eme-calendar.php

<?php

if ( ! defined( 'ABSPATH' ) ) {
	exit; // Exit if accessed directly.
}

function eme_get_calendar_shortcode( $atts ) {
	eme_enqueue_frontend();

    // normalize attribute keys, lowercase
    $atts = array_change_key_case( (array) $atts, CASE_LOWER );

	$atts = shortcode_atts(
		[
			'category'       => 0,
			'notcategory'    => 0,
			'full'           => 0,
			'month'          => '',
			'year'           => '',
			'echo'           => 0,
			'long_events'    => 0,
			'ignore_filter'  => 0,
			'author'         => '',
			'contact_person' => '',
			'location_id'    => '',
			'template_id'    => 0,
			'holiday_id'     => 0,
			'htmltable'      => 1,
			'htmldiv'        => 0,
			'weekdays'       => '',
		],
		$atts
	);

	$echo = filter_var($atts['echo'], FILTER_VALIDATE_BOOLEAN);
	$full = filter_var($atts['full'], FILTER_VALIDATE_BOOLEAN);
	$long_events = filter_var($atts['long_events'], FILTER_VALIDATE_BOOLEAN);

	$month = $atts['month'];
	$year = intval($atts['year']);
	$category = $atts['category'];
	$notcategory = $atts['notcategory'];
	$author = $atts['author'];
	$contact_person = $atts['contact_person'];
	$location_id = $atts['location_id'];
	$template_id = $atts['template_id'];
	$holiday_id = $atts['holiday_id'];
	$htmltable = $atts['htmltable'];
	$htmldiv = $atts['htmldiv'];
	$weekdays = $atts['weekdays'];
	$ignore_filter = $atts['ignore_filter'];

	// Allow specific months/years for the calendar display
	if (isset($_GET['calmonth']) && $_GET['calmonth'] != '') {
		$month = eme_sanitize_request($_GET['calmonth']);
	}
	if ($month != 'this_month' && $month != 'next_month') {
		$month = intval($month);
	}
	if ($month == 'this_month') {
		$eme_date_obj_tmp = new ExpressiveDate('now', EME_TIMEZONE);
		$eme_date_obj_tmp->startOfMonth();
		$month = $eme_date_obj_tmp->format('m');
	}
	if (isset($_GET['calyear']) && $_GET['calyear'] != '') {
		$year = intval($_GET['calyear']);
	}

	if (!empty($year) && empty($month)) {
		$month = 1;
	}

	$location_id_arr = [];
	if (!$ignore_filter && isset($_REQUEST['eme_eventAction']) && eme_sanitize_request($_REQUEST['eme_eventAction']) == 'filter') {
		if (!empty($_REQUEST['eme_scope_filter'])) {
			$scope = eme_sanitize_request($_REQUEST['eme_scope_filter']);
			if (preg_match('/^([0-9]{4})-([0-9]{2})-[0-9]{2}--[0-9]{4}-[0-9]{2}-[0-9]{2}$/', $scope, $matches)) {
				$year  = $matches[1];
				$month = $matches[2];
			}
		}
		if (!empty($_REQUEST['eme_author_filter']) && intval($_REQUEST['eme_author_filter']) > 0) {
			$author = intval($_REQUEST['eme_author_filter']);
		}
		if (!empty($_REQUEST['eme_contact_filter']) && intval($_REQUEST['eme_contact_filter']) > 0) {
			$contact_person = intval($_REQUEST['eme_contact_filter']);
		}
		if (!empty($_REQUEST['eme_loc_filter'])) {
			if (is_array($_REQUEST['eme_loc_filter'])) {
				$arr = eme_array_remove_empty_elements(eme_sanitize_request($_REQUEST['eme_loc_filter']));
				if (!empty($arr)) {
					$location_id_arr = $arr;
				}
			} else {
				$location_id_arr[] = eme_sanitize_request($_REQUEST['eme_loc_filter']);
			}
		}
		if (!empty($_REQUEST['eme_city_filter'])) {
			$cities  = eme_sanitize_request($_REQUEST['eme_city_filter']);
			$tmp_ids = eme_get_city_location_ids($cities);
			if (empty($location_id_arr)) {
				$location_id_arr = $tmp_ids;
			} else {
				$location_id_arr = array_intersect($location_id_arr, $tmp_ids);
			}
			if (empty($location_id_arr)) {
				$location_id = -1;
			}
		}
		if (!empty($_REQUEST['eme_country_filter'])) {
			$countries = eme_sanitize_request($_REQUEST['eme_country_filter']);
			$tmp_ids   = eme_get_country_location_ids($countries);
			if (empty($location_id_arr)) {
				$location_id_arr = $tmp_ids;
			} else {
				$location_id_arr = array_intersect($location_id_arr, $tmp_ids);
			}
			if (empty($location_id_arr)) {
				$location_id = -1;
			}
		}
		if (!empty($_REQUEST['eme_cat_filter'])) {
			if (is_array($_REQUEST['eme_cat_filter'])) {
				$arr = eme_array_remove_empty_elements(eme_sanitize_request($_REQUEST['eme_cat_filter']));
				if (!empty($arr)) {
					$category = join(',', $arr);
				}
			} else {
				$category = eme_sanitize_request($_REQUEST['eme_cat_filter']);
			}
		}
	}
	if ($location_id != -1 && !empty($location_id_arr)) {
		$location_id = join(',', $location_id_arr);
	}

