<?php
/* Copyright (C) 2006      Roman Ozana			<ozana@omdesign.cz>
 * Copyright (C) 2011	   Juanjo Menent		<jmenent@2byte.es>
 * Copyright (C) 2013-2014 Laurent Destailleur	<eldy@users.sourceforge.net>
 * Copyright (C) 2012	   Regis Houssin		<regis.houssin@inodbox.com>
 * Copyright (C) 2019-2024  Frédéric France     <frederic.france@free.fr>
 * Copyright (C) 2024		MDW							<mdeweerd@users.noreply.github.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <https://www.gnu.org/licenses/>.
 */

/**
 *       \file       htdocs/comm/action/class/ical.class.php
 *       \ingroup    agenda
 *       \brief      File of class to parse ical calendars
 */
require_once DOL_DOCUMENT_ROOT.'/core/lib/xcal.lib.php';
require_once DOL_DOCUMENT_ROOT.'/core/lib/geturl.lib.php';


/**
 *  Class to read/parse ICal calendars
 */
class ICal
{
	/**
	 * @var string	Name of remote HTTP file to read
	 */
	public $file;

	/**
	 * @var string  Text in file
	 */
	public $file_text;

	/**
	 * @var array Array to save iCalendar parse data
	 */
	public $cal;

	/**
	 * @var int Number of Events
	 */
	public $event_count;

	/**
	 * @var int Number of Todos
	 */
	public $todo_count;

	/**
	 * @var int Number of Freebusy
	 */
	public $freebusy_count;

	/**
	 * @var string Help variable save last key (multiline string)
	 */
	public $last_key;

	/**
	 * @var string error message
	 */
	public $error;


	/**
	 * Constructor
	 */
	public function __construct()
	{
	}

	// phpcs:disable PEAR.NamingConventions.ValidFunctionName.ScopeNotCamelCaps
	/**
	 *  Read text file, icalender text file
	 *
	 *  @param  string  		$file       File
	 *  @return string|null					Content of remote file read or null if error
	 */
	public function read_file($file)
	{
		// phpcs:enable
		$this->file = $file;
		$file_text = '';

		//$tmpresult = getURLContent($file, 'GET', '', 1, [], ['http', 'https'], 2, 0);	// To test with any URL
		$tmpresult = getURLContent($file, 'GET');
		if ($tmpresult['http_code'] != 200) {
			$file_text = null;
			$this->error = 'Error: '.$tmpresult['http_code'].' '.$tmpresult['content'];
		} else {
			$file_text = preg_replace("/[\r\n]{1,} /", "", $tmpresult['content']);
		}
		//var_dump($tmpresult);

		return $file_text; // return all text
	}

	// phpcs:disable PEAR.NamingConventions.ValidFunctionName.ScopeNotCamelCaps
	/**
	 * Returns the number of calendar events
	 *
	 * @return int
	 */
	public function get_event_count()
	{
		// phpcs:enable
		return $this->event_count;
	}

	// phpcs:disable PEAR.NamingConventions.ValidFunctionName.ScopeNotCamelCaps
	/**
	 * Returns the number of to do
	 *
	 * @return int
	 */
	public function get_todo_count()
	{
		// phpcs:enable
		return $this->todo_count;
	}

	/**
	 * Translate Calendar
	 *
	 * @param	string	 	$uri			Url
	 * @param	string		$usecachefile	Full path of a cache file to use a cache file
	 * @param	int			$delaycache		Delay in seconds for cache (by default 3600 secondes)
	 * @return	array|string
	 */
	public function parse($uri, $usecachefile = '', $delaycache = 3600)
	{
		$this->cal = array(); // new empty array

		$this->event_count = -1;
		$this->file_text = '';

		// Save file into a cache
		if ($usecachefile) {
			include_once DOL_DOCUMENT_ROOT.'/core/lib/files.lib.php';
			$datefile = dol_filemtime($usecachefile);
			$now = dol_now('gmt');
			//print $datefile.' '.$now.' ...';
			if ($datefile && $datefile > ($now - $delaycache)) {
				// We reuse the cache file
				$this->file_text = file_get_contents($usecachefile);
			}
		}

