */
  virtual bool operator==(const Timestamp &rhs);
  virtual bool operator!=(const Timestamp &rhs);
  virtual bool operator>(const Timestamp &rhs);
  virtual bool operator>=(const Timestamp &rhs);
  virtual bool operator<(const Timestamp &rhs);
  virtual bool operator<=(const Timestamp &rhs);

  /**
   * Operator overload for adding/subtracting another Date
   * (or subclass) to/from this temporal.  When subtracting
   * or adding two Dates, we return a new Date instance.
   *
   * @param Date instance to add/subtract to/from
   */
  const Date operator-(const Date &rhs);
  const Date operator+(const Date &rhs);
  Date& operator+=(const Date &rhs);
  Date& operator-=(const Date &rhs);

  /**
   * Operator to add/subtract a Time from a Time.
   * We can return a Time new temporal instance.
   *
   * @param Temporal instance to add/subtract to/from
   */
  const Date operator-(const Time &rhs);
  const Date operator+(const Time &rhs);
  Date& operator-=(const Time &rhs);
  Date& operator+=(const Time &rhs);


  /**
   * Operator overload for adding/subtracting a DateTime
   * (or subclass) to/from this temporal.  When subtracting
   * or adding two Dates, we return a new Date instance.
   *
   * @param DateTime instance to add/subtract to/from
   */
  const Date operator-(const DateTime &rhs);
  const Date operator+(const DateTime &rhs);
  Date& operator+=(const DateTime &rhs);
  Date& operator-=(const DateTime &rhs);


  /**
   * Operator overload for when a DateTime instance is
   * assigned to a Date.  We do a copy of the DateTime's
   * date-related components.
   *
   * @param The DateTime to copy from
   */
  Date& operator=(const DateTime &rhs);

  virtual bool is_valid_date() const {return is_valid();}
  virtual bool is_valid_datetime() const {return is_valid();}
  virtual bool is_valid_time() const {return false;}
  virtual bool is_valid_timestamp() const
  {
    return is_valid() && in_unix_epoch();
  }

  /** Returns whether the temporal value is valid date. */
  virtual bool is_valid() const;
  /* Returns whether the Date (or subclass) instance is in the Unix Epoch. */
  virtual bool in_unix_epoch() const;

  /**
   * Fills a supplied char string with a
   * string representation of the Date
   * value.
   *
   * @param C-String to fill.
   * @param Length of to C-String
   * @returns length of string written (including trailing '\0').
   *          If output was truncated, returns length that would have
   *          been outputted.
   */
  virtual int to_string(char *to, size_t to_len) const;

  /**
   * Maximum length of C-String needed to represent type
   * (including '\0').
   */
  static const int MAX_STRING_LENGTH= 11;

  /**
   * Attempts to populate the Date instance based
   * on the contents of a supplied string.
   *
   * Returns whether the conversion was
   * successful.
   *
   * @param String to convert from
   * @param Length of supplied string (not including trailing '\0').
   */
  virtual bool from_string(const char *from, size_t from_len);

  /**
   * Fills a supplied 8-byte integer pointer with an
   * integer representation of the Date
   * value.
   *
   * @param Integer to fill.
   */
  virtual void to_int64_t(int64_t *to) const;

  /**
   * Fills a supplied 4-byte integer pointer with an
   * integer representation of the Date
   * value.
   *
   * @param Integer to fill.
   */
  virtual void to_int32_t(int32_t *to) const;

  /**
   * Attempts to populate the Date instance based
   * on the contents of a supplied 4-byte integer.
   *
   * Returns whether the conversion was
   * successful.
   *
   * @param Integer to convert from
   */
  virtual bool from_int32_t(const int32_t from);

  /**
   * Fills a supplied int64_t with the Julian Day Number
   * representation of this Date.
   *
   * @note Julian Day Number != julian day!
   *
   * Julian Day Number is the monotonically increasing number
   * of days from the start of the Julian calendar (~4713 B.C.)
   *
   * julian day is the ordinal day number of a day in a year.
   *
   * @param int64_t to fill
   */
  void to_julian_day_number(int64_t *to) const;

  /**
   * Attempts to populate the Date instance based
   * on the contents of a supplied Julian Day Number
   *
   * Returns whether the conversion was
   * successful.
   *
   * @param Integer to convert from
   */
  bool from_julian_day_number(const int64_t from);

  /**
   * Fills a supplied tm pointer with an
   * representation of the Date
   * value.
   *
   * @param tm to fill.
   */
  virtual void to_tm(struct tm *to) const;

  /**
   * Attempts to populate the Date instance based
   * on the contents of a supplied pointer to struct tm
   * (broken time).
   *
   * Returns whether the conversion was
   * successful.
   *
   * @param Pointe rto the struct tm to convert from
   */
  virtual bool from_tm(const struct tm *from);

  /**
   * Attempts to convert the Date value into
   * a supplied time_t.
   *
   * @param Pointer to a time_t to convert to
   */
  virtual void to_time_t(time_t *to) const;