	$result = eme_get_calendar(
		full: $full,
		month: $month,
		year: $year,
		do_echo: $echo,
		long_events: $long_events,
		category: $category,
		author: $author,
		contact_person: $contact_person,
		location_id: $location_id,
		notcategory: $notcategory,
		template_id: $template_id,
		weekdays: $weekdays,
		holiday_id: $holiday_id,
		htmltable: $htmltable,
		htmldiv: $htmldiv
	);

	return $result;
}

function eme_get_calendar( $category=0, $notcategory=0, $full=0, $month='', $year='', $do_echo=0, $long_events=0, $author='', $contact_person='', $location_id='', $template_id=0, $holiday_id=0, $htmltable=1, $htmldiv=0, $weekdays='' ) {
	global $wp_locale;

	$do_echo     = filter_var( $do_echo, FILTER_VALIDATE_BOOLEAN );
        $full        = filter_var( $full, FILTER_VALIDATE_BOOLEAN );
        $long_events = filter_var( $long_events, FILTER_VALIDATE_BOOLEAN );

	if ( ! empty( $weekdays ) ) {
		$weekday_arr = explode( ',', $weekdays );
	} else {
		$weekday_arr = [];
	}

	// this comes from global WordPress preferences
	$start_of_week = get_option( 'start_of_week' );

	// allow month=next_month
	if ( $month == 'next_month' ) {
		$eme_date_obj_tmp = new ExpressiveDate( 'now', EME_TIMEZONE );
		$eme_date_obj_tmp->startOfMonth()->addOneMonth();
		$month = $eme_date_obj_tmp->format( 'm' );
		$year  = $eme_date_obj_tmp->format( 'Y' );
	}
	$eme_date_obj = new ExpressiveDate( 'now', EME_TIMEZONE );

	if ( get_option( 'eme_use_client_clock' ) && !empty( $_COOKIE['eme_client_time'] ) ) {
		try {
			$client_timeinfo = eme_sanitize_request( json_decode( $_COOKIE['eme_client_time'], true ) );
			if ( ! is_array( $client_timeinfo ) ) {
				$client_timeinfo = [];
			}
		} catch ( Exception $error ) {
			$client_timeinfo = [];
		}
		// avoid php warnings
		if ( ! isset( $client_timeinfo['eme_client_unixtime'] ) ) {
			$client_timeinfo['eme_client_mday'] = (int) $eme_date_obj->format( 'j' );
		}
		if ( ! isset( $client_timeinfo['eme_client_unixtime'] ) ) {
			$client_timeinfo['eme_client_month'] = (int) $eme_date_obj->format( 'n' );
		}
		if ( ! isset( $client_timeinfo['eme_client_unixtime'] ) ) {
			$client_timeinfo['eme_client_fullyear'] = (int) $eme_date_obj->format( 'Y' );
		}
		// these come from client unless their clock is wrong
		$iNowDay   = sprintf( '%02d', $client_timeinfo['eme_client_mday'] );
		$iNowMonth = sprintf( '%02d', $client_timeinfo['eme_client_month'] );
		$iNowYear  = sprintf( '%04d', $client_timeinfo['eme_client_fullyear'] );
		// some checks
		if ( abs( $eme_date_obj->format( 'j' ) - $iNowDay ) > 30 ) {
			$iNowDay = 0;
		}
		if ( abs( $eme_date_obj->format( 'n' ) - $iNowMonth ) > 11 ) {
			$iNowMonth = 0;
		}
		if ( abs( $eme_date_obj->format( 'Y' ) - $iNowYear ) > 1 ) {
			$iNowYear = 0;
		}
		if ( empty( $iNowDay ) || empty( $iNowMonth ) || empty( $iNowYear ) ) {
			[$iNowYear, $iNowMonth, $iNowDay] = explode( '-', $eme_date_obj->getDate() );
		}
	} else {
		// Get current year, month and day
		[$iNowYear, $iNowMonth, $iNowDay] = explode( '-', $eme_date_obj->getDate() );
	}