		// read FILE text
		if (empty($this->file_text)) {
			$this->file_text = $this->read_file($uri);

			if ($usecachefile && !is_null($this->file_text)) {
				// Save the file content into cache file
				file_put_contents($usecachefile, $this->file_text, LOCK_EX);
				dolChmod($usecachefile);
			}
		}

		$file_text_array = preg_split("[\n]", $this->file_text);

		// is this text vcalendar standard text ? on line 1 is BEGIN:VCALENDAR
		if (!stristr($file_text_array[0], 'BEGIN:VCALENDAR')) {
			return 'error not VCALENDAR';
		}

		$insidealarm = 0;
		$tmpkey = '';
		$tmpvalue = '';
		$type = '';
		foreach ($file_text_array as $text) {
			$text = trim($text); // trim one line
			if (!empty($text)) {
				// get Key and Value VCALENDAR:Begin -> Key = VCALENDAR, Value = begin
				list($key, $value) = $this->retun_key_value($text);
				//var_dump($text.' -> '.$key.' - '.$value);

				switch ($text) { // search special string
					case "BEGIN:VTODO":
						$this->todo_count += 1; // new to do begin
						$type = "VTODO";
						break;

					case "BEGIN:VEVENT":
						$this->event_count +=  1; // new event begin
						$type = "VEVENT";
						break;

					case "BEGIN:VFREEBUSY":
						$this->freebusy_count += 1; // new event begin
						$type = "VFREEBUSY";
						break;

					case "BEGIN:VCALENDAR": // all other special string
					case "BEGIN:DAYLIGHT":
					case "BEGIN:VTIMEZONE":
					case "BEGIN:STANDARD":
						$type = $value; // save array under value key
						break;

					case "END:VTODO": // end special text - goto VCALENDAR key
					case "END:VEVENT":
					case "END:VFREEBUSY":
					case "END:VCALENDAR":
					case "END:DAYLIGHT":
					case "END:VTIMEZONE":
					case "END:STANDARD":
						$type = "VCALENDAR";
						break;

						// Manage VALARM that are inside a VEVENT to avoid fields of VALARM to overwrites fields of VEVENT
					case "BEGIN:VALARM":
						$insidealarm = 1;
						break;
					case "END:VALARM":
						$insidealarm = 0;
						break;

					default: // no special string (SUMMARY, DESCRIPTION, ...)
						if ($tmpvalue) {
							$tmpvalue .= $text;
							if (!preg_match('/=$/', $text)) {	// No more lines
								$key = $tmpkey;
								$value = quotedPrintDecode(preg_replace('/^ENCODING=QUOTED-PRINTABLE:/i', '', $tmpvalue));
								$tmpkey = '';
								$tmpvalue = '';
							}
						} elseif (preg_match('/^ENCODING=QUOTED-PRINTABLE:/i', $value)) {
							if (preg_match('/=$/', $value)) {
								$tmpkey = $key;
								$tmpvalue .= preg_replace('/=$/', "", $value); // We must wait to have next line to have complete message
							} else {
								$value = quotedPrintDecode(preg_replace('/^ENCODING=QUOTED-PRINTABLE:/i', '', $tmpvalue.$value));
							}
						}                    	//$value=quotedPrintDecode($tmpvalue.$value);
						if (!$insidealarm && !$tmpkey) {
							$this->add_to_array($type, $key, $value); // add to array
						}
						break;
				}
			}
		}

		//var_dump($this->cal);
		return $this->cal;
	}

	// phpcs:disable PEAR.NamingConventions.ValidFunctionName.ScopeNotCamelCaps
	/**
	 * Add to $this->ical array one value and key.
	 *
	 * @param 	string 	$type		Type ('VTODO', 'VEVENT', 'VFREEBUSY', 'VCALENDAR'...)
	 * @param 	string 	$key		Key	('DTSTART', ...). Note: Field is never 'DTSTART;TZID=...' because ';...' was before removed and added as another property
	 * @param 	string 	$value		Value
	 * @return	void
	 */
	public function add_to_array($type, $key, $value)
	{
		// phpcs:enable

