get_calendar()

get_calendar( array $args = array() ): void|string

function get_calendar( $args = array() ) {
	global $wpdb, $m, $monthnum, $year, $wp_locale, $posts;

	$defaults = array(
		'initial'   => true,
		'display'   => true,
		'post_type' => 'post',
	);

	$original_args = func_get_args();
	$args          = array();

	if ( ! empty( $original_args ) ) {
		if ( ! is_array( $original_args[0] ) ) {
			if ( isset( $original_args[0] ) && is_bool( $original_args[0] ) ) {
				$defaults['initial'] = $original_args[0];
			}
			if ( isset( $original_args[1] ) && is_bool( $original_args[1] ) ) {
				$defaults['display'] = $original_args[1];
			}
		} else {
			$args = $original_args[0];
		}
	}

	/**
	 * Filter the `get_calendar` function arguments before they are used.
	 *
	 * @since 6.8.0
	 *
	 * @param array $args {
	 *     Optional. Arguments for the `get_calendar` function.
	 *
	 *     @type bool   $initial   Whether to use initial calendar names. Default true.
	 *     @type bool   $display   Whether to display the calendar output. Default true.
	 *     @type string $post_type Optional. Post type. Default 'post'.
	 * }
	 */
	$args = apply_filters( 'get_calendar_args', wp_parse_args( $args, $defaults ) );

	if ( ! post_type_exists( $args['post_type'] ) ) {
		$args['post_type'] = 'post';
	}

	$w = 0;
	if ( isset( $_GET['w'] ) ) {
		$w = (int) $_GET['w'];
	}

	/*
	 * Normalize the cache key.
	 *
	 * The following ensures the same cache key is used for the same parameter
	 * and parameter equivalents. This prevents `post_type > post, initial > true`
	 * from generating a different key from the same values in the reverse order.
	 *
	 * `display` is excluded from the cache key as the cache contains the same
	 * HTML regardless of this function's need to echo or return the output.
	 *
	 * The global values contain data generated by the URL query string variables.
	 */
	$cache_args = $args;
	unset( $cache_args['display'] );

	$cache_args['globals'] = array(
		'm'        => $m,
		'monthnum' => $monthnum,
		'year'     => $year,
		'week'     => $w,
	);

	wp_recursive_ksort( $cache_args );
	$key   = md5( serialize( $cache_args ) );
	$cache = wp_cache_get( 'get_calendar', 'calendar' );

	if ( $cache && is_array( $cache ) && isset( $cache[ $key ] ) ) {
		/** This filter is documented in wp-includes/general-template.php */
		$output = apply_filters( 'get_calendar', $cache[ $key ], $args );

		if ( $args['display'] ) {
			echo $output;
			return;
		}

		return $output;
	}

	if ( ! is_array( $cache ) ) {
		$cache = array();
	}

	$post_type = $args['post_type'];

	// Quick check. If we have no posts at all, abort!
	if ( ! $posts ) {
		$gotsome = $wpdb->get_var(
			$wpdb->prepare(
				"SELECT 1 as test
				FROM $wpdb->posts
				WHERE post_type = %s
				AND post_status = 'publish'
				LIMIT 1",
				$post_type
			)
		);

		if ( ! $gotsome ) {
			$cache[ $key ] = '';
			wp_cache_set( 'get_calendar', $cache, 'calendar' );
			return;
		}
	}

	// week_begins = 0 stands for Sunday.
	$week_begins = (int) get_option( 'start_of_week' );