	$iSelectedYear  = $year;
	$iSelectedMonth = $month;
	if ( empty( $iSelectedMonth ) ) {
		$iSelectedMonth = $iNowMonth;
	}
	if ( empty( $iSelectedYear ) ) {
		$iSelectedYear = $iNowYear;
	}
	$iSelectedMonth = sprintf( '%02d', $iSelectedMonth );

	$lang = eme_detect_lang();

	// Get name and number of days of specified month
	$eme_date_obj->setDay( 1 );
	$eme_date_obj->setMonth( $iSelectedMonth );
	$eme_date_obj->setYear( $iSelectedYear );
	$iDaysInMonth   = (int) $eme_date_obj->getDaysInMonth();
	$fullMonthName  = $wp_locale->get_month( $eme_date_obj->format( 'm' ) );
	$shortMonthName = $wp_locale->get_month_abbrev( $fullMonthName );
	// Get friendly month name, but since DateTime::format doesn't respect the locale, we need eme_localized_date
	if ( $full ) {
		$sMonthName = $fullMonthName;
	} else {
		$sMonthName = $shortMonthName;
	}
	// take into account some locale info: some always best show full month name, some show month after year, some have a year suffix
	$showMonthAfterYear = 0;
	$yearSuffix         = '';
	switch ( $lang ) {
		case 'hu':
			$showMonthAfterYear = 1;
			break;
		case 'ja':
			$showMonthAfterYear = 1;
			$sMonthName         = $fullMonthName;
			$yearSuffix         = '年';
			break;
		case 'ko':
			$showMonthAfterYear = 1;
			$sMonthName         = $fullMonthName;
			$yearSuffix         = '년';
			break;
		case 'zh':
			$showMonthAfterYear = 1;
			$sMonthName         = $fullMonthName;
			$yearSuffix         = '年';
			break;
	}
	if ( $showMonthAfterYear ) {
		$cal_datestring = "$iSelectedYear$yearSuffix $sMonthName";
	} else {
		$cal_datestring = "$sMonthName $iSelectedYear$yearSuffix";
	}

	if ( $full && has_filter( 'eme_cal_full_yearmonth' ) ) {
		$cal_datestring = apply_filters( 'eme_cal_full_yearmonth', $cal_datestring, $iSelectedMonth, $iSelectedYear );
	}
	if ( ! $full && has_filter( 'eme_cal_small_yearmonth' ) ) {
		$cal_datestring = apply_filters( 'eme_cal_small_yearmonth', $cal_datestring, $iSelectedMonth, $iSelectedYear );
	}

	// Get previous year and month
	$iPrevYear  = $iSelectedYear;
	$iPrevMonth = $iSelectedMonth - 1;
	if ( $iPrevMonth <= 0 ) {
		--$iPrevYear;
		$iPrevMonth = 12; // set to December
	}
	$iPrevMonth = sprintf( '%02d', $iPrevMonth );

	// Get next year and month
	$iNextYear  = $iSelectedYear;
	$iNextMonth = $iSelectedMonth + 1;
	if ( $iNextMonth > 12 ) {
		++$iNextYear;
		$iNextMonth = 1;
	}
	$iNextMonth = sprintf( '%02d', $iNextMonth );

	// Get number of days of previous month
	$eme_date_obj2 = new ExpressiveDate( 'now', EME_TIMEZONE );
	$eme_date_obj2->setDay( 1 );
	$eme_date_obj2->setMonth( $iPrevMonth );
	$eme_date_obj2->setYear( $iPrevYear );
	$iPrevDaysInMonth = (int) $eme_date_obj2->getDaysInMonth();

	// Get numeric representation of the day of the week of the first day of specified (current) month
	// remember: first day of week is a Sunday
	// if you want the day of the week to begin on Monday: start_of_week=1, Tuesday: start_of_week=2, etc ...
	// So, if e.g. the month starts on a Sunday and start_of_week=1 (Monday), then $iFirstDayDow is 6
	$iFirstDayDow = (int) $eme_date_obj->getDayOfWeekAsNumeric() - $start_of_week;
	if ( $iFirstDayDow < 0 ) {
		$iFirstDayDow += 7;
	}

