カスタム投稿タイプ用カレンダーウィジット

custom_post_type_calendar.php

<?php
/*
Plugin Name: Custom Post Type Calendar
Author: nagasawa@barbwire.co.jp
Plugin URI: https://munyagu.com/
Description: Calendar for custom post type archive.
Version: 0.1
License: GPLv2 or later
License URI: http://www.gnu.org/licenses/gpl-2.0.html
*/

/**
 * Widget API: WP_Widget_Custom_Post_Type_Calendar class
 *
 * @package WordPress
 * @subpackage Widgets
 * @since 4.4.0
 */

/**
 * Core class used to implement the Calendar widget.
 *
 * @since 2.8.0
 *
 * @see WP_Widget
 */
class WP_Widget_Custom_Post_Type_Calendar extends WP_Widget {
	/**
	 * Ensure that the ID attribute only appears in the markup once
	 *
	 * @since 4.4.0
	 *
	 * @static
	 * @var int
	 */
	private static $instance = 0;

	/**
	 * Sets up a new Calendar widget instance.
	 *
	 * @since 2.8.0
	 */
	public function __construct() {
		$widget_ops = array(
			'classname' => 'widget_calendar',
			'description' => __( 'A calendar of your site&#8217;s Posts.' ),
			'customize_selective_refresh' => true,
		);
		parent::__construct( 'custom-post-type-calendar', __( 'Custom Post Type Calendar' ), $widget_ops );
	}

	/**
	 * Outputs the content for the current Calendar widget instance.
	 *
	 * @since 2.8.0
	 *
	 * @param array $args     Display arguments including 'before_title', 'after_title',
	 *                        'before_widget', and 'after_widget'.
	 * @param array $instance The settings for the particular instance of the widget.
	 */
	public function widget( $args, $instance ) {
		$title = ! empty( $instance['title'] ) ? $instance['title'] : '';
		$post_type = ! empty( $instance['post_type'] ) ? $instance['post_type'] : 'post';

		/** This filter is documented in wp-includes/widgets/class-wp-widget-pages.php */
		$title = apply_filters( 'widget_title', $title, $instance, $this->id_base );

		echo $args['before_widget'];
		if ( $title ) {
			echo $args['before_title'] . $title . $args['after_title'];
		}
		if ( 0 === self::$instance ) {
			echo '<div id="calendar_wrap" class="calendar_wrap">';
		} else {
			echo '<div class="calendar_wrap">';
		}
		get_custom_post_type_calendar(true, true, $post_type);
		echo '</div>';
		echo $args['after_widget'];

		self::$instance++;
	}

	/**
	 * Handles updating settings for the current Calendar widget instance.
	 *
	 * @since 2.8.0
	 *
	 * @param array $new_instance New settings for this instance as input by the user via
	 *                            WP_Widget::form().
	 * @param array $old_instance Old settings for this instance.
	 * @return array Updated settings to save.
	 */
	public function update( $new_instance, $old_instance ) {
		$instance = $old_instance;
		$instance['title'] = sanitize_text_field( $new_instance['title'] );
		$instance['post_type'] = sanitize_text_field( $new_instance['post_type'] );

		return $instance;
	}

	/**
	 * Outputs the settings form for the Calendar widget.
	 *
	 * @since 2.8.0
	 *
	 * @param array $instance Current settings.
	 */
	public function form( $instance ) {
		$instance = wp_parse_args( (array) $instance, array( 'title' => '', 'post_type' => '' ) );
		$title = sanitize_text_field( $instance['title'] );
		$post_type = sanitize_text_field( $instance['post_type'] );
		?>
		<p><label for="<?php echo $this->get_field_id('title'); ?>"><?php _e('Title:'); ?></label>
		<input class="widefat" id="<?php echo $this->get_field_id('title'); ?>" name="<?php echo $this->get_field_name('title'); ?>" type="text" value="<?php echo esc_attr($title); ?>" /></p>

		<p><label for="<?php echo $this->get_field_id('post_type'); ?>"><?php _e('Post Type:'); ?></label>
		<input class="widefat" id="<?php echo $this->get_field_id('post_type'); ?>" name="<?php echo $this->get_field_name('post_type'); ?>" type="text" value="<?php echo esc_attr($post_type); ?>" /></p>
		<?php
	}
}



/**
 * Display calendar with days that have posts as links for custom post type.
 *
 * The calendar is cached, which will be retrieved, if it exists. If there are
 * no posts for the month, then it will not be displayed.
 *
 *
 * @global wpdb      $wpdb
 * @global int       $m
 * @global int       $monthnum
 * @global int       $year
 * @global WP_Locale $wp_locale
 * @global array     $posts
 *
 * @param bool $initial Optional, default is true. Use initial calendar names.
 * @param bool $echo    Optional, default is true. Set to false for return.
 * @param bool $echo    Optional, default is 'post'. Set custom post type.
 * @return string|void String when retrieving.
 */
function get_custom_post_type_calendar( $initial = true, $echo = true, $post_type = 'post' ) {
	global $wpdb, $m, $monthnum, $year, $wp_locale, $posts;

	$key = md5( $m . $monthnum . $year );
	$cache = wp_cache_get( 'get_custom_post_type_calendar', 'custom_post_type_calendar' );

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

		if ( $echo ) {
			echo $output;
			return;
		}

		return $output;
	}

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

	// Quick check. If we have no posts at all, abort!
	if ( ! $posts ) {
		$gotsome = $wpdb->get_var("SELECT 1 as test FROM $wpdb->posts WHERE post_type = '{$post_type}' AND post_status = 'publish' LIMIT 1");
		if ( ! $gotsome ) {
			$cache[ $key ] = '';
			wp_cache_set( 'get_custom_post_type_calendar', $cache, 'custom_post_type_calendar' );
			return;
		}
	}

	if ( isset( $_GET['w'] ) ) {
		$w = (int) $_GET['w'];
	}
	// week_begins = 0 stands for Sunday
	$week_begins = (int) get_option( 'start_of_week' );
	$ts = current_time( 'timestamp' );

