/*
 * This file is a part of Winix
 * and is not publicly distributed
 *
 * Copyright (c) 2012, Tomasz Sowa
 * All rights reserved.
 *
 */

#include "timezone.h"




TimeZone::TimeZone()
{
	Clear();
}




void TimeZone::Clear()
{
	tz_id         = -1;
	tz_offset     = 0;
	tz_has_dst    = false;
	tz_dst_offset = 0;
	tz_dst_start.Clear();
	tz_dst_end.Clear();
}



time_t TimeZone::CalcLocalOffset(const PT::Date & utc_date)
{
time_t offset;

	offset = tz_offset;

	// !! CHECK ME need to be tested

	if( tz_has_dst )
	{
		PT::Date local(utc_date);

		local += tz_offset;
		local.year      = tz_dst_start.year;
		tz_dst_end.year = tz_dst_start.year;

		if( tz_dst_start <= local && local < tz_dst_end )
			offset += tz_dst_offset;
	}

return offset;
}



time_t TimeZone::ToLocal(time_t utc_time)
{
	time_t offset = CalcLocalOffset(PT::Date(utc_time));

return utc_time + offset;
}


PT::Date TimeZone::ToLocal(const PT::Date & utc_date)
{
	PT::Date local(utc_date);
	local += CalcLocalOffset(utc_date);

return local;
}


time_t TimeZone::CalcUTCOffset(const PT::Date & local_date)
{
time_t offset;

	offset = tz_offset;

	if( tz_has_dst )
	{
		// !! CHECK ME need to be tested

		PT::Date local(local_date);
		local -= tz_dst_offset;
		local.year      = tz_dst_start.year;
		tz_dst_end.year = tz_dst_start.year;

		if( tz_dst_start <= local && local < tz_dst_end )
			offset += tz_dst_offset;
	}

return offset;
}


time_t TimeZone::ToUTC(time_t local_time)
{
	time_t offset = CalcUTCOffset(PT::Date(local_time));

return local_time - offset;
}



PT::Date TimeZone::ToUTC(const PT::Date & local_date)
{
time_t offset;
PT::Date utc(local_date);

	offset = CalcUTCOffset(local_date);
	utc   -= offset;

return utc;
}



bool TimeZone::SetTz(PT::Space & space)
{
bool result = true;

	tz_id      = space.Int(L"tz_id", -1);
	tz_offset  = space.Long(L"tz_offset",  0);
	tz_has_dst = space.Bool(L"tz_has_dst", false);

	time_t h13 = 60 * 60 * 13; // 13 hours
	time_t h15 = 60 * 60 * 15; // 15 hours
	time_t h24 = 60 * 60 * 24; // 24 hours

	if( tz_offset < -h13 || tz_offset > h15 )
		result = false;

	if( tz_has_dst )
	{
		tz_dst_start.year = 1970;
		tz_dst_end.year   = 1970;

		if( !tz_dst_start.ParseMonthDayTime(space.Text(L"tz_dst_start")) )
			result = false;

		if( !tz_dst_end.ParseMonthDayTime(space.Text(L"tz_dst_end")) )
			result = false;

		tz_dst_offset = space.Long(L"tz_dst_offset");

		if( tz_dst_offset < -h24 || tz_dst_offset > h24 )
			result = false;
	}
	else
	{
		tz_dst_start.Clear();
		tz_dst_end.Clear();
		tz_dst_offset = 0;
	}

	if( !result )
		Clear();

return result;
}