	// On what day the previous month begins
	if ( $iFirstDayDow > 0 ) {
		$iPrevShowFrom = $iPrevDaysInMonth - $iFirstDayDow + 1;
	} else {
		$iPrevShowFrom = $iPrevDaysInMonth;
	}

	// we'll look for events in the requested month and 7 days before and after
	$calbegin = "$iPrevYear-$iPrevMonth-$iPrevShowFrom";
	$calend   = "$iNextYear-$iNextMonth-07";
	$events   = eme_get_events( scope: "$calbegin--$calend", location_id: $location_id, category: $category, author: $author, contact_person: $contact_person, notcategory: $notcategory );

	$eventful_days = [];
	if ( $events ) {
		// go through the events and slot them into the right d-m index
		foreach ( $events as $event ) {
			if ( $event['event_status'] == EME_EVENT_STATUS_PRIVATE && ! is_user_logged_in() ) {
				continue;
			}
			$eme_date_obj_end = new ExpressiveDate( $event['event_end'], EME_TIMEZONE );
			$eme_date_obj_now = new ExpressiveDate( 'now', EME_TIMEZONE );
			// when hiding past events, we hide those which end date is lower than today
			if ( get_option( 'eme_cal_hide_past_events' ) && $eme_date_obj_end < $eme_date_obj_now ) {
				continue;
			}

			// if $long_events is set then show a date as eventful if there is an multi-day event which runs during that day
			if ( $long_events ) {
				$eme_date_obj_tmp = new ExpressiveDate( $event['event_start'], EME_TIMEZONE );
				// just to be safe we need a reasonable end datetime too
				if ( $eme_date_obj_end < $eme_date_obj_tmp ) {
					$eme_date_obj_end = $eme_date_obj_tmp->copy();
				}
				// we'll start at the beginning of the first day the event begins, so when we add one day (in the while loop below)
				// the last day is taken also into account if the end time would be smaller than the start time
				$eme_date_obj_tmp->startOfDay();
				while ( $eme_date_obj_tmp <= $eme_date_obj_end ) {
					$event_eventful_date = $eme_date_obj_tmp->getDate();
					if ( isset( $eventful_days[ $event_eventful_date ] ) && is_array( $eventful_days[ $event_eventful_date ] ) ) {
						$eventful_days[ $event_eventful_date ][] = $event;
					} else {
						$eventful_days[ $event_eventful_date ] = [ $event ];
					}
					$eme_date_obj_tmp->addOneDay();
				}
			} else {
				//Only show events on the day that they start
				$event_start_date = eme_get_date_from_dt( $event['event_start'] );
				if ( isset( $eventful_days[ $event_start_date ] ) && is_array( $eventful_days[ $event_start_date ] ) ) {
					$eventful_days[ $event_start_date ][] = $event;
				} else {
					$eventful_days[ $event_start_date ] = [ $event ];
				}
			}
		}
	}

	// we found all the events for the wanted days, now get them in the correct format with a good link
	if ( $template_id ) {
		$event_format = eme_get_template_format( $template_id );
	} else {
		$event_format = get_option( 'eme_full_calendar_event_format' );
	}

	$event_title_format           = get_option( 'eme_small_calendar_event_title_format' );
	$event_title_separator_format = get_option( 'eme_small_calendar_event_title_separator' );
	$cells                        = [];
	$holidays                     = [];
	$holiday_titles               = [];
	if ( $holiday_id ) {
		$holidays = eme_get_holiday_listinfo( intval($holiday_id) );
		if ( $holidays ) {
			foreach ( $holidays as $day_key => $info ) {
				if ( ! empty( $info['name'] ) ) {
					$holiday_title = trim( eme_esc_html( $info['name'] ) );
					$eme_holiday_class = 'eme-cal-holidays';
					if ( empty( $info['class'] ) ) {
						$class = $eme_holiday_class;
					} else {
						$class = sanitize_html_class( $info['class'] );
					}

					if ( empty( $info['link'] ) ) {
						$holiday_text = $info['name'];
					} else {
						$holiday_text = "<a href='" . $info['link'] . "' target='_blank'>" . $info['name'] . '</a>';
					}

