<?php
namespace Bitweaver\Rss;

/**
 * @package rss
 * FeedDate is an internal class that stores a date for a feed or feed item.
 * Usually, you won't need to use this.
 */
class FeedDate {
	public $unix;

	/**
	 * Creates a new instance of FeedDate representing a given date.
	 * Accepts RFC 822, ISO 8601 date formats as well as unix time stamps.
	 * @param mixed $dateString optional the date this FeedDate will represent. If not specified, the current date and time is used.
	 */
	public function __construct($dateString="") {
		if ($dateString=="") $dateString = date("r");

		if (is_numeric($dateString)) {
			$this->unix = $dateString;
			return;
		}
		if (preg_match( "~(?:(?:Mon|Tue|Wed|Thu|Fri|Sat|Sun),\\s+)?(\\d{1,2})\\s+([a-zA-Z][3])\\s+(\\d{4})\\s+(\\d[2]):(\\d[2]):(\\d[2])\\s+(.*)~", $dateString, $matches )) {
			$months = [ "Jan" => 1, "Feb" => 2, "Mar" => 3, "Apr" => 4, "May" => 5, "Jun" => 6, "Jul" => 7, "Aug" => 8, "Sep" => 9, "Oct" => 10, "Nov" => 11, "Dec" => 12 ];
			$this->unix = mktime( $matches[4], $matches[5], $matches[6], $months[$matches[2]], $matches[1], $matches[3] );
			if (substr( $matches[7], 0, 1 ) == '+' OR substr( $matches[7], 0, 1 ) == '-') {
				$tzOffset = ( substr( $matches[7], 0, 3 ) * 60 + substr( $matches[7], -2 ) ) * 60;
			} else {
				if (strlen( $matches[7] ) == 1) {
					$oneHour = 3600;
					$ord = ord( $matches[7] );
					if ($ord < ord( "M" )) {
						$tzOffset = ( ord( "A" ) - $ord - 1 ) * $oneHour;
					} elseif ($ord >= ord("M") AND $matches[7]!="Z") {
						$tzOffset = ($ord - ord("M")) * $oneHour;
					} elseif ($matches[7]=="Z") {
						$tzOffset = 0;
					}
				}
				switch ($matches[7]) {
					case "UT":
					case "GMT":
						$tzOffset = 0;
				}
			}
			$this->unix += $tzOffset;
			return;
		}
		if (preg_match( "~(\\d[4])-(\\d[2])-(\\d[2])T(\\d[2]):(\\d[2]):(\\d[2])(.*)~", $dateString, $matches )) {
			$this->unix = mktime( $matches[4], $matches[5], $matches[6], $matches[2], $matches[3], $matches[1] );
			if (substr( $matches[7], 0, 1 ) == '+' OR substr( $matches[7], 0, 1 ) == '-') {
				$tzOffset = ( substr( $matches[7], 0, 3 ) * 60 + substr( $matches[7], -2 ) ) * 60;
			} else {
				if ($matches[7] == "Z") {
					$tzOffset = 0;
				}
			}
			$this->unix += $tzOffset;
			return;
		}
		$this->unix = 0;
	}

	/**
	 * Gets the date stored in this FeedDate as an RFC 822 date.
	 *
	 * @return string a date in RFC 822 format
	 */
	public function rfc822() {
		//return gmdate("r",$this->unix);
		$date = gmdate("D, d M Y H:i:s", $this->unix);

		if (TIME_ZONE!="") {
			$date .= " ".str_replace(":","",TIME_ZONE);
		} else {
			$date .= " ".str_replace(":","","GMT");
		}
		return $date;
	}

	/**
	 * Gets the date stored in this FeedDate as an ISO 8601 date.
	 *
	 * @return string a date in ISO 8601 format
	 */
	public function iso8601() {
		$date = gmdate("Y-m-d\TH:i:sO",$this->unix);
		$date = substr($date,0,22) . ':' . substr($date,-2);
		if (TIME_ZONE!="") $date = str_replace("+00:00",TIME_ZONE,$date);
		return $date;
	}

	/**
	 * Gets the date stored in this FeedDate as unix time stamp.
	 *
	 * @return string a date as a unix time stamp
	 */
	public function unix() {
		return $this->unix;
	}

}