diff --git a/includes/class-wc-comments.php b/includes/class-wc-comments.php
index bc5b721589b..54f0d7f0f51 100644
--- a/includes/class-wc-comments.php
+++ b/includes/class-wc-comments.php
@@ -1,19 +1,17 @@
 <?php
-
-if ( ! defined( 'ABSPATH' ) ) {
-	exit; // Exit if accessed directly
-}
-
 /**
  * Comments
  *
  * Handle comments (reviews and order notes).
  *
- * @class    WC_Comments
- * @version  2.3.0
- * @package  WooCommerce/Classes/Products
- * @category Class
- * @author   WooThemes
+ * @package WooCommerce/Classes/Products
+ * @version 2.3.0
+ */
+
+defined( 'ABSPATH' ) || exit;
+
+/**
+ * Comments class.
  */
 class WC_Comments {
 
@@ -21,34 +19,34 @@ class WC_Comments {
 	 * Hook in methods.
 	 */
 	public static function init() {
-		// Rating posts
+		// Rating posts.
 		add_filter( 'comments_open', array( __CLASS__, 'comments_open' ), 10, 2 );
 		add_filter( 'preprocess_comment', array( __CLASS__, 'check_comment_rating' ), 0 );
 		add_action( 'comment_post', array( __CLASS__, 'add_comment_rating' ), 1 );
 		add_action( 'comment_moderation_recipients', array( __CLASS__, 'comment_moderation_recipients' ), 10, 2 );
 
-		// Clear transients
+		// Clear transients.
 		add_action( 'wp_update_comment_count', array( __CLASS__, 'clear_transients' ) );
 
-		// Secure order notes
+		// Secure order notes.
 		add_filter( 'comments_clauses', array( __CLASS__, 'exclude_order_comments' ), 10, 1 );
 		add_filter( 'comment_feed_where', array( __CLASS__, 'exclude_order_comments_from_feed_where' ) );
 
-		// Secure webhook comments
+		// Secure webhook comments.
 		add_filter( 'comments_clauses', array( __CLASS__, 'exclude_webhook_comments' ), 10, 1 );
 		add_filter( 'comment_feed_where', array( __CLASS__, 'exclude_webhook_comments_from_feed_where' ) );
 
-		// Count comments
+		// Count comments.
 		add_filter( 'wp_count_comments', array( __CLASS__, 'wp_count_comments' ), 10, 2 );
 
-		// Delete comments count cache whenever there is a new comment or a comment status changes
+		// Delete comments count cache whenever there is a new comment or a comment status changes.
 		add_action( 'wp_insert_comment', array( __CLASS__, 'delete_comments_count_cache' ) );
 		add_action( 'wp_set_comment_status', array( __CLASS__, 'delete_comments_count_cache' ) );
 
-		// Support avatars for `review` comment type
+		// Support avatars for `review` comment type.
 		add_filter( 'get_avatar_comment_types', array( __CLASS__, 'add_avatar_for_review_comment_type' ) );
 
-		// Review of verified purchase
+		// Review of verified purchase.
 		add_action( 'comment_post', array( __CLASS__, 'add_comment_purchase_verification' ) );
 	}
 
@@ -56,8 +54,8 @@ class WC_Comments {
 	 * See if comments are open.
 	 *
 	 * @since  3.1.0
-	 * @param  bool $open
-	 * @param  int $post_id
+	 * @param  bool $open    Whether the current post is open for comments.
+	 * @param  int  $post_id Post ID.
 	 * @return bool
 	 */
 	public static function comments_open( $open, $post_id ) {
@@ -75,7 +73,8 @@ class WC_Comments {
 	 * shop managers can view orders anyway.
 	 *
 	 * The frontend view order pages get around this filter by using remove_filter('comments_clauses', array( 'WC_Comments' ,'exclude_order_comments'), 10, 1 );
-	 * @param  array $clauses
+	 *
+	 * @param  array $clauses A compacted array of comment query clauses.
 	 * @return array
 	 */
 	public static function exclude_order_comments( $clauses ) {
@@ -84,7 +83,10 @@ class WC_Comments {
 	}
 
 	/**
+	 * Exclude order comments from feed.
+	 *
 	 * @deprecated 3.1
+	 * @param mixed $join Deprecated.
 	 */
 	public static function exclude_order_comments_from_feed_join( $join ) {
 		wc_deprecated_function( 'WC_Comments::exclude_order_comments_from_feed_join', '3.1' );
@@ -93,7 +95,7 @@ class WC_Comments {
 	/**
 	 * Exclude order comments from queries and RSS.
 	 *
-	 * @param  string $where
+	 * @param  string $where The WHERE clause of the query.
 	 * @return string
 	 */
 	public static function exclude_order_comments_from_feed_where( $where ) {
@@ -102,8 +104,9 @@ class WC_Comments {
 