					// if there's an event that day, the day-number is a link and will be set later on
					// otherwise we set the day-number
					if ( isset( $eventful_days[ $day_key ] ) ) {
						$holiday_titles[ $day_key ] = $holiday_title;
						$cells[ $day_key ]          = "<br><span class='$class'>$holiday_text</span><br>";
					} else {
						$event_date = explode( '-', $day_key );
						$event_day  = ltrim( $event_date[2], '0' );
						if ( ! empty( $info['link'] ) ) {
							$event_day = "<a href='" . $info['link'] . "' target='_blank'>" . $event_day . '</a>';
						}
						$cells[ $day_key ] = "<span class='$eme_holiday_class' title='$holiday_title'>$event_day</span>";
						if ( $full ) {
							$cells[ $day_key ] .= "<br /><span class='$class'>$holiday_text</span><br>";
						}
					}
				}
			}
		}
	}

	foreach ( $eventful_days as $day_key => $events ) {
		// Set the date into the key
		$events_titles = [];
		if ( isset( $holiday_titles[ $day_key ] ) ) {
			$events_titles[] = $holiday_titles[ $day_key ];
		}
		foreach ( $events as $event ) {
			$event_title     = eme_replace_event_placeholders( $event_title_format, $event, 'html', $lang, 0 );
			$event_title     = eme_replace_calendar_placeholders( $event_title, $event, $day_key, 'html', $lang );
			$events_titles[] = $event_title;
		}
		$link_title = implode( $event_title_separator_format, $events_titles );

		$cal_day_link = eme_calendar_day_url( $day_key );
		// Let's add the possible options
		// template_id is not being used per event
		if ( ! empty( $location_id ) ) {
			$cal_day_link = add_query_arg( [ 'location_id' => $location_id ], $cal_day_link );
		}
		if ( ! empty( $category ) ) {
			$cal_day_link = add_query_arg( [ 'category' => $category ], $cal_day_link );
		}
		if ( ! empty( $notcategory ) ) {
			$cal_day_link = add_query_arg( [ 'notcategory' => $notcategory ], $cal_day_link );
		}
		// the hash char and everything following it in a GET is not getting through a browser request, so we replace "#_MYSELF" with just "_MYSELF" here
		$author         = str_replace( '#_MYSELF', '_MYSELF', $author );
		$contact_person = str_replace( '#_MYSELF', '_MYSELF', $contact_person );

		if ( ! empty( $author ) ) {
			$cal_day_link = add_query_arg( [ 'author' => $author ], $cal_day_link );
		}
		if ( ! empty( $contact_person ) ) {
			$cal_day_link = add_query_arg( [ 'contact_person' => $contact_person ], $cal_day_link );
		}

		$event_date = explode( '-', $day_key );
		$event_day  = ltrim( $event_date[2], '0' );
		// there might already be something in the cell if there's a holiday
		if ( isset( $cells[ $day_key ] ) ) {
			$holiday_info = $cells[ $day_key ];
		} else {
			$holiday_info = '';
		}

		// if there is a specific class filter for the urls, do it
		$class = '';
		if ( has_filter( 'eme_calday_url_class_filter' ) ) {
			$class = apply_filters( 'eme_calday_url_class_filter', $class );
		}
		if ( ! empty( $class ) ) {
			$class = "class='$class'";
		}

		$cells[ $day_key ] = "<span class='span-eme-calday span-eme-calday-$event_day'><a title='$link_title' href='$cal_day_link' $class>$event_day</a></span>";
		if ( $full ) {
			$cells[ $day_key ] .= "$holiday_info<ul class='eme-calendar-day-event'>";
			foreach ( $events as $event ) {
				$cal_day_content    = eme_replace_event_placeholders( $event_format, $event, 'html', $lang, 0 );
				$cal_day_content    = eme_replace_calendar_placeholders( $cal_day_content, $event, $day_key, 'html', $lang );
				$cells[ $day_key ] .= $cal_day_content;
			}
			$cells[ $day_key ] .= '</ul>';
		}
	}

	// If previous month
	$isPreviousMonth = ( $iFirstDayDow > 0 );

	// Initial day on the calendar
	$iCalendarDay = ( $isPreviousMonth ) ? $iPrevShowFrom : 1;

	$isNextMonth = false;
	$sCalTblRows = '';
	$sCalDivRows = '';