	// Let's figure out when we are.
	if ( ! empty( $monthnum ) && ! empty( $year ) ) {
		$thismonth = (int) $monthnum;
		$thisyear  = (int) $year;
	} elseif ( ! empty( $w ) ) {
		// We need to get the month from MySQL.
		$thisyear = (int) substr( $m, 0, 4 );
		// It seems MySQL's weeks disagree with PHP's.
		$d         = ( ( $w - 1 ) * 7 ) + 6;
		$thismonth = (int) $wpdb->get_var(
			$wpdb->prepare(
				"SELECT DATE_FORMAT((DATE_ADD('%d0101', INTERVAL %d DAY) ), '%%m')",
				$thisyear,
				$d
			)
		);
	} elseif ( ! empty( $m ) ) {
		$thisyear = (int) substr( $m, 0, 4 );
		if ( strlen( $m ) < 6 ) {
			$thismonth = 1;
		} else {
			$thismonth = (int) substr( $m, 4, 2 );
		}
	} else {
		$thisyear  = (int) current_time( 'Y' );
		$thismonth = (int) current_time( 'm' );
	}

	$unixmonth = mktime( 0, 0, 0, $thismonth, 1, $thisyear );
	$last_day  = gmdate( 't', $unixmonth );

	// Get the next and previous month and year with at least one post.
	$previous = $wpdb->get_row(
		$wpdb->prepare(
			"SELECT MONTH(post_date) AS month, YEAR(post_date) AS year
			FROM $wpdb->posts
			WHERE post_date < '%d-%d-01'
			AND post_type = %s AND post_status = 'publish'
			ORDER BY post_date DESC
			LIMIT 1",
			$thisyear,
			zeroise( $thismonth, 2 ),
			$post_type
		)
	);

	$next = $wpdb->get_row(
		$wpdb->prepare(
			"SELECT MONTH(post_date) AS month, YEAR(post_date) AS year
			FROM $wpdb->posts
			WHERE post_date > '%d-%d-%d 23:59:59'
			AND post_type = %s AND post_status = 'publish'
			ORDER BY post_date ASC
			LIMIT 1",
			$thisyear,
			zeroise( $thismonth, 2 ),
			$last_day,
			$post_type
		)
	);

	/* translators: Calendar caption: 1: Month name, 2: 4-digit year. */
	$calendar_caption = _x( '%1$s %2$s', 'calendar caption' );
	$calendar_output  = '<table id="wp-calendar" class="wp-calendar-table">
	<caption>' . sprintf(
		$calendar_caption,
		$wp_locale->get_month( $thismonth ),
		gmdate( 'Y', $unixmonth )
	) . '</caption>
	<thead>
	<tr>';

	$myweek = array();

	for ( $wdcount = 0; $wdcount <= 6; $wdcount++ ) {
		$myweek[] = $wp_locale->get_weekday( ( $wdcount + $week_begins ) % 7 );
	}

	foreach ( $myweek as $wd ) {
		$day_name         = $args['initial'] ? $wp_locale->get_weekday_initial( $wd ) : $wp_locale->get_weekday_abbrev( $wd );
		$wd               = esc_attr( $wd );
		$calendar_output .= "\n\t\t<th scope=\"col\" aria-label=\"$wd\">$day_name</th>";
	}

	$calendar_output .= '
	</tr>
	</thead>
	<tbody>
	<tr>';

	$daywithpost = array();

	// Get days with posts.
	$dayswithposts = $wpdb->get_results(
		$wpdb->prepare(
			"SELECT DISTINCT DAYOFMONTH(post_date)
			FROM $wpdb->posts WHERE post_date >= '%d-%d-01 00:00:00'
			AND post_type = %s AND post_status = 'publish'
			AND post_date <= '%d-%d-%d 23:59:59'",
			$thisyear,
			zeroise( $thismonth, 2 ),
			$post_type,
			$thisyear,
			zeroise( $thismonth, 2 ),
			$last_day
		),
		ARRAY_N
	);

	if ( $dayswithposts ) {
		foreach ( (array) $dayswithposts as $daywith ) {
			$daywithpost[] = (int) $daywith[0];
		}
	}

	// See how much we should pad in the beginning.
	$pad = calendar_week_mod( (int) gmdate( 'w', $unixmonth ) - $week_begins );
	if ( $pad > 0 ) {
		$calendar_output .= "\n\t\t" . '<td colspan="' . esc_attr( $pad ) . '" class="pad"> </td>';
	}