	// Let's figure out when we are
	if ( ! empty( $monthnum ) && ! empty( $year ) ) {
		$thismonth = zeroise( intval( $monthnum ), 2 );
		$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 = $wpdb->get_var("SELECT DATE_FORMAT((DATE_ADD('{$thisyear}0101', INTERVAL $d DAY) ), '%m')");
	} elseif ( ! empty( $m ) ) {
		$thisyear = (int) substr( $m, 0, 4 );
		if ( strlen( $m ) < 6 ) {
			$thismonth = '01';
		} else {
			$thismonth = zeroise( (int) substr( $m, 4, 2 ), 2 );
		}
	} else {
		$thisyear = gmdate( 'Y', $ts );
		$thismonth = gmdate( 'm', $ts );
	}

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

	// Get the next and previous month and year with at least one post
	$previous = $wpdb->get_row("SELECT MONTH(post_date) AS month, YEAR(post_date) AS year
		FROM $wpdb->posts
		WHERE post_date < '$thisyear-$thismonth-01'
		AND post_type = '{$post_type}' AND post_status = 'publish'
			ORDER BY post_date DESC
			LIMIT 1");
	$next = $wpdb->get_row("SELECT MONTH(post_date) AS month, YEAR(post_date) AS year
		FROM $wpdb->posts
		WHERE post_date > '$thisyear-$thismonth-{$last_day} 23:59:59'
		AND post_type = '{$post_type}' AND post_status = 'publish'
			ORDER BY post_date ASC
			LIMIT 1");

	/* 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">
	<caption>' . sprintf(
		$calendar_caption,
		$wp_locale->get_month( $thismonth ),
		date( '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 = $initial ? $wp_locale->get_weekday_initial( $wd ) : $wp_locale->get_weekday_abbrev( $wd );
		$wd = esc_attr( $wd );
		$calendar_output .= "\n\t\t<th scope=\"col\" title=\"$wd\">$day_name</th>";
	}

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

	<tfoot>
	<tr>';

	if ( $previous ) {
		$calendar_output .= "\n\t\t".'<td colspan="3" id="prev"><a href="' . get_month_link( $previous->year, $previous->month ) . '">&laquo; ' .
			$wp_locale->get_month_abbrev( $wp_locale->get_month( $previous->month ) ) .
		'</a></td>';
	} else {
		$calendar_output .= "\n\t\t".'<td colspan="3" id="prev" class="pad">&nbsp;</td>';
	}

	$calendar_output .= "\n\t\t".'<td class="pad">&nbsp;</td>';

	if ( $next ) {
		$calendar_output .= "\n\t\t".'<td colspan="3" id="next"><a href="' . get_month_link( $next->year, $next->month ) . '">' .
			$wp_locale->get_month_abbrev( $wp_locale->get_month( $next->month ) ) .
		' &raquo;</a></td>';
	} else {
		$calendar_output .= "\n\t\t".'<td colspan="3" id="next" class="pad">&nbsp;</td>';
	}

	$calendar_output .= '
	</tr>
	</tfoot>

	<tbody>
	<tr>';

	$daywithpost = array();

	// Get days with posts
	$dayswithposts = $wpdb->get_results("SELECT DISTINCT DAYOFMONTH(post_date)
		FROM $wpdb->posts WHERE post_date >= '{$thisyear}-{$thismonth}-01 00:00:00'
		AND post_type = '{$post_type}' AND post_status = 'publish'
		AND post_date <= '{$thisyear}-{$thismonth}-{$last_day} 23:59:59'", ARRAY_N);
	if ( $dayswithposts ) {
		foreach ( (array) $dayswithposts as $daywith ) {
			$daywithpost[] = $daywith[0];
		}
	}

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

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

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

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

		if ( in_array( $day, $daywithpost ) ) {
			// any posts today?
			$date_format = date( _x( 'F j, Y', 'daily archives date format' ), strtotime( "{$thisyear}-{$thismonth}-{$day}" ) );
			/* translators: Post calendar label. 1: Date */
			$label = sprintf( __( 'Posts published on %s' ), $date_format );
			$link = get_day_link( $thisyear, $thismonth, $day );
			if( 'post' !== $post_type ){
				$link .= '?post_type=' . $post_type;
			}
			$calendar_output .= sprintf(
				'<a href="%s" aria-label="%s">%s</a>',
				$link,
				esc_attr( $label ),
				$day
			);
		} else {
			$calendar_output .= $day;
		}
		$calendar_output .= '</td>';

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

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

	$cache[ $key ] = $calendar_output;
	wp_cache_set( 'get_custom_post_type_calendar', $cache, 'custom_post_type_calendar' );

	if ( $echo ) {
		/**
		 * Filters the HTML calendar output.
		 *
		 * @since 3.0.0
		 *
		 * @param string $calendar_output HTML output of the calendar.
		 */
		echo apply_filters( 'get_custom_post_type_calendar', $calendar_output );
		return;
	}
	/** This filter is documented in wp-includes/general-template.php */
	return apply_filters( 'get_custom_post_type_calendar', $calendar_output );
}

add_action( 'widgets_init', function () {
	register_widget( 'WP_Widget_Custom_Post_Type_Calendar' );
});

Based WordPress4.6.9 wp-includes/general-template.php.