	// Generate rows for the calendar
	for ( $i = 0; $i < 6; $i++ ) { // 6-weeks range
		if ( $isNextMonth ) {
			continue;
		}
		$sCalTblRows .= '<tr>';
		$sCalDivRows .= "<div class='emeDivTableRow'>";

		for ( $j = 0; $j < 7; $j++ ) { // 7 days a week
			// we need the calendar day with 2 digits for the planned events
			$iCalendarDay_padded = sprintf( '%02d', $iCalendarDay );
			if ( $isPreviousMonth ) {
				$calstring = "$iPrevYear-$iPrevMonth-$iCalendarDay_padded";
			} elseif ( $isNextMonth ) {
				$calstring = "$iNextYear-$iNextMonth-$iCalendarDay_padded";
			} else {
				$calstring = "$iSelectedYear-$iSelectedMonth-$iCalendarDay_padded";
			}

			// each day in the calendar has the name of the day as a class by default
			$eme_date_obj = new ExpressiveDate( $calstring, EME_TIMEZONE );
			$sClass       = $eme_date_obj->format( 'D' );
			if ( isset( $holidays[ $calstring ] ) ) {
					$sClass .= ' holiday';
			}

			if ( isset( $cells[ $calstring ] ) ) {
				if ( $isPreviousMonth ) {
					$sClass .= " eventful-pre event-day-$iCalendarDay";
				} elseif ( $isNextMonth ) {
					$sClass .= " eventful-post event-day-$iCalendarDay";
				} elseif ( $calstring == "$iNowYear-$iNowMonth-$iNowDay" ) {
					$sClass .= " eventful-today event-day-$iCalendarDay";
				} else {
					$sClass .= " eventful event-day-$iCalendarDay";
				}
				$sCalTblCell = "<td class='$sClass'>" . $cells[ $calstring ] . "</td>\n";
				$sCalDivCell = "<div class='emeDivTableCell $sClass'>" . $cells[ $calstring ] . "</div>\n";
			} else {
				if ( $isPreviousMonth ) {
					$sClass .= ' eventless-pre';
				} elseif ( $isNextMonth ) {
					$sClass .= ' eventless-post';
				} elseif ( $calstring == "$iNowYear-$iNowMonth-$iNowDay" ) {
					$sClass .= ' eventless-today';
				} else {
					$sClass .= ' eventless';
				}
				$sCalTblCell = "<td class='$sClass'><span class='span-eme-calday span-eme-calday-$iCalendarDay'>$iCalendarDay</span></td>\n";
				$sCalDivCell = "<div class='emeDivTableCell $sClass'>$iCalendarDay</div>\n";
			}

			// only show wanted columns
			if ( count( $weekday_arr ) ) {
				$day_of_week = $eme_date_obj->getDayOfWeekAsNumeric();
				if ( eme_is_numeric_array( $weekday_arr ) && in_array( $day_of_week, $weekday_arr ) ) {
					$sCalTblRows .= $sCalTblCell;
					$sCalDivRows .= $sCalDivCell;
				}
			} else {
				$sCalTblRows .= $sCalTblCell;
				$sCalDivRows .= $sCalDivCell;
			}

			// Next day
			++$iCalendarDay;
			if ( $isPreviousMonth && $iCalendarDay > $iPrevDaysInMonth ) {
				$isPreviousMonth = false;
				$iCalendarDay    = 1;
			}
			if ( ! $isPreviousMonth && ! $isNextMonth && $iCalendarDay > $iDaysInMonth ) {
				$isNextMonth  = true;
				$iCalendarDay = 1;
			}
		}
		$sCalTblRows .= "</tr>\n";
		$sCalDivRows .= "</div>\n";
	}

	$weekday_names        = [ __( 'Sunday' ), __( 'Monday' ), __( 'Tuesday' ), __( 'Wednesday' ), __( 'Thursday' ), __( 'Friday' ), __( 'Saturday' ) ];
	$weekday_header_class = [ 'Sun_header', 'Mon_header', 'Tue_header', 'Wed_header', 'Thu_header', 'Fri_header', 'Sat_header' ];
	$sCalTblDayNames      = '';
	$sCalDivDayNames      = '';
	// respect the beginning of the week offset
	for ( $i = $start_of_week; $i < $start_of_week + 7; $i++ ) {
		$j = $i;
		if ( $j >= 7 ) {
			$j -= 7;
		}
		// only show wanted columns
		if ( ! empty( $weekday_arr ) ) {
			if ( ! eme_is_numeric_array( $weekday_arr ) || ! in_array( $j, $weekday_arr ) ) {
				continue;
			}
		}

