WordPress Enhanced Pagination (Digg-style pagination)

enhanced_pagination.php

<?php

// Define a namespace
namespace Startuply\Extensions;

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

/**
 * Helper class to paginate posts
 */
class Pagination {
	// Will show "first page" and "last page" links
	protected $show_last_links;
	// Does pagination needs to be centered?
	protected $centered;
	// Number of links near current page link
	protected $adjacents;
	// Number of posts per page
	protected $per_page;
	// Number of the current page
	protected $current_page;
	// Contains total amount of pages
	protected $total_pages;

	/**
	 * Pagination constructor.
	 *
	 * @param bool $show_last_links Whether navigation links needs to be showed or not
	 * @param bool $centered True is the pagination needs to be centered
	 */
	public function __construct( $show_last_links = true, $centered = true ) {
		// Assign a total amount of pages
		global $wp_query;
		$this->total_pages = $wp_query->max_num_pages;

		// Get the current page, first page by default
		$this->current_page = get_query_var( 'paged', 0 );
		// Get the amount of posts per page, 10 posts by default
		$this->per_page = get_query_var( 'posts_per_page', 10 );
		// Show "first page" and "last page" links display to true or false
		$this->show_last_links = $show_last_links;
		// Set our adjacents to 3 links by default
		$this->adjacents = 3;
	}

	/**
	 * Class setter. If method does not exist, it will be created via magic method.
	 *
	 * @param string $name Name of the property
	 * @param mixed $value Value of the property
	 */
	public function __set( $name, $value ) {
		// Check if method exists or not
		if ( method_exists( $this, $name ) ) {
			$this->$name( $value );
		} else {
			// Getter/Setter not defined so set as property of object
			$this->$name = $value;
		}
	}

	/**
	 * Class getter. Return the value of method/property or null otherwise.
	 *
	 * @param string $name Name of the property
	 *
	 * @return mixed Value of the property
	 */
	function __get( $name ) {
		// Check if method exists or not
		if ( method_exists( $this, $name ) ) {
			return $this->$name();
		} elseif ( property_exists( $this, $name ) ) {
			// Getter/Setter not defined so return property if it exists
			return $this->$name;
		}

		return null;
	}


	/**
	 * Show previous page link and link on the first page
	 */
	public function show_prev_navigation() {
		// Show the previous page link, if we're not on the first page
		if ( $this->current_page != 0 ) {
			// If "first page" link is enabled
			if ( $this->show_last_links ) : ?>
                <a class="first" href="<?php echo get_pagenum_link( 1 ); ?>">
					<?php _e( '&laquo;&laquo; First', 'startuply' ); ?>
                </a>
			<?php endif; ?>

            <a class="prev" href="<?php echo get_pagenum_link( $this->current_page - 1 ); ?>">
				<?php _e( '&laquo;&nbsp;', 'startuply' ); ?>
            </a>

		<?php }
	}

	/**
	 * Show next page link and link on the last page
	 */
	public function show_next_navigation() {
		// Show the next page link, if we're not of the last page
		if ( $this->current_page < $this->total_pages ) { ?>
            <a class="next" href="<?php echo get_pagenum_link( $this->current_page + 1 ); ?>">
				<?php _e( '&nbsp;&raquo;', 'startuply' ); ?>
            </a>

			<?php
			// If "last page" link is enabled
			if ( $this->show_last_links ) : ?>
                <a class="last" href="<?php echo get_pagenum_link( $this->total_pages ); ?>">
					<?php _e( 'Last &raquo;&raquo;', 'startuply' ); ?>
                </a>
			<?php endif;
		}
	}

	/**
	 * Turn the page number into link
	 *
	 * @param integer $page_number Number of the page
	 *
	 * @return string Resulted link
	 */
	protected function single_link( $page_number ) {
		// Is it a current page?
		$is_current_page = ( $this->current_page == $page_number );
		// Is it the first page?
		$is_first_page = ( $this->current_page == 0 && $page_number == 1 );

		// Check which class we need to set
		if ( $is_current_page || $is_first_page ) {
			// Set "active" class if it's current page
			return '<a class="active">' . $page_number . '</a>';
		} else {
			// Add the link to the array
			return '<a class="inactive" href="' . get_pagenum_link( $page_number ) . '">' . $page_number . '</a>';
		}
	}

	/**
	 * Show pagination links
	 *
	 * @see Inspired by http://www.strangerstudios.com/sandbox/pagination/diggstyle.php
	 */
	public function links() {
		// Initialize our links array
		$links = array();

		/*
		 * Algorithm of digg-style pagination
		 */

		// Need at least 10 pages to bother breaking it up
		if ( $this->total_pages < 4 + ( $this->adjacents * 2 ) ) {
			// Loop through the whole pages
			for ( $counter = 1; $counter < ( $this->total_pages + 1 ); $counter ++ ) {
				$links[] = $this->single_link( $counter );
			}

			// If at least 9 pages, we can hide some
		} elseif ( $this->total_pages > 2 + ( $this->adjacents * 2 ) ) {
			/*
			 * Current page number < 7, close to beginning; only hide later pages
			 */
			if ( $this->current_page < 1 + ( $this->adjacents * 2 ) ) {
				// Show links
				for ( $counter = 1; $counter < 4 + ( $this->adjacents * 2 ); $counter ++ ) {
					$links[] = $this->single_link( $counter );
				}

				// Add ellipsis to the end
				$links[] = '<span class="dots">...</span>';

				/*
				 * In the middle; Hide some front and some back
				 */
			} elseif ( $this->total_pages - ( $this->adjacents * 2 ) > $this->current_page && $this->current_page > ( $this->adjacents * 2 ) ) {
				// Add ellipsis to the beginning
				$links[] = '<span class="dots">...</span>';

				// Show links
				for ( $counter = $this->current_page - $this->adjacents; $counter <= $this->current_page + $this->adjacents; $counter ++ ) {
					$links[] = $this->single_link( $counter );
				}

				// Add ellipsis to the end
				$links[] = '<span class="dots">...</span>';

				/*
				 * Close to end; only hide early pages
				 */
			} else {
				// Add ellipsis to the beginning
				$links[] = '<span class="dots">...</span>';

				// Show links
				for ( $counter = $this->total_pages - ( 2 + ( $this->adjacents * 2 ) ); $counter <= $this->total_pages; $counter ++ ) {
					$links[] = $this->single_link( $counter );
				}
			}
		}

		// Push the array into string
		echo implode( "\n", $links );
	}

	/**
	 * Show pagination links
	 */
	public function get_links() {
		// Set centering class
		$center = $this->centered ? 'aligncenter' : '';

		// If we have at least two pages
		if ( $this->total_pages > 1 ) { ?>
            <div class="pagination <?php echo $center; ?>">
				<?php
				$this->show_prev_navigation();
				$this->links();
				$this->show_next_navigation();
				?>
            </div>
		<?php }
	}
}