		//print 'type='.$type.' key='.$key.' value='.$value.'<br>'."\n";

		if (empty($key)) {
			$key = $this->last_key;
			switch ($type) {
				case 'VEVENT':
					$value = $this->cal[$type][$this->event_count][$key].$value;
					break;
				case 'VFREEBUSY':
					$value = $this->cal[$type][$this->freebusy_count][$key].$value;
					break;
				case 'VTODO':
					$value = $this->cal[$type][$this->todo_count][$key].$value;
					break;
			}
		}

		if (($key == "DTSTAMP") || ($key == "LAST-MODIFIED") || ($key == "CREATED")) {
			$value = $this->ical_date_to_unix($value);
		}
		//if ($key == "RRULE" ) $value = $this->ical_rrule($value);

		if (stristr($key, "DTSTART") || stristr($key, "DTEND") || stristr($key, "DTSTART;VALUE=DATE") || stristr($key, "DTEND;VALUE=DATE")) {
			if (stristr($key, "DTSTART;VALUE=DATE") || stristr($key, "DTEND;VALUE=DATE")) {
				list($key, $value) = array($key, $value);
			} else {
				list($key, $value) = $this->ical_dt_date($key, $value);
			}
		}

		switch ($type) {
			case "VTODO":
				$this->cal[$type][$this->todo_count][$key] = $value;
				break;

			case "VEVENT":
				$this->cal[$type][$this->event_count][$key] = $value;
				break;

			case "VFREEBUSY":
				$this->cal[$type][$this->freebusy_count][$key] = $value;
				break;

			default:
				$this->cal[$type][$key] = $value;
				break;
		}
		$this->last_key = $key;
	}

	// phpcs:disable PEAR.NamingConventions.ValidFunctionName.ScopeNotCamelCaps
	/**
	 * Parse text "XXXX:value text some with : " and return array($key = "XXXX", $value="value");
	 *
	 * @param 	string 	$text	Text
	 * @return 	array
	 */
	public function retun_key_value($text)
	{
		// phpcs:enable
		/*
		preg_match("/([^:]+)[:]([\w\W]+)/", $text, $matches);

		if (empty($matches))
		{
			return array(false,$text);
		}
		else
		{
			$matches = array_splice($matches, 1, 2);
			return $matches;
		}*/
		return explode(':', $text, 2);
	}

	// phpcs:disable PEAR.NamingConventions.ValidFunctionName.ScopeNotCamelCaps
	/**
	 * Parse RRULE  return array
	 *
	 * @param 	string 	$value	string
	 * @return 	array
	 */
	public function ical_rrule($value)
	{
		// phpcs:enable
		$result = array();
		$rrule = explode(';', $value);
		foreach ($rrule as $line) {
			$rcontent = explode('=', $line);
			$result[$rcontent[0]] = $rcontent[1];
		}
		return $result;
	}

	// phpcs:disable PEAR.NamingConventions.ValidFunctionName.ScopeNotCamelCaps
	/**
	 * Return Unix time from ical date time format (YYYYMMDD[T]HHMMSS[Z] or YYYYMMDD[T]HHMMSS)
	 *
	 * @param 	string		$ical_date		String date
	 * @return 	int
	 */
	public function ical_date_to_unix($ical_date)
	{
		// phpcs:enable
		$ical_date = str_replace('T', '', $ical_date);
		$ical_date = str_replace('Z', '', $ical_date);

		$ntime = 0;
		// TIME LIMITED EVENT
		$date = array();
		if (preg_match('/([0-9]{4})([0-9]{2})([0-9]{2})([0-9]{0,2})([0-9]{0,2})([0-9]{0,2})/', $ical_date, $date)) {
			$ntime = dol_mktime((int) $date[4], (int) $date[5], (int) $date[6], (int) $date[2], (int) $date[3], (int) $date[1], true);
		}