  /**
   * Attempts to populate the Date instance based
   * on the contents of a supplied time_t
   *
   * Returns whether the conversion was
   * successful.
   *
   * @param time_t to convert from
   */
  virtual bool from_time_t(const time_t from);

  /**
   * Fills a supplied my_decimal with a representation of
   * the Date value.
   *
   * @param Pointer to the my_decimal to fill
   */
  virtual void to_decimal(my_decimal *to) const;

  friend class TemporalInterval;
  friend class Timestamp;
};

/* Forward declare needed for friendship */
class DateTime;

/**
 * Class representing temporal components having only
 * a time component, with no date structure
 */
class Time: public Temporal
{
public:
  Time() :Temporal() {}
  /* Maximum number of seconds in 23:59:59 (24 * 60 * 60) */
  static const uint32_t MAX_CUMULATIVE_SECONDS= 86400L;

  /**
   * Comparison operator overloads to compare a Time against
   * another Time value.
   *
   * @param Time to compare against.
   */
  bool operator==(const Time &rhs);
  bool operator!=(const Time &rhs);
  bool operator>(const Time &rhs);
  bool operator>=(const Time &rhs);
  bool operator<(const Time &rhs);
  bool operator<=(const Time &rhs);
  /**
   * Operator to add/subtract a Time from a Time.
   * We can return a Time new temporal instance.
   *
   * @param Temporal instance to add/subtract to/from
   */
  const Time operator-(const Time &rhs);
  const Time operator+(const Time &rhs);
  Time& operator-=(const Time &rhs);
  Time& operator+=(const Time &rhs);

  bool is_valid_date() const {return false;}
  bool is_valid_datetime() const {return false;}
  bool is_valid_time() const {return is_valid();}
  bool is_valid_timestamp() const {return false;}
  /** Returns whether the temporal value is valid date. */
  bool is_valid() const;

  /**
   * Fills a supplied char string with a
   * string representation of the Time
   * value.
   *
   * @param C-String to fill
   * @param Length of to C-String
   * @returns length of string written (not including trailing '\0').
   *          If output was truncated, returns length that would have
   *          been outputted.
   */
  int to_string(char *to, size_t to_len) const;

  /**
   * Maximum length of C-String needed to represent type
   * (including '\0').
   */
  static const int MAX_STRING_LENGTH= 9;


  /**
   * Attempts to populate the Time instance based
   * on the contents of a supplied string.
   *
   * Returns whether the conversion was
   * successful.
   *
   * @param String to convert from
   * @param Length of supplied string
   */
  bool from_string(const char *from, size_t from_len);

  /**
   * Fills a supplied 4-byte integer pointer with an
   * integer representation of the Time
   * value.
   *
   * @param Integer to fill.
   */
  void to_int32_t(int32_t *to) const;

  /**
   * Attempts to populate the Time instance based
   * on the contents of a supplied 4-byte integer.
   *
   * Returns whether the conversion was
   * successful.
   *
   * @param Integer to convert from
   */
  bool from_int32_t(const int32_t from);

  /**
   * Attempts to populate the Time instance based
   * on the contents of a supplied time_t
   *
   * Returns whether the conversion was
   * successful.
   *
   * @note
   *
   * We can only convert *from* a time_t, not back
   * to a time_t since it would be a lossy conversion.
   *
   * @param time_t to convert from
   */
  bool from_time_t(const time_t from);

  /**
   * Fills a supplied my_decimal with a representation of
   * the Time value.
   *
   * @param Pointer to the my_decimal to fill
   */
  void to_decimal(my_decimal *to) const;

  friend class Date;
  friend class DateTime;
};

/**
 * Class representing temporal components in a valid
 * SQL datetime range, including a time component
 */
class DateTime: public Date
{
public:
  DateTime() :Date() {}

  friend class TemporalInterval;

  /** Returns whether the DateTime (or subclass) instance
   *  is in the Unix Epoch.
   */
  bool in_unix_epoch() const;
  /** Returns whether the temporal value is valid datetime. */
  virtual bool is_valid() const;

  /**
   * It's not possible to convert to and from a DateTime and
   * a 4-byte integer, so let us know if we try and do it!
   */
  void to_int32_t(int32_t *) const {assert(0);}
  bool from_int32_t(int32_t) {assert(0); return false;}

  /**
   * Fills a supplied char string with a
   * string representation of the DateTime
   * value.
   *
   * @param C-String to fill
   * @param Length of to C-String
   * @returns length of string written (not including trailing '\0').
   *          If output was truncated, returns length that would have
   *          been outputted.
   */
  virtual int to_string(char *to, size_t to_len) const;

  /**
   * Maximum length of C-String needed to represent type
   * (including '\0').
   */
  static const int MAX_STRING_LENGTH= 27;

