Wordpress Numeric Pagination Class that enables you to set the classes of each LI and A html tag.

class-wp-numeric-pagination.php

<?php
/**
 * Numeric Pagination Class
 * @author Alexandre Plennevaux https://pixeline.be
 * 
 * This class returns a list of LI > A. It is up to you to set the wrapping NAV > UL around your function call.
 * 
 * @usage (setting specific classes)
 *
 * // Sets the css classes you want to be used for the output
 *
 * $li_classes = array('ends' => 'arrow', 'default' => '' );
 * $a_classes = array('default'=>'page-numbers', 'prev'=>'prev', 'next'=>'next', 'current'=>'current' );
 * $prevnext_text = array('prev' => '<i class="icon-arrow2"></i>', 'next'=> '<i class="icon-arrow2"></i>'); 
 * 
 * // Call the function
 * echo new Numeric_Pagination($a_classes, $li_classes, $prevnext_text);
 *
 * 
 */	

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}
if ( ! class_exists( 'Numeric_Pagination' ) ) {

	class Numeric_Pagination {

		public $li_classes = array('ends' => 'arrow', 'default' => '' );
		public $a_classes = array('default'=>'page-numbers', 'prev'=>'prev', 'next'=>'next', 'current'=>'current' );
		public $prevnext_text = array('prev' => '<i class="icon-arrow2"></i>', 'next'=> '<i class="icon-arrow2"></i>');
		
		public function __construct($a_classes = null,  $li_classes = null, $prevnext_text  = null) {

			global $wp_query;

			// Exit early if no need for pagination.
			if ( $wp_query->max_num_pages <= 1 )
				return;

			// Set defaults
			if (null !== $a_classes) {
				$this->a_classes = $a_classes;
			}
			if (null !== $li_classes) {
				$this->li_classes = $li_classes;
			}
			if (null !== $prevnext_text) {
				$this->prevnext_text = $prevnext_text;
			}
		}


		public function __toString()
		{
			global $wp_query;
			
			$big = 999999999; // need an unlikely integer
			$pages = paginate_links( array(
					'base'               => str_replace( $big, '%#%', esc_url( get_pagenum_link( $big ) ) ),
					'format'             => '?paged=%#%',
					'current'            => max( 1, get_query_var('paged') ),
					'total'              => $wp_query->max_num_pages,
					'type'               => 'array',
					'end_size'           => 2,
					'mid_size'           => 3,
					'prev_next'          => true,
					'prev_text'          => $this->prevnext_text['prev'],
					'next_text'          => $this->prevnext_text['next']
				) );

			$output = '';

			if( is_array( $pages ) && count( $pages ) > 0 ) {

				$paged = ( 0 === get_query_var('paged') ) ? 1 : get_query_var('paged');

				foreach ( $pages as $k => $page ) {

					$li_class = (0 === $k ||  (count($pages)-1) === $k) ? $this->li_classes['ends'] : $this->li_classes['default'] ;
					$output .= '<li class="'.$li_class.'">'. $this->replace_anchor_classes($page) . '</li>';
				}
			}

			return $output;
		}

		function replace_anchor_classes($anchor){
			
			$anchor = preg_replace('/page-numbers/', $this->a_classes['default']  , $anchor);
			$anchor = preg_replace('/prev/', $this->a_classes['prev'] , $anchor);
			$anchor = preg_replace('/next/', $this->a_classes['next']  , $anchor);
			$anchor = preg_replace('/current/', $this->a_classes['current']  , $anchor);

			return $anchor;
		}
	}
}