 	/**
 	 * Exclude webhook comments from queries and RSS.
+	 *
 	 * @since  2.2
-	 * @param  array $clauses
+	 * @param  array $clauses A compacted array of comment query clauses.
 	 * @return array
 	 */
 	public static function exclude_webhook_comments( $clauses ) {
@@ -112,7 +115,10 @@ class WC_Comments {
 	}
 
 	/**
+	 * Exclude webhooks comments from feed.
+	 *
 	 * @deprecated 3.1
+	 * @param mixed $join Deprecated.
 	 */
 	public static function exclude_webhook_comments_from_feed_join( $join ) {
 		wc_deprecated_function( 'WC_Comments::exclude_webhook_comments_from_feed_join', '3.1' );
@@ -120,8 +126,9 @@ class WC_Comments {
 
 	/**
 	 * Exclude webhook comments from queries and RSS.
+	 *
 	 * @since  2.1
-	 * @param  string $where
+	 * @param  string $where The WHERE clause of the query.
 	 * @return string
 	 */
 	public static function exclude_webhook_comments_from_feed_where( $where ) {
@@ -131,13 +138,13 @@ class WC_Comments {
 	/**
 	 * Validate the comment ratings.
 	 *
-	 * @param  array $comment_data
+	 * @param  array $comment_data Comment data.
 	 * @return array
 	 */
 	public static function check_comment_rating( $comment_data ) {
-		// If posting a comment (not trackback etc) and not logged in
-		if ( ! is_admin() && isset( $_POST['comment_post_ID'], $_POST['rating'], $comment_data['comment_type'] ) && 'product' === get_post_type( $_POST['comment_post_ID'] ) && empty( $_POST['rating'] ) && '' === $comment_data['comment_type'] && 'yes' === get_option( 'woocommerce_enable_review_rating' ) && 'yes' === get_option( 'woocommerce_review_rating_required' ) ) {
-			wp_die( __( 'Please rate the product.', 'woocommerce' ) );
+		// If posting a comment (not trackback etc) and not logged in.
+		if ( ! is_admin() && isset( $_POST['comment_post_ID'], $_POST['rating'], $comment_data['comment_type'] ) && 'product' === get_post_type( absint( $_POST['comment_post_ID'] ) ) && empty( $_POST['rating'] ) && '' === $comment_data['comment_type'] && 'yes' === get_option( 'woocommerce_enable_review_rating' ) && 'yes' === get_option( 'woocommerce_review_rating_required' ) ) { // WPCS: input var ok, CSRF ok.
+			wp_die( esc_html__( 'Please rate the product.', 'woocommerce' ) );
 			exit;
 		}
 		return $comment_data;
@@ -145,16 +152,17 @@ class WC_Comments {
 
 	/**
 	 * Rating field for comments.
-	 * @param int $comment_id
+	 *
+	 * @param int $comment_id Comment ID.
 	 */
 	public static function add_comment_rating( $comment_id ) {
-		if ( isset( $_POST['rating'] ) && 'product' === get_post_type( $_POST['comment_post_ID'] ) ) {
-			if ( ! $_POST['rating'] || $_POST['rating'] > 5 || $_POST['rating'] < 0 ) {
+		if ( isset( $_POST['rating'], $_POST['comment_post_ID'] ) && 'product' === get_post_type( absint( $_POST['comment_post_ID'] ) ) ) { // WPCS: input var ok, CSRF ok.
+			if ( ! $_POST['rating'] || $_POST['rating'] > 5 || $_POST['rating'] < 0 ) { // WPCS: input var ok, CSRF ok, sanitization ok.
 				return;
 			}
-			add_comment_meta( $comment_id, 'rating', (int) esc_attr( $_POST['rating'] ), true );
+			add_comment_meta( $comment_id, 'rating', intval( $_POST['rating'] ), true ); // WPCS: input var ok, CSRF ok.
 
-			$post_id = isset( $_POST['comment_post_ID'] ) ? (int) $_POST['comment_post_ID'] : 0;
+			$post_id = isset( $_POST['comment_post_ID'] ) ? absint( $_POST['comment_post_ID'] ) : 0; // WPCS: input var ok, CSRF ok.
 			if ( $post_id ) {
 				self::clear_transients( $post_id );
 			}
@@ -163,8 +171,9 @@ class WC_Comments {
 
 	/**
 	 * Modify recipient of review email.
-	 * @param array $emails
-	 * @param int $comment_id
+	 *
+	 * @param array $emails     Emails.
+	 * @param int   $comment_id Comment ID.
 	 * @return array
 	 */
 	public static function comment_moderation_recipients( $emails, $comment_id ) {
@@ -179,7 +188,8 @@ class WC_Comments {
 
 	/**
 	 * Ensure product average rating and review count is kept up to date.
-	 * @param int $post_id
+	 *
+	 * @param int $post_id Post ID.
 	 */
 	public static function clear_transients( $post_id ) {
 