  /**
   * Attempts to populate the DateTime instance based
   * on the contents of a supplied string.
   *
   * Returns whether the conversion was
   * successful.
   *
   * @param String to convert from
   * @param Length of supplied string
   */
  bool from_string(const char *from, size_t from_len);

  /**
   * Fills a supplied 8-byte integer pointer with an
   * integer representation of the DateTime
   * value.
   *
   * @param Integer to fill.
   */
  void to_int64_t(int64_t *to) const;

  /**
   * Attempts to populate the DateTime instance based
   * on the contents of a supplied time_t
   *
   * Returns whether the conversion was
   * successful.
   *
   * @param time_t to convert from
   */
  bool from_time_t(const time_t from);

  /**
   * Attempts to populate the DateTime instance based
   * on the contents of a supplied 8-byte integer.
   *
   * Returns whether the conversion was
   * successful.
   *
   * @param Integer to convert from
   * @param convert if conversion to canonical representation
   *        should be attempted
   */
  bool from_int64_t(const int64_t from, bool convert);

  bool from_int64_t(const int64_t from) {
    return from_int64_t(from, true);
  }

  /**
   * Fills a supplied tm pointer with an
   * representation of the DateTime
   * value.
   *
   * @param tm to fill.
   */
  void to_tm(struct tm *to) const;

  /**
   * Fills a supplied my_decimal with a representation of
   * the DateTime value.
   *
   * @param Pointer to the my_decimal to fill
   */
  void to_decimal(my_decimal *to) const;

  friend class Timestamp;
};

/**
 * Class representing temporal components in the UNIX epoch
 */
class Timestamp: public DateTime
{
public:
  Timestamp() :DateTime() {}

  /**
   * Comparison operator overloads to compare this against
   * a Date value.
   *
   * @param Timestamp to compare against.
   */
  bool operator==(const Date &rhs);
  bool operator!=(const Date &rhs);
  bool operator>(const Date &rhs);
  bool operator>=(const Date &rhs);
  bool operator<(const Date &rhs);
  bool operator<=(const Date &rhs);

  /**
   * Comparison operator overloads to compare this against
   * a DateTime value.
   *
   * @param DateTime to compare against.
   */
  bool operator==(const DateTime &rhs);
  bool operator!=(const DateTime &rhs);
  bool operator>(const DateTime &rhs);
  bool operator>=(const DateTime &rhs);
  bool operator<(const DateTime &rhs);
  bool operator<=(const DateTime &rhs);

  /**
   * Comparison operator overloads to compare this against
   * another Timestamp value.
   *
   * @param Timestamp to compare against.
   */
  bool operator==(const Timestamp &rhs);
  bool operator!=(const Timestamp &rhs);
  bool operator>(const Timestamp &rhs);
  bool operator>=(const Timestamp &rhs);
  bool operator<(const Timestamp &rhs);
  bool operator<=(const Timestamp &rhs);

  bool is_valid_timestamp() const {return is_valid();}
  /** Returns whether the temporal value is valid timestamp. */
  virtual bool is_valid() const;

  /**
   * Attempts to convert the Timestamp value into
   * a supplied time_t.
   *
   * @param Pointer to a time_t to convert to
   */
  void to_time_t(time_t *to) const;
};

/**
 * Operator overload to an output stream for a Timestamp.
 */
std::ostream& operator<<(std::ostream& os, const Timestamp& subject);

/**
 * Class representing temporal components in the UNIX epoch
 * with an additional microsecond component.
 */
class MicroTimestamp: public Timestamp
{
public:
  MicroTimestamp() :Timestamp() {}
  /** Returns whether the temporal value is valid micro-timestamp. */
  bool is_valid() const;

  /**
   * Fills a supplied char string with a
   * string representation of the MicroTimestamp
   * value.
   *
   * @param C-String to fill
   * @param Length of to C-String
   * @returns length of string written (not including trailing '\0').
   *          If output was truncated, returns length that would have
   *          been outputted.
   */
  int to_string(char *to, size_t to_len) const;

  /**
   * Maximum length of C-String needed to represent type
   * (including '\0').
   */
  static const int MAX_STRING_LENGTH= 27;

  /**
   * Fills a supplied timeval pointer with an
   * representation of the MicroTimestamp
   * value.
   *
   * Returns whether the conversion was
   * successful.
   *
   * @param timeval to fill.
   */
  void to_timeval(struct timeval *to) const;
};

/**
 * Class representing temporal components in the UNIX epoch
 * with an additional nanosecond component.
 */
class NanoTimestamp: public Timestamp
{
public:
  NanoTimestamp() :Timestamp() {}
  /** Returns whether the temporal value is valid nano-timestamp. */
  bool is_valid() const;

  /**
   * Fills a supplied timespec pointer with an
   * representation of the NanoTimestamp
   * value.
   *
   * Returns whether the conversion was
   * successful.
   *
   * @param timespec to fill.
   */
  void to_timespec(struct timespec *to) const;
};

} /* end namespace drizzled */

#endif /* DRIZZLED_TEMPORAL_H */