WP Coupon - Sort by Popularity default in Category coupon page

// Sort by Popularity default in Category coupon page
add_action( 'init', function() {
	remove_action( 'wpcoupon_coupon_category_before_sidebar', 'wpcoupon_coupon_cat_filter_box', 10 );
	remove_filter( 'pre_get_posts', 'wpcoupon_coupon_cat_query' );

	add_action( 'wpcoupon_coupon_category_before_sidebar', 'custom_wpcoupon_coupon_cat_filter_box', 10 );
	add_filter( 'pre_get_posts', 'custom_wpcoupon_coupon_cat_query' );


} );

/**
 * Custom query for custom tax
 *
 * @todo: fix page not found on coupon page tax
 *
 * @param $query
 * @return mixed
 */
function custom_wpcoupon_coupon_cat_query( $query ) {
	if ( get_query_var( 'taxonomy' ) == 'coupon_category' && $query->is_main_query() ) {
		$cate_id = get_queried_object_id();

		$coupon_type = 'all';
		$available_coupon_type = wpcoupon_get_coupon_types();
		$all_coupon_in_cat = wpcoupon_get_all_coupon_from_cat( $cate_id );
		$get_coupon_var = ( isset( $_GET['coupon_type'] ) ) ? sanitize_text_field( wp_unslash( $_GET['coupon_type'] ) ) : '';
		$filtered_sortby = ( isset( $_GET['sort_by'] ) ) ? sanitize_text_field( wp_unslash( $_GET['sort_by'] ) ) : 'newest';

		$number_active = intval( wpcoupon_get_option( 'coupon_cate_number', 15 ) );
		$query->set( 'posts_per_page', $number_active );

		if ( ( ! isset( $_GET['coupon_type'] ) && ! isset( $_GET['sort_by'] ) ) || ( ( '' == $get_coupon_var || 'all' == $get_coupon_var ) && 'newest' == $filtered_sortby ) ) {

			if ( isset( $all_coupon_in_cat['not_expired'] ) && isset( $all_coupon_in_cat['expired'] ) ) {
				$post_in = array_merge( $all_coupon_in_cat['not_expired'], $all_coupon_in_cat['expired'] );

				$query->set( 'post__in', $post_in );
				$query->set( 'orderby', 'post__in' );
				if( ! isset( $_GET['sort_by'] ) ) {
					$query->set( 'meta_key', '_wpc_used' );
					$query->set( 'orderby', 'meta_value_num' );
					$query->set( 'order', 'desc' );
					$query->set( 'meta_type', 'NUMERIC' );
				}
				
			}
		} else {
			if ( isset( $get_coupon_var ) && array_key_exists( $get_coupon_var, $available_coupon_type ) ) {
				$coupon_type = $get_coupon_var;
			}
			$paged = ( get_query_var( 'paged' ) ) ? get_query_var( 'paged' ) : 1;
			
			$query->set( 'paged', $paged );
			$now = current_time( 'timestamp' );
			$meta_query = array();

			if ( 'all' != $coupon_type ) {
				$meta_query = array(
					'relation' => 'AND',
					array(
						'key' => '_wpc_coupon_type',
						'value' => $coupon_type,
						'compare' => '=',
					),
				);
			}

			switch ( $filtered_sortby ) {
				case 'popularity':
					$query->set( 'meta_key', '_wpc_used' );
					$query->set( 'orderby', 'meta_value_num' );
					$query->set( 'order', 'desc' );
					$query->set( 'meta_type', 'NUMERIC' );
					break;
				case 'ending-soon':
					$query->set( 'meta_key', '_wpc_expires' );
					$query->set( 'meta_value', $now );
					$query->set( 'meta_compare', '>=' );
					$query->set( 'meta_type', 'NUMERIC' );
					$query->set( 'orderby', 'meta_value_num' );
					$query->set( 'order', 'asc' );
					break;
				case 'expired':
					$meta_query[] = array(
						array(
							'key' => '_wpc_expires',
							'compare' => 'EXISTS',
						),
						array(
							'key' => '_wpc_expires',
							'type' => 'NUMERIC',
							'value' => 0,
							'compare' => '>',
						),
						array(
							'key' => '_wpc_expires',
							'value' => $now,
							'type' => 'NUMERIC',
							'compare' => '<=',
						),
					);