		if ( $full ) {
			$sCalTblDayNames .= "<td class='" . $weekday_header_class[ $j ] . "'>" . $wp_locale->get_weekday_abbrev( $weekday_names[ $j ] ) . '</td>';
			$sCalDivDayNames .= "<div class='emeDivTableHead " . $weekday_header_class[ $j ] . "'>" . $wp_locale->get_weekday_abbrev( $weekday_names[ $j ] ) . '</div>';
		} else {
			$sCalTblDayNames .= "<td class='" . $weekday_header_class[ $j ] . "'>" . $wp_locale->get_weekday_initial( $weekday_names[ $j ] ) . '</td>';
			$sCalDivDayNames .= "<div class='emeDivTableHead " . $weekday_header_class[ $j ] . "'>" . $wp_locale->get_weekday_initial( $weekday_names[ $j ] ) . '</div>';
		}
	}

	// the real links are created via jquery when clicking on the prev-month or next-month class-links
	$random        = ( rand( 100, 200 ) );
	$cal_div_id    = "eme-calendar-$random";
	$previous_link = "<a class='prev-month eme-cal-prev-month' href='#' data-full='$full' data-htmltable='$htmltable' data-htmldiv='$htmldiv' data-long_events='$long_events' data-month='$iPrevMonth' data-year='$iPrevYear' data-category='$category' data-author='$author' data-contact_person='$contact_person' data-location_id='$location_id' data-notcategory='$notcategory' data-template_id='$template_id' data-holiday_id='$holiday_id' data-weekdays='$weekdays' data-language='$lang' data-calendar_divid='$cal_div_id'>&lt;&lt;</a>";
	$next_link     = "<a class='next-month eme-cal-next-month' href=\"#\" data-full='$full' data-htmltable='$htmltable' data-htmldiv='$htmldiv' data-long_events='$long_events' data-month='$iNextMonth' data-year='$iNextYear' data-category='$category' data-author='$author' data-contact_person='$contact_person' data-location_id='$location_id' data-notcategory='$notcategory' data-template_id='$template_id' data-holiday_id='$holiday_id' data-weekdays='$weekdays' data-language='$lang' data-calendar_divid='$cal_div_id'>&gt;&gt;</a>";

	$full ? $class = 'eme-calendar-full' : $class = 'eme-calendar';
	$calendar      = "<div class='$class' id='$cal_div_id'>";

	if ( count( $weekday_arr ) ) {
		$colspan = count( $weekday_arr );
	} else {
		$colspan = 7;
	}
	if ( $full ) {
		$fullclass = 'fullcalendar';
	} else {
		$fullclass = 'smallcalendar';
	}

	$CalTblHead = "<th class='month_name' colspan='$colspan'>$previous_link $cal_datestring $next_link</th>\n";
	$CalDivHead = "<div class='emeDivTableHead month_name'>$previous_link $cal_datestring $next_link</div>\n";
	// Build the heading portion of the calendar table
	if ( $htmltable && ! $htmldiv ) {
		$calendar .= "<table class='eme-calendar-table $fullclass'>\n" .
				'<thead><tr>' . $CalTblHead . "</tr></thead>\n" .
				"<tr class='days-names'>" . $sCalTblDayNames . "</tr>\n";
		$calendar .= $sCalTblRows;
		$calendar .= "</table>\n";
	} else {
		$calendar .= "<div class='emeDivTable $fullclass'>\n" .
				"<div class='emeDivTableHeading'><div class='emeDivTableRow'>" . $CalDivHead . "</div></div>\n" .
		"</div><div class='emeDivTable $fullclass'>\n" .
				"<div class='emeDivTableRow days-names'>" . $sCalDivDayNames . "</div>\n";
		$calendar .= $sCalDivRows;
		$calendar .= "</div>\n";
	}
	$calendar .= '</div>';

