/*
 * This file is a part of PikoTools
 * and is distributed under the (new) BSD licence.
 * Author: Tomasz Sowa <t.sowa@ttmath.org>
 */

/* 
 * Copyright (c) 2012, Tomasz Sowa
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 *  * Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *    
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *    
 *  * Neither the name Tomasz Sowa nor the names of contributors to this
 *    project may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef headerfile_picotools_mainparser_mainparser
#define headerfile_picotools_mainparser_mainparser

#include <ctime>



namespace PT
{


/*
	this class represents a Date (year, month, day, hour, min, sec)
	it has O(1) algorithm when converting from/to time_t (seconds from unix epoch)

	algorithm description:
	http://alcor.concordia.ca/~gpkatch/gdate-algorithm.html
	http://alcor.concordia.ca/~gpkatch/gdate-method.html
*/
class Date
{
public:


	/*
		default c-ctor sets the unix epoch (Clear method): 1970.01.01 00:00:00
	*/
	Date();


	/*
		converting from Date, time_t (seconds from unix epoch), tm structure
	*/
	Date(const Date & d);
	Date(time_t t);
	Date(const tm & t);
	Date & operator=(const Date & d);
	Date & operator=(time_t t);
	Date & operator=(const tm & t);


	/*
		adding/subtracting time_t (seconds from unix epoch)
	*/
	Date operator+(time_t t) const;
	Date operator-(time_t t) const;
	Date & operator+=(time_t t);
	Date & operator-=(time_t t);


	/*
		converts time_t in seconds (from unix epoch) to this object
	*/
	void FromTime(time_t t);


	/*
		converts tm structure to this object
	*/
	void FromTm(const tm & t);


	/*
		returns time_t (in seconds from unix epoch)
	*/
	time_t ToTime() const;


	/*
		return tm structure
		only tm_year, tm_mon, tm_mday, tm_hour,	tm_min, tm_sec fields are set
		the rest is equal to zero
	*/
	tm ToTm() const;


	/*
		getting/setting the number of days from 0000:03:01 (year 0, month 3 - March, day 1)
		(ToDays() and FromDays() can work even with a year less than 1970)
	*/
	long long ToDays() const;
	void FromDays(long long g);


	/*
		returns a difference in second between two dates
		(always a value greater than zero)
	*/
	time_t operator-(const Date & d) const;


	/*
		'Compare' returns zero if this and d are equal
		return value less than zero if this is lower than d
		and a value greater than zero if this is greater than d
	*/
	int Compare(const Date & d) const;


	/*
		returns true if year, month and day are the same
	*/
	bool IsTheSameDay(const Date & d) const;


	/*
		returns true if hour, min and sec are the same
	*/
	bool IsTheSameHour(const Date & d) const;


	/*
		operators for comparing
	*/
	bool operator==(const Date & d) const;
	bool operator!=(const Date & d) const;
	bool operator>(const Date & d) const;
	bool operator>=(const Date & d) const;
	bool operator<(const Date & d) const;
	bool operator<=(const Date & d) const;


	/*
		set unix epoch: 1970.01.01 00:00:00
	*/
	void Clear();


	/*
		assert a correct date (values will be from the correct range)
		year:  1970 - 10000
		month: 1 - 12
		day:   1 - MonthLen
		hour:  0 - 23
		min:   0 - 59
		sec:   0 - 59
	*/
	void AssertCorrectDate();


	/*
		returns how many days there is in a month
		y - year  1970 - ...
		m - month 1-12
	*/
	static int  MonthLen(int y, int m);


	/*
		returns true if 'y' is a leap year
		leap year has one additional day (in february) - so the year lasts 366 days
	*/
	static bool IsYearLeap(int y);


	/*
		returns true if the currecn year is a leap year
	*/
	bool IsYearLeap() const;


	/*
		returns a day index from a week
		sunday - 0
		monday - 1
		...
		saturday - 6
	*/
	int WeekDay() const;


	/*
		this method outputs to the given stream: YYYY-MM-DD, eg. 1990.02.12
		ISO 8601 format
	*/
	template<class Stream>
	void SerializeDay(Stream & out) const;


	/*
		this method outputs to the given stream: HH:MM:SS, eg: 13:05:39
		ISO 8601 format
	*/
	template<class Stream>
	void SerializeHour(Stream & out) const;


	/*
		this method outputs to the given stream: YYYY-MM-DD HH:MM:SS, eg: 1990-02-12 13:05:39
		ISO 8601 format
	*/
	template<class Stream>
	void Serialize(Stream & out) const;


	/*
		the date
	*/
	int year;		// 1970 - ...
	int month;		// 1 - 12
	int day;		// 1 - 31
	int hour;		// 0 - 23
	int min;		// 0 - 59
	int sec;		// 0 - 59


private:

	void AssertRange(int & val, int val_min, int val_max);

	template<class Stream>
	void SerializeInt(Stream & out, int val) const;

};



template<class Stream>
void Date::SerializeInt(Stream & out, int val) const
{
	if( val < 10 )
		out << '0';

	out << val;
}



template<class Stream>
void Date::SerializeDay(Stream & out) const
{
	// !! IMPROVE ME the year should be printed with 4 digits, e.g. 0001 when the year is equal to one
	out	<< year << '-';
	SerializeInt(out, month);
	out	<< '-';
	SerializeInt(out, day);
}


template<class Stream>
void Date::SerializeHour(Stream & out) const
{
	SerializeInt(out, hour);
	out	<< ':';
	SerializeInt(out, min);
	out	<< ':';
	SerializeInt(out, sec);
}

template<class Stream>
void Date::Serialize(Stream & out) const
{
	SerializeDay(out);
	out << ' ';
	SerializeHour(out);
}





} // namespace

#endif