					$query->set( 'meta_key', '_wpc_expires' );
					$query->set( 'orderby', 'meta_value' );
					$query->set( 'meta_type', 'NUMERIC' );
					$query->set( 'order', 'desc' );
					break;
				default:
					$query->set( 'orderby', 'menu_order date' );
					$query->set( 'order', 'desc' );
					break;
			}
			if ( ! empty( $meta_query ) ) {
				$query->set( 'meta_query', $meta_query );
			}
		}
	}

	return $query;
}
add_filter( 'pre_get_posts', 'wpcoupon_coupon_cat_query' );

/**
 * Render filter box for category
 *
 * @since 1.2.6
 */
function custom_wpcoupon_coupon_cat_filter_box() {
	$is_enable_filter = wpcoupon_get_option( 'coupon_cate_sidebar_filter', true );
	$title = wpcoupon_get_option( 'coupon_cate_filter_title', 'Filter' );
	if ( ! $is_enable_filter ) {
		return;
	}
	$filtered_sortby = ( isset( $_GET['sort_by'] ) ) ? sanitize_text_field( wp_unslash( $_GET['sort_by'] ) ) : 'popularity';

	?>
	<aside class="widget widget_coupon_cat_filter">
		<h4 class="widget-title"><?php echo wp_kses_post( $title ); ?></h4> 
		<div class="shadow-box">
			<?php
				$current_url = wpcoupon_current_url();
				$filter_url = add_query_arg( array( 'coupon_type' => '' ), $current_url );
				$base_pagenum = get_pagenum_link( 1 );
				global $wp_query;
				$paged = ( get_query_var( 'paged' ) ) ? get_query_var( 'paged' ) : 1;
				$max_pages = $wp_query->max_num_pages;
			if ( $max_pages >= ( $paged + 1 ) ) {
				$next_page = ( $paged + 1 );
			} else {
				$next_page = $paged;
			}

			?>
			<input type="hidden" class="store_base_pagenum_url" name="store_base_pagenum_url" value="<?php echo get_pagenum_link( 1, false ); ?>"/>
			<input type="hidden" class="store_pagenum_url" name="store_pagenum_url" value="<?php echo get_pagenum_link( $paged ); ?>"/>
			<input type="hidden" class="store_next_pagenum_url" name="store_next_pagenum_url" value="<?php echo get_pagenum_link( $next_page ); ?>"/>

			<div class="couponcat-sortby-wrapper ui list">
				<h5><?php echo esc_html_e( 'Sort by', 'wp-coupon' ); ?></h5>
				<div class="item">
					<label for="store-sortby-newest">
						<input id="store-sortby-newest" <?php checked( 'newest', $filtered_sortby ); ?> type="radio" class="coupon-cat-sortby sortby-newest" name="coupon-cat-sortby" value="newest" />
						<span class="filter-sortby-name"><?php echo esc_html_e( 'Newest', 'wp-coupon' ); ?></span>
					</label>
				</div>

				<div class="item">
					<label for="store-sortby-popularity">
						<input id="store-sortby-popularity" <?php checked( 'popularity', $filtered_sortby ); ?> type="radio" class="coupon-cat-sortby sortby-popularity" name="coupon-cat-sortby" value="popularity" />
						<span class="filter-sortby-name"><?php echo esc_html_e( 'Popularity', 'wp-coupon' ); ?></span>
					</label>
				</div>
				
				<div class="item">
					<label for="store-sortby-endingsoon">
						<input id="store-sortby-endingsoon" <?php checked( 'ending-soon', $filtered_sortby ); ?> type="radio" class="coupon-cat-sortby sortby-ending-soon" name="coupon-cat-sortby" value="ending-soon" />
						<span class="filter-sortby-name"><?php echo esc_html_e( 'Ending Soon', 'wp-coupon' ); ?></span>
					</label>
				</div>

				<div class="item">
					<label for="store-sortby-expired">
						<input id="store-sortby-expired" <?php checked( 'expired', $filtered_sortby ); ?> type="radio" class="coupon-cat-sortby sortby-expired" name="coupon-cat-sortby" value="expired" />
						<span class="filter-sortby-name"><?php echo esc_html_e( 'Expired', 'wp-coupon' ); ?></span>
					</label>
				</div>

			</div>
		</div>
	</aside>
	<?php
}
add_action( 'wpcoupon_coupon_category_before_sidebar', 'wpcoupon_coupon_cat_filter_box', 10 );