//
// Timezone.h
//
// Library: Foundation
// Package: DateTime
// Module:  Timezone
//
// Definition of the Timezone class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef Foundation_Timezone_INCLUDED
#define Foundation_Timezone_INCLUDED


#include "Poco/Foundation.h"
#include "Poco/Timestamp.h"


namespace Poco {


class Foundation_API Timezone
	/// This class provides information about the current timezone.
{
public:
	static int utcOffset();
		/// Returns the offset of local time to UTC, in seconds.
		///     local time = UTC + utcOffset() + dst().

	static int dst();
		/// Returns the daylight saving time offset in seconds if
		/// daylight saving time is in use.
		///     local time = UTC + utcOffset() + dst().

	static int dst(const Poco::Timestamp& timestamp);
		/// Returns the daylight saving time offset in seconds if
		/// daylight saving time is in use for the given time.
		///     local time = UTC + utcOffset() + dst().

	static bool isDst(const Timestamp& timestamp);
		/// Returns true if daylight saving time is in effect
		/// for the given time. Depending on the operating system
		/// platform this might only work reliably for certain
		/// date ranges, as the C library's localtime() function
		/// is used.

	static int tzd();
		/// Returns the time zone differential for the current timezone.
		/// The timezone differential is computed as utcOffset() + dst()
		/// and is expressed in seconds.

	static std::string name();
		/// Returns the timezone name currently in effect.

	static std::string standardName();
		/// Returns the timezone name if not daylight saving time is in effect.

	static std::string dstName();
		/// Returns the timezone name if daylight saving time is in effect.

	static void reloadCache();
		/// Reloads the cached UTC offset from the system.
		/// This is typically done internally when a change to the
		/// TZ environment variable is detected, but can be called
		/// explicitly if needed.
};


} // namespace Poco


#endif // Foundation_Timezone_INCLUDED