	if ( $do_echo ) {
		echo $calendar;
	} else {
		return $calendar;
	}
}

// for both logged in and not logged in users
add_action( 'wp_ajax_eme_calendar', 'eme_calendar_ajax' );
add_action( 'wp_ajax_nopriv_eme_calendar', 'eme_calendar_ajax' );
function eme_calendar_ajax() {
	check_ajax_referer( 'eme_frontend', 'eme_frontend_nonce' );
	( ! empty( $_POST['full'] ) ) ? $full                     = 1 : $full = 0;
	( ! empty( $_POST['htmltable'] ) ) ? $htmltable           = 1 : $htmltable = 0;
	( ! empty( $_POST['htmldiv'] ) ) ? $htmldiv               = 1 : $htmldiv = 0;
	( ! empty( $_POST['long_events'] ) ) ? $long_events       = 1 : $long_events = 0;
	( ! empty( $_POST['category'] ) ) ? $category             = eme_sanitize_request( $_POST['category'] ) : $category = 0; // this can be a string like 0+1 or 0,3
	( ! empty( $_POST['notcategory'] ) ) ? $notcategory       = eme_sanitize_request( $_POST['notcategory'] ) : $notcategory = 0; // this can be a string like 0+1 or 0,3
	( ! empty( $_POST['calmonth'] ) ) ? $month                = eme_sanitize_request( $_POST['calmonth'] ) : $month = ''; // this can be a number or text (like next_month)
	( ! empty( $_POST['calyear'] ) ) ? $year                  = intval( $_POST['calyear'] ) : $year = '';
	( ! empty( $_POST['author'] ) ) ? $author                 = eme_sanitize_request( $_POST['author'] ) : $author = ''; // can be a name of a person
	( ! empty( $_POST['contact_person'] ) ) ? $contact_person = eme_sanitize_request( $_POST['contact_person'] ) : $contact_person = ''; // can be a name of a person
	( ! empty( $_POST['location_id'] ) ) ? $location_id       = eme_sanitize_request( $_POST['location_id'] ) : $location_id = ''; // this can be a string like 0+1 or 0,3
	( ! empty( $_POST['template_id'] ) ) ? $template_id       = intval( $_POST['template_id'] ) : $template_id = '';
	( ! empty( $_POST['holiday_id'] ) ) ? $holiday_id         = intval( $_POST['holiday_id'] ) : $holiday_id = '';
	( ! empty( $_POST['weekdays'] ) ) ? $weekdays             = eme_sanitize_request( $_POST['weekdays'] ) : $weekdays = ''; // this can be a string like 0,2,3,5

	echo eme_get_calendar( full: $full, month: $month, year: $year, long_events: $long_events, category: $category, author: $author, contact_person: $contact_person, location_id: $location_id, notcategory: $notcategory, template_id: $template_id, weekdays: $weekdays, holiday_id: $holiday_id, htmltable: $htmltable, htmldiv: $htmldiv );
	wp_die();
}

function eme_replace_calendar_placeholders( $format, $event, $cal_day, $target = 'html', $lang = '' ) {
	// replace EME language tags as early as possible
        $format = eme_translate_string( $format );

	if ( $target == 'htmlmail' || $target == 'html_nohtml2br' ) {
		$target = 'html';
	}
	if ( has_filter( 'eme_cal_format_prefilter' ) ) {
		$format = apply_filters( 'eme_cal_format_prefilter', $format, $event, $cal_day );
	}

	$event_start_date = eme_get_date_from_dt( $event['event_start'] ); // Just the YYYY-MM-DD part
	$event_end_date   = eme_get_date_from_dt( $event['event_end'] );
	$needle_offset    = 0;
	preg_match_all( '/#(ESC|URL)?@?_?[A-Za-z0-9_]+(\{(?>[^{}]+|(?2))*\})*+/', $format, $placeholders, PREG_OFFSET_CAPTURE );
	foreach ( $placeholders[0] as $orig_result ) {
		$result             = $orig_result[0];
		$orig_result_needle = $orig_result[1] - $needle_offset;
		$orig_result_length = strlen( $orig_result[0] );
		$replacement        = '';
		$found              = 1;
		if ( preg_match( '/#_IS_START_DAY/', $result ) ) {
			if ( $cal_day == $event_start_date ) {
				$replacement = 1;
			} else {
				$replacement = 0;
			}
		} elseif ( preg_match( '/#_IS_END_DAY/', $result ) ) {
			if ( $cal_day == $event_end_date ) {
				$replacement = 1;
			} else {
				$replacement = 0;
			}
		} elseif ( preg_match( '/#_IS_NOT_START_OR_END_DAY|#_IS_NOT_START_OR_END_DATE/', $result ) ) {
			if ( $cal_day != $event_start_date && $cal_day != $event_end_date ) {
				$replacement = 1;
			} else {
				$replacement = 0;
			}
		} else {
			$found = 0;
		}
		if ( $found ) {
			$format         = substr_replace( $format, $replacement, $orig_result_needle, $orig_result_length );
			$needle_offset += $orig_result_length - strlen( $replacement );
		}
	}

	// now, replace any language tags found in the format itself
	$format = eme_translate( $format, $lang );

	return do_shortcode( $format );
}