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


#ifndef Foundation_DateTimeFormat_INCLUDED
#define Foundation_DateTimeFormat_INCLUDED


#include "Poco/Foundation.h"
#include <unordered_set>


namespace Poco {


class RegularExpression;


class Foundation_API DateTimeFormat
	/// Definition of date/time formats and various
	/// constants used by DateTimeFormatter and DateTimeParser.
{
public:

	// predefined date formats
	static const std::string ISO8601_FORMAT;
		/// The date/time format defined in the ISO 8601 standard.
		///
		/// Examples:
		///   2005-01-01T12:00:00+01:00
		///   2005-01-01T11:00:00Z

	static const std::string ISO8601_REGEX;

	static const std::string ISO8601_FRAC_FORMAT;
		/// The date/time format defined in the ISO 8601 standard,
		/// with fractional seconds.
		///
		/// Examples:
		///   2005-01-01T12:00:00.000000+01:00
		///   2005-01-01T11:00:00.000000Z

	static const std::string RFC822_FORMAT;
		/// The date/time format defined in RFC 822 (obsoleted by RFC 1123).
		///
		/// Examples:
		///   Sat, 1 Jan 05 12:00:00 +0100
		///   Sat, 1 Jan 05 11:00:00 GMT

	static const std::string RFC822_REGEX;

	static const std::string RFC1123_FORMAT;
		/// The date/time format defined in RFC 1123 (obsoletes RFC 822).
		///
		/// Examples:
		///   Sat, 1 Jan 2005 12:00:00 +0100
		///   Sat, 1 Jan 2005 11:00:00 GMT

	static const std::string RFC1123_REGEX;

	static const std::string HTTP_FORMAT;
		/// The date/time format defined in the HTTP specification (RFC 2616),
		/// which is basically a variant of RFC 1036 with a zero-padded day field.
		///
		/// Examples:
		///   Sat, 01 Jan 2005 12:00:00 +0100
		///   Sat, 01 Jan 2005 11:00:00 GMT

	static const std::string HTTP_REGEX;

	static const std::string RFC850_FORMAT;
		/// The date/time format defined in RFC 850 (obsoleted by RFC 1036).
		///
		/// Examples:
		///   Saturday, 1-Jan-05 12:00:00 +0100
		///   Saturday, 1-Jan-05 11:00:00 GMT

	static const std::string RFC850_REGEX;

	static const std::string RFC1036_FORMAT;
		/// The date/time format defined in RFC 1036 (obsoletes RFC 850).
		///
		/// Examples:
		///   Saturday, 1 Jan 05 12:00:00 +0100
		///   Saturday, 1 Jan 05 11:00:00 GMT

	static const std::string RFC1036_REGEX;

	static const std::string ASCTIME_FORMAT;
		/// The date/time format produced by the ANSI C asctime() function.
		///
		/// Example:
		///   Sat Jan  1 12:00:00 2005

	static const std::string ASCTIME_REGEX;

	static const std::string SORTABLE_FORMAT;
		/// A simple, sortable date/time format.
		///
		/// Example:
		///   2005-01-01 12:00:00

	static const std::string SORTABLE_REGEX;
	// ^(\d\d\d\d-\d\d-\d\d \d\d:\d\d:\d\d)$

	// names used by formatter and parser
	static const std::string WEEKDAY_NAMES[7];
		/// English names of week days (Sunday, Monday, Tuesday, ...).

	static const std::string MONTH_NAMES[12];
		/// English names of months (January, February, ...).

	static bool hasFormat(const std::string& fmt);
		/// Returns true if fmt is a known standard format.

	static bool isValid(const std::string& dateTime);
		/// Returns true if dateTime validates against at least one supported format.

private:
	typedef std::unordered_set<std::string> Formatlist;
	static Formatlist FORMAT_LIST;
};


} // namespace Poco


#endif // Foundation_DateTimeFormat_INCLUDED