	$newrow      = false;
	$daysinmonth = (int) gmdate( 't', $unixmonth );

	for ( $day = 1; $day <= $daysinmonth; ++$day ) {
		if ( $newrow ) {
			$calendar_output .= "\n\t</tr>\n\t<tr>\n\t\t";
		}

		$newrow = false;

		if ( (int) current_time( 'j' ) === $day
			&& (int) current_time( 'm' ) === $thismonth
			&& (int) current_time( 'Y' ) === $thisyear
		) {
			$calendar_output .= '<td id="today">';
		} else {
			$calendar_output .= '<td>';
		}

		if ( in_array( $day, $daywithpost, true ) ) {
			// Any posts today?
			$date_format = gmdate( _x( 'F j, Y', 'daily archives date format' ), strtotime( "{$thisyear}-{$thismonth}-{$day}" ) );
			/* translators: Post calendar label. %s: Date. */
			$label            = sprintf( __( 'Posts published on %s' ), $date_format );
			$calendar_output .= sprintf(
				'<a href="%s" aria-label="%s">%s</a>',
				get_day_link( $thisyear, $thismonth, $day ),
				esc_attr( $label ),
				$day
			);
		} else {
			$calendar_output .= $day;
		}

		$calendar_output .= '</td>';

		if ( 6 === (int) calendar_week_mod( (int) gmdate( 'w', mktime( 0, 0, 0, $thismonth, $day, $thisyear ) ) - $week_begins ) ) {
			$newrow = true;
		}
	}

	$pad = 7 - calendar_week_mod( (int) gmdate( 'w', mktime( 0, 0, 0, $thismonth, $day, $thisyear ) ) - $week_begins );
	if ( 0 < $pad && $pad < 7 ) {
		$calendar_output .= "\n\t\t" . '<td class="pad" colspan="' . esc_attr( $pad ) . '"> </td>';
	}

	$calendar_output .= "\n\t</tr>\n\t</tbody>";

	$calendar_output .= "\n\t</table>";

	$calendar_output .= '<nav aria-label="' . __( 'Previous and next months' ) . '" class="wp-calendar-nav">';

	if ( $previous ) {
		$calendar_output .= "\n\t\t" . sprintf(
			'<span class="wp-calendar-nav-prev"><a href="%1$s">« %2$s</a></span>',
			get_month_link( $previous->year, $previous->month ),
			$wp_locale->get_month_abbrev( $wp_locale->get_month( $previous->month ) )
		);
	} else {
		$calendar_output .= "\n\t\t" . '<span class="wp-calendar-nav-prev"> </span>';
	}

	$calendar_output .= "\n\t\t" . '<span class="pad"> </span>';

	if ( $next ) {
		$calendar_output .= "\n\t\t" . sprintf(
			'<span class="wp-calendar-nav-next"><a href="%1$s">%2$s »</a></span>',
			get_month_link( $next->year, $next->month ),
			$wp_locale->get_month_abbrev( $wp_locale->get_month( $next->month ) )
		);
	} else {
		$calendar_output .= "\n\t\t" . '<span class="wp-calendar-nav-next"> </span>';
	}

	$calendar_output .= '
	</nav>';

	$cache[ $key ] = $calendar_output;
	wp_cache_set( 'get_calendar', $cache, 'calendar' );

	/**
	 * Filters the HTML calendar output.
	 *
	 * @since 3.0.0
	 * @since 6.8.0 Added the `$args` parameter.
	 *
	 * @param string $calendar_output HTML output of the calendar.
	 * @param array  $args {
	 *     Optional. Array of display arguments.
	 *
	 *     @type bool   $initial   Whether to use initial calendar names. Default true.
	 *     @type bool   $display   Whether to display the calendar output. Default true.
	 *     @type string $post_type Optional. Post type. Default 'post'.
	 * }
	 */
	$calendar_output = apply_filters( 'get_calendar', $calendar_output, $args );

	if ( $args['display'] ) {
		echo $calendar_output;
		return;
	}

	return $calendar_output;
}