		//if (empty($date[4])) print 'Error bad date: '.$ical_date.' - date1='.$date[1];
		//print dol_print_date($ntime,'dayhour');exit;
		return $ntime; // ntime is a GTM time
	}

	// phpcs:disable PEAR.NamingConventions.ValidFunctionName.ScopeNotCamelCaps
	/**
	 * Return unix date from iCal date format
	 *
	 * @param 	string 		$key			Key. Example: 'DTSTART', 'DTSTART;TZID=US-Eastern'
	 * @param 	string 		$value			Value. Example: '19970714T133000', '19970714T173000Z', '19970714T133000'
	 * @return 	array{0:string,1:int}|array{0:string,1:array<string,int|string>}
	 */
	public function ical_dt_date($key, $value)
	{
		// phpcs:enable
		$return_value = array();

		// Analyse TZID
		$temp = explode(";", $key);

		if (empty($temp[1])) { // not TZID in key
			$value = $this->ical_date_to_unix($value);
			return array($key, $value);
		}

		$value = str_replace('T', '', $value);

		$key = $temp[0];
		$temp = explode("=", $temp[1]);
		$return_value[$temp[0]] = $temp[1];
		$return_value['unixtime'] = $value;

		return array($key, $return_value);
	}

	// phpcs:disable PEAR.NamingConventions.ValidFunctionName.ScopeNotCamelCaps
	/**
	 * Return sorted eventlist as array or false if calendar is empty
	 *
	 * @return array|false
	 */
	public function get_sort_event_list()
	{
		// phpcs:enable
		$temp = $this->get_event_list();
		if (!empty($temp)) {
			usort($temp, array(&$this, "ical_dtstart_compare"));
			return $temp;
		} else {
			return false;
		}
	}

	// phpcs:disable PEAR.NamingConventions.ValidFunctionName.ScopeNotCamelCaps
	/**
	 * Compare two unix timestamp
	 *
	 * @param 	array 	$a		Operand a
	 * @param 	array 	$b		Operand b
	 * @return 	integer
	 */
	public function ical_dtstart_compare($a, $b)
	{
		// phpcs:enable
		return strnatcasecmp($a['DTSTART']['unixtime'], $b['DTSTART']['unixtime']);
	}

	// phpcs:disable PEAR.NamingConventions.ValidFunctionName.ScopeNotCamelCaps
	/**
	 * Return eventlist array (not sorted eventlist array)
	 *
	 * @return array
	 */
	public function get_event_list()
	{
		// phpcs:enable
		return (empty($this->cal['VEVENT']) ? array() : $this->cal['VEVENT']);
	}

	// phpcs:disable PEAR.NamingConventions.ValidFunctionName.ScopeNotCamelCaps
	/**
	 * Return freebusy array (not sort eventlist array)
	 *
	 * @return array
	 */
	public function get_freebusy_list()
	{
		// phpcs:enable
		return (empty($this->cal['VFREEBUSY']) ? array() : $this->cal['VFREEBUSY']);
	}

	// phpcs:disable PEAR.NamingConventions.ValidFunctionName.ScopeNotCamelCaps
	/**
	 * Return to do array (not sorted todo array)
	 *
	 * @return array
	 */
	public function get_todo_list()
	{
		// phpcs:enable
		return $this->cal['VTODO'];
	}

	// phpcs:disable PEAR.NamingConventions.ValidFunctionName.ScopeNotCamelCaps
	/**
	 * Return base calendar data
	 *
	 * @return array
	 */
	public function get_calender_data()
	{
		// phpcs:enable
		return $this->cal['VCALENDAR'];
	}

	// phpcs:disable PEAR.NamingConventions.ValidFunctionName.ScopeNotCamelCaps
	/**
	 * Return array with all data
	 *
	 * @return array
	 */
	public function get_all_data()
	{
		// phpcs:enable
		return $this->cal;
	}
}