@@ -196,8 +206,6 @@ class WC_Comments {
 	 * new comment or the status of a comment changes. Cache
 	 * will be regenerated next time WC_Comments::wp_count_comments()
 	 * is called.
-	 *
-	 * @return void
 	 */
 	public static function delete_comments_count_cache() {
 		delete_transient( 'wc_count_comments' );
@@ -223,12 +231,14 @@ class WC_Comments {
 					'all'            => 0,
 				);
 
-				$count = $wpdb->get_results( "
+				$count = $wpdb->get_results(
+					"
 					SELECT comment_approved, COUNT(*) AS num_comments
 					FROM {$wpdb->comments}
 					WHERE comment_type NOT IN ('order_note', 'webhook_delivery')
 					GROUP BY comment_approved
-				", ARRAY_A );
+				", ARRAY_A
+				);
 
 				$approved = array(
 					'0'            => 'moderated',
@@ -267,8 +277,9 @@ class WC_Comments {
 
 	/**
 	 * Make sure WP displays avatars for comments with the `review` type.
+	 *
 	 * @since  2.3
-	 * @param  array $comment_types
+	 * @param  array $comment_types Comment types.
 	 * @return array
 	 */
 	public static function add_avatar_for_review_comment_type( $comment_types ) {
@@ -277,7 +288,8 @@ class WC_Comments {
 
 	/**
 	 * Determine if a review is from a verified owner at submission.
-	 * @param int $comment_id
+	 *
+	 * @param int $comment_id Comment ID.
 	 * @return bool
 	 */
 	public static function add_comment_purchase_verification( $comment_id ) {
@@ -294,7 +306,7 @@ class WC_Comments {
 	 * Get product rating for a product. Please note this is not cached.
 	 *
 	 * @since 3.0.0
-	 * @param WC_Product $product
+	 * @param WC_Product $product Product instance.
 	 * @return float
 	 */
 	public static function get_average_rating_for_product( &$product ) {
@@ -303,14 +315,18 @@ class WC_Comments {
 		$count = $product->get_rating_count();
 
 		if ( $count ) {
-			$ratings = $wpdb->get_var( $wpdb->prepare("
+			$ratings = $wpdb->get_var(
+				$wpdb->prepare(
+					"
 				SELECT SUM(meta_value) FROM $wpdb->commentmeta
 				LEFT JOIN $wpdb->comments ON $wpdb->commentmeta.comment_id = $wpdb->comments.comment_ID
 				WHERE meta_key = 'rating'
 				AND comment_post_ID = %d
 				AND comment_approved = '1'
 				AND meta_value > 0
-			", $product->get_id() ) );
+			", $product->get_id()
+				)
+			);
 			$average = number_format( $ratings / $count, 2, '.', '' );
 		} else {
 			$average = 0;
@@ -328,18 +344,22 @@ class WC_Comments {
 	 * Get product review count for a product (not replies). Please note this is not cached.
 	 *
 	 * @since 3.0.0
-	 * @param WC_Product $product
+	 * @param WC_Product $product Product instance.
 	 * @return int
 	 */
 	public static function get_review_count_for_product( &$product ) {
 		global $wpdb;
 
-		$count = $wpdb->get_var( $wpdb->prepare("
+		$count = $wpdb->get_var(
+			$wpdb->prepare(
+				"
 			SELECT COUNT(*) FROM $wpdb->comments
 			WHERE comment_parent = 0
 			AND comment_post_ID = %d
 			AND comment_approved = '1'
-		", $product->get_id() ) );
+		", $product->get_id()
+			)
+		);
 
 		$product->set_review_count( $count );
 
@@ -353,14 +373,16 @@ class WC_Comments {
 	 * Get product rating count for a product. Please note this is not cached.
 	 *
 	 * @since 3.0.0
-	 * @param WC_Product $product
-	 * @return array of integers
+	 * @param WC_Product $product Product instance.
+	 * @return int[]
 	 */
 	public static function get_rating_counts_for_product( &$product ) {
 		global $wpdb;
 
 		$counts     = array();
-		$raw_counts = $wpdb->get_results( $wpdb->prepare( "
+		$raw_counts = $wpdb->get_results(
+			$wpdb->prepare(
+				"
 			SELECT meta_value, COUNT( * ) as meta_value_count FROM $wpdb->commentmeta
 			LEFT JOIN $wpdb->comments ON $wpdb->commentmeta.comment_id = $wpdb->comments.comment_ID
 			WHERE meta_key = 'rating'
@@ -368,10 +390,12 @@ class WC_Comments {
 			AND comment_approved = '1'
 			AND meta_value > 0
 			GROUP BY meta_value
-		", $product->get_id() ) );
+		", $product->get_id()
+			)
+		);
 
 		foreach ( $raw_counts as $count ) {
-			$counts[ $count->meta_value ] = absint( $count->meta_value_count );
+			$counts[ $count->meta_value ] = absint( $count->meta_value_count ); // WPCS: slow query ok.
 		}
 
 		$product->set_rating_